Anatomy and Physiology Reviewer PDF

cardiovascular system circulate blood continuously to supply oxygenated blood to the entire body and carry deoxygenated blood back to the heart. Anatomy - is the study of the structure and...

cardiovascular system circulate blood continuously to supply oxygenated blood to the entire body and carry deoxygenated blood back to the heart. Anatomy - is the study of the structure and shape of the body and its parts and their Organism – represents the highest level of structural organization. It is the relationships to one another. The term anatomy is derived from two Greek collective whole of the different organ systems working together to keep us words “tomy” meaning to cut, and “ana” meaning apart. alive. Gross Anatomy – study or observation of large body structures such as The Organ Systems: the heart and the bones. Integumentary System – is the external covering of the body or the skin Microscopic Anatomy – the study of body structures that are too small (protection). This covering is waterproof and serves as a cushion to prevent the to be seen with the naked eye organs from getting damaged. It helps regulating body temperature by excreting Physiology – the study of how the body and its parts work or function. (physio = nature; urea and salts (excretion). Temperature, pressure, and pain receptors located in ology = the study of). Examples of subdivisions of physiology: the skin alert us of what is happening on the skin’s surface (sensation). neurophysiology explains the workings of the nervous system while cardiac Responsible for the synthesis of vitamin D. physiology studies the function of the heart. Skeletal system – consists of bones, cartilages, ligaments, and joints. Serves as a framework and support for the human body. Also serves protective purposes as Relationship between Anatomy and Physiology: it encloses the brain. Hematopoiesis (blood cell formation) is the production of all the cellular components of blood and blood plasma that occur within the cavity Structure determines what functions can take place. For example, the lungs are of the skeleton. The hard substance of the bones also acts as a storehouse for not muscular chambers like the heart and cannot pump blood through the body, minerals (calcium). but because the walls of their air sacs are very thin, they can exchange gases and Muscular System – have only one function to either contract or shorten that are provide oxygen to the body. responsible for movement. The activity of the skeletal muscles account for the The Six levels of Structural Organization: mobility of the body. Types are: the involuntary smooth and cardiac muscles and the voluntary skeletal muscles. The muscles also contract to produce heat. Chemical level – this the simplest level of the structural ladder. At this level, Nervous System – is the body’s fast acting control system. Organs included are the atoms, tiny building blocks of matter, combine to form molecules such as brain, spinal cord, nerves, and sensory receptors. The sensory receptors detect water, sugar, and proteins. changes (stimuli) and send nerve impulses to and from the central nervous Cellular level – molecules associate in specific ways to form microscopic system for interpretation and assessment. A response is then sent out by cells, the smallest unit of all living things. All cells have some common activating the appropriate body effectors (muscle and glands). The brain and functions, but individual cells vary widely in size and shape, reflecting their spinal cord are the two main components of the CNS. The reflex is a fast-acting function in the body. response from the spinal cord. Tissues – consist of groups of similar cells that have a common function. The Endocrine System – controls body activities but at a slower pace. They produce basic tissue types namely: epithelial, connective, muscular, and neural. hormones that target specific organs. The endocrine glands are the pituitary, Organs – a structure composed of two or more tissue types that performs a thyroid, parathyroid, adrenals, thymus, pancreas, pineal, ovaries (for females), specific function for the body. At this level extremely complex functions and the testes (for males). The endocrine glands despite being an organ system become possible. For example, the small intestine which is a combination of are situated all over the body, but its organs serve the same purpose of producing all four tissue types. hormones to stimulate other bodily functions. The hormones do not pass through Organ System – is a group of organs that work together to accomplish a a duct. common purpose. For example, the heart along with the blood vessels of the  Cardiovascular system – primary organs of this system are the heart and blood all our internal organs and bodily fluids. The skin is selectively permeable vessels. The heart acts as a blood pump, containing the blood that carries oxygen, against water keeping all our body fluids inside and keeping our skin nutrients, hormones, and other substances to and from the tissue cells where waterproof. exchange occurs. White blood cells and chemicals in the blood act as defense Movement against harmful substances. The muscular system either contracts or shortens to manipulate the Lymphatic System – organs included are the lymphatic vessels, lymph nodes, and skeletal system to do actions like walking, swimming, and even talking. other lymphoid organs such as the spleen and tonsils. They cleanse the blood and Movement also occurs internally when blood circulates all around our house cells that provide immunity (e.g. white blood cells). They bring fluid leaked body, food is being digested, urine are propelled, and etc. from the blood back to the blood vessels. Lymphadenitis – inflammation of the lymph nodes Responsiveness or Irritability Lymphadenopathy – a disease affecting the lymph nodes This is the ability to sense changes (stimuli) in the environment or Respiratory System – main function is to keep the body well oxygenated and take internally and respond to them. Highly irritable nerve cells communicate out carbon dioxide. This system consists of the nasal passages, pharynx, larynx, changes via electrical impulses rapidly to the nervous system which is trachea, bronchi, and the lungs filled with tiny air sacs. responsible for sending out commands in response to stimulus. Digestive System – basically a tube running from the mouth to the anus. The organs of the digestive system include the oral cavity (mouth), esophagus, Digestion stomach, small and large intestines, and rectum plus several accessory organs For simple cell organisms like the amoeba, the cell itself does digestion (liver, salivary glands, pancreas, and others). They break down food to get but for complex organisms such as a human being, the digestive system is nutrients and reclaim water necessary for the body. The liver produces bile to responsible for breaking down complex molecules into simpler ones help break down fat while the pancreas produces enzymes used by the small easily absorbed into the blood. The cardiovascular system then intestine. Undigested food leaves the body through the anus as feces. distributes the nutrient-filled and oxygen-rich blood throughout the body. Urinary System – removes nitrogenous wastes from the blood and flushes it out Eupepsia – good digestion as urine. It is called an excretory system composed of the kidneys, ureters, Dyspepsia – bad digestion bladder, and urethra. Help maintain the body’s water and electrolyte balance regulating the acid-base balance in the blood. The urinary system activates Metabolism vitamin D. This system also reabsorbs calcium. Metabolism is a broad term used to define all chemical reactions that Reproductive System – the male testes produce sperm while the ovaries of the occur in our body that are regulated chiefly by hormones from the female produce the ova, when paired produce offspring (procreation). In the male endocrine system. It involves breaking complex substances to simpler reproductive system (testes is the primary organ), it is made up of scrotum, penis, ones (metabolism), building large structures from smaller ones accessory glands, and the duct system, which carries sperm to the outside of the (anabolism), production of nutrients, and harnessing ATP. body. In females (ovary is the primary organ), the uterine tubes, uterus, and vagina. The fertilized egg resides in the female’s uterus. Excretion This involves removing excreta or wastes from the body during digestion The 8 Necessary