Anatomy and Physiology Guide PDF

1: Atlas A Major Themes of Anatomy and Physiology The Scope of Anatomy and Physiology 1. Define Anatomy. Anatomy is the study of the structure of the body. 2. Examples of Different Ways of Studying Human Anatomy: Dissection Imaging techniques (...

1: Atlas A Major Themes of Anatomy and Physiology The Scope of Anatomy and Physiology 1. Define Anatomy. Anatomy is the study of the structure of the body. 2. Examples of Different Ways of Studying Human Anatomy: Dissection Imaging techniques (MRI, CT scans) Comparative anatomy 3. Gross Anatomy: Involves structures that can be seen with the naked eye. 4. Histology: The study of tissues. 5. Cytology: The study of cells. 6. Define Physiology. Physiology is the study of the function of the body. 7. Subdisciplines of Physiology: Study specific systems (e.g., cardiovascular physiology) or processes in general. Scientific Method 1. Inductive Method: Making generalizations based on observations. Primarily used for anatomy. 2. Hypothetico-Deductive Method: Formulating hypotheses and conducting experiments to test them. Primarily used for physiology. 3. Key Terms: Hypothesis: A testable prediction. Sample size: Number of subjects in a study. Controls: Groups used for comparison in experiments. Placebo: A substance with no therapeutic effect used as a control.  Peer review: Evaluation of work by others in the same field. Double-blind studies: Neither participants nor experimenters know who is receiving a particular treatment. Fact: An objective and verifiable observation. Law: A statement based on repeated experimental observations. Theory: A well-substantiated explanation of some aspect of the natural world. Human Structure 1. Hierarchy of Complexity: Atoms → Molecules → Organelles → Cells → Tissues → Organs → Organ systems → Organism. 2. Definitions: Organism: An individual living being. Organ system: A group of organs that work together to perform a specific function. Organ: A structure composed of two or more tissue types that work together to perform a specific function. Tissue: A group of similar cells that perform a specific function. Cell: The basic unit of life. Organelles: Structures within a cell that perform specific functions. Molecules: Groups of atoms bonded together. Atoms: The smallest units of matter. Human Function 1. Properties of Life: Organization, cellular composition, metabolism, responsiveness, movement, homeostasis, development, reproduction, and evolution. 2. Living Things: Exhibit a higher level of organization than the nonliving world. Composed of cells. 3. Metabolism: Sum of all chemical reactions in the body. Anabolism: Building up complex molecules.  Catabolism: Breaking down complex molecules. 4. Responsiveness: The ability to sense and react to stimuli. 5. Movement: Most organisms can move from place to place or move materials internally. 6. Homeostasis: The ability to maintain stable internal conditions. 7. Development: Differentiation: Transformation of generalized cells into cells with specialized tasks. Growth: Increase in size. 8. Reproduction: Producing copies of themselves and passing on genes. 9. Evolution: Genetic change from generation to generation. 10. Homeostasis Mechanisms: Accomplished by negative feedback mechanisms. 11. Components of Homeostasis: Stimulus: A change in the environment. Receptor: Detects the change. Control center: Processes the information and sends instructions. Effector: Carries out the instructions to restore balance. 12. Loss of Homeostatic Control: Can lead to disease or death. 13. Dynamic Equilibrium: Internal conditions fluctuate within a range around a set point. 14. Negative Feedback: A mechanism that reverses a deviation from the set point. 15. Examples of Negative Feedback: Thermostat controlling room temperature.  Body temperature regulation (vasodilation and sweating when hot; vasoconstriction and shivering when cold). 16. Blood Pressure Regulation: Stimulus: Low blood pressure. Receptor: Baroreceptors. Control center: Cardiac center in the brain stem. Effector: Heart. 17. Positive Feedback: A self-amplifying cycle. Leads to an even greater change in the same direction. 18. Examples of Positive Feedback: Childbirth, blood clotting. 19. Harmful Positive Feedback: Fever causing a metabolic rate increase, leading to a further increase in body temperature. Matter and Energy 1. Flow of Matter and Energy: Tend to flow down gradients. 2. Physiological Gradient: Differences in variables like concentration, pressure, temperature. 3. Movement Down the Gradient: From high value to low value. 4. Movement Up the Gradient: From low value to high value, requiring energy. 5. Blood Flow: Moves from high pressure to low pressure (down the gradient). The Language of Medicine 1. Precision in Terminology: Critical for accurate communication in medical contexts. Atlas A: General Orientation to Human Anatomy  1. General Anatomical Terminology: Anatomical position: Standard reference position. Body planes: Sagittal, frontal, transverse. Directional terms: Ventral/dorsal, anterior/posterior, cephalic/caudal, superior/inferior, medial/lateral, proximal/distal, superficial/deep. 2. Major Body Regions: Axial region: Head, neck, trunk. Appendicular region: Limbs. Abdominal quadrants and regions: Used for clinical assessments. 3. Body Cavities and Membranes: Cranial cavity: Contains the brain. Vertebral canal: Contains the spinal cord. Thoracic cavity: Contains the heart and lungs. Abdominopelvic cavity: Contains digestive organs, spleen, kidneys, etc. Mediastinum: Central compartment of the thoracic cavity. Pericardium: Membrane around the heart. Pleurae: Membranes around the lungs. Peritoneum: Membrane lining the abdominal cavity. 2: The Chemistry of Life Introduction to Chemistry and the Atom 1. A chemical element is the simplest form of matter to have unique chemical properties. 2. There are 92 naturally occurring elements. 3. Six elements account for 98.5% of the body’s weight. What are these 6? Oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. 4. Minerals are inorganic elements extracted from soil and passed up the food chain to humans. Most are calcium and phosphorous, and the rest is made up of chlorine, magnesium, potassium, sodium, and sulfur. 5. Electrolytes are mineral salts needed for nerve and muscle function. 6. The nucleus of an atom is composed of protons and neutrons. 7. Protons have a positive electrical charge, whereas neutrons have no charge.  8. The atomic number of an element is the number of protons in the nucleus. 9. The atomic mass of an element is the total of its protons and neutrons. 10. An element can have atoms with different numbers of neutrons. These are called isotopes. So they have the same atomic number but different mass numbers. 