Human Anatomy and Physiology PDF

Human Anatomy and Physiology  INTRODUCTION Anatomy is the scientific discipline that investigates the body’s structure—for example, the shape and size of bones. Physiology is the scientific investigation of the processes or functions of living things. Anatomy Anatomy can be considered at dif...

Human Anatomy and Physiology  INTRODUCTION Anatomy is the scientific discipline that investigates the body’s structure—for example, the shape and size of bones. Physiology is the scientific investigation of the processes or functions of living things. Anatomy Anatomy can be considered at different levels. Developmental anatomy studies the structural changes that occur between conception and adulthood. Embryology a subspecialty of developmental anatomy, considers changes from conception to the end of the eighth week of development. Cytology examines the structural features of cells. Histology examines tissues, which are composed of cells and the materials surrounding them. Pathological anatomy is the study of anatomy based on the changes caused by diseases. Anatomy Gross anatomy, the study of structures that can be examined without the aid of a microscope, can be approached from either a systemic or a regional perspective. Microscopic anatomy, is the study of the minute structures of the body not visible to the naked eye with the aid of a microscope. Physiology Like anatomy, physiology can be considered at many levels. Cell physiology examines the processes occurring in cells, and systemic physiology considers the functions of organ systems. Developmental physiology examines the processes or functions of the structures caused by changes as the body develops. Pathological anatomy studies the changes in functions of the body due to age and diseases. Clinical Connection The non-invasive Diagnostic techniques used to assess the aspects of our body functions and structures. Palpation examine (a part of the body) by touch, especially for medical purposes Auscultation the action of listening to sounds from the heart, lungs, or other organs, typically with a stethoscope, as a part of medical diagnosis. Percussion diagnostic procedure that entails striking the body directly or indirectly with short, sharp taps of a finger or, rarely, a hammer. Characteristics of a Living Organism Refers to the basic life processes that distinguishes living organisms from non living organisms. Six Important Life Processes oMetabolism o Growth oResponsiveness o Differentiation oMovement o Reproduction Metabolism Refers to all the metabolic processes that occur in the cells of all living organisms. Catabolism – the breaking down of complex molecules to simple molecules Anabolism – the building up of complex molecules from simple molecules Responsiveness is an organism’s ability to sense changes in its external or internal environment and adjust to those changes. Responses include such actions as moving toward food or water and moving away from danger or poor environmental conditions. Growth refers to an increase in the size or number of cells, which produces an overall enlargement of all or part of an organism. For example, a muscle enlarged by exercise is composed of larger muscle cells than those of an untrained muscle, and the skin of an adult has more cells than the skin of an infant. Movement Refers to the motion of the whole body. Cellular Physical Differentiation includes the changes an organism undergoes through time, beginning with fertilization and ending at death. Differentiation is change in cell structure and function from generalized to specialized Morphogenesis is change in the shape of tissues, organs, and the entire organism. Reproduction is the formation of new cells or new organisms. Withoutreproduction of cells, growth and development are not possible. Without reproduction of organisms, species become extinct Homeostasis Homeostasis is the existence and maintenance of a relatively constant environment within the body. A small amount of fluid surrounds each body cell. For cells to function normally, the volume, temperature, and chemical content of this fluid must remain within a narrow range. Body Fluids Maintaining it is important. Intracellular Fluid – fluids found within the cell (cytoplasm) Extracellular Fluid – fluids found outside of the cell (Plasma, Interstitial fluid, Transcellular fluid) ICF and Body Functions Cellular function depends on the composition of Intracellular fluids Body’s internal environment Composition changes as it moves ECF and Body Locations Blood Plasma – blood vessels Lymph – lymphatic vessels Cerebrospinal Fluid – brain and spinal cord Synovial Fluid – joints Aqueous Humor and Vitreous body – eyes BodyCavity Fluids – peritoneal, pleural, pericardial Homeostasis A conditionof equilibrium or balance in the body’s internal environment It is dynamic Narrow range compatible with life Whole body contributes to maintain internal environment within the normal limits. Control of Homeostasis Physical insults Changes in internal environment Physiological stress disruption Homeostasis Homeostaticmechanisms to keep body levels within the normal range Age specific Gender specific Unique Unconsciously happens “changes in structures causes changes in function” Feedback System Cycle of Events Body is monitored and remonitored to be maintained in a Controlled Condition Three Basic Components Receptors – input information; monitor changes in the controlled condition; skin Control Center – processing of information; brain; sets range of values to be maintained; nerve impulses Effectors – output command; produce responses that change the controlled condition Negative Feedback Mostsystems of the body are regulated by negative-feedback mechanisms, which maintain homeostasis. Negative means that any deviation from the set point is made smaller or is resisted; therefore, in a negative-feedback mechanism, the response to the original stimulus results in deviation from the set point, becoming smaller. Positive Feedback Positive-feedbackmechanisms occur when a response to the original stimulus results in the deviation from the set point becoming even greater. At times, this type of response is required to re-achieve homeostasis. Negative and Positive Feedback Twobasic principles to remember are that (1) many disease states result from the failure of negative-feedback mechanisms to maintain homeostasis and (2) some positive-feedback mechanisms can be detrimental instead of helpful. Structural and Functional Organization of the Human Body The body can be studied at six levels of organization: Chemical level Cellular level Tissue level Organ level Organ system level Whole organism level Chemical Level Thechemical level involves interactions between atoms, which are tiny building blocks of matter. Atoms combine to form molecules, such as water, sugar, fats, and proteins Atoms, molecules and macromolecules. Cell level Cells are the basic structural and functional units of plants and animals. Molecules combine to form organelles (little organs), which are the small structures that make up cells. Tissue Level A tissue is composed of a group of similar cells and the materials surrounding them. The characteristics of the cells and surrounding materials determine the functions of the tissue. The numerous tissues that make up the body are classified into four basic types: epithelial, connective, muscle, and nervous. Organ Level Anorgan is composed of two or more tissue types that perform one or more common functions. The urinary bladder, heart, stomach, and lung are examples of organs Organ System Level An organ system is a group of organs that together perform a common function or set of functions and are therefore viewed as a unit. Organism Level Anorganism is any living thing considered as a whole—whether composed of one cell, such as a bacterium, or of trillions of cells, such as a human. The human organism is a complex of organ systems, all mutually dependent on one another. Human Body Organization Major features: Body Cavities – empty or hollow spaces Membranes – sheets of covering Organsystems – housed inside the cavities Body Cavities DorsalCavity – Cranial and Vertebral cavities VentralCavity – Mediastinum(cardiac cavity), Thoracic and Abdominopelvic cavity Body Membranes Pleural membrane Peritoneum Pericardium Pleural Membranes Located in the Thoracic cavity Parietal pleura covers/lines the Pleural cavity Visceral Pleura covers/lines the lungs Serous Fluid found in between visceral and parietal Pleura that acts as lubrication to avoid friction during motion. Peritoneum Located in the abdominal cavity Peritoneum covers/lines the Parietal Peritoneal cavity Visceral Peritoneum covers/lines the abdominal organs Serous Fluid found in between visceral and parietal Peritoneum that acts as lubrication to avoid friction during motion. Pericardium Located in the Cardiac cavity Pericardium covers/lines the Parietal Cardiac cavity Visceral Pleura covers/lines the Heart Serous Fluid found in between visceral and parietal Pericarduim that acts as lubrication to avoid friction during motion. Organ Systems Overview Organ Systems There are 11 organ systems Groupsof organs that together perform a common function or set of functions and are therefore viewed as a unit. Canbe classified according to their functionality Body Covering Integumentary System Skin, hair, nails and various glands Covers the body Receptors – respond to stimuli Helps regulate body temperature Integration and Coordination Nervous System Brain, spinal cord, nerves and senses Integrates information from receptors and sends impulses or response Endocrine System All Glands that secrete hormones Integrates metabolic function Absorption and Excretion Digestive System Alimentary tract and accessory organs Receives, breaks down and absorbs nutrients Respiratory System Exchange gasses between blood and air Lungs and passageways Urinary System Kidneys, bladder, ureter and urethra Removes waste from blood and maintains water and electrolyte balance Support and Movement Skeletal System Bones, joints and ligaments Supports, protects and provide framework Stores inorganic salts/nutrients Houses blood forming tissues Muscular System All muscles in the body Provide movement, posture and body heat(through contractions) Transport Cardiovascular System Heart and blood vessels Distributes oxygen and nutrients while removing waste Lymphatic System Lymphatic vessels, nodes and lymphatic organs Immunity Gross Anatomy Gross anatomy, the study of structures that can be examined without the aid of a microscope, can be approached from either a systemic or a regional perspective. Anatomical Position Common visual reference Stands erect, feet together, eyes forward, palms facing anteriorly, thumbs pointing away from the body Body Sections/Planes: 1. A sagittal section divides the body into right and left portions. 2. A transversesection divides the body into superior and inferior portions. It is often called a “ cross section ”. 