Life Functions to Maintain Life: and metabolism such as excreting indigestible food as feces, the urinary Maintaining Boundaries system disposes nitrogen-containing metabolic wastes in urine. This life function enables organisms to set boundaries all over their body so that whatever is inside is distinct from what is found outside. An example is our Integumentary System that serve as an outer covering for  Reproduction Acclimatization – the process of being accustomed to a new climate or This occurs in a cellular or organismal level. The cellular level of new conditions. reproduction is observed when a cell divides to form two identical daughter cells that are used for growth or repair. Reproducing a whole Homeostasis: new organism is the task of the reproductive system, which occurs when This is the body’s ability to maintain relatively stable internal conditions even a sperm cell fertilizes an egg cell forming a zygote which will then fully though the external conditions are continuously changing. “Homeo” means same, while develop into a baby, this is also regulated precisely by hormones from the “stasis” means standing still, but despite that it does not mean there are no changes endocrine system. occurring inside the body instead it indicates a dynamic state of equilibrium. In this Growth process, all the organ systems play a role in maintaining certain conditions needed to Hormones play a major role in stimulating activities for growth. The rate keep the body in equilibrium. of cell-constructing activities must overcome that of cell destruction. Homeostatic Controls: Survival Needs: The two organ systems mainly responsible for communication in achieving Nutrients – these energy rich chemicals are found in food. Carbohydrates are the homeostasis, is our endocrine and nervous system. The send out electrical impulses via major energy providing fuel for our body. Proteins, and to a lesser extent, fats help nerves or bloodborne hormones that act as messengers. build the structures of the body. Fats also serve as cushion and reserve fuel. Vitamins and minerals are needed in chemical reactions and oxygen transport in The 3 Components of Homeostatic Control Mechanisms: the blood. Receptor – a sensor that monitors and responds to changes in the environment Oxygen – approximately 20% of the air we breathe is oxygen. The respiratory and called stimuli, cardiovascular system team up to make it readily available for the blood and other This information is then sent to the control center via an afferent pathway organs. This is the most essential. Control Center – assesses the situation and determines the appropriate response Water – this accounts for 60 to 80 percent of our body weight. Is the most Effector – efferent information from the control center travels through an efferent abundant fluid that serves as a base for bodily secretions and excretions, that are pathway to the effector, which provides a means for the control center’s response taken from the food or liquids we ingest. Water is lost by evaporation in the lungs to the stimulus. The results of the response then feedback to influence the and skin during excretions. This is the most abundant. stimulus. Positive feedback (production is continuous until the process is done) Normal body temperature – at extremely low body temperatures (below 37 amplifies the stimulus while negative feedback slows it down. (e.g. given of degrees Celsius), the rate of metabolism is slow up to a certain point wherein it positive feedback: the more contraction during childbirth the more oxytocin is eventually stops. When the body temperature is too high, chemical reactions produced, whereas in negative feedback (whatever is in excess is suppressed): proceed rapidly causing proteins to break down. the pancreas produce insulin to lower sugar while glucagon is produced to raise Atmospheric pressure – force exerted on the surface of the body by the weight of sugar levels back to normal, these productions stop once everything returns to its the air. At high altitudes where the thin is air and atmospheric pressure is low, usual state). gas exchange may be too slow to support metabolism. Pressure decreases at higher temperature. Hypothalamus – the thermal regulator in the brain Eustachian tube - extends from the middle ear to the upper part of the throat behind the nose. Also known as the auditory tube, it helps keep the middle ear healthy by equalizing pressure, clearing secretions, and protecting it from pathogens that might otherwise cause infections. 2 pathways: Afferent, Ascending, Spinothalamic, Sensory tract – carry sensory impulses to the CNS Efferent, Descending, Corticospinal, Motor tract – information from the cortex of the brain Anatomical Position – assuming that the body is in a standard position so that it is easier to understand what body part is being talked about. In humans, the standard anatomical position is standing erect with the feet parallel and the arms hanging at the sides with the palms facing forward. Directional Terms – anatomical terms used by medical personnel and anatomists to point out where one part is in relation the other part. Axial Parts – the head, neck, and body (the center of the body) Apendicular Parts – arms and legs connected to the axis of the body Anterior or Ventral – front of the body (for humans only) Posterior or Dorsal – back of the body (for humans only) Superior or Cranial – features towards the top of your body, like the head Inferior or Caudal – parts below Anterior Body Landmarks: Medial – structures towards the midline Lateral – structures farther away from the midline Abdominal – anterior body trunk Fibular – lateral part of the leg Proximal – closer to the origin of the body part or the point of attachment of a inferior to ribs Frontal – forehead limb to the trunk Acromial - point of shoulder Inguinal – area where the thigh meets Distal – farther away from the origin of a body part or the point of attachment of Antebrachial – forearm the trunk a limb to the body trunk Antecubital – anterior surface of elbow Mental – chin Superficial (External) – toward or at the body surface Axillary – armpit Nasal – nose area Deep (Internal) – internal or inside the body surface Brachial – arm Oral – mouth Regional Terms – visible landmarks on the surface of the body used to designate specific Buccal – cheek area Orbital – eye area body areas. Carpal – wrist Patellar – anterior knee Cervical – neck area Pelvic – area overlying the pelvis Coxal – hip anteriorly Crural – leg Pubic – genital region Deltoid – curve of the shoulder formed Sternal – breastbone area by large deltoid muscle Tarsal – ankle region Digital – fingers, toe Thoracic – chest Femoral – thigh Umbilical – navel Costal - ribs  Posterior Body Landmarks: and other visceral organs, as well as serve as the central region that divides the right and left lung. The cavity inferior to the diaphragm is the abdominopelvic Calcaneal – heel of the foot Plantar – the sole of the foot cavity sometimes broken down into the abdominal cavity housing the stomach, Cephalic – head Popliteal – posterior of the knee liver, intestines, and other organs. The inferior pelvic cavity houses the Femoral – thigh Sacral – area between hips reproductive organs, bladder, and rectum. Gluteal – buttock Scapular – shoulder blade region Four Quadrants of the Abdominopelvic Cavity: Lumbar – area of back between ribs and Sural – the posterior surface of the leg hips, the loin or the posterior of the calf - The terms “left/right” and “upper/lower” are always from the perspective of Occipital – posterior surface of head or Vertebral – area of the spinal column the anatomical position, not your perspective. Be careful not to mix up your right and base of the skull Otic – ears left regions, as this is where most students make a mistake! Olecranal – posterior surface of the elbow Perineal – area between the anus and the external of the genital - All four quadrants contain portions of the small and large intestines. Pectoral – chest muscle Right Upper Quadrant - Liver, stomach, gallbladder, duodenum, right kidney, Palmar – palm of the hands pancreas, and the right adrenal gland. Body Planes and Sections: Right Lower Quadrant - appendix, reproductive organs, right ureter. Section – a cut made to see the internal Left Upper Quadrant - Liver, stomach, pancreas, left kidney, spleen, and the left adrenal gland. Plane – an imaginary line where the section is made Left Lower Quadrant - left ureter, reproductive organs Sagittal Section – an anatomical plane which divides