11. Isotopes that are unstable and disintegrate, giving off energy, are called radioisotopes. 12. Electrons surround the nucleus in electron shells or energy levels. The electrons in the outermost shell are called valence electrons. 13. Electrons have a negative electrical charge. 14. The atomic mass of electrons is negligible and therefore not considered in an element’s atomic mass. 15. The number of electrons is equal to the number of protons, so an atom is electrically neutral. 16. Shells hold a limited number of electrons; the one closest to the nucleus contains a maximum of 2, the next a maximum of 8, and the third a maximum of 18. 17. If an atom gains or loses electrons, it is called an ion. 18. An anion has a negative charge since it has gained an electron(s). 19. A cation has a positive charge since it has lost an electron(s). 20. What is ionization? The process by which an atom or molecule gains or loses electrons to form ions. 21. In sodium chloride, NaCl, sodium has one electron in its outer shell, which it gives up. Chlorine has seven electrons in its outer shell, and gaining an electron from sodium fills its outer shell. 22. Molecules may also be ions; for example, phosphate (PO43–) and bicarbonate (HCO3–). 23. Physiologically, ions with opposite charges tend to follow each other through the body. When sodium is excreted in the urine, chlorine tends to follow it. 24. Electrolytes are salts that ionize in water, forming solutions that can conduct electricity. 25. Why are electrolytes important? They are essential for nerve and muscle function, hydration, blood pH, and repairing damaged tissues. 26. What is the definition of a molecule? A group of two or more atoms held together by chemical bonds. 27. What is the definition of a compound? A substance made up of two or more different elements that are chemically bonded together. Chemical Bonds  1. The valence electrons determine the chemical properties and reactivity of an element. 2. An atom tends to bond with other atoms that will fill its outer shell and produce a stable number of valence electrons. This is the octet rule. 3. Chemical bonds hold atoms or molecules together. Can you list the three types? Ionic bonds, covalent bonds, and hydrogen bonds. 4. An ionic bond is the attraction of a cation to an anion, as in NaCl. 5. What happens to the bond of NaCl when it is placed in water? The ionic bond dissociates, and the Na+ and Cl- ions are surrounded by water molecules. 6. A covalent bond forms by the sharing of electrons between two atoms. 7. When shared electrons spend approximately equal time around each nucleus, the result is a nonpolar covalent bond. 8. When shared electrons spend more time around one nucleus, they form a polar covalent bond that results in a small charge difference between different regions of the molecule. This is represented as δ– and δ+. 9. What type - polar molecules or nonpolar molecules - will mix easily with water? Polar molecules. 10. A hydrogen bond is a weak attraction between a slightly positive hydrogen atom in one molecule and a slightly negative oxygen or nitrogen atom in another. 11. Water molecules form hydrogen bonds with each other. Hydrogen bonds may form between different regions of a single large molecule. Can you give an example of this? Proteins or DNA. 12. The weakest bond is the hydrogen bond, then ionic, then polar covalent, then nonpolar covalent bonds are the strongest. Water, Mixtures, and Chemical Reactions 1. Most mixtures in the body consist of chemicals dissolved in water. 2. Water molecules are polar and form hydrogen bonds. 3. This polarity gives water properties that account for its ability to support life: solvency, cohesion, adhesion, chemical reactivity, and thermal stability. 4. Why is water sometimes called the universal solvent? Because it can dissolve a wide variety of substances due to its polarity. 5. Substances that dissolve in water, such as sugar, are said to be hydrophilic. 6. Substances that do not dissolve in water, such as fats, are said to be hydrophobic. 7. To be soluble in water, a molecule must be polar molecules or ionic compounds. 8. When sodium chloride is dissolved in water, water molecules form a hydration sphere around each ion. 9. What is the difference between adhesion and cohesion? Adhesion is the tendency of water molecules to stick to other substances, while cohesion is the tendency of water molecules to stick to each other. 10. Water participates in many chemical reactions because of its ability to ionize other chemicals and also because of its ability to become ionized itself. 11. Two types of chemical reactions that water is involved in are hydrolysis (where large molecules are broken down into smaller ones) and dehydration synthesis (where two simple molecules are joined together to form a larger molecule). 12. Water has a high heat capacity, what does this mean? It can absorb a lot of heat without a significant increase in temperature. 13. Water’s high heat capacity gives it thermal stability, what does this help the body with? It helps the body maintain a stable internal temperature. 14. Water is also an effective coolant because it carries away so much heat energy when it evaporates. 15. There are 3 basic types of mixtures: solutions, colloids, and suspensions. 16. A solution consists of particles of matter called a solute mixed with a more abundant substance, usually water, called a solvent. If a solution is 40% protein, what % is the solute and what % is the solvent? 40% solute and 60% solvent. 17. In solutions, solute particles do not scatter light and are usually small enough to pass through a cell membrane. Can you give an example? Saltwater. 18. Colloid particles are larger and so scatter light (makes the mixture cloudy) and usually are too large to pass through a cell membrane. 19. Which mixture - colloids or suspensions - do the particles settle out? Suspensions. 20. An acid is any proton donor, that is, a molecule that releases H+ in water. A base is a proton acceptor. 21. Acidity is expressed in terms of pH. 22. The pH scale is logarithmic, so that a change of one whole number on the scale represents a 10- fold change in H+ concentration. 23. What is a buffer? A substance that resists changes in pH by neutralizing added acids or bases. 24. Define energy. The capacity to do work. 25. What is potential energy? Stored energy. 26. What is kinetic energy? The energy of motion.  27. What type of energy is chemical energy? Potential energy. 28. What about heat? Kinetic energy. 29. In human physiology, the most relevant free energy is stored in chemical bonds. 