3. A coronal section divides the body into anterior and posterior sections Regional Terms Names of specific body areas Axial – main axis (head, neck and trunk) Appendicular – the limbs (upper and lower) The Four Quadrants The abdomen is often subdivided superficially into quadrants by two imaginary lines that intersect at the navel Right Upper Quadrant (RUQ) Left Upper Quadrant (LUQ) Right Lower Quadrant (RLQ) Left Lower Quadrant (LLQ) The Four Quadrants of the Abdomen  The Nine Regions The abdomen is sometimes subdivided into regions by four imaginary lines: two horizontal and two vertical. o RightHypochondriac o Epigastric o Left Hypochondriac o Right Lumbar o Umbilical o Left Lumbar o Right Iliac o Hypogastric o Left Iliac The Nine Regions of the Abdomen Directional Terms Refers to the body in the Anatomical Position Standardized terms are paired with terms of relative position Relative position – position relative to another part (superior-inferior, medial- lateral, etc.) Chemical Level of Organization Chemical Level of Organization Thechemical level involves interactions between atoms, which are tiny building blocks of matter. Atoms combine to form molecules, such as water, sugar, fats, and proteins Atoms, molecules and macromolecules. Chemical Level of Organization Elements and Atoms An element is the simplest type of matter, having unique chemical properties. An atom (from the Greek word: atomos, indivisible) is the smallest particle of an element that has the chemical characteristics of that element. Chemical Level of Organization Molecules and Compounds A molecule is composed of two or more atoms chemically combined to form a structure that behaves as an independent unit. A compound is a substance resulting from the chemical combination of two or more different types of atoms. Chemical Reactions and Energy In a chemical reaction, atoms, ions, molecules, or compounds interact either to form or to break chemical bonds. Reactants substances that enter into a chemical reaction Products substances that result from the chemical reaction Types of Chemical Reactions Synthesis Reactions Decomposition Reactions Reversible Reactions Oxidation-Reduction Reactions Synthesis Reactions Anabolism When two or more reactants chemically combine to form a new and larger product, the process is called a synthesis reaction. Dehydration reaction – water-out reaction; water is a byproduct of anabolism Synthesis Reactions Synthesis reactions produce the molecules characteristic of life, such as ATP, proteins, carbohydrates, lipids, and nucleic acids. Allof the synthesis reactions that occur within the body are collectively referred to as anabolism. The growth, maintenance, and repair of the body could not take place without anabolic reactions Decomposition Reactions A decompositionreaction is the reverse of a synthesis reaction—a larger reactant is chemically broken down into two or more smaller products. Hydrolysis reaction – water is split into two parts to be used in new molecules Decomposition Reactions The decomposition reactions occurring in the body are collectively called catabolism. They include the digestion of food molecules in the intestine and within cells, the breakdown of fat stores, and the breakdown of foreign matter and microorganisms in certain blood cells that protect the body.  All of the anabolic and catabolic reactions in the body are collectively defined as metabolism. Reversible Reactions Ina reversible reaction, the reaction can proceed from reactants to products or from products to reactants. When the rate of product formation is equal to the rate of the reverse reaction, the reaction system is said to be at equilibrium. At equilibrium, the amount of reactants relative to the amount of products remains constant. Oxidation-Reduction Reactions Chemicalreactions that result from the exchange of electrons between the reactants are called oxidation- reduction reactions. Theloss of an electron by an atom is called oxidation, and the gain of an electron is called reduction.  Synthesisand decomposition reactions can be oxidation- reduction reactions. Thus, a chemical reaction can be described in more than one way. Inorganic Chemistry Water has remarkable properties due to its polar nature. A molecule of water is formed when an atom of oxygen forms polar covalent bonds with two atoms of hydrogen. Water accounts for approximately 50% of the weight of a young adult female and 60% of a young adult male Plasma, the liquid portion of blood, is 92% water. Water Water has physical and chemical properties well suited for its many functions in living organisms. Stabilizing Body Temperature Water can absorb large amounts of heat and remain at a fairly stable temperature; therefore, it tends to resist large temperature fluctuations. Water Protection Water is an effective lubricant that provides protection against damage resulting from friction. For example, tears protect the surface of the eye from rubbing of the eyelids. Chemical Reactions Many of the chemical reactions necessary for life do not take place unless the reacting molecules are dissolved in water Water Mixing Medium A mixture is a combination of two or more substances physically blended together, but not chemically combined. Solution Solute Solvent Inorganic Salts Inorganic salts are the sources of ions of: Sodium chloride Potassium Calcium Magnesium Phosphate Carbonate Bicarbonate Sulfate Organic Chemistry The four major groups of organic molecules essential to living organisms are carbohydrates, lipids, proteins, and nucleic acids. Carbohydrates Carbohydrates are composed primarily of carbon, hydrogen, and oxygen atoms and range in size from small to very large. Carbohydrates are important parts of other organic molecules, and they can be broken down to provide the energy necessary for life. Monosaccharides Simple sugars that build up large carbohydrates(building blocks of carbohydrates) Glucose, Fructose and Galactose Deoxyribose and Ribose Disaccharides Condensed by Dehydration Reaction Sucrose, Lactose and Maltose Sucroseis glucose and fructose combined; Lactose, or milk sugar, is glucose combined with galactose; maltose, or malt sugar, is two glucose molecules joined together. Polysaccharides consistof many monosaccharides bound together to form long chains that are either straight or branched. Condensed by Dehydration Reactions Starchand Cellulose(from plants), Glycogen(from animals) Lipids Lipids are a second major group of organic molecules common to living systems. Like carbohydrates, they are composed principally of carbon, hydrogen, and oxygen, but some lipids contain small amounts of other elements, such as phosphorus and nitrogen. Lipids Fats are a major type of lipid. Like carbohydrates, the fats humans ingest are broken down by hydrolysis reactions in cells to release energy for use by those cells. Fats also provide protection by surrounding and padding organs, and under-the-skin fats act as an insulator to prevent heat loss Lipids Triglycerides constitute 95% of the fats in the human body. Triglycerides consist of two different types of building blocks: one glycerol and three fatty acids. Glycerolis a 3-carbon molecule with a hydroxyl group attached to each carbon atom, and each fatty acid consists of a straight chain of carbon atoms with a carboxyl group attached at one end Lipids Phospholipids are similar to triglycerides, except that one of the fatty acids bound to the glycerol is replaced by a molecule containing phosphate and, usually, nitrogen Lipids Steroids differ in chemical structure from other lipid molecules, but their solubility characteristics are similar. All steroid molecules are composed of carbon atoms bound together into four ringlike structures Important steroid molecules include cholesterol, bile salts, estrogen, progesterone, and testosterone. Lipids Anotherclass of lipids is the fat- soluble vitamins. Their structures are not closely related to one another, but they are nonpolar molecules essential for many normal body functions. Proteins All proteins contain carbon, hydrogen, oxygen, and nitrogen bound together by covalent bonds, and most proteins contain some sulfur. In addition, some proteins contain small amounts of phosphorus, iron, and iodine. The molecular mass of proteins can be very large. For the purpose of comparison, the molecular mass of water is approximately 18, sodium chloride 58, and glucose 180, but the molecular mass of proteins ranges from approximately 1000 to several million Proteins Proteins regulate body processes, act as a transportation system, provide protection, help muscles contract, and provide structure and energy. Peptide bonds Dipeptide Polypeptide Proteins Proteins regulate body processes, act as a transportation system, provide protection, help muscles contract, and provide structure and energy Protein Structure Thebasic building blocks for proteins are the 20 amino acid molecules. Each amino acid has an amine group, a carboxyl group, a hydrogen atom, and a side chain designated by the symbol R attached to the same carbon atom. Theside chain can be a variety of chemical structures, and the differences in the side chains make the amino acids different from one another  Proteins perform many roles in the body Most abundant and important compounds in the body Protein Functions Enzymes – a protein catalyst that increases the rate at which a chemical reaction proceeds without the enzyme being permanently changed. *temperature and pH affects enzyme function Hormones – functions as a regulatory control; endocrine Antibodies – serves as the primary defense mechanism Nucleic Acids: DNA and RNA The nucleic acids are large molecules composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus. Deoxyribonucleic acid (DNA) is the genetic material of cells, and copies of DNA are transferred from one generation of cells to the next generation. DNA contains the information that determines the structure of proteins. Ribonucleic acid (RNA) is structurally related to DNA, and three types of RNA also play important roles in protein synthesis. Nucleic Acids: DNA and RNA Both DNA and RNA consist of basic building blocks called nucleotides. Each nucleotide is composed of a monosaccharide to which a nitrogenous base and a phosphate group are attached Nucleic Acids: DNA and RNA DNA has two strands of nucleotides joined together to form a twisted, ladderlike structure called a double helix. The sides of the ladder are formed by covalent bonds between the deoxyribose molecules and phosphate groups of adjacent nucleotides. The rungs of the ladder are formed by the bases of the nucleotides of one side connected to the bases of the other side by hydrogen bonds. Nucleic Acids: DNA and RNA Eachnucleotide of DNA contains one of the organic bases: adenine, thymine, cytosine, or guanine. Codon a unit of three nucleotides Purines – adenine and guanine Pyrimidines – thymine and cytosine Nucleic Acids: DNA Deoxyribonucleicacid (DNA) is the genetic material of cells Copies of DNA are transferred from one generation of cells to the next generation. DNA containsthe information that determines the structure of proteins. Nucleic Acids: RNA Ribonucleicacid (RNA) is structurally related to DNA Three types of RNA also play important roles in protein synthesis. RNA’sstructure is similar to a single strand of DNA. LikeDNA, four different nucleotides make up the RNA molecule, and the nitrogenous bases are the same, except that thymine is replaced with uracil Nucleic Acids: RNA messenger RNA (mRNA) - molecule in cells that carries codes from the DNA in the nucleus to the sites of protein synthesis in the cytoplasm transfer RNA (tRNA) - small molecule in cells that carries amino acids to organelles called ribosomes, where they are linked into proteins ribosomal RNA (rRNA) - During protein synthesis, rRNA ensures that the mRNA and ribosomes are aligned correctly, and it catalyzes the formation of peptide bonds between two aligned amino acids High Energy Compounds Adenosine monophosphate (AMP) – one phosphate group Adenosine diphosphate (ADP) – two phosphate group Adenosine triphosphate (ATP) – three phosphate groups; principle molecule for storing and transferring energy in the cells Atomic Composition of the Body Hydrogen – 60% Oxygen – 25.7% Carbon – 10.2% Nitrogen – 2.4% Calcium – 0.2% Phosphorus – 0.1% Sulfur – 0.1% Trace Elements – 0.8% Molecular Composition of the Body Water – 80% Protein – 15% Lipids – 2% Carbohydrates, nucleic Acids and others – 1% Cell Biology Introduction Allof the cells of an individual originate from a single fertilized cell. During development, cell division and specialization give rise to a