the body into right and left Nine Abdominopelvic Regions: parts Midsagittal Section – the cut is made down the median plane dividing the body Umbilical Region – the centermost region, deep to and surrounding the umbilicus into equal left and right parts Epigastric Region – “epi = above” plus “gastric = stomach”; superior to the Parasagittal Section – a section parallel to the sagittal section umbilical region Coronal or Frontal Section – division between an organism’s dorsal (back) and Hypogastric (Pubic) Region – inferior to the umbilical region; “hypo = below” ventral (front) halves Right and Left iliac (inguinal regions) – iliac = superior part of the hip bone; Transverse Plane – splits the body into top and bottom; also called cross section lateral to the hypogastric region Right and Left Lumbar Regions – lie lateral to the umbilical region; lumbus = loin Body Cavities: Right and Left Hypochondriac Regions – flank the epigastric region and contain Dorsal Body Cavity – divided into the cranial cavity which is the space inside the the lower ribs; chondro = cartilage bony skull that houses the brain, while the spinal cavity extends from the cranial cavity to the end of the vertebral column and houses the spinal cord which is a continuation of the brain. Ventral Body Cavity – much larger than the dorsal cavity. It houses the visceral organs within the chest and abdomen. It is divided into the superior thoracic cavity that is separated from the rest of the ventral cavity by a dome shaped muscle, the diaphragm. The lungs, heart and other organs in the thoracic cavity are protected by the rib cage. The mediastinum itself houses the heart, trachea, Four Quadrants of the Abdominopelvic Region: Other Body Cavities: Oral and digestive cavities – the oral cavity contains the teeth and the tongue which continues down the cavity of the digestive organs opening to the exterior of the anus Nasal Cavity – located within and posterior to the nose, part of the respiratory system passageways Orbital Cavities – houses the eyes in the skull and present them in an anterior position Middle ear cavities – carved into the skull lie medial to the eardrums; they contain tiny bones that transmit sound vibrations to the hearing receptors in the inner ears The Nine Abdominopelvic Regions:  In general, the cells have three main regions: the nucleus, cytoplasm, and the plasma membrane. (generalized cell) Cells – are the structural units of all living things; there are about 50 to 100 trillion of Parts of the Cell: these in the human body Nucleus – the gene-containing “headquarters” of the cell (nucle = kernal). Its shape 5 People who contributed to the Cell theory: conforms to the cell. It contains three recognizable regions: the chromatin, nucleoli, Robert Hooke – In 1665, he observed plant tissue/cork under a crude microscope and nuclear envelope. and saw structures that reminded him of the long rows of monk’s rooms, hence DNA (deoxyribonucleic acid) - is much like a blueprint that contains all the instructions naming these structures cells. He coined the term ‘cellulae’. needed for building the whole body; so, as you might expect, human DNA Anton Van Leeuwenhoek – in 1663, he was a Dutch microscope maker and was the differs from frog DNA. More specifically, DNA has the instructions for building first to view living cells (organisms). He used a drop of pondwater and scrapings proteins. DNA is also necessary for cell reproduction. A cell that has lost or from his teeth to observe these cells and referred to them as ‘animalcules’. ejected its nucleus (for whatever reason) is programmed only to die. Matthias Schleiden – a German scientist/botanist. In 1838, he studied plants and projected that plants are made of cells. Nuclear Envelope – the double membrane barrier enclosing the nucleus, which Theodor Schwann – German scientist/zoologist. In 1839, after studying plant and contains a fluid- filled space or “moat” in between the two membranes. It encloses animal cells he was able to discover that animals are also made of cells. Published a jelly-like fluid called the “nucleoplasm” in which other nuclear elements are the 1st statement of the cell theory. suspended. Rudolf Virchow – German physician. Based on his investigations and research, he stated that all cells come from pre-existing cells, which is the 2nd statement of the At various points, when the nuclear membranes fuse, “nuclear pores” penetrate cell theory. through the fused region which allow substances to pass through. Nucleoli – small, dark-staining, round bodies that is the site for ribosome formation. The Cell Theory: Chromatin – a loose network of bumpy threads that are formed when DNA 1. A cell is the basic and functional unit of all living organisms. combines with protein when the cell does not divide. During instances when the 2. The activity of an organism depends on the collective activities of its cells. cell divides, the chromatin threads coil and condense to form dense, rodlike bodies 3. According to the principle of complementarity, the biochemical activities of cells called chromosomes. are dictated by the relative number of their specific subcellular structures. 4. Continuity of life has a cellular basis. The Plasma Membrane - is a fragile, transparent barrier that contains the cell contents and separates them from the surrounding environment. * The three parts were discovered between 1665 – 1838. I took 173 years to The Fluid Mosaic Model: formulate the cell theory. The structure of the plasma membrane consists of two lipid (fat) layers The cells are primarily made of carbon, oxygen, nitrogen and oxygen plus much smaller arranged tail to tail in which protein molecules float. The proteins, some of elements. Living cells are about 60% water. which are free to move, form a constantly changing pattern or mosaic, hence the Interstitial fluid – a dilute saltwater solution derived from blood that constantly bathe name of the model that describes the plasma membrane. Most of the lipid our body cells and is where exchanges between blood and cells are portion is phospholipids (some with attached sugar groups), but a substantial made. amount of cholesterol is found in plasma membranes too.  The hydrophilic heads line the inner and outer surface of the bilayer while by fine protein filaments. Thicker protein filaments extend from the the hydrophobic tails of the phospholipid molecules line the center of the plaques inside the cells to the plaques on the cells opposite sides. bilayer. The self-orienting property of the phospholipids allows biological o Gap junctions (communicating) - commonly seen in the heart and membranes to reseal themselves quickly when torn. The hydrophobic makeup between embryonic cells, function mainly to allow communication. of the membrane interior makes the plasma membrane relatively impermeable Connexons, hollow cylinders of protein, connect and span the entire width to most water-soluble molecules. The cholesterol helps keep the membrane of the abutting membranes. Chemical molecules, such as nutrients or ions, fluid. can pass directly through the water-filled connexon channels from one cell to another. The proteins attached to the bilayer have specialized functions. Some proteins are enzymes. Many of the proteins protruding from the cell exterior are The Cytoplasm - is the cellular material outside the nucleus and inside the plasma receptors for hormones or other chemical messengers or are binding sites for membrane. It is the site of most cellular activities, so you might think of the anchoring the cell to fibers or to other structures inside or outside the cell. Most cytoplasm as the factory area of the cell. It has three major elements: proteins that span the membrane are involved in transport. Some cluster Cytosol - is semitransparent fluid that suspends the other elements. together to form protein channels (tiny pores) through which water and small Organelles - are the metabolic machinery of the cell. Each type of organelle is water-soluble molecules or ions can move; others act as carriers that bind to a substance and move it through the membrane. specialized to carry out a specific function for the cell. Inclusions - are chemical substances that may or may not be present, Glycoproteins – branching sugar groups that bind to the proteins. They depending on the specific cell type. Most inclusions are stored nutrients or determine your blood type, act as receptors that certain bacteria, viruses, or cell products. (e.g. lipid droplets common in fat cells, glycogen granules toxins can bind to, and play a role in cell-to-cell recognition and interactions. abundant in liver and muscle cells, pigments such as melanin in skin and hair Because of their presence, the cell surface is a fuzzy, sticky, sugar-rich area called cells, mucus and other secretory products.) the glycocalyx. Definite changes in glycoproteins occur in cells that are transforming into cancer cells. Cytoplasmic Organelles: Membrane Junctions: Literally little organs are specialized cellular compartments each performing its own job to maintain the life of the cell. Many organelles are bounded by a membrane like Plasma Membrane specializations: the plasma membrane. These membrane boundaries allow organelles to maintain an internal environment quite different from that of the surrounding cytosol. 