30. The course of a chemical reaction is symbolized by a chemical equation, with reactants on the left side and products on the right side. 31. What happens in a decomposition reaction and can you give some examples? A larger molecule is broken down into smaller ones, such as the breakdown of glycogen to glucose. 32. What happens in a synthesis reaction and can you give some examples? Smaller molecules combine to form a larger one, such as the formation of proteins from amino acids. 33. The rate of a reaction increases when what happens? (give three factors that increase the rate) Higher temperature, increased concentration of reactants, and the presence of a catalyst. 34. What is a catalyst? A substance that increases the rate of a chemical reaction without being consumed in the process. 35. All the chemical reactions that take place in the body are collectively termed metabolism, this can be broken down into catabolism and anabolism. Organic Compounds: Carbohydrates and Lipids 1. Organic chemistry is the study of compounds containing carbon. 2. Carbon atoms readily combine with each other to form carbon backbones in the form of long chains, branched molecules, and rings. Some organic molecules are gigantic macromolecules with large molecular weights. 3. What are the four groups of organic molecules? Carbohydrates, lipids, proteins, and nucleic acids. 4. What is a polymer? A large molecule made up of repeating subunits called monomers. What is a monomer? A small, repeating unit that serves as the building block of a polymer. 5. In dehydration synthesis, two monomers are joined together by a covalent bond to make a dimer. A hydroxyl (–OH) group is removed from one monomer and a hydrogen (–H) from another, producing water as a by-product. 6. The opposite of dehydration synthesis is hydrolysis. During hydrolysis, water is added to break the covalent bonds between monomers. 7. The primary function of carbohydrates is to provide energy. 8. What are the three "sizes" of carbohydrate molecules? Monosaccharides, disaccharides, and polysaccharides. 9. What are the three monosaccharides? Glucose, fructose, and galactose.  10. Which monosaccharide is "blood sugar"? Glucose. 11. Disaccharides are sugars composed of how many monosaccharides? Two. List the three disaccharides. Sucrose, lactose, and maltose. 12. Polysaccharides are used for energy storage. What is the polysaccharide used by humans? Glycogen. 13. Where are the two places that glycogen is stored? Liver and muscles. 14. Starch is the energy-storage polysaccharide made by plants. 15. Carbohydrates are a source of energy, but they can be used to form structural components such as glycolipids and glycoproteins on cell membranes. 16. Carbohydrates mix (can dissolve) with water so they are called hydrophilic. 17. Lipids are hydrophobic. 18. What type of covalent bond do they have more of compared to carbs or proteins? Nonpolar covalent bonds. 19. What does a triglyceride (neutral fat) molecule consist of? One glycerol molecule and three fatty acids. Each bond is formed by what type of process? Dehydration synthesis. 20. The three functions of fat are insulation, padding (shock absorption), and energy storage. 21. Describe the structure of phospholipids. Phospholipids consist of two fatty acids, a glycerol molecule, and a phosphate group. 22. Which parts are hydrophobic and which parts are hydrophilic? The fatty acid tails are hydrophobic, and the phosphate head is hydrophilic. 23. What is the most important function of phospholipids? They form the cell membrane. 24. How are phospholipids arranged in a cell membrane? Tail-to-tail. 25. Cholesterol is the “parent” steroid from which all other steroids are synthesized, including some hormones (cortisol, progesterone, estrogens, testosterone) and bile acids. Organic Compounds: Proteins and Nucleic Acids 1. A protein is a polymer of amino acids. 2. There are 20 amino acids involved in proteins of the human body. 3. What specific name is given to the bond between amino acids? Peptide bond. 4. Proteins have complex coiled and folded structures (called their conformation) that is critical to their function. Many proteins use conformation changes as part of their function. Extreme conformational changes, however, can destroy function. This is called denaturation. 5. Two situations that can destroy function (denaturation) is extreme heat or pH changes. 6. Proteins have up to four levels of complexity, what are those four levels? How would you describe each level? Primary structure: The sequence of amino acids in a polypeptide chain. Secondary structure: The folding or coiling of the polypeptide chain into alpha-helices and beta-pleated sheets. Tertiary structure: The overall three-dimensional shape of a polypeptide. Quaternary structure: The arrangement of multiple polypeptide chains into a functional protein. 7. What level of complexity/structure do globular proteins and fibrous proteins have? Can you give examples of each? Globular proteins: Tertiary or quaternary structure (e.g., hemoglobin, enzymes). Fibrous proteins: Secondary structure (e.g., collagen, keratin). 8. What is the difference between globular proteins and fibrous proteins? Globular proteins are compact and spherical, while fibrous proteins are elongated and strand-like. 9. What level of structure is displayed in hemoglobin? Quaternary structure. 10. Proteins can change conformation reversibly, and this property is important to processes such as muscle contraction and enzyme function. 11. Proteins have a variety of functions in the body. Give some examples of different functions for proteins. Enzymes, antibodies, transport proteins, structural proteins, hormones. 12. What are enzymes? Proteins that act as biological catalysts. What does "biological catalyst" mean? A substance that speeds up a chemical reaction without being consumed. 13. Enzymes lower the activation energy of reactions. 14. Can you describe the process of an enzyme binding to a substrate? What is happening and what it forms? The enzyme binds to the substrate at the active site, forming an enzyme-substrate complex, which then converts the substrate into products. Do enzymes have the ability to bind to any random substrate or are they selective? They are selective. 15. Are enzymes reusable? Yes. 16. What are two factors that change the shape (denature) of an enzyme? Temperature and pH. 17. Nucleic acids are polymers of nucleotides. What are the two nucleic acids? DNA and RNA. 18. The best known nucleotide is Adenosine triphosphate (ATP). Why is it so important for our body? It provides energy for cellular processes. 19. The second and third phosphate groups of ATP are high-energy covalent bonds. 