wide variety of cell types, such as nerve, muscle, bone , and blood cells. Introduction Eachcell type has important characteristics that are critical to normal body function, including cell metabolism and energy use; synthesis of molecules, such as proteins and nucleic acids; communication between cells; reproduction; and inheritance. One of the important reasons for maintaining homeostasis is to keep the trillions of cells that form the body functioning normal Introduction Cytology – the study of the cell Varies in size and structures Contains a nucleus and cytoplasm housed in a cell/plasma membrane. Introduction Cells are the basic units of all living things, including humans. Cells within the body may have quite different structures and functions, yet they share several common characteristics. The plasma membrane, or cell membrane, forms the outer boundary of the cell, through which the cell interacts with its external environment. The nucleus is usually located centrally; it directs cell activities, most of which take place in the cytoplasm, located between the plasma membrane and the nucleus. Within cells, specialized structures called organelles perform specific functions Cell Theory Rudolf Virchow – he discovered that cells originate from other cells through cell division Watsonand Creek – discovered the molecular structures of DNA(genetic substances of the cell) Schneider and Schwann – stated that all plants and animals contain cells as the basic unit of life. Cell Theory Antonie van Leeuwenhoek – accurately described cells through microscopic observation Robert Hooke – discovered cells in a cork Functions of the Cell Cellmetabolism and energy use. The chemical reactions that occur within cells are referred to as metabolic reactions and are collectively known as cell metabolism. Functions of the Cell Synthesis of molecules. The different cells of the body synthesize various types of molecules, including proteins, nucleic acids, and lipids. Functions of the Cell Communication. Cells produce and respond to chemical and electrical signals that allow them to communicate with one another. Functions of the Cell Reproduction and inheritance. Most cells contain a complete copy of all the genetic information of the individual. This genetic information ultimately determines the structural and functional characteristics of the cell. Cell Membrane Membranic potential for ion regulation Extremely thin; highly permeable Barriers Membrane lipids – phospholipid bilayer Nucleus Directsactivity of the cell; contains genetic materials Nuclearmembrane/envelope; nucleoplasm Nucleolus – produces ribosomes Chromatin – forms chromatin for reproduction; contains coded information Nuclear pore – for communication Cytoplasm Between plasma membrane and nucleus Where metabolic reactions take place All materials inside the cell outside the nucleus Clean fluid called the cytosol Contains the organelles Ribosomes RibosomalRNA and proteins form large and small subunits; some are attached to endoplasmic reticulum, whereas others (free ribosomes) are distributed throughout the cytoplasm Serves as site of protein synthesis Rough Endoplpasmic Reticulum (RER) Membranous tubules and flattened sacs with attached ribosomes Synthesizes proteins and transports them to Golgi apparatus Smooth Endoplpasmic Reticulum (SER) Membranous tubules and flattened sacs with no attached ribosomes Manufactures lipids and carbohydrates; detoxifies harmful chemicals; stores calcium Golgi Apparatus Flattened membrane sacs stacked on each other Modifies, packages, and distributes proteins and lipids for secretion or internal use Lysosome Membrane-bound vesicle pinched off Golgi apparatus Contains digestive enzymes Peroxisosome Membrane-bound vesicle Serves as one site of lipid and amino acid degradation; breaks down hydrogen peroxide Proteasome Tubelike protein complexes in the cytoplasm Break down proteins in the cytoplasm Mitochondria Spherical, rod-shaped, or threadlike structures; enclosed by double membrane; inner membrane forms projections called cristae Are major sites of ATP synthesis when oxygen is available Centrioles Pair of cylindrical organelles in the centrosome, consisting of triplets of parallel microtubules Serve as centers for microtubule formation; determine cell polarity during cell division; form the basal bodies of cilia and flagell Cilla Extensions of the plasma membrane containing doublets of parallel microtubules; 10 μm in length Move materials over the surface of cells Flagella Extensionof the plasma membrane containing doublets of parallel microtubules; 55 μm in length In humans, propels spermatozoa Microvilli Extension of the plasma membrane containing microfilaments Increase surface area of the plasma membrane for absorption and secretion; modified to form sensory receptor  Movements Through Cell Membranes The cell membrane controls what passes through it. B. Mechanisms of movement across the membrane may be: PASSIVE - requiring no energy from the cell (diffusion, facilitated diffusion, osmosis, and filtration) ACTIVE MECHANISMS - requiring cellular energy (active transport, endocytosis, and exocytosis)  Passive Mechanisms Diffusion It is caused by the random motion of molecules Involves the movement of molecules from an area of greater concentration to one of lesser concentration until equilibrium is reached  Passive Mechanisms Diffusion It is caused by the random motion of molecules b. Involves the movement of molecules from an area of greater concentration to one of lesser concentration until equilibrium is reached  Passive Mechanisms Diffusion Diffusion enables oxygen and carbon dioxide molecules to be exchanged between the air and the blood in the lungs, and between blood and tissue cells.  Passive Mechanisms Facilitated Diffusion Facilitated diffusion uses membrane proteins that function as carriers to move molecules (such as glucose) across the cell membrane. The number of carrier molecules in the cell membrane limits the rate of this process  Passive Mechanisms Osmosis Osmosis is a special case of diffusion in which water moves from an area of greater water concentration (where there is less osmotic pressure) across a selectively permeable membrane to an area of lower water concentration (where there is greater osmotic pressure) Osmosis  Passive Mechanisms A solution with the same osmotic pressure as body fluids is called ISOTONIC One with higher osmotic pressure than body fluids is HYPERTONIC One with lower osmotic pressure is HYPOTONIC *the pressure that would have to be applied to a pure solvent to prevent it from passing into a given solution by osmosis, often used to express the concentration of the solution.  Passive Mechanisms Filtration Because of hydrostatic pressure, molecules can be forced through membranes by the process of filtration. b. Bl o o d p r e ss u r e is a t y p e o f hydrostatic pressure Active Mechanisms Active Transport a. Active transport uses ATP to move molecules from areas of low concentration to areas of high concentration through carrier molecules in cell membranes. b. As much as 40% of a cell's energy supply may be used to fuel this process. Active Mechanisms c. The union of the specific particle to be transported with its carrier protein triggers the release of cellular energy (ATP), which in turn alters the shape of the carrier protein, releasing the particle to the other side of the membrane. Active Mechanisms Particles that are actively transported include: Sugars Amino Acids Sodium Potassium Calcium Hydrogen Ions Nutrient molecules in the intestines. Active Mechanisms Active Mechanisms Active Mechanisms Endocytosis and Exocytosis In endocytosis, molecules that are too large to be transported by other means are engulfed by an invagination of the cell membrane and carried into the cell surrounded by a vesicle. Exocytosis is the reverse of endocytosis Active Mechanisms Three forms of endocytosis are pinocytosis, phagocytosis, and receptor-mediated endocytosis Pinocytosis is a form of endocytosis in which cells engulf liquids. Active Mechanisms Phagocytosis is a form of endocytosis in which the cell takes in larger particles, such as a white blood cell engulfing a bacterium Receptor-mediated endocytosis allows the cell to take in very specific molecules (ligands) that pair up with specific receptors on the cell surface. Cell Life Cycle Thecell life cycle includes the changes a cell undergoes from the time it is formed until it divides to produce two new cells. The life cycle of a cell has two stages: interphase and cell division Cell Life Cycle Thecell life cycle includes the changes a cell undergoes from the time it is formed until it divides to produce two new cells. The life cycle of a cell has two stages: interphase and cell division Cell Life Cycle Interphase Interphase is the phase between cell divisions; nearly all of the life cycle of a typical cell is spent in interphase. During this time, the cell carries out the metabolic activities necessary for life and performs its specialized functions—for example, secreting - digestive enzymes Cell Life Cycle Interphase can be divided into three subphases, called G1, S, and G2. DuringG1 (the first gap phase), the cell carries out routine metabolic activities. During the S phase (the synthesis phase), the DNA is replicated (new DNA is synthesized). Duringthe G2 phase (the second gap phase), the cell prepares for cell division. Cell Life Cycle DNA Replication DNA replication is the process by which two new strands of DNA are made, using the two existing strands as templates. During interphase, DNA and its associated proteins appear as dispersed chromatin threads within the nucleus. Cell Life Cycle Cell division Cell division produces the new cells necessary for growth and tissue repair. A parent cell divides to form two daughter cells, each having the same amount and type of DNA as the parent cell. Cell Life Cycle Cell division Cell division involves two major events: division of the chromosomes into two new nuclei and division of the cytoplasm to form two new cells, each of which contains one of the newly formed nuclei. The nuclear events are called mitosis, and the cytoplasmic division is called cytokinesis Cell Life Cycle Mitosis Mitosis is the division of a cell’s chromosomes into two new nuclei, each of which has the same amount and type of DNA During mitosis, the chromatin becomes very densely coiled to form compact chromosomes called mitotic chromosomes. Cell Life Cycle Mitosis Mitosis is divided into four phases: prophase, metaphase, anaphase, and telophase Cell Life Cycle Mitosis During prophase, the chromatin condenses to form mitotic chromosomes. The centrioles divide and migrate to each pole of the cell and microtubules called spindle fibers extend from the centrioles to the centromeres of the chromosomes. In late prophase, the nucleolus and nuclear envelope disappear. Cell Life Cycle Mitosis In metaphase, the chromosomes align near the center of the cell. Cell Life Cycle Mitosis At the beginning of anaphase, the chromatids separate. At this point, one of the two identical sets of chromosomes are moved by the spindle fibers toward the centrioles at each of the poles of the cell. At the end of anaphase, each set of chromosomes has reached an opposite pole of the cell, and the cytoplasm begins to divide Cell Life Cycle Mitosis During telophase, nuclear envelopes form around each set of chromosomes to form two separate nuclei. The chromosomes begin to uncoil and resemble the genetic material characteristic of interphase. Cell Life Cycle Cytokinesis is the division of the cell’s cytoplasm to produce two new cells. Cytokinesis begins in anaphase and continues through telophase. The first sign of cytokinesis is the formation of a cleavage furrow, an indentation of the plasma membrane that forms midway between the centrioles. Cell Life Cycle Cytokinesis A contractile ring composed primarily of actin filaments pulls the plasma membrane inward, dividing the cell into halves.Cytokinesis is complete when the membranes of the halves separate at the cleavage furrow to form two separate cells  Which of the following functioning proteins are found in the plasma membrane? a. channel proteins b. marker molecules c. receptor molecules d. enzymes e. All of these are correct.  