1. Microvilli – finger-like projections that increase surface area for absorption. 2. Membrane junctions – tight junctions, desmosomes, gap junctions Mitochondria - The outer membrane is smooth and featureless, but the inner membrane has shelf-like protrusions called cristae. Oxygen is used to break down Kinds of junctions: foods. As the foods are broken down, energy is released. Much of this energy o Tight junctions (impermeable) - adjacent plasma membranes fuse escapes as heat, but some is captured and used to form ATP molecules. ATP together tightly like a zipper to prevent fluids from leaking (e.g. in small (adenosine triphosphate) provides the energy for all cellular work, and every intestines to prevent digestive enzymes from seeping into the blood living cell requires a constant supply of ATP. stream). Ribosomes - are the actual sites of protein synthesis in the cell. They are tiny, o Desmosomes (anchoring) - are anchoring junctions scattered like rivets bilobed, dark bodies made of proteins and one variety of RNA called ribosomal along the sides of abutting cells. They prevent cells subjected to RNA. Either found floating in the cytoplasm or attached to membranes. mechanical stress (such as skin cells) from being pulled apart. Button-like Endoplasmic reticulum - is a system of fluid-filled cisterns (tubules, or canals) junctions form on the adjacent plasma membranes which are connected that coil and twist through the cytoplasm. It accounts for about half of a cell’s  membrane. It serves as a mini-circulatory system for the cell because it provides Cilia “eyelashes” - are whip-like cellular extensions that move substances along a network of channels for carrying substances (primarily proteins) from one part the cell surface. They are formed when centrioles line up beneath the plasma of the cell to another. membrane and microtubules sprout. If the projections formed by the centrioles o Rough ER - it is studded with ribosomes. It is the cell membrane’s are substantially longer, they are called flagella. factory. The proteins made on its ribosomes migrate into the Microvilli “little shaggy hairs” - are tiny, fingerlike extensions of the plasma tubules of the rough ER, where they fold into their functional membrane that project from an exposed cell surface. They tremendously increase three-dimensional shapes and then are dispatched to other areas surface area. (found lining intestinal and kidney tubule cells) of the cell in transport vesicles. (most abundant in cells that make Cell Diversity: and export proteins like pancreas cells) o Smooth ER – not involved in protein synthesis. It aids in lipid 1. Cells that connect body parts: synthesis (breakdown and synthesis of fats and cholesterol) and Fibroblast – The elongated shape of this cell lies along the cable-like fibers detoxification substances in the cells. Most abundant in liver cells that it secretes. It has an abundant rough ER and a large Golgi apparatus and cells of the male testes. to make and secrete the protein building blocks of these fibers. Golgi apparatus - appears as a stack of flattened membranous sacs, associated Erythrocyte - This cell carries oxygen in the bloodstream. Other with swarms of tiny vesicles. It is generally found close to the nucleus and is the organelles have been shed. principal traffic director for cellular proteins. Its major function is to modify and 2. Cells that covers and lines body organs: package proteins (sent to it by the rough ER via transport vesicles) in specific Epithelial cells – hexagonal in shape with abundant intermediate ways, depending on their destination. filaments to resist tearing. Lysosomes - which appear in different sizes, are membranous bags containing 3. Cells that move organs and body parts: powerful digestive enzymes. They are the cell’s demolition site rich in phagocytes, Skeletal muscle and smooth muscle cells - These cells are elongated and the cells that dispose of bacteria and cell debris. When lysosomes rupture, the cell filled with abundant contractile filaments, so they can shorten forcefully self-digests. and move the bones or change the size of internal organs. Peroxisomes - are membranous sacs containing powerful oxidase that is used to 4. Cells that store nutrients: detoxify several poisonous or harmful substances. Their most important function Fat cell - The huge spherical shape of a fat cell is produced by a large lipid is to disarm dangerous free radicals. Free radicals are unstable atoms with droplet in its cytoplasm. unpaired electrons that may scramble nucleic acids and proteins that may cause 5. Cells that fights disease: diseases. Peroxisomes are abundant in the liver and kidney cells. The Macrophage – is a phagocytic cell that has long pseudopods “fake feet” to peroxisomes convert these free radicals to hydrogen peroxide then the enzyme reach infection sites and digests the infectious microorganisms with catalase converts the excess hydrogen peroxide to water. lysosomes. Cytoskeleton - acts as a cell s bones and muscles by furnishing an internal 6. Cells that gathers information and controls body functions: framework that determines cell shape, supports other organelles, and provides Nerve cell (neuron) - This cell has long processes (extensions) for the machinery for intracellular transport and various types of cellular receiving messages and transmitting them to other structures in the body. movements. The cytoskeleton is made up of: 7. Cells of reproduction: Centrioles – direct the formation of the mitotic spindle in cell division. They are Oocytes (female) – The largest cell in the body, this egg cell contains rod-shaped bodies that lie at right angles to each other; internally they are made several copies of all organelles, for distribution to the daughter cells that up of a pinwheel array of fine microtubules and occur in pairs. arise when the fertilized egg divides to become an embryo. Cell Extensions:  Sperm cells (male) - This cell is long and streamlined, built for swimming The molecules are assisted by a membrane carrier. to the egg for fertilization. Its flagellum acts as a motile whip to propel the Diffusion through the plasma membrane: sperm. Simple diffusion – unassisted diffusion of solutes through a semi-permeable Cell Physiology membrane. Solutions - is a homogeneous mixture of two or more components. Osmosis - diffusion of water through a specific channel protein (aquaporin) or Solvent – present in the largest amount of a solution. through the lipid bilayer. Solute – components or substances present in smaller amounts. Carrier-mediated facilitated - diffusion via protein carrier specific for one chemical; binding of substrate causes shape change in transport protein. Intracellular fluid - collectively, the nucleoplasm and the cytosol, is a solution containing This carrier is for large lipid insoluble solutes. (protein carrier has a small amounts of gases (oxygen and carbon dioxide), nutrients, and salts, dissolved in specific shape for binding) water. Channel-mediated facilitated diffusion - through a channel protein; mostly ions Interstitial fluid - the fluid that continuously bathes the exterior of our cells. It contains selected on basis of size and charge. This channel is for small lipid nutrients (amino acids, sugars, fatty acids, vitamins), regulatory substances such as insoluble solutes. (straight channel) hormones and neurotransmitters, salts, and waste products. Filtration - is the process by which water and solutes are forced through a Selective permeability - means that a barrier allows some substances to pass through it membrane (or capillary wall) by fluid, or hydrostatic pressure (is usually exerted by the while excluding others. blood). It is not as selective but is still a passive process but