3: Cellular Form and Function Cells and the Plasma Membrane 1. Define cell theory. Cell theory states that all living organisms are composed of cells, and all cells arise from pre-existing cells. The cell is the simplest structural and functional unit of life. Cells of all species exhibit remarkable biochemical unity. 2. All cells have similarities in structure. What are three components of a cell you can see with a microscope? The plasma membrane, cytoplasm, and nucleus. 3. Define extracellular fluid and intracellular fluid. Extracellular fluid (ECF) is the fluid outside cells, while intracellular fluid (ICF) is the fluid within cells. 4. What are different examples of extracellular fluid? Blood plasma, lymph, and interstitial fluid. 5. What is the difference between cytoplasm and cytosol? Cytoplasm includes all the contents within the cell membrane, excluding the nucleus, while cytosol is the fluid component of the cytoplasm. 6. What defines the boundaries of the cell? The plasma membrane. 7. The plasma membrane consists of two organic molecules; what are they? Phospholipids and proteins. 8. How are phospholipids arranged in the bilayer? Which part of a phospholipid is polar (hydrophilic) and which part is nonpolar (hydrophobic)? Phospholipids are arranged in a bilayer with hydrophilic (polar) heads facing outward and hydrophobic (nonpolar) tails facing inward. 9. Which type of molecule can go through the phospholipid bilayer? Small, nonpolar molecules like oxygen and carbon dioxide. 10. Which types of molecules must use a protein channel or carrier? Ions and large polar molecules. 11. Define integral (transmembrane) proteins.  Integral proteins span the entire membrane and can act as channels or carriers. Many are floating freely or anchored to the cytoskeleton. 12. Peripheral proteins are found where in relationship to the membrane? On the inner or outer surface of the membrane, not embedded within the lipid bilayer. 13. List at least 7 functions of membrane proteins. Transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to the cytoskeleton and extracellular matrix, and acting as receptors. 14. What is the difference between a channel and a gated-channel? A channel is always open, allowing substances to pass through, while a gated-channel opens or closes in response to a stimulus. 15. All animal cells have a ____________ external to the plasma membrane. What does it consist of? Glycocalyx; it consists of glycoproteins and glycolipids. 16. What are microvilli? What purpose do they serve? Where would you find cells with microvilli? Microvilli are finger-like extensions of the plasma membrane that increase surface area for absorption. They are found in the small intestine. 17. What are cilia? If they are motile, where would they be found? Cilia are hair-like structures that can move fluid, mucus, and materials over the cell surface. Motile cilia are found in the respiratory tract. 18. Cilia beat within a saline layer at the cell’s surface, how is water, sodium, and chloride affected? Water follows sodium and chloride ions, creating a saline layer that allows cilia to beat freely. 19. What are flagella and where do they occur in humans? What is the purpose of flagella compared to cilia? Flagella are long, whip-like structures used for cell movement. In humans, they are found on sperm cells. Flagella are used for propulsion, while cilia move substances across the cell surface. 20. What are pseudopods? Which type of cell has pseudopods? Pseudopods are temporary, arm-like projections of the cell membrane used for movement and feeding. They are found in amoebas and some white blood cells. Plasma Membrane Transport 1. What is meant by a plasma membrane being selectively permeable? It allows certain molecules to pass through while blocking others. 2. What are the passive mechanisms of membrane transport? Diffusion, osmosis, and facilitated diffusion. 3. What is filtration? Can you give an example of where it occurs in the human body? Filtration is the movement of water and solutes through a membrane by hydrostatic pressure. It occurs in the kidneys. 4. What is simple diffusion? Does this require a membrane? Simple diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration. It does not require a membrane. 5. How do substances move? (direction of movement) From an area of higher concentration to an area of lower concentration. 6. In simple diffusion, how do the substances move across a cell membrane? Directly through the lipid bilayer or through protein channels. 7. Substances have diffusion rates based on five factors, what are those five? Temperature, molecular weight, concentration gradient, membrane surface area, and membrane permeability. 8. What is osmosis? The diffusion of water across a selectively permeable membrane. 9. Water can move by both simple diffusion and facilitated diffusion. What is an aquaporin? A protein channel that specifically facilitates the diffusion of water. 10. Which direction will water move if on one side of a membrane there is a solution containing molecules that are nonpermeating? Water will move towards the side with the nonpermeating molecules. 11. Define osmolality. The concentration of solutes in a solution. 12. What is tonicity? The ability of a solution to affect the fluid volume and pressure within a cell. 13. How would you describe a hypotonic solution? What happens to a red blood cell if placed in a hypotonic solution? A hypotonic solution has a lower concentration of solutes compared to the cell. A red blood cell will swell and may burst. 14. How would you describe a hypertonic solution? What happens to a red blood cell if placed in a hypertonic solution? A hypertonic solution has a higher concentration of solutes compared to the cell. A red blood cell will shrink. 15. How would you describe an isotonic solution? What happens to a red blood cell if placed in an isotonic solution? Which I.V. fluid is isotonic to plasma? An isotonic solution has the same concentration of solutes as the cell. A red blood cell will remain unchanged. Normal saline (0.9% NaCl) is isotonic to plasma. 16. In carrier-mediated transport, what are the differences between uniports, symports, and antiports? Uniports transport one type of molecule, symports transport two types in the same direction, and antiports transport two types in opposite directions. 17. Carrier-mediated transport can be facilitated diffusion or active transport. What are the differences between facilitated diffusion and active transport? Facilitated diffusion does not require ATP and moves substances down their concentration gradient. Active transport requires ATP and moves substances against their concentration gradient. 