Which of the following functioning proteins are found in the plasma membrane? a. channel proteins b. marker molecules c. receptor molecules d. enzymes e. All of these are correct.  Ifa cell is placed in a(n) solution, lysis of the cell may occur. a. hypertonic b. hypotonic c. isotonic d. isosmotic  Ifa cell is placed in a(n) solution, lysis of the cell may occur. a. hypertonic b. hypotonic c. isotonic d. isosmotic.Which of these organelles produces large amounts of ATP? a. nucleus b. mitochondria c. ribosomes d. endoplasmic reticulum e. lysosomes.Which of these organelles produces large amounts of ATP? a. nucleus b. mitochondria c. ribosomes d. endoplasmic reticulum e. lysosomes  Cytoplasm is found a. in the nucleus. b. outside the nucleus and inside the plasma membrane. c. outside the plasma membrane. d. inside mitochondria. e. everywhere in the cell.  Cytoplasm is found a. in the nucleus. b. outside the nucleus and inside the plasma membrane. c. outside the plasma membrane. d. inside mitochondria. e. everywhere in the cell. Tissues Tissues and Histology Tissuesare collections of specialized cells and the extracellular substances surrounding them. Body tissues are classified into four types, based on the structure of the cells, the composition of the noncellular substances surrounding the cells (called the extracellular matrix), and the functions of the cells. Tissues and Histology The four primary tissue types, from which all organs of the body are formed, are epithelial tissue, connective tissue, muscle tissue, and nervous tissue Tissues and Histology Histologyis the microscopic study of tissues. Much information about a person’s health can be gained by examining tissues. Tissues and Histology A biopsyis the process of removing tissue samples from patients surgically or with a needle for diagnostic purposes An autopsy is an examination of the organs of a dead body to determine the cause of death or to study the changes caused by a disease. Embryonic Tissue Approximately 13 or 14 days after fertilization, the embryonic stem cells that give rise to a new individual form a slightly elongated disk consisting of two layers, the epiblast and the hypoblast. Cells of the epiblast then migrate between the two layers to form the three embryonic germ layers: the ectoderm, the mesoderm, and the endoderm Embryonic Tissue Theendoderm, the inner layer, forms the lining of the digestive tract and its derivatives. The mesoderm, the middle layer, forms tissues such as muscle, bone, and blood vessels. The ectoderm, the outer layer, forms the skin; a portion of the ectoderm called neuroectoderm becomes the nervous system Epithelial Tissue Epithelial tissue, or epithelium, covers and protects surfaces, both outside and inside the body Epithelial Tissue(characteristics) Mostly composed of cells. Epithelial tissue consists almost entirely of cells, with very little extracellular matrix between them. Covers body surfaces. Epithelial tissue covers body surfaces and forms glands that are derived developmentally from body surfaces Epithelial Tissue(characteristics) Distinctcell surfaces. Most epithelial tissues have cells with: one free, or apical surface not attached to other cells; a lateral surface attached to other epithelial cells; and a basal surface attached to a basement membrane. Epithelial Tissue(characteristics) Cell and matrix connections. Specialized cell contacts bind adjacent epithelial cells together and to the extracellular matrix of the basement membrane Nonvascular. Blood vessels in the underlying connective tissue do not penetrate the basement membrane to reach the epithelium; thus, all gases and nutrients carried in the blood must reach the epithelium by diffusing from blood vessels across the basement membrane. Epithelial Tissue(characteristics) Capable of regeneration. Epithelial cells retain the ability to undergo mitosis and therefore are able to replace damaged cells with new epithelial cells. Epithelial Tissue(major functions) Protecting underlying structures. For example, the outer layer of the skin and the epithelium of the oral cavity protect the underlying structures from abrasion as a barrier. Epithelium Acting prevents many substances from moving through it. Epithelial Tissue(major functions) Permitting the passage of substances. Epithelium allows many substances to move through it. Secreting substances. Mucous glands, sweat glands, and the enzyme- secreting portions of the pancreas are all composed of epithelial cells that secrete their products onto surfaces or into ducts that carry them to other areas of the body Epithelial Tissue(major functions) Absorbing substances. The plasma membranes of certain epithelial tissues contain carrier proteins, which regulate the absorption of materials Classification of Epithelial Tissues Epithelialtissues are classified primarily according to the number of cell layers and the shape of the superficial cells. There are three major types of epithelium based on the number of cell layers in each: Classification of Epithelial Tissues Simple epithelium consists of a single layer of cells, with each cell extending from the basement membrane to the free surface. Stratifiedepithelium consists of more than one layer of cells, but only the basal layer attaches the deepest layer to the basement membrane. Classification of Epithelial Tissues Pseudostratified columnar epithelium is a special type of simple epithelium. The prefix pseudo- means “false,” so this type of epithelium appears to be stratified but is not. Classification of Epithelial Tissues There are three types of epithelium based on idealized shapes of the epithelial cells: Squamous cells are flat or scalelike. (cubelike) cells are cube- Cuboidal shaped—about as wide as they are tall. Columnar (tall and thin, similar to a column) cells tend to be taller than they are wide. Classification of Epithelial Tissues Inmost cases, an epithelium is given two names, such as simple squamous, stratified squamous, simple columnar, or pseudostratified columnar. The first name indicates the number of layers, and the second indicates the shape of the cells at the free surface Functional Characteristics Epithelialtissues have many functions, including forming a barrier between a free surface and the underlying tissues and secreting, transporting, and absorbing selected molecules. The structure and organization of cells within each epithelial type reflect these functions Functional Characteristics Cell Layers and Cell Shapes Simple epithelium, with its single layer of cells, covers surfaces. In the lungs it facilitates the diffusion of gases; in the kidneys it filters blood; in glands it secretes cellular products; and in the intestines it absorbs nutrients Functional Characteristics Cell Layers and Cell Shapes Goblet cells, which are specialized columnar epithelial cells. The goblet cells contain abundant organelles, such as ribosomes, endoplasmic reticulum, Golgi apparatuses, and secretory vesicles, that are responsible for synthesizing and secreting mucus. Functional Characteristics Free Surfaces The free surfaces of epithelial tissues can be smooth or folded; they may have microvilli or cilia. Smooth surfaces reduce friction. For example, the lining of blood vessels is a simple squamous epithelium that reduces friction as blood flows through the vessels Functional Characteristics Cell Connections Cells have structures that hold them to one another or to the basement membrane. These structures do three things: (1) mechanically bind the cells together, (2) help form a permeability barrier, and (3) provide a mechanism for intercellular communication. Functional Characteristics CellConnections Desmosomes, disk-shaped structures with especially adhesive glycoproteins that bind cells to one another; attach the cells to the basement membrane and to one another Hemidesmosomes, similar to one-half of a desmosome, attach epithelial cells to the basement membrane Functional Characteristics CellConnections Tight junctions hold cells together and form a permeability barrier An adhesion belt of glycoproteins is found just below the tight junction. It is located between the plasma membranes of adjacent cells and acts as a weak glue that holds cells together. A gap junction is a small, specialized contact region between cells containing protein channels that aid intercellular communication by allowing ions and small molecules to pass from one cell to another Functional Characteristics Cell Connections Glands Glandsare secretory organs. Many glands are composed primarily of epithelium, with a supporting network of connective tissue. Theseglands develop from an infolding or outfolding of epithelium in the embryo. Glands If the gland maintains an open contact with the epithelium from which it developed, a duct is present. Glands with ducts are called exocrine glands, and their ducts are lined with epithelium. Glands Alternatively, some glands become separated from the epithelium of their origin and have no ducts; these are called endocrine glands. Endocrine glands have extensive blood vessels. The cellular products of endocrine glands, which are called hormones are secreted into the bloodstream and carried throughout the body Glands multicellularglands exocrine glands that are composed of many cells unicellular glands exocrine glands that are composed of a single cell *Goblet cells are unicellular glands that secrete mucus. Glands Multicellular glands can be classified according to the structure of their ducts and secretory regions. Simple - glands have a single duct Compound - glands with ducts that branch Tubular - glands with secretory regions shaped as tubules Acinar or Alveolar - shaped in saclike structures Glands Multicellular glands can be classified according to the structure of their ducts and secretory regions. Simple - glands have a single duct Compound - glands with ducts that branch Tubular - glands with secretory regions shaped as tubules Acinar or Alveolar - shaped in saclike structures Connective Tissue Connective tissue is abundant—it makes up part of every organ in the body. Connectivetissue differs from the other three tissue types in that it consists of cells separated from each other by abundant extracellular matrix. Connective tissue is diverse in both structure and function Functions of Connective Tissue Connective tissue performs the following major functions: Enclosing and separating other tissues. Sheets of connective tissue form capsules around organs, such as the liver and kidneys. Connecting tissues to one another. Strong cables, or bands, of connective tissue called tendons attach muscles to bone, whereas connective tissue bands called ligaments hold bones together. Functions of Connective Tissue Supporting and moving parts of the body. Bones of the skeletal system provide rigid support for the body, and the semirigid cartilage supports structures such as the nose, ears, and joint surfaces. Storing compounds. Adipose tissue (fat) stores high-energy molecules, and bones store minerals, such as calcium and Functions of Connective Tissue Cushioning and insulating. Adipose tissue cushions and protects the tissue it surrounds and provides an insulating layer beneath the skin that helps conserve heat. Transporting. Blood transports the gases, nutrients, enzymes, hormones, and cells of the immune system throughout the body. Functions of Connective