this time involving a pressure gradient (pushes solute-containing fluid (filtrate) from the higher-pressure area to the Two types pf transport across a membrane: lower-pressure area). E.g. water and small solutes filtered out from the capillaries into Passive transport - substances are transported across the membrane without any the kidney tubules as urine. energy input from the cell. Active processes: Active transport - the cell provides the metabolic energy (ATP) that drives the transport process. Whenever a cell uses some of its ATP supply to move substances across the membrane, the process is referred to as active. They may be too large to pass through Passive processes: membrane channels, the membrane may lack special protein carriers for their transport, they may not be able to dissolve in the fat core, or they may have to move uphill against Diffusion - is an important means of passive membrane transport for every cell of their concentration gradients. the body. In this process the molecules move down their concentration gradient (higher concentrations to lower). The two most important means of active membrane transport: The hydrophobic core of the plasma membrane is a physical barrier to diffusion. Active transport – also called solute pumping, active transport uses ATP to However, molecules will diffuse through the plasma membrane if any of the following are energize its protein carriers, which are called solute pumps. They move against the true: concentration gradient which is why it requires energy since the process is no longer spontaneous. E.g. sodium-potassium pump simultaneously carries sodium ions (Na+) The molecules are small enough to pass through the membrane s pores (channels out of and potassium ions (K+) into the cell is necessary for normal transmission of formed by membrane proteins). impulses by nerve cells. (sodium out, potassium in) The molecules are lipid soluble.  Vesicular transport - which involves help from ATP, moves substances into or out Cell life cycle - is the series of changes a cell goes through from the time it is of cells without their crossing the plasma membrane. formed until it divides. 2 major periods of the cycle: Types of vesicular transport: Interphase - the cell grows and carries on its usual metabolic activities. This is also called the cell’s “metabolic phase.” Exocytosis - moves substances like hormones, mucus, or cellular wastes out of cells. The product to be released is first packaged (typically by the Golgi apparatus) into a small DNA Replication – takes place before cell division. membranous sac called a vesicle. Exocytosis involves a docking process in which DNA is composed of building blocks called nucleotides, each consisting of transmembrane proteins on the vesicles, fancifully called v-SNAREs (v for vesicle), deoxyribose sugar, a phosphate group, and a nitrogen-containing base. Essentially DNA recognize certain plasma membrane proteins, called tSNAREs (t for target), and bind with is a double helix, a ladderlike molecule that is coiled into a spiral staircase shape. them. This binding causes the membranes to corkscrew together and fuse and open a pore where the vesicle contents are released. Process of DNA Replication: Endocytosis - includes those ATP-requiring processes that take up, or engulf, DNA uncoils and separate to form two nucleotide chains that serve as a new extracellular substances by enclosing them in a small membranous vesicle. Once the template. The new strands then bond with their complementary nucleotides yielding two vesicle, or sac, is formed, it detaches from the plasma membrane and moves into the identical DNA molecules comprising an old strand and one newly assembled nucleotide cytoplasm, where it typically fuses with a lysosome and its contents are digested or in strand. (Adenine to Thymine; Cytosine to Guanine) some cases release the contents by exocytosis. Cell division – the cell reproduces itself. It consists of two events: Mitosis and Cytokinesis. Phagocytosis – or “cell eating” is when the cell membranes separate relatively large particles such as bacteria or dead body cells by forming pseudopods to Mitosis - results in the formation of two daughter nuclei with the same genes as engulf these particles. The membrane then forms a vacuole enclosing the the mother nucleus. engulfed particle which lysosomes then fuse to and digest the vacuole’s The 4 stages of Mitosis: contents. The undigested material is expelled by exocytosis. This is not a means of getting nutrients, protective only. Prophase – the chromatin threads start to coil and shorten forming chromosomes and because DNA has already been replicated the chromosomes have two sister Pinocytosis – “cell drinking” is when the plasma membrane indents to form a chromatids held together by a small button-like centromere. The centrioles tiny pit, and then its edges fuse around the droplet of extracellular fluid outside the nuclear envelope move towards the end of the cell forming the mitotic containing dissolved proteins or fats e.g. absorption in the cells lining the small spindle (made of microtubules). By the end of the prophase the nuclear envelope intestine. and the nucleoli have already broken down and the chromosomes have attached Receptor mediated endocytosis - In this process, plasma membrane receptor randomly at the fibers by their centromeres. proteins bind only with certain substances. Once the substances bind to the Metaphase - the chromosomes cluster and line up at the metaphase plate (the receptors, the membrane forms a vesicle and pinches off the membrane. Inside center of the spindle midway between the centrioles) so that a straight line of the vesicle, the receptors separate from the attached substances and the vesicles chromosomes is seen. splits. The vesicle with the empty receptors go back to the membrane to be Anaphase – the centromeres split, and the daughter chromosomes are being recycled while the vesicle containing the substances are either bound for pulled towards the ends of the opposite sides of the cell. This phase is over when digestion by the lysosomes or packaging in the golgi apparatus. the chromosomes stop moving. Cell Division:  Telophase – basically the opposite of prophase where the chromosomes uncoil Transcription - involves the transfer of information from DNA s base sequence to become threadlike chromatin again. The spindle breaks down and disappears, into the complementary base sequence of mRNA. Only DNA and mRNA are a nuclear envelope forms around each chromatin mass, and nucleoli appear in involved in transcription. Each three-base sequence specifying an amino acid on each of the daughter nuclei. the DNA gene is called a triplet, and the corresponding three-base sequences on mRNA are called codons. Cytokinesis – it begins during the late anaphase and early telophase stage. A contractile Translation - Translation occurs in the cytoplasm and involves three major ring made of microfilaments forms a cleavage furrow over the midline of the spindle, and varieties of RNA. mRNA leaves nucleus and attaches to ribosome, and translation it eventually squeezes or pinches the original cytoplasmic mass into two parts. Two begins. Incoming tRNA recognizes a complementary mRNA codon calling for its identical daughter cells are formed after cell division much smaller than the mother cell. amino acid by binding via its anticodon to the codon. As the ribosome moves along Binucleate or multinucleate cells – formed when the cytoplasm does not divide. the mRNA, a new amino acid is added to the growing protein chain. Released tRNA reenters the cytoplasmic pool, ready to be recharged with a new amino acid. Protein Synthesis: Body Tissues: Traditionally, a gene is defined as a DNA segment that carries the information for building one protein or polypeptide chain. Proteins are very important in carrying out the Tissues – group of cells that are similar in function and structure. The four bodily functions. Fibrous (structural) proteins are the major building materials for cells. primary tissue types epithelium (covering), connective tissue (support), nervous tissue Other proteins, the globular (functional) proteins, do things other than build structures. (control), and muscle (movement). tissues are organized into organs such as the heart, For example, all enzymes, biological catalysts that regulate chemical reactions in the cells, kidneys, and lungs. are functional proteins. 