18. Define facilitated diffusion. Is ATP consumed? Which direction is the substance moved - with or against the gradient? Facilitated diffusion is the passive transport of molecules across a membrane via a carrier protein. ATP is not consumed, and substances move with the gradient. 19. Define primary active transport. Is ATP consumed? Which direction is the substance moved - with or against the gradient? Primary active transport uses ATP to move substances against their concentration gradient. 20. The sodium-potassium (Na+/K+ pump) is an example of what type of transport? Primary active transport. 21. Each cycle of the pump hydrolyzes one ATP and exchanges how many Na+ for how many K+? Three Na+ ions are exchanged for two K+ ions.  22. Because of the sodium-potassium pump, the most abundant cation in extracellular fluid is ______ and is ______ in intracellular fluid. Sodium (Na+) is most abundant in extracellular fluid, and potassium (K+) is most abundant in intracellular fluid. 23. What does vesicular transport move? Is ATP used? Vesicular transport moves large particles, macromolecules, and fluids. ATP is used. 24. What is endocytosis? The process by which cells take in substances by engulfing them in a vesicle. 25. What is phagocytosis? Can you give some examples of what might be phagocytized? Phagocytosis is the engulfing of large particles or cells. Examples include bacteria and dead cell debris. 26. What is pinocytosis? How does this process occur? Pinocytosis is the ingestion of fluid and dissolved solutes. The cell membrane folds inward to form a vesicle. 27. What is receptor-mediated endocytosis? How does this process occur? Receptor-mediated endocytosis involves the binding of specific molecules to receptors on the cell surface, triggering vesicle formation. 28. What is exocytosis? Where might this occur? Exocytosis is the process of vesicles fusing with the plasma membrane to release their contents outside the cell. It occurs in the secretion of hormones and neurotransmitters. 4: Genes and Cellular Function DNA and RNA—The Nucleic Acids 1. DNA and other nucleic acids are composed of: Nucleotides, each of which is made up of a sugar, a phosphate group, and a nitrogenous base. 2. What are the three bases that are pyrimidines? What are the two bases that are purines? Pyrimidines: Cytosine, thymine, and uracil. Purines: Adenine and guanine. 3. Describe the structure of DNA. What is the backbone made up of? DNA is a double helix with a backbone made up of sugar (deoxyribose) and phosphate groups. 4. What two bases form two hydrogen bonds with each other? What two bases form three hydrogen bonds with each other? What is an example of a base pair?  Adenine and thymine form two hydrogen bonds. Guanine and cytosine form three hydrogen bonds. Example of a base pair: A-T and G-C. 5. The essential function of DNA is to: Store and transmit genetic information. 6. What is chromatin? Chromatin is a complex of DNA and protein found in the nucleus of eukaryotic cells. 7. Human chromatin consists of 46 long filaments called: Chromosomes. 8. What organelle is DNA packed into? The nucleus. 9. What is a nucleosome? A nucleosome is a structural unit of chromatin, consisting of a segment of DNA wound around a core of histone proteins. 10. What does a nucleosome consist of? A nucleosome consists of DNA wrapped around histone proteins. 11. The core particle is a disc-shaped cluster of eight proteins called: Histones, with the DNA wound around it like ribbon around a spool. 12. When a cell is preparing to divide, it copies its entire nuclear: DNA. Each chromosome is made up of two sister chromatids that then coil further. 13. Sister chromatids are joined at a: Centromere, which has a kinetochore on each side. 14. Ribonucleic acid (RNA) is produced in three types: Messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). 15. RNA and DNA have significant differences although both are nucleic acids. What are some of these differences? DNA is double-stranded, contains deoxyribose sugar, and uses thymine. RNA is single-stranded, contains ribose sugar, and uses uracil. Genes and Their Action 1. The classical concept of a gene was as an abstract “unit of heredity” by which a: Trait passes to offspring. 2. We now define a gene as: A segment of DNA that codes for a specific protein or RNA molecule.  3. The 46 human chromosomes come in two sets of: 23 each, one set from each parent. Define genome: A genome is the complete set of genes or genetic material present in a cell or organism. 4. The genetic code is a system that enables: The translation of genetic information into proteins. 5. The minimum code to symbolize: 20 amino acids is 3 nucleotides per amino acid. 6. What is a base triplet? A sequence of three DNA nucleotides that stands for one amino acid. 7. Messenger RNA contains a “mirror image” of each base triplet, and this group of three bases is called a: Codon. 8. The possible combinations of three bases would yield a maximum of: 64 codons; therefore, some amino acids are specified by more than one codon. 9. The code also contains stop codons, which end: Protein synthesis. What does the start codon code for? Methionine. 10. DNA and RNA collaborate to make proteins. 11. What specifies which proteins a cell can make? The sequence of nucleotides in DNA. 12. Different cells have different active genes. A given cell uses only one-third to two-thirds of its genes. 13. When a gene is activated, an: RNA copy is made; this migrates to the cytoplasm where its code is “read” by a ribosome. 14. What is transcription? The process of copying genetic information from DNA to RNA. 15. What is translation? The process of converting the information in mRNA into a sequence of amino acids to build a protein. DNA Replication and the Cell Cycle 1. DNA replication is necessary prior to: Cell division and is accomplished through complementary base pairing. 2. What is the cell cycle and what are the four main phases? The cell cycle is the series of events that take place in a cell leading to its division and duplication. The four main phases are G1, S, G2, and M. 3. What phase is an interval between cell division and DNA replication?  G1 phase. 4. During this time the cell is doing what? Growing and carrying out normal functions. 5. What phase is the period during which the cell makes a duplicate copy of its centrioles and its entire nuclear DNA? S phase. 6. During which phase does the cell finish replicating its centrioles and synthesizes enzymes that control cell division; it also checks replication for errors? G2 phase. 7. What phase is the period during which a cell replicates its nucleus and then pinches in two to form two new daughter cells? M phase (mitosis). 