Tissue Protecting. Cells of the immune system and blood protect against toxins and tissue injury, as well as against microorganisms. Bones protect underlying structures from injury Cells of Connective Tissue The specialized cells of the various connective tissues produce the extracellular matrix. The name of the cell identifies the cell functions by means of one of the following suffixes: -blast, -cyte, or -clast. Cells of Connective Tissue Adipose cells, or fat cells, also called adipocytes, contain large amounts of lipid. Adipose cells are rare in some connective tissue types, such as cartilage; abundant in others, such as loose connective tissue. Cells of Connective Tissue Mast cells commonly lie beneath membranes in loose connective tissue and along small blood vessels of organs. They contain chemicals, such as heparin, histamine, and proteolytic enzymes, that are released in response to injury, such as trauma and infection, and play important roles in inflammation. Cells of Connective Tissue Whiteblood cells, or leukocytes, continuously move from blood vessels into connective tissues Macrophages are found in some connective tissue types. They are derived from monocytes, a type of white blood cell. Platelets are fragments of hemopoetic cells containing enzymes and special proteins that function in the clotting process to reduce bleeding from a wound. Cells of Connective Tissue Undifferentiated mesenchymal cells are a type of adult stem cell that persist in connective tissue. They have the potential to form multiple cell types, such as fibroblasts or smooth muscle cells, in response to injury Extracellular Matrix The extracellular matrix of connective tissue has three major components: (1) protein fibers, (2) ground substance consisting of nonfibrous protein and other molecules, and (3) fluid. Extracellular Matrix Thestructure of the matrix gives connective tissue types most of their functional characteristics—for example, they enable bones and cartilage to bear weight, tendons and ligaments to withstand tension, and the skin’s dermis to withstand punctures, abrasions, and other abuse. Extracellular Matrix ProteinFibers of the Matrix Three types of protein fibers— collagen, reticular, and elastic— help form connective tissue. Collagen fibers consist of collagen, which is the most abundant protein in the body. Collagen fibers are very strong and flexible, like microscopic ropes, but quite inelastic. Extracellular Matrix Protein Fibers of the Matrix Elastic fibers consist of a protein called elastin. As the name suggests, this protein has the ability to return to its original shape after being stretched or compressed, giving tissue an elastic quality. Extracellular Matrix Ground Substance of the Matrix Two types of large, nonfibrous molecules, called hyaluronic acid and proteoglycans, are part of the extracellular matrix. Extracellular Matrix Ground Substance of the Matrix These molecules constitute most of the ground substance of the matrix the “shapeless” background against which the collagen fibers are seen through the microscope. However, the molecules themselves are not shapeless but highly structured Connective Tissue Classifications Connective tissue types blend into one another, and the transition points cannot be identified precisely. As a result, connective tissue is somewhat arbitrarily classified by the type and proportions of cells and extracellular matrix components Connective Tissue Classifications Twomajor categories of connective tissue are embryonic and adult Connective Tissue Classifications Twomajor categories of connective tissue are embryonic and adult Connective Tissue Classifications Twomajor categories of connective tissue are embryonic and adult Connective Tissue Loose Connective Tissue Loose connective tissue consists of relatively few protein fibers that form a lacy network, with numerous spaces filled with ground substance and fluid. Three subdivisions of loose connective tissue are areolar, adipose, and reticular Connective Tissue Loose Connective Tissue Areolar tissue is the “loose packing” material of most organs and other tissues Adipose tissue consists of adipocytes, which contain large amounts of lipid Reticular tissue forms the framework of lymphatic tissue Connective Tissue Dense Connective Tissue Dense connective tissue has a relatively large number of protein fibers, which form thick bundles and fill nearly all of the extracellular space. Connective Tissue Dense Connective Tissue Dense regular connective tissue has protein fibers in the extracellular matrix that are oriented predominantly in one direction. Dense regular elastic connective tissue consists of parallel bundles of collagen fibers and abundant elastic fibers Dense irregular connective tissue contains protein fibers arranged as a meshwork of randomly oriented fibers. Connective Tissue Supporting Connective Tissue Cartilage is composed of cartilage cells within an extensive and relatively rigid matrix. The surface of nearly all cartilage is surrounded by a layer of dense irregular connective tissue called the perichondrium Connective Tissue Supporting Connective Tissue There are three types of cartilage: Hyaline cartilage has large amounts of both collagen fibers and proteoglycans Hyaline cartilage is found where strong support and some flexibility are needed, such as in the rib cage and within the trachea and bronchi Hyaline cartilage forms most of the skeleton before it is replaced by bone in the embryo, and it is involved in growth that increases the length of bones Connective Tissue Supporting Connective Tissue There are three types of cartilage: Fibrocartilage has more collagen fibers than proteoglycans It is found in areas of the body where a great deal of pressure is applied to joints, such as in the knee, in the jaw, and between vertebrae. Connective Tissue Supporting Connective Tissue There are three types of cartilage: Elastic cartilage has numerous elastic fibers in addition to collagen and proteoglycans dispersed throughout its matrix. It is found in areas that have rigid but elastic properties, such as the external ears Connective Tissue Bone Bone is a hard connective tissue that consists of living cells and mineralized matrix. Bone matrix has organic and inorganic portions. Muscle Tissue Themain characteristic of muscle tissue is that it contracts, or shortens, with a force and therefore is responsible for movement. Muscle Tissue Themain characteristic of muscle tissue is that it contracts, or shortens, with a force and therefore is responsible for movement. Muscle Tissue Themain characteristic of muscle tissue is that it contracts, or shortens, with a force and therefore is responsible for movement. Muscle Tissue Themain characteristic of muscle tissue is that it contracts, or shortens, with a force and therefore is responsible for movement. Nervous tissue Nervous tissue is found in the brain, spinal cord, and nerves and is characterized by the ability to conduct electrical signals called action potentials. Nervoustissue consists of neurons, which are responsible for its conductive ability, and support cells called neuroglia Nervous tissue Neurons, or nerve cells, are the conducting cells of nervous tissue. A neuron is composed of three major parts: a cell body, dendrites, and an axon Neuroglia (nerve glue) are the support cells of the brain, spinal cord, and peripheral nerves. Neuroglia nourish, protect, and insulate neurons. Tissue Membranes A membrane is a thin sheet of tissue that covers a structure or lines a cavity Mucous membranes line cavities and canals that open to the outside of the body, such as the digestive, respiratory, excretory, and reproductive passages Serous membranes line cavities, such as the pericardial, pleural, and peritoneal cavities, that do not open to the exterior Synovial membranes Synovial membranes line freely movable joints. They produce synovial fluid, which is rich in hyaluronic acid, making the joint fluid very slippery, thus facilitating smooth movement within the joint. Skeletal System  INTRODUCTION Human skeleton initially cartilages and fibrous membranes Hyaline cartilage is the most abundant cartilage By age 25 the skeleton is completely hardened 206 bones make up the adult skeleton (20% of body mass) 80 bones of the axial skeleton 126 bones of the appendicular skeleton  Function of the skeletal system Support - Rigid, strong bone is well suited for bearing weight and is the major supporting tissue of the body Protection - Bone is hard and protects the organs it surrounds. For example, the skull encloses and protects the brain, and the vertebrae surround the spinal cord. Movement - Skeletal muscles attach to bones by tendons, which are strong bands of connective tissue Storage - minerals in the blood are taken into bone and stored. Blood cell production - Many bones contain cavities filled with red bone marrow, which gives rise to blood cells and platelets The skeletal system has four components: bones, cartilage, tendons, and ligaments.  Microscopic structure Bone cells are called osteocytes Osteocytes transport nutrients and wastes The extracellular matrix of bone is largely collagen and inorganic salts Collagen gives bone resilience Inorganic salts make bone hard  Bone histology Boneconsists of extracellular bone matrix and bone cells. The bone cells produce the bone matrix, become entrapped within it, and break it down so that new matrix can replace the old matrix.  Bone matrix Byweight, mature bone matrix is normally about 35% organic and 65% inorganic material. The organic material consists primarily of collagen and proteoglycans. The inorganic material consists primarily of a calcium phosphate crystal called hydroxyapatite  Bone cells Bonecells are categorized as osteoblasts, osteocytes, and osteoclasts.  osteoblasts Theyproduce collagen and proteoglycans, which are packaged into vesicles by the Golgi apparatus and released from the cell by exocytosis. Osteoblastsalso release matrix vesicles, membrane-bound sacs formed when the plasma membrane buds, or protrudes outward, and pinches off. Ossificationor osteogenesis, is the formation of bone by osteoblasts. Ossification occurs by appositional growth on the surface of previously existing bone or cartilage.  osteocyte Once an osteoblast becomes surrounded by bone matrix, it is referred to as an osteocyte The spaces occupied by the osteocyte cell bodies are called lacunae and the spaces occupied by the osteocyte cell processes are called canaliculi  osteoclasts Osteoclasts are bone-destroying cells. These cells perform reabsorption, or breakdown, of bone that mobilizes crucial Ca2+ and phosphate ions for use in many metabolic processes. Spongy bone and compact bone  Spongy bone Spongy bone consists of interconnecting rods or plates of bone called trabeculae. Between the trabeculae are spaces, which in life are filled with bone marrow and blood vessels.  Spongy bone Spongy bone is a.k.a. cancellous bone  Compact bone Haversian canal - Vessels that run parallel to the long axis of the bone are contained within central (haversian) canals. Central canals are lined with endosteum and contain blood vessels, nerves, and loose connective tissue. Concentric lamellae - are circular layers of bone matrix that surround a common center, the central canal. An osteon - or haversian system, consists of a single central canal, its contents, and associated concentric lamellae and osteocytes. In cross section, an osteon resembles a circular target; the “bull’s-eye” of the target is the central canal, and 4–20 concentric lamellae form the rings.  