1. Epithelial tissue - is the lining, covering, and glandular tissue of the body. Amino acids - are the building blocks of proteins and are joined during protein synthesis. Epithelial functions include protection, absorption, filtration, and secretion. The three bases along the side of the ladderlike DNA where information is encoded. Characteristics of Epithelium: Epithelial cells fit closely together and are bound by desmosomes and DNA never leaves the nucleus in interphase cells. Thus, DNA requires not only a decoder tight junctions. but also a messenger to achieve its task of specifying the structure of proteins to be built This membrane always has an apical surface (exposed to the body’s at the ribosomes. This task is carried out by the ribosomal RNA. RNA differs from DNA in exterior or to the cavity of an internal organ). being single-stranded and in having ribose sugar instead of deoxyribose and a uracil (U) The lower surface of an epithelium rests on a basement membrane. base instead of thymine (T). Epithelial tissues are avascular and depend on diffusion from the 3 Varieties or RNA: capillaries in the underlying connective tissue for food and oxygen. If well nourished, epithelial cells regenerate themselves easily. Transfer RNA (tRNA) - small cloverleaf-shaped molecules. Ribosomal RNA (rRNA) - helps form the ribosomes, where proteins are Classification of Epithelium: built. Simple Epithelia – one layer of cells most concerned with absorption, Messenger RNA (mRNA) - are long, single nucleotide strands that secretion, and filtration. resemble half of a DNA molecule and carry the message containing o Simple squamous epithelium - a single layer of thin squamous instructions for protein synthesis from the DNA gene in the nucleus to the cells resting on a basement membrane. (in air sacs of the lungs ribosomes in the cytoplasm. and serous membranes) Two major phases of protein synthesis: o Simple cuboidal epithelium - one layer of cuboidal cells resting on a basement membrane, is common in glands and their ducts (for  example, the salivary glands and pancreas, kidney tubules, wall of Characteristics of Connective tissues: ovaries). Most connective tissues are well-vascularized. but there are exceptions. o Simple columnar epithelium – made of a single layer of tall cells Tendons and ligaments have a poor blood supply, and cartilages are that fit closely together. Goblet cells, which produce a lubricating avascular. Consequently, all these structures heal very slowly when mucus, are often seen in this type of epithelium. (lining of the injured. digestive tract) Connective tissues are made up of many different types of cells plus o Pseudostratified columnar epithelium – all the cells rest on a varying amounts of a nonliving substance found outside the cells, called basement membrane however; the cells are of different heights the extracellular matrix. giving of a false stratified effect (for absorption and secretion). A Extracellular matrix - is produced by the connective tissue cells and then ciliated variety (more precisely called pseudostratified ciliated secreted to their exterior, has two main elements, a structureless ground columnar epithelium) lines most of the respiratory tract. (goblet substance and fibers. cells produce mucus, mucus is propelled by the cilia outwards) Stratified Epithelia – more than a single layer of cells more durable than The ground substance of the matrix is composed largely of water plus some the simple epithelia, these epithelia function primarily to protect. adhesion proteins (serve as a glue) and large, charged polysaccharide o Stratified squamous epithelium – the cells at the free edge are molecules. Because of its extracellular matrix, connective tissue can form a squamous while the ones at the base are cuboidal or columnar. soft packing tissue around other organs, to bear weight, and to withstand They deal with friction (esophagus, the mouth, and the outer stretching and other abuses, such as abrasion, that no other tissue could portion of the skin) endure. o Stratified cuboidal epithelium - typically has just two cell layers with (at least) the surface cells being cuboidal in shape. (found in Classification of Connective tissues: ducts of large glands that are limited in secreting) Bone - sometimes called osseous tissue, is composed of osteocytes (bone o Stratified columnar epithelium - are columnar cells, but its basal cells) sitting in cavities called lacunae and surrounded by layers of a very cells vary in size and shape. (found in ducts of large glands that hard matrix that contains calcium salts in addition to large numbers of are limited in secreting) collagen fibers. o Transitional Epithelium - is a highly modified, stratified squamous Cartilage - is less hard and more flexible than bone. Its major cell type is epithelium that forms the lining of only a few organs the urinary chondrocytes (cartilage cells). It is found in only a few places in the body. bladder, the ureters, and part of the urethra. (hyaline cartilage - has abundant collagen fibers hidden by a rubbery Glandular Epithelia - A gland consists of one or more cells that make and matrix with a glassy blue white appearance) secrete a product. This product, called a secretion (an active process), Fibrocartilage - forms the cushion-like disks between the vertebrae of the typically contains protein molecules in an aqueous (water-based) fluid. spinal column o Endocrine glands – ductless glands and have no connection to the Elastic cartilage - is found in structures with elasticity. surface. Their secretions (all hormones) diffuse directly into the Dense connective tissues - also called dense fibrous tissue, has collagen blood vessels that weave through the glands. fibers as its main matrix element with rows of fibroblasts in between. o Exocrine glands - retain their ducts, and their secretions empty They form tendons (attach skeletal muscles to bones) and ligaments through the ducts to the epithelial surface. (sweat and oil glands, (attach bones to bones at joints). liver, pancreas) Loose connective tissues - are softer and have more cells and fewer fibers 2. Connective tissue – connect body parts. They are primarily involved in protecting, than any other connective tissue type except blood. supporting, and binding together other body tissues.  Areolar tissue - most widely distributed connective tissue variety in the Series of events in tissue repair: body, is a soft, pliable, cobwebby tissue that cushions and protects the body organs it wraps with wandering phagocytes. The universal packing Inflammation sets the stage. The fluid rich in clotting proteins and other tissue and connective tissue glue. Can form an edema (fluid retention or substances to seep into the injured area from the bloodstream forming a clot swelling) This is the lamina propria underlying the mucosa. (when exposed to air forms a scab faster) to prevent blood loss. Adipose tissue – “signet ring cells” is an areolar tissue in which adipose Granulation tissue forms. Granulation tissue is a delicate pink tissue (fat) cells predominate. Found in the subcutaneous layer of our skin and composed largely of new capillaries that grow into the damaged area from serve as an insulator and cushion for the body. undamaged blood vessels. The phagocytes dispose of the blood clot and Reticular connective tissue - consists of a delicate network of interwoven connective tissues to produce collagen to form the scab. reticular fibers associated with reticular cells, which resemble fibroblasts. Granuloma – overgrowth of granulation tissue. (forms the stroma which supports many free blood cells) Regeneration and fibrosis effect permanent repair. The epithelium starts to Blood - or vascular tissue, is considered a connective tissue because it regenerate underneath the scab and when finished the scab detaches consists of blood cells surrounded by a nonliving, fluid matrix called blood revealing the new epithelium with an underlying area of fibrosis (scar). plasma. Keloid – overgrowth of the tissue. The body does not recognize that the skin 3. Muscle tissue - are highly specialized to contract, or shorten, to produce is already healed. movement. Chalone – a glycoprotein released by the actively dividing cells that inhibit Skeletal muscles - tissue is packaged by connective tissue sheets into mitosis. organs called skeletal muscles, which are attached to the skeleton. They Neoplasms – “new growth” or tumor. It is an abnormal mass of proliferating cells. are voluntary muscles. Cardiac muscle – found only in the heart. These are involuntary muscles. Benign – cells are not cancerous or won’t spread Smooth muscle – has no