8. What is interphase? The phase of the cell cycle in which the cell spends the majority of its time, including G1, S, and G2 phases. 9. The length of the cell cycle varies depending on what? Can you give some examples? The type of cell and its function. For example, skin cells divide frequently, while nerve cells rarely divide. 10. Some cells cease to divide for days, years, or the rest of one’s life; these are said to be in what phase? G0 phase. 11. An inability to stop cycling and enter this phase is characteristic of what type of cells? Cancer cells. 12. Cells divide by two mechanisms: mitosis and meiosis;: Meiosis is restricted to the production of eggs and sperm, and mitosis serves all the other functions of cell division. 13. List some of the things mitosis is responsible for. Growth, tissue repair, and asexual reproduction. 14. Mitosis has four phases: what are those four phases? Prophase, metaphase, anaphase, and telophase. 15. Can you describe what is happening during each of these phases? Prophase: Chromosomes condense, nuclear envelope breaks down, spindle fibers form.  Metaphase: Chromosomes align at the cell equator. Anaphase: Sister chromatids are pulled apart to opposite poles. Telophase: Nuclear envelopes reform, chromosomes decondense. 16. What is cytokinesis? How does it occur? Define cleavage furrow. Cytokinesis is the division of the cytoplasm to form two daughter cells. It occurs by the formation of a cleavage furrow, which is a contractile ring that pinches the cell into two. 5: The Human Tissues The Study of Tissues Define histology. Histology is the study of tissues. What is a tissue? A tissue is a group of similar cells that perform a specific function. What are the four primary tissues? 1. Epithelial 2. Connective 3. Muscle 4. Nervous How do these tissues differ? Epithelial: Covers body surfaces and lines cavities. Connective: Supports, binds, and protects organs. Muscle: Produces movement. Nervous: Transmits impulses for coordination, regulation, integration, and sensory reception. What is the matrix composed of? The matrix is composed of fibers and ground substance. Epithelial Tissue Describe epithelial tissue. Epithelial tissue consists of closely packed cells with little extracellular material, forming continuous sheets. Where would you find epithelial tissue? Epithelial tissue is found on body surfaces, lining body cavities, and forming glands. Epithelium almost always lies on a layer of loose ___________ tissue and is dependent on this for what? Loose connective tissue; it provides nutrients and waste removal. What does the basement membrane do? The basement membrane anchors the epithelium to the underlying connective tissue. Epithelia are classified into two broad categories: what are those two categories? 1. Simple epithelium 2. Stratified epithelium Can you contrast the two categories? How are they different? Simple epithelium: Single layer of cells. Stratified epithelium: Multiple layers of cells. Generally, a simple epithelium has only _____ layer of cells. One Three types of simple epithelia are named for the shapes of their cells: What are these three and how could you describe their appearance? 1. Simple squamous: Flat and thin. 2. Simple cuboidal: Cube-shaped. 3. Simple columnar: Tall and column-like. How would you describe pseudostratified columnar epithelium? Pseudostratified columnar epithelium appears to have multiple layers due to varying cell heights but is actually a single layer. Simple columnar and pseudostratified columnar epithelia often produce ________, which is secreted by _______ cells. Mucus; goblet cells Stratified epithelium may have from 2 to 20 layers of cells with only the deepest layer resting on the basement membrane. Three types of stratified epithelia are named for the shapes of the surface cells: what are these types? 1. Stratified squamous 2. Stratified cuboidal  3. Stratified columnar A fourth type, transitional epithelium, was erroneously thought to represent a transitional stage between stratified squamous and stratified columnar, and the name has persisted. Stratified squamous epithelium is the ____ ____________ epithelium in the body. Most widespread The deepest layers of cells are cuboidal to columnar and undergo continual _________. Mitosis Daughter cells push toward the surface and become flatter (more scaly). Eventually the cells migrate to the surface where they die and flake off, a process called ________________ or desquamation. Exfoliation Where is keratinized epithelium found and what gives it the ability to repel water? Keratinized epithelium is found in the skin; keratin protein gives it water-repellent properties. Nonkeratinized epithelium lacks the surface layer of dead cells; it is found where? In moist areas such as the mouth, esophagus, and vagina. Transitional epithelium is limited to where in the body? The urinary tract, including the bladder. Connective Tissue What does connective tissue consist of? What are some of its functions? Can you give examples of each? Connective tissue consists of cells, fibers, and ground substance. Functions include: Support: Bone Binding: Tendons and ligaments Protection: Adipose tissue Transport: Blood Fibrous connective tissue is the most diverse type. Fibrous connective tissue consists of _______ and _________ components in a ground substance. Cellular; fibrous Cellular components include the following types, depending on the tissue. Fibroblasts: Produce fibers and ground substance.  Macrophages: Engulf and digest debris and pathogens. Leukocytes: White blood cells involved in immune response. Plasma cells: Synthesize antibodies. Adipocytes: Store fat. Fibrous components include three types of protein fibers. Collagenous fibers: Strong and flexible. Reticular fibers: Thin and form a supportive network. Elastic fibers: Stretch and recoil. Where is ground substance found? Ground substance is found in the extracellular matrix of connective tissues. Fibrous connective tissue is divided into two broad categories: loose connective tissue and dense connective tissue. Loose connective tissue: Examples include areolar and reticular tissue. Dense connective tissue: Examples include dense regular and dense irregular tissue. Describe the appearance of areolar tissue? Where is it found? Areolar tissue has a loose arrangement of fibers and cells in a gel-like ground substance; it is found under epithelia and around organs. How would you describe reticular tissue? Reticular tissue has a network of reticular fibers that support cells in lymphoid organs. Dense regular connective tissue is named for two properties: what are those two properties? 