Compact bone Circumferential lamellae - The outer surfaces of compact bone are formed by circumferential lamellae, which are thin plates that extend around the bone Interstitial lamellae - Between the osteons are interstitial lamellae, which are remnants of concentric or circumferential lamellae that were partially removed during bone remodeling. Perforatingcanals - Blood vessels from the periosteum or medullary cavity enter the bone through perforating canals (Volkmann canals), which run perpendicular to the long axis of the bone  Compact bone Periosteum -The periosteum is a complex structure composed of an outer fibrous layer that lends structural integrity and an inner cambium layer that possesses osteogenic potential. Sharpey'sfibres - (bone fibres, or perforating fibres) are a matrix of connective tissue consisting of bundles of strong predominantly type I collagen fibres connecting periosteum to bone.  Compact bone Compact bone is denser and has fewer spaces than spongy bone. Blood vessels enter the substance of the bone itself, and the lamellae of compact bone are primarily oriented around those blood vessels.  Compact bone Central (Haversian) canal Concentric lamellae Osteon(haversion system) Circumferential lamellae Interstitial lamellae Perforating canals (volkmanns canal)  BONE CLASSIFICATIONS Long Bones Short Bones Sesamoid (round) Bones Flat Bones Irregular Bones Wormian (sutural) Bones  Parts of a long bone Diaphysis - The diaphysis, or shaft, is composed primarily of compact bone, but it can also contain some spongy bone. The end of a long bone is mostly spongy bone, with an outer layer of compact bone. Articular cartilage - Within joints, the end of a long bone is covered with hyaline cartilage called articular cartilage Anepiphysis is the part of a long bone that develops from a center of ossification distinct from that of the diaphysis  Parts of a long bone The epiphyseal plate, or growth plate, separates the epiphysis from the diaphysis Growth in bone length occurs at the epiphyseal plate. Consequently, growth in length of the long bones of the arm, forearm, thigh, and leg occurs at both ends of the diaphysis, whereas growth in length of the hand and foot bones occurs at one end of the diaphysis. epiphyseal line Medullary cavity - In addition to the small spaces within spongy bone and compact bone, the diaphysis of a long bone can have a large internal space called the medullary cavity.  Parts of a long bone Red marrow is the site of blood cell formation, and yellow marrow is mostly adipose tissue. In the fetus, the spaces within bones are filled with red marrow. The conversion of red marrow to yellow marrow begins just before birth and continues well into adulthood. The periosteum is a connective tissue membrane that covers the outer surface of a bone. The outer fibrous layer is dense irregular collagenous connective tissue that contains blood vessels and nerves. The inner layer is a single layer of bone cells, including osteoblasts, osteoclasts, and osteochondral progenitor cells  Parts of a long bone Perforating fibers - These bundles of collagen fibers are called perforating fibers, or Sharpey fibers, and they strengthen the attachment of the tendons or ligaments to the bone. Endosteum - The endosteum is a single layer of cells that lines the internal surfaces of all cavities within bones, such as the medullary cavity of the diaphysis and the smaller cavities in spongy and compact bone  PARTS OF A LONG BONE Epiphysis Distal Proximal Diaphysis Compact bone Spongy bone Articular cartilage Periosteum Endosteum Medullary cavity Trabeculae Bone marrow Red marrow and yellow marrow  Structure of Flat, Short, and Irregular Bones Flat bones contain an interior framework of spongy bone sandwiched between two layers of compact bone Short and irregular bones have a composition similar to the epiphyses of long bones—compact bone surfaces surrounding a spongy bone center with small spaces that are usually filled with marrow Short and irregular bones are not elongated and have no diaphyses. However, certain regions of these bones, such as the processes(projections), have epiphyseal growth plates and therefore small epiphyses. Some of the flat and irregular bones of the skull have air-filled spaces called sinuses, which are lined by mucous membranes.  Bone development  Bone development During fetal development, bone forms in two patterns— intramembranous ossification and endochondral ossification. Intramembranous ossification takes place in connective tissue membranes, and endochondral ossification takes place in cartilage. Bothmethods initially produce woven bone, which is then remodeled. After remodeling, bone formed by intramembranous ossification cannot be distinguished from bone formed by endochondral ossification.  Intramembranous Ossification Atapproximately the fifth week of development in an embryo, embryonic mesenchyme condenses around the developing brain to form a membrane of connective tissue with delicate, randomly oriented collagen fibers. Intramembranous ossification of the membrane begins at approximately the eighth week of embryonic development and is completed by approximately 2 years of age. Many skull bones, part of the mandible (lower jaw), and the diaphyses of the clavicles (collarbones) develop by intramembranous ossification  Intramembranous ossification The locations in the membrane where ossification begins are called centers of ossification. The centers of ossification expand to form a bone by gradually ossifying the membrane.  Intramembranous ossification Intramembranous ossification begins when some of the mesenchymal cells in the membrane become osteochondral progenitor cells, which specialize to become osteoblasts. The osteoblasts produce bone matrix that surrounds the collagen fibers of the connective tissue membrane, and the osteoblasts become osteocytes. As a result of this process, many tiny trabeculae of woven bone develop  INTRAMEMBRANOUS OSSIFICATION Additionalosteoblasts gather on the surfaces of the trabeculae and produce more bone, thereby causing the trabeculae to become larger and longer. Spongy bone forms as the trabeculae join together, resulting in an interconnected network of trabeculae separated by spaces.  Intramembranous ossification Thus, the end products of intramembranous bone formation are bones with outer compact bone surfaces and spongy centers. Remodeling converts woven bone to lamellar bone and contributes to the final shape of the bone.  INTRAMEMBRANOUS OSSIFICATION Cellswithin the spaces of the spongy bone specialize to form red bone marrow, and cells surrounding the developing bone specialize to form the periosteum. Osteoblasts from the periosteum lay down bone matrix to form an outer surface of compact bone  Endocondral ossification The formation of cartilage begins at approximately the end of the fourth week of embryonic development. Endochondral ossification of some of this cartilage starts at approximately the eighth week of embryonic development, but this process might not begin in other cartilage until as late as 18–20 years of age. Bones of the base of the skull, part of the mandible, the epiphyses of the clavicles, and most of the remaining skeletal system develop through endochondral ossification  Endochondral ossification Endochondral ossification begins as mesenchymal cells aggregate in regions of future bone formation. The mesenchymal cells become osteochondral progenitor cells that become chondroblasts. The chondroblasts produce a hyaline cartilage model having the approximate shape of the bone that will later be formed As the chondroblasts are surrounded by cartilage matrix, they become chondrocytes. The cartilage model is surrounded by perichondrium, except where a joint will form connecting one bone to another bone. The perichondrium is continuous with tissue that will become the joint capsule later in development  Endochondral ossification Whenblood vessels invade the perichondrium surrounding the cartilage model, osteochondral progenitor cells within the perichondrium become osteoblasts. Theperichondrium becomes the periosteum when the osteoblasts begin to produce bone. The osteoblasts produce compact bone on the surface of the cartilage model, forming a bone collar.  Endochondral ossification Twoother events occur at the same time that the bone collar is forming. First, the cartilage model increases in size as a result of interstitial and appositional cartilage growth. Second,the chondrocytes in the center of the cartilage model absorb some of the cartilage matrix and hypertrophy or enlarge.  Endochondral ossification Blood vessels grow into the enlarged lacunae of the calcified cartilage. Osteoblasts and osteoclasts migrate into the calcified cartilage area from the periosteum by way of the connective tissue surrounding the outside of the blood vessels. The osteoblasts produce bone on the surface of the calcified cartilage, forming bone trabeculae, which changes the calcified cartilage of the diaphysis into spongy bone. This area of bone formation is called the primary ossification center.  Endochondral ossification Asbone development proceeds, the cartilage model continues to grow, more perichondrium becomes periosteum, and the bone collar thickens and extends farther along the diaphysis.  Endochondral ossification Inlong bones, the diaphysis is the primary ossification center, and additional sites of ossification, called secondary ossification centers, appear in the epiphyses. The events occurring at the secondary ossification centers are the same as those at the primary ossification centers, except that the spaces in the epiphyses do not enlarge to form a medullary cavity as in the diaphysis.  Endochondral ossification Replacement of cartilage by bone continues in the cartilage model until all the cartilage, except that in the epiphyseal plate and on articular surfaces, has been replaced by bone  Endochondral ossification Inmature bone, spongy and compact bone are fully developed, and the epiphyseal plate has become the epiphyseal line. The only cartilage present is the articular cartilage at the ends of the bone  Bone growth Long bones and bony projections increase in length because of growth at the epiphyseal plate. Long projections of bones, such as the processes of vertebrae, also have epiphyseal plates. Growthat the epiphyseal plate involves the formation of new cartilage by interstitial cartilage growth followed by appositional bone growth on the surface of the cartilage. The epiphyseal plate is organized into four zones  Growth in bone length The zone of resting cartilage is nearest the epiphysis and contains randomly arranged chondrocytes that do not divide rapidly The chondrocytes in the zone of proliferation produce new cartilage through interstitial cartilage growth. In the zone of hypertrophy, the chondrocytes produced in the zone of proliferation mature and enlarge The zone of calcification is very thin and contains hypertrophied chondrocytes and calcified cartilage matrix. The hypertrophied chondrocytes die, and blood vessels from the diaphysis grow into the area.  Growth in articular cartilage The process of growth in articular cartilage is similar to that occurring in the epiphyseal plate, except that the chondrocyte columns are not as obvious. The chondrocytes near the surface of the articular cartilage are similar to those in the zone of resting cartilage of the epiphyseal plate. In the deepest part of the articular cartilage, nearer bone tissue, the cartilage is calcified and ossified to form new bone. When the epiphyses reach their full size, the growth of cartilage and its replacement by bone cease. The articular cartilage, however, persists throughout life and does not become ossified as the epiphyseal plate does.  