striations unlike the two. Found in the walls of Malignant – non-encapsulated, cancerous and can spread via blood hollow organs such as the stomach, uterus, and blood vessels. Peristalsis “Metastasis” – spread a wavelike motion that keeps food moving through the small intestine, is Direct extension – it grows on neighboring cells typical of its activity. Hematologic- spread via blood 4. Nervous tissue - we think of cells called neurons which are responsible for Lymphatic spread – via the lymph irritability and conductivity. The neuron’s cytoplasm is drawn into long processes Transplantation – cell from a tumor is planted somewhere else (extensions), that allow a single neuron to conduct an impulse over long distances in the body. A special group of supporting cells called neuroglia insulate, support, Hyperplasia - increase in cell number and protect the delicate neurons in the structures of the nervous system the brain, Hypertrophy – increase in cell size spinal cord, and nerves. Atrophy – decrease in size of organ due to lack of stimulation or use Tissue Repair (Wound Healing) Regeneration - replacement of destroyed tissue by the same kind of cells. Fibrosis - involves repair by dense (fibrous) connective tissue, that is, by the formation of scar tissue. (depending on the type of tissue damaged and severity of the damage) * clean cuts (incisions) heal much more successfully than ragged tears of the tissue.  Serous fluid – function is lubrication; if there is no fluid in the space rupturing Which are also referred to as tissue membranes, is a thin layer or sheet of cells may occur (proteins and water) that cover the outside of our body (skin), organs (pericardium), internal Two layers: Parietal – wall outside the organ; Visceral – touching the organ passageways that open to the exterior of the body (mucosa of stomach), and the ▪ Pericardium – serous membrane lining the heart (fluid is lining of the moveable joint cavities. pericardial fluid) ▪ Peritoneum – serous membrane lining the digestive tract (fluid is The body membranes are broken down into two major groups, namely: peritoneal fluid) ▪ Pleura – serous membrane surrounding the lungs (fluid is pleural Epithelial membranes and Connective tissue membranes fluid) Epithelial cells – make up the lining of many tissues in the body, when packed tightly create a barrier that protects us from the pathogens found externally; they also allow Parietal Pleura is attached to the rib cage while the visceral pleura is attached to sweating to keep our body cool; are also flexible the lung itself. Connective tissue membranes – represented by the synovial membranes that are Epithelial membranes – are comprised of both epithelial tissue and connective composed of areolar connective tissue and contain no epithelial tissue at all; they tissue, they are also called covering and lining membranes, it includes the line the fibrous capsules surrounding the joints; layers of membrane form a cutaneous, mucous, and serous membranes; they encapsulate organs, such as the synovial sac containing the synovial fluid designed to lubricate the joints allowing kidneys. They are always exposed to air and is a dry membrane. free movement. Cutaneous membrane – this is our skin; is composed of a keratinizing The Integumentary System: stratified squamous epithelium which has an underlying dermis (the second Functions: Protection, Insulation, Excretion, Vitamin D Synthesis, Sensation layer of skin which is the most impenetrable since it is comprised of elastic and fibrous connective tissue); differs from other membranes because it is Protection – preventing the entrance of harmful foreign material into the body exposed to air and is a dry membrane Insulation/Heat regulation – maintaining body temperature (protective function); the keratin prevents water loss because when water evaporates it Mucous membrane – wet membrane; composed of epithelium (notably tough brings with it heat (in sweat) to withstand tearing) resting on a loose connective tissue membrane called a Cushion – protects the body from bumps leading to mechanical injury lamina propria (a thin vascular layer of connective tissue beneath the (protective function) epithelium of a mucous membrane), found usually surrounding body organs and body orifices (respiratory, digestive, urinary, and reproductive tracts); Excretion – it excretes salts like sodium chloride, urea via the sweat differs from the cutaneous membrane as it is always moist and is often Vitamin D Synthesis – manufactured in the skin through the cholesterol found in adapted for secretion or absorption the skin by the action of sunlight Epithelium that may secrete mucus: stratified squamous epithelium, simple columnar Sensation – our ability to feel changes outside epithelium Types of damage: Serous membranes – also called serosa, composed of a layer of simple squamous epithelium resting on a thin layer of areolar connective tissue, in Mechanical damage – cuts and bumps contrast with the mucous membrane, serous membranes line cavities closed to the exterior (except the dorsal cavity and joint cavities) Chemical damage – from harmful chemicals like acids and bases  Bacterial damage – from harmful bacteria ✓ Stratum corneum – outermost layer of the epidermis consisting of 20 to 30 dead layers of keratinocytes that are constantly being shed are referred to as corni fed UV Radiation – harmful effects of the sun or horny cells; the stratum corneum rubs and flakes off like the dandruff as Thermal damage – heat or cold familiar with everyone (average person sheds about 18 kg/40 lbs in a lifetime); young adults take 4-6 weeks(25 to 45 days) to finish cell turnover from the basal Desiccation – drying out layer to the stratum corneum while it takes a month and a half for older adults to Structure of the Skin: finish it ✓ Outer epidermis – made up of stratified squamous epithelium that is capable of o Keratinocytes represent the major cell type of the epidermis, the keratinizing or becoming hard and tough; it is avascular (no blood supply of its outermost of the layers of the skin, making up about 90 percent of the cells own, which is why whenever we shave, we never bleed); sensory receptors are there. They originate in the deepest layer of the epidermis, the stratum here basale and move up to the final barrier layer of the skin, the stratum o Epidermal dendritic cells - which are important in alerting and activating corneum immune system cells to a threat such as bacterial or viral invasion. o Melanin – accumulation of melanin make membrane bound granules (Immune cells) called melanosomes; These granules then move to the ends of the melanocyte’s spidery arms, where they are taken up by nearby keratinocytes. Inside the keratinocytes, the melanin forms a pigment Layers of the epidermis: umbrella over the superficial, or sunny, side of their nuclei and shields ✓ Stratum basale (bah-sah-leh) – contains column shaped basal cells that constantly their genetic material (DNA) from the damaging effects of ultraviolet divide and are pushed to the surface (stratum germinativum – germinating radiation in sunlight. Freckles and moles are seen where melanin is layer); it is also home to melanocytes that produce melanin (pigment responsible concentrated in one spot for skin color, production is increased when expose to sunlight to protect the skin Homeostatic Imbalance: from harmful UV rays); most adequately nourished as it is the first layer after the dermis ✓ Overexposure to the sun may alter the DNA of skin cells; it also results to a leathery skin; people with the herpes simplex virus or cold sore (having blisters o Freckles and moles – areas of our skin with high concentration of melanin around the mouth and lips even in the neck) are likely to have an eruption due to overexposure ✓ Stratum spinosum – composed of basal cells that have matured into squamous cells called keratinocytes, which are responsible for producing protein, a ✓ Dermis – also referred to as the “hide” the strong stretchy envelope that binds the protective protein that make up skin, nails, and hair. This is where keratinization body together; leather bags and goods are treated animal hides; the dense fibrous begins. connective tissues making up the dermis are classified into two: ✓ Stratum granulosum – made up of keratinocytes that have moved up from the squamous cells; as these cells move out, they flatten and stick together, eventually o Papillary layer – is the upper dermal region or the outer layer of the drying and dying out dermis; It is uneven and has