1. Densely packed fibers 2. Parallel arrangement The parallel arrangement is an adaptation to directional pull, where would this be found? In tendons and ligaments. In general, the only cells are __________. Fibroblasts __________ tissue is a dense regular connective tissue found in the vocal cords and some ligaments of the vertebral column. It also forms wavy sheets in the walls of the large and medium arteries, allowing expansion and recoil of these arteries. Elastic Dense irregular connective tissue also has closely packed collagen fibers, how do these collagen bundles run? They run in random directions. What is dense irregular connective tissue able to resist? It can resist unpredictable stresses. Where is dense irregular connective tissue found? In the dermis of the skin and capsules around organs. Adipose tissue, or fat, is tissue in which ___________ are the dominant cell type. Adipocytes Stored triglycerides in adipocytes are constantly being turned over, with an equilibrium between synthesis and hydrolysis, energy _______ and energy _______. Storage; release What are some functions of adipose tissue? Energy storage Insulation Cushioning Most adipose tissue is ______ fat (that is actually colored yellow), but fetuses, infants, and children have a heat-generating tissue called _________ fat, which accounts for up to 6% of an infant’s weight. White; brown Cartilage is a supportive connective tissue with a flexible rubbery matrix. Cells called ___________ secrete and surround themselves with matrix until they are trapped in cavities called ________, at which time they are called _____________. Chondroblasts; lacunae; chondrocytes How does cartilage receive nutrients and get rid of waste? Why does cartilage heal slowly? Cartilage is avascular and relies on diffusion for nutrient and waste exchange, leading to slow healing. Cartilage is classified based on the predominant type of fiber. Hyaline cartilage: Clear and glassy with fine collagen fibers. Elastic cartilage: Contains conspicuous elastic fibers. Fibrocartilage: Has coarse, visible bundles of collagen. Elastic cartilage and most hyaline cartilage are surrounded by a sheath of dense irregular connective tissue called the _________________. Perichondrium The term “bone” refers either to an organ such as the femur and mandible, composed of multiple tissue types, or to bone tissue (osseous tissue), which makes up most of the mass of the bones. Spongy bone: Found in the ends of long bones and the interior of other bones. Compact (dense) bone: Forms the outer layer of bones. Compact bone is arranged in cylinders of tissue that surround ________ (haversian or osteonic) canals that run longitudinally through long bones. What travels through the canals? Central; blood vessels and nerves Bone matrix is deposited in concentric ____________ around each central canal. Lamellae What forms an osteon? A central canal and its surrounding lamellae. Mature bone cells are called? Osteocytes Tiny canals called _________ radiate between lacunae allowing osteocytes to contact each other. Canaliculi The bone as a whole is covered with a? Periosteum Two-thirds of the dry weight of bone is ________ and __________ salts deposited around the collagen fibers. Calcium; phosphate Blood is a _______ connective tissue that travels through tubular vessels. Fluid The primary function of blood is to do what? Transport cells and dissolved matter throughout the body. Blood consists of ________ as the ground substance, and _____ and ______ fragments called formed elements. Plasma; cells; cell What cell is the most abundant formed element? What do they lack and what do they do? Erythrocytes (red blood cells); they lack nuclei and transport oxygen. Nervous and Muscular Tissues—Excitable Tissues Leukocytes (white blood cells) have various roles in immune defenses; they have conspicuous _______. Nuclei What are platelets and what are they involved in? Platelets are cell fragments involved in blood clotting. The basis for nerve and muscle excitation is an electrical charge difference called what? Membrane potential Nervous tissue consists of neurons and neuroglia (glial cells), which _______ and _______ the neurons. Support and protect Neurons detect ________, respond, and transmit _____________ rapidly. Stimuli; information What is a neurosoma, and what does it contain? A neurosoma is the cell body of a neuron, containing the nucleus and most organelles. What are dendrites and axons? Which direction do the electrical signals go in these? Dendrites: Receive signals and conduct them toward the neurosoma. Axons: Conduct signals away from the neurosoma. Glial cells outnumber neurons and make up most of the volume of nervous tissue; what do they provide? Support, protection, and nourishment for neurons. Muscular tissue is specialized to contract when stimulated; its primary function is to? Produce movement. Muscular tissue is responsible for what? Movement, posture, and heat production. The three types of muscle are skeletal, cardiac, and smooth, which differ in what? Structure, location, and control (voluntary or involuntary). Skeletal muscle consists of long cells called _______ ________. Muscle fibers Most skeletal muscle is attached where? Are there exceptions to this? To bones; exceptions include muscles of the tongue and some facial muscles. Each fiber contains multiple _________ adjacent to the plasma membrane. Nuclei Skeletal muscle appears striated, what gives it this appearance? The arrangement of actin and myosin filaments. Skeletal muscle is also _______________ in that it is under conscious control. Voluntary Cardiac muscle is limited to the _________. Heart Cardiac muscle cells are called myocytes or ___________. Cardiocytes Myocytes contain only one nucleus. True Cardiac muscle appears what? Striated What do intercalated discs allow for? They allow for synchronized contraction of cardiac muscle cells. Cardiac muscle is considered _____________ because it usually is not under conscious control. Involuntary Smooth muscle lacks _________ and is ______________. Striations; involuntary Describe the shape and location of the nucleus of smooth muscle cells. Smooth muscle cells are spindle-shaped with a single, centrally located nucleus. Most of the smooth muscle, called visceral muscle, forms layers where at in the body? In the walls of hollow organs such as the intestines, bladder, and blood vessels. How does smooth muscle have an impact on blood flow and pressure? By contracting and relaxing, it regulates the diameter of blood vessels. Cell Junctions, Glands, and Membranes Describe cell junctions. Cell junctions are connections between cells that hold them together and enable communication. These attachments enable cells to do what? Resist stress, communicate, and control the movement of substances. A _________ junction completely