Growth in bone width Longbones increase in width (diameter) and other bones increase in size or thickness because of appositional bone growth beneath the periosteum. osteoblasts from the periosteum lay down bone to form a series of ridges with grooves between them. The periosteum covers the bone ridges and extends down into the bottom of the grooves, and one or more blood vessels of the periosteum lie within each groove. As the osteoblasts continue to produce bone, the ridges increase in size, extend toward each other, and meet to change the groove into a tunnel  Growth in bone width THE NAME OF THE PERIOSTEUM IN THE TUNNEL CHANGES TO ENDOSTEUM BECAUSE THE MEMBRANE NOW LINES AN INTERNAL BONE SURFACE. OSTEOBLASTS FROM THE ENDOSTEUM LAY DOWN BONE TO FORM A CONCENTRIC LAMELLA. THE PRODUCTION OF ADDITIONAL LAMELLAE FILLS IN THE TUNNEL, ENCLOSES THE BLOOD VESSEL, AND PRODUCES AN OSTEON When a bone grows in width slowly, the surface of the bone becomes smooth as osteoblasts from the periosteum lay down even layers of bone to form circumferential lamellae. The circumferential lamellae break down during remodeling to form osteons  Factors affecting bone growth The potential shape and size of a bone and an individual’s final adult height are determined genetically, but factors such as nutrition and hormones can greatly modify the expression of those genetic factors.  Factors affecting bone growth Nutrition Because bone growth requires chondroblast and osteoblast proliferation, any metabolic disorder that affects the rate of cell proliferation or the production of collagen and other matrix components affects bone growth, as does the availability of calcium or other minerals needed in the mineralization process.  Factors affecting bone growth VITAMIND IS NECESSARY FOR THE NORMAL ABSORPTION OF CALCIUM FROM THE INTESTINES. THE BODY CAN EITHER SYNTHESIZE OR INGEST VITAMIN D. ITS RATE OF SYNTHESIS INCREASES WHEN THE SKIN IS EXPOSED TO SUNLIGHT. Causes rickets Vitamin C is necessary for collagen synthesis by osteoblasts. Normally, as old collagen breaks down, new collagen is synthesized to replace it. Vitamin C deficiency results in bones and cartilage that are deficient in collagen because collagen synthesis is impaired. Causes scurvy.  Factors affecting bone growth Hormones Hormones are very important in bone growth. Growth hormone from the anterior pituitary increases general tissue growth, including overall bone growth, by stimulating interstitial cartilage growth and appositional bone growth. Excessive growth hormone secretion results in pituitary gigantism, whereas insufficient growth hormone secretion results in pituitary dwarfism  Factors affecting bone growth Thyroid hormone is also required for normal growth of all tissues, including cartilage; therefore, a decrease in this hormone can result in a smaller individual. Sex hormones also influence bone growth. Estrogen (a class of female sex hormones) and testosterone (a male sex hormone) initially stimulate bone growth, which accounts for the burst of growth at puberty when production of these hormones increases.  Bone remodeling Inthis process, osteoclasts remove old bone and osteoblasts deposit new bone. Bone remodeling converts woven bone into lamellar bone and is involved in several important functions, including bone growth, changes in bone shape, adjustment of the bone to stress, bone repair, and calcium ion (Ca2+) regulation in the body.  Bone remodeling Bone remodeling involves a basic multicellular unit (BMU), a temporary assembly of osteoclasts and osteoblasts that travels through or across the surface of bone, removing old bone matrix and replacing it with new bone matrix. The average life span of a BMU is approximately 6 months, and BMU activity renews the entire skeleton every 10 years  Mechanical Stress and Bone Strength The amount of stress applied to a bone can modify the bone’s strength through remodeling, the formation of additional bone, alteration in trabecular alignment to reinforce the scaffolding, or other changes. Mechanical stress applied to bone increases osteoblast activity in bone tissue, and the removal of mechanical stress decreases osteoblast activity. In addition, pressure in bone causes an electrical change that increases the activity of osteoblasts  Bone repair Hematoma formation. When a bone is fractured, the blood vessels in the bone and surrounding periosteum are damaged and a hematoma forms. A hematoma is a localized mass of blood released from blood vessels but confined within an organ or a space. Usually, the blood in a hematoma forms a clot, which consists of fibrous proteins that stop the bleeding.  Bone repair Callus formation. A callus is a mass of tissue that forms at a fracture site and connects the broken ends of the bone. An internal callus forms between the ends of the broken bone, as well as in the marrow cavity if the fracture occurs in the diaphysis of a long bone. The external callus forms a collar around the opposing ends of the bone fragments. Osteochondral progenitor cells from the periosteum become osteoblasts, which produce bone, and chondroblasts, which produce cartilage. Cartilage production is more rapid than bone production, and the cartilage from each side of the break eventually grows together.  Bone repair Callus ossification. Like the cartilage models formed during fetal development, the cartilage in the external callus is replaced by woven spongy bone through endochondral ossification. The result is a stronger external callus.  Bone repair Boneremodeling. Filling the gap between bone fragments with an internal callus of woven bone is not the end of the repair process because woven bone is not as structurally strong as the original lamellar bone. Repair is complete only when the woven bone of the internal callus and the dead bone adjacent to the fracture site have been replaced by compact bone.  Calcium homeostasis Calcium homeostasis is maintained by two hormones: parathyroid hormone and calcitonin. Parathyroid hormone (PTH) is the major regulator of blood Ca2+ levels. PTH, secreted from the parathyroid glands when blood Ca2+ levels are too low, stimulates an increase in the number of osteoclasts, which break down bone and elevate blood Ca2+ levels Calcitonin,secreted from the thyroid gland when blood Ca2+ levels are too high, decreases osteoclast activity by binding to receptors on the osteoclasts. An increase in blood Ca2+ stimulates the thyroid gland to secrete calcitonin, which inhibits osteoclast activity. Gross Anatomy Gross Anatomy Gross Anatomy Skeletal organization 206 bones in a normal adult 80 axial bones 126 appendicular bones Skeletal organization Cranium 22 skull bones 8 cranial bones 14 facial bones Skeletal organization Cranium Frontal – frontal suture, nasion, roof of orbits, frontal sinus, supra orbital foramen, frontal eminence and metopic suture Parietal – flat side wall of the cranium, roof of cranium, sagittal suture, parietal eminence Skeletal organization Cranium Occipital – back of skull, base, foramen magnum, occipital condyle, lambdoidal suture Temporal – side walls of cranium, floor of cranium, floor and side of orbits, EAM, mandibular fossa, mastoid, styloid and zygomatic process, Skeletal organization Cranium Sphenoid – base of cranium, side of skull, floor and side of orbits, sella turcica, sphenoid sinus, greater wing(SOF), lesser wing(optic canal) Ethmoid – roof and walls of nasal cavity, cranial floor, walls of orbits, cribriform plate, perpendicular plate(septum), middle nasal chonchae, ethmoid sinus and crista galli Skeletal organization Facial Bones Maxillary Palatine Zygomatic Lacrimal Nasal Vomer Mandible Inferior nasal conchae Skeletal organization Hyoid bone Auditory ossicles Malleus hammer Incus anvil Stapes stirrup Skeletal organization Vertebral Column Stacks of vertebrae Separated by cartilaginous intervertebral disks 26 in adults 33 in children Skeletal organization Vertebral Column Cervical 7 Thoracic 12 Lumbar 5 Sacral 4-5(fused) Coccygeal 3-4(fused) Skeletal organization Vertebral Column features natural curvatures Cervical lordotic Thoracic kyphotic Lumbar lordotic Sacrococcygeal kyphotic Skeletal organization Vertebral Column features Thoracic vertebrae Rib facets Vertebral prominence C7 Intervertebral foramen pedicles of spine Intervertebral disks Skeletal organization Vertebral Column features Typical vertebrae Largest body Thick short almost square spinous process Lumbar as the most normal and has: Vertebral body Pedicles Lamina Spinous process Transverse process Vertebral foramen Facets Skeletal organization Vertebral Column features Typical vertebrae Lumbar as the most normal and has: Vertebral body Pedicles Lamina Spinous process Transverse process Vertebral foramen Facets Skeletal organization Cervical vertebrae Atlas C1, supports head, pivot joint Axis C2, dens and odontoid Bifid spinous process C3-C7 Vertebral prominence C7 Skeletal organization Thoracic vertebrae Long spinous process that points inferiorly Rib facets Skeletal organization Sacrum 4-5 fused bones Median sacral crest Cauda equina Posterior wall of pelvic cavity Posterior sacral foramen Coccyx tailbone Cardiovascular System INTRODUCTION The heart is actually two pumps in one. The right side of the heart receives blood from the body and pumps blood through the pulmonary circulation, which carries blood to the lungs and returns it to the left side of the heart. In the lungs, carbon dioxide diffuses from the blood into the lungs, and oxygen diffuses from the lungs into the blood. The left side of the heart pumps blood through the systemic circulation, which delivers oxygen and nutrients to all the remaining tissues of the body. INTRODUCTION Humans have a closed circulatory system, typical of all vertebrates, in which blood is confined to vessels and is distinct from the interstitial fluid. The heart pumps blood into large vessels that branch into smaller ones leading into the organs. Materials are exchanged by diffusion between the blood and the interstitial fluid bathing the cells. Functions of the Heart Generating blood pressure Routing blood. Ensuring one-way blood flow Regulating blood supply The Blood A. Plasma Liquid portion of the blood. Contains clotting factors, hormones, antibodies, dissolved gases, nutrients and waste The Blood B. Erythrocytes - Red Blood Cells Carry hemoglobin and oxygen. Do not have a nucleus and live only about 120 days. Can not repair themselves. The Blood C. Leukocytes – White Blood cells Fight infection and are formed in the bone marrow Five types – neutrophils, lymphocytes, eosinophils, basophils, and monocytes. The Blood D. Thrombocytes – Platelets. These are cell fragment that are formed in the bone marrow Clot Blood by sticking together – via protein fibers called fibrin. Disorders of the Circulatory System Anemia - lack of iron in the blood, low RBC count Leukemia - white blood cells proliferate wildly, causing anemia Hemophilia - bleeder’s disease, due to lack of fibrinogen in thrombocytes Heart Murmur - abnormal heart beat, caused by valve problems Heart attack - blood vessels around the heart become blocked with plaque, also called myocardial infarction Anatomy of the Heart Anatomy of the Heart Anatomy of the Heart PericardiumThe pericardium, or pericardial sac, is a double layered, closed sac that surrounds the heart. Fibrous pericardium Serous pericardium Parietal pericardium Visceral pericardium Anatomy of the Heart Anatomy of the Heart Heart Wall The heart wall is composed of three layers of tissue: the epicardium, myocardium, and endocardium Anatomy of the Heart Heart Wall The epicardium, or visceral pericardium, is a thin serous membrane that constitutes the smooth, outer surface of the heart. The serous pericardium is called the epicardium when considered a part of the heart and the visceral pericardium when considered a part of the pericardium. Anatomy of the Heart Heart Wall The thick, middle layer of the heart, the myocardium, is composed of cardiac muscle cells and is responsible for the heart’s ability to contract. Anatomy of the Heart Heart Wall The smooth, inner surface of the heart chambers, called the