peglike projections from its superior surface, ✓ Stratum lucidum – is not present in all skin regions, occurs only where the skin is called dermal papillae (papill = nipple), which indent the epidermis hairless and thick (on the palms of the hands, soles of the feet); located between above. The dermal papilla is responsible for the fingerprints because of its the stratum granulosum and stratum corneum peg-like projections and have a furrow between projections forming the  fingerprint. Function is to help in gripping because of its rough texture in Herpes Simplex – or cold sores, caused by a virus and appears when there is a decrease the surface, increases stability in gripping and prevent slipping. in the immune system function Herpes simplex labialis (lips) – Type I; is transferrable to the inguinal o Nociceptors – a sensory receptor for pain. o Meissner’s corpuscle – for touch (mechanoreceptor); rapidly adapting; Herpes simplex inguinalis (pubic) – Type II; is transferrable to the labia. respond to low frequency vibrations (found in the dermal papillae) o Thermoreceptors – detect changes in temperature ✓ A long period of blood restriction to the skin causes cell death; decubitus ulcers o Merkel cells - which are associated with sensory nerve endings and serve (pressure sores or bed sores) are injuries to skin and underlying tissue resulting as touch receptors called Merkel discs. (slow); respond to light touch. from prolonged pressure on the skin. Bedsores most often develop on skin that (found in the stratum basale) covers bony areas of the body, such as the heels, ankles, hips and tailbone. o Pacinian corpuscles – deep pressure receptors; also called lamellar Three pigments that contribute to skin color: corpuscle (found in the reticular layer) o Ruffini’s corpuscles – mechanoreceptor in the subcutaneous layer; ✓ The amount and kind (yellow, reddish brown, or black) of melanin in the regulate the sensation of stretched skin, hand and finger positioning, epidermis. and motion detection. o Melanin is produced by melanocytes. Eumelanin (black-brown). Pheomelanin (reddish yellow). Melanin makes you dark. o Reticular layer – deepest layer of the skin where the pressure receptors ✓ The amount of carotene deposited in the stratum corneum and subcutaneous are located (Pacinian corpuscles); contains irregularly arranged tissue. (Carotene is an orange-yellow pigment plentiful in carrots and other connective tissue fibers, as well as blood vessels, sweat and oil glands, and orange, deep yellow, or leafy green vegetables.) deep pressure receptors called lamellar corpuscles (the most obvious ✓ The amount of oxygen-rich hemoglobin (pigment in red blood cells) in the dermal sensory receptor as they form large onion like structures in the dermis blood vessels that give a reddish skin color (blush). and hypodermis; composed of flattened cells, collagen fibers and a lymph- ✓ Emotions can affect the color of the skin. like fluid); Phagocytes found here (and, in fact, throughout the dermis) act to prevent bacteria that have managed to get through the epidermis Cyanosis – occurs evidently in Caucasian people when the hemoglobin is from penetrating any deeper into the body. Collagen is for toughness of poorly oxygenated (cut off blood supply) causing the skin to appear blue; the dermis, a decrease in collagen synthesis makes the skin elastic common during heart failure and severe breathing difficulties; checked in (sagging). fair skinned people by pressing the nail beds to test circulation of blood (capillary check); in black people, cyanosis is apparent in their nail beds o Ehlers-Danlos syndrome – a defect in collagen production; skin becomes or the conjunctiva of the eyes or underneath their tongue very elastic and also affect the joints; there will be hypermobility of the Emotions may also alter skin color: skin meaning it stretches a lot. ✓ Redness or erythema – any abnormal redness of the skin caused by the dilation o Dermatosparaxis – when the skin is hyperelastic making the skin fragile. of the capillaries due to augmented flow of blood; blushing is a transient form of erythema; it may also indicate fever, blushing, irritation, or allergies; whenever o The subcutaneous layer – the adipose layer or hypodermis (not a part of we are put in a “fight or flight” situation, our body releases adrenaline which the skin) that act as shock absorber and acts as a padding for the body. makes our heart beat faster to supply more blood causing the capillaries to dilate Stores excess fat and act as a cushion to protect the body from injury. ✓ Pallor or blanching – under certain types of emotional stress people become pale, pale skin may also signify anemia, low blood pressure, or impaired blood flow into  the area; turning pale occurs in the face because blood is being sent out to areas sac when not yet infected, when infected the sac attaches to the where blood is needed the most during fight or flight situation surrounding tissues making it difficult to remove entirely (infected sac – higher chance of recurrence) ✓ Jaundice/yellow cast – signifies a disorder in the liver where there is an absorption of excess bile in the blood, circulated throughout the body, and Sweat glands – also called sudoriferous glands, are widely distributed all over deposited in body tissues (too much bilirubin which the liver uses to create bile); the body (more than 2.5 million per person); sweat glands are classified into bilirubins are taken from destroyed red blood cells in the spleen (may indicate eccrine and apocrine Hepatitis) Eccrine glands - are far more numerous and found all over the body, these glands produce sweat (water, salts, vitamin C, traces ✓ Bruises or black and blue marks– occurs when the capillaries near the skins of metabolic waste like urea, uric acid, ammonia, and lactic acid). surface are broken (due to impact or a hard blow) and blood starts to leak it Apocrine glands – are confined to the axillary (armpit) and genital begins to cause a discoloration on the skin (red-dark blue-purple-yellow/green) areas of our body; are usually larger than eccrine glands, and their e.g. Hematoma – bruising; hema – blood; oma – suffix for tumors (appears bluish ducts empty into hair follicles. Their secretion contains fatty acids black) and proteins, as well as all the substances present in eccrine secretion; consequently, it may have a milky or yellowish color. Skin appendages – include cutaneous glands, hair and hair follicles, and nails which all The secretion is odorless, but when bacteria that live on the skin play a unique role in maintaining homeostasis use its proteins and fats as a source of nutrients for their growth, Cutaneous glands – are exocrine glands (glands that secrete their products it takes on a musky, unpleasant odor. The intensity of the odor through a duct onto an epithelial surface rather than directly into the depends on the person (example: diet) bloodstream); these glands are broken down into two groups: both types reside o Deodorant – kills the bacteria that causes the odor almost entirely in the dermis o Antiperspirant – prevents the sweat glands from producing sweat Sebaceous glands – also called oil glands, are found all over the skin except in Hair and hair follicles: our palms and the sole of the feet because they are hairless regions; they produce sebum (seb = oil) to help lubricate our skin and prevent the hair Hair follicles –are compound structures composed of the inner epidermal sheath from becoming brittle; is most active when there is a high production and an outer dermal sheath (a connective tissue); This dermal region supplies of the male sex hormones (androgens) in both sexes during adolescence (so blood vessels to the epidermal portion and reinforces it. Its nipplelike papilla this is basically the oiliest phase of our lives) provides the blood supply to the matrix in the hair bulb. o Whitehead - sebaceous gland duct is blocked by sebum, causing an Hair shaft – hair seen above your scalp. accumulation of sebum and a protrusion Matrix – growth zone of the hair. o Blackhead - if the accumulated material oxidizes and dries, it darkens Root – part of the hair enclosed in the follicle. o Acne - is an active infection of the sebaceous glands accompanied by Hair Shaft - is the part of your hair that can be seen above your scalp. It is made of pimples on the skin a protein called keratin, compacted and fused together. o Seborrhea - known as cradle cap in infants, is caused by overactivity Hair bulb - is situated at the base of each hair follicle and c