encircles an epithelial cell near its apical surface and joins it tightly to the neighboring cells. Tight Transmembrane cell-adhesion proteins link adjacent cells and seal off the intercellular space preventing what? The passage of substances between cells. A __________ is a patch that holds cells together like a snap. What does this junction keep cells from doing? Where are they commonly seen? Desmosome; it prevents cells from pulling apart; commonly seen in the skin and heart. J-shaped proteins hook the __________ to a protein plaque on the inner surface of the plasma membrane. Cytoskeleton A _______ (communicating) junction is formed by a connexon. Gap Each connexon consists of a ring of what? Six transmembrane proteins. What types of things can pass through this junction? Ions, glucose, amino acids, and other small solutes. Where are these junctions found? What do they allow the flow of? Where are these junctions absent? Found in cardiac and smooth muscle, they allow the flow of electrical signals; absent in skeletal muscle. A gland is a cell or organ that does what? Secretes substances for use elsewhere in the body or for elimination. The product of the gland is called a ____________ if it is useful to the body and an __________ if it is a waste product. Secretion; excretion How are glands classified? By their method of secretion and the nature of their secretions. Exocrine glands usually maintain contact with the surface by way of a ______. What are some examples? Duct; examples include sweat, salivary, and mammary glands. Endocrine glands have no _______; they secrete their products into what? Ducts; they secrete their products into the bloodstream. The secretions, called ________, function as chemical messengers that act on cells elsewhere in the body. Hormones Examples of endocrine glands include what? Pituitary, thyroid, and adrenal glands. Some glands have both exocrine and endocrine function, can you list some examples? Pancreas, ovaries, and testes. Unicellular glands are secretory cells found in an epithelium that is __________. An example is the goblet cells of the respiratory tract, which secrete _________. Predominantly non-secretory; mucus Contrast simple and compound exocrine glands. Simple glands: Have a single unbranched duct. Compound glands: Have a branched duct. Tubular glands have duct and secretory portions of _________ diameter. Uniform Glands may also be classified by the nature of their secretions. Serous glands: Produce thin, watery fluids, such as sweat. Mucous glands: Secrete mucin, which absorbs water to form mucus; an example is goblet cells. Exocrine glands are also classified according to how their products are released—merocrine, apocrine, and holocrine. Merocrine glands (eccrine glands): Release products by exocytosis, such as tear glands. Apocrine glands: Lipid droplets combine in the cytosol then bud from the cell surface.  Holocrine glands: Accumulate the product in their cells, and then these cells disintegrate to release the product; an example is sebaceous glands. Membranes line body cavities and cover their viscera, as well as cover the outside of the body. The largest membrane of the body is the cutaneous membrane (skin): It consists of stratified squamous epithelium (epidermis) and a layer of connective tissue (dermis); it resists dehydration and protects against infection. The two principal kinds of internal membranes are what? 1. Mucous membranes 2. Serous membranes A mucous membrane (mucosa) lines passageways that open to the exterior environment, such as? The digestive, respiratory, urinary, and reproductive tracts. Mucous membranes consist of what? An epithelium, a lamina propria (areolar connective tissue), and sometimes a muscularis mucosae (smooth muscle layer). What does the mucus do in these areas? Traps particles and protects underlying tissues. Where would a serous membrane (serosa) be? Lining the thoracic and abdominal cavities and covering the organs within these cavities. A serous membrane consists of what type of tissue? Simple squamous epithelium on a thin layer of areolar connective tissue. These membranes produce what type of fluid? Serous fluid The circulatory system is lined with what type of tissue? Endothelium (simple squamous epithelium) The endothelium and supporting connective tissues make up a membrane called the tunica ___________ of the blood vessels and the ______________ of the heart. Interna; endocardium Some membranes made only of connective tissue include the ________ mater around the brain; some membranes made only of epithelium include the anterior surfaces of the ________ of the eye. Meninges; cornea What is the difference between hypertrophy and hyperplasia?  Hypertrophy: Increase in cell size. Hyperplasia: Increase in cell number. What is a neoplasia? The development of a tumor (benign or malignant). What are the two ways damaged tissue repairs? 1. Regeneration 2. Fibrosis What is scar tissue primarily composed of? Collagen What types of tissues repair well and which do not? Repair well: Epithelial tissues, bone, areolar connective tissue, dense irregular connective tissue, and blood-forming tissue. Do not repair well: Skeletal muscle, cartilage, and cardiac muscle. 6: The Integumentary System The Skin and Subcutaneous Tissue What does the integumentary system include? Define dermatology. The integumentary system includes the skin, hair, nails, and glands. Dermatology is the study of the skin and its disorders. The skin is the ________ organ of the body and consists of the outer ________ and the deeper ________. The ______________ underlies this latter layer but is not a true part of the skin. The skin is the largest organ of the body and consists of the outer epidermis and the deeper dermis. The hypodermis underlies this latter layer but is not a true part of the skin. Where is thick skin found? What does thick skin contain? Thick skin is found on the palms of the hands and soles of the feet. It contains sweat glands but no hair follicles or sebaceous (oil) glands. The skin provides six important functions, what are those functions? Can you give examples of each? 1. Protection: Against pathogens and UV radiation. 2. Sensation: Contains sensory receptors for touch, pain, and temperature. 3. Thermoregulation: Regulates body temperature through sweat and blood flow. 4. Vitamin D synthesis: Initiates the production of vitamin D.  5. Excretion: Removes waste products through sweat. 6. Nonverbal communication: Facial expressions. The epidermis is what type of tissue? What does it lack? How does it get nutrients and remove waste? The epidermis is a keratinized stratified squamous epithelium. It lacks blood vessels and gets nutrients and removes