endocardium, consists of simple squamous epithelium over a layer of connective tissue. The smooth, inner surface allows blood to move easily through the heart. The endocardium also covers the surfaces of the heart valves. Anatomy of the Heart Heart Wall Anatomy of the Heart Anatomy of the Heart Anatomy of the Heart Heart Chambers and Valves: Right and Left Atria The right atrium has three major openings: The openings from the superior vena cava and the inferior vena cava receive blood from the body, and the opening of the coronary sinus receives blood from the heart itself. The left atrium has four relatively uniform openings that receive blood from the four pulmonary veins from the lungs. The two atria are separated from each other by the interatrial septum. Anatomy of the Heart Heart Chambers and Valves: Right and Left Ventricles The atria open into the ventricles through atrioventricular canals. Each ventricle has one large, superiorly placed outflow route near the midline of the heart. The right ventricle opens into the pulmonary trunk, and the left ventricle opens into the aorta. The two ventricles are separated from each other by the interventricular septum Anatomy of the Heart Atrioventricular Valves An atrioventricular valve is in each atrioventricular canal and is composed of cusps, or flaps. Atrioventricular valves allow blood to flow from the atria into the ventricles but prevent blood from flowing back into the atria. The atrioventricular valve between the right atrium and the right ventricle has three cusps and is therefore called the tricuspid valve. The atrioventricular valve between the left atrium and the left ventricle has two cusps and is therefore called the bicuspid valve, or mitral valve Anatomy of the Heart Semilunar Valves Within the aorta and pulmonary trunk are the aortic semilunar and pulmonary semilunar (half-moon shaped) valves, respectively. Each valve consists of three pocketlike semilunar cusps, the free inner borders of which meet in the center of the artery to block blood flow Route of Blood Flow Route of Blood Flow Anatomy of the Heart Conducting System A conducting system relays action potentials through the heart. This system consists of modified cardiac muscle cells that form two nodes (knots or lumps) and a conducting bundle Anatomy of the Heart Conducting System The sinoatrial (SA) node is medial to the opening of the superior vena cava, and the atrioventricular (AV) node is medial to the right atrioventricular valve. The AV node gives rise to a conducting bundle of the heart, the atrioventricular (AV) bundle (bundle of His) Anatomy of the Heart Conducting System The inferior terminal branches of the bundle called Purkinje fibers, are large-diameter cardiac muscle fibers. Because cells of the SA node spontaneously generate action potentials at a greater frequency than other cardiac muscle cells, these cells are called the pacemaker of the heart Anatomy of the Heart Conducting System Cardiac Arrhythmias Tachycardia: Heart rate in excess of 100bpm Bradycardia: Heart rate less than 60 bpm Sinus arrhythmia: Heart rate varies 5% during respiratory cycle and up to 30% during deep respiration Cardiac Cycle Heart is two pumps that work together, right and left half Repetitive contraction (systole) and relaxation (diastole) of heart chambers Blood moves through circulatory system from areas of higher to lower pressure. Contraction of heart produces the pressure Heart Sounds First heart sound or “lubb” Atrioventricular valves and surrounding fluid vibrations as valves close at beginning of ventricular systole Second heart sound or “dupp” Results from closure of aortic and pulmonary semilunar valves at beginning of ventricular diastole, lasts longer Third heart sound (occasional) Caused by turbulent blood flow into ventricles and detected near end of first one-third of diastole Functions of the Circulatory System The circulatory system comprises two sets of blood vessels: pulmonary vessels and systemic vessels. Pulmonary vessels transport blood from the right ventricle, through the lungs, and back to the left atrium. Systemic vessels transport blood through all parts of the body from the left ventricle and back to the right atrium Functions of the Circulatory System Carries blood Exchangesnutrients, waste products, and gases with tissues. Transports substances Helps regulate blood pressure Directs blood flow to tissues Structural Features of Blood Vessels The three main types of blood vessels are arteries, capillaries, and veins. Arteries carry blood away from the heart. capillaries, the most common blood vessel type. veins, vessels that carry blood toward the heart Structural Features of Blood Vessels Arteriovenous anastomoses allow blood to flow from arterioles to small veins without passing through capillaries. Structural Features of Blood Vessels Structural Features of Blood Vessels Structural Features of Blood Vessels Structural Features of Blood Vessels Structural Features of Blood Vessels Structural Features of Blood Vessels Structural Features of Blood Vessels Structural Features of Blood Vessels Structural Features of Blood Vessels Structural Features of Blood Vessels Structural Features of Blood Vessels Structural Features of Blood Vessels Respiratory System INTRODUCTION The respiratory system helps us in what we commonly call breathing but is more appropriately termed respiration. Respiration includes four processes: (1) ventilation, the movement of air into and out of the lungs; (2) gas exchange between the air in the lungs and the blood, sometimes called external respiration; (3) the transport of oxygen and carbon dioxide in the blood; and (4) gas exchange between the blood and the tissues, sometimes called internal respiration. INTRODUCTION Inaddition to respiration, the respiratory system performs the following functions: Regulation of blood pH Production of chemical mediators. Voice production Olfaction Protection INTRODUCTION Structurally, the respiratory system is divided into the upper respiratory tract and the lower respiratory tract. Theupper respiratory tract includes the external nose, the nasal cavity, the pharynx with its associated structures, and the larynx; the lower respiratory tract includes the trachea, the bronchi and smaller bronchioles, and the lungs INTRODUCTION Functionally, the respiratory system is divided into two regions. Theconducting zone is exclusively for air movement and extends from the nose to the bronchioles. The respiratory zone is within the lungs and is where gas exchange between air and blood takes place. Anatomy and Histology of the Respiratory System Conducting Zone The conducting zone consists of respiratory system structures adapted for air movement, cleaning, warming, and humidification. Gases are simply moved from the external environment to the area where they interact with blood Anatomy and Histology of the Respiratory System Conducting Zone Nose – nasus; consist of the external nose and nasal cavity - extends from the nares to the choanae; vestibule: anterior part of the nasal - Hard palate: separates the nasal from oral cavity - Nasal septum that divides the nasal cavity to left and right - Meatus in the chonae that leads to the PNS and Nasolacrimal ducts Anatomy and Histology of the Respiratory System Conducting Zone Nose – The nasal cavity has five functions: Serves as a passageway for air Cleans the air Humidifies and warms the air Contains the olfactory epithelium Helps determine voice sound Anatomy and Histology of the Respiratory System Conducting Zone Pharynx – the pharynx (throat) common opening of both digestive and respiratory systems Nasopharynx – posterior to chonae superior to soft palate; auditory tubes open to nasopharynx to equalize pressure in the internal ear Anatomy and Histology of the Respiratory System Conducting Zone Pharynx Oropharynx – extends from the soft palate to the epiglottis - The oral cavity opens into the oropharynx through the fauces. Air, food, and drink all pass through the oropharynx. - Two sets of tonsils, called the palatine tonsils and the lingual tonsils, are located near the fauces. Anatomy and Histology of the Respiratory System Conducting Zone Pharynx Laryngopharynx –tip of the epiglottis to the esophagus and passes posterior to the larynx. - Food and drink pass through the laryngopharynx to the esophagus. A small amount of air is usually swallowed with the food and drink. - The laryngopharynx is lined with moist stratified squamous epithelium Anatomy and Histology of the Respiratory System Conducting Zone Larynx – located in the anterior part of the throat and extends from the base of the tongue to the trachea; connected by membranes and/or muscles superiorly to the hyoid bone - Six of the nine cartilages are paired, and three are unpaired. The largest of the cartilages is the unpaired thyroid (shield; refers to the shape of the cartilage) cartilage, or Adam’s apple Anatomy and Histology of the Respiratory System Conducting Zone Larynx –most inferior cartilage is the unpaired cricoid (ring-shaped) cartilage; forms the base of the larynx on which the other cartilages rest. - The third unpaired cartilage is the epiglottis (on the glottis); attached to the thyroid cartilage, projects superiorly as a free flap toward the tongue, differs from the other cartilages in that it consists of elastic rather than hyaline cartilage. Anatomy and Histology of the Respiratory System Conducting Zone Larynx – arytenoid cartilage, corniculate cartilage and cuneiform cartilage; all paired - two pairs of ligaments extend from the anterior surface of the arytenoid cartilages to the posterior surface of the thyroid cartilage. - The superior ligaments are covered by a mucous membrane called the vestibular folds, or false vocal cords. - The inferior ligaments are covered by a mucous membrane called the vocal folds, or true vocal cords Anatomy and Histology of the Respiratory System Conducting Zone Larynx – The larynx performs four important functions: - The thyroid and cricoid cartilages maintain an open passageway for air movement. - The larynx prevents swallowed materials from entering the lower respiratory - The vocal folds are the primary source of sound production. - The pseudostratified ciliated columnar epithelium lining the larynx produces mucus, which traps debris in air. Anatomy and Histology of the Respiratory System Conducting Zone Trachea – the trachea, or windpipe, is a membranous tube attached to the. It consists of dense regular connective tissue and smooth muscle reinforced with 15– 20 C-shaped pieces of hyaline cartilage. - Supports the anterior and lateral sides of trachea - Trachealis muscle ligamentous membrane and smooth muscle that supports the posterior of the trachea; can contract when coughing - Thetrachea has an inside diameter of 12 mm and a length of 10–12 cm Anatomy and Histology of the Respiratory System Conducting Zone Trachea – The trachea divides to form two smaller tubes called main bronchi, or primary bronchi (bronchus; windpipe), each of which extends to a lung. -The most inferior tracheal cartilage forms a ridge called the carina -mucous membrane in the carina is very sensitive Anatomy and Histology of the Respiratory System Conducting Zone Tracheobronchial Tree – beginning with the trachea, all the respiratory passageways are called the tracheobronchial tree - Right main bronchus is larger in diameter and more directly in line with the trachea - Lobar bronchi secondary bronchi within each lung - Segmental bronchi tertiary bronchi - Bronchioles - Terminal Bronchioles - Approximately 16 generations of branching occur from the trachea to the terminal bronchioles Anatomy and Histology of the Respiratory System Conducting Zone Tracheobronchial Tree – Relaxation and contraction of the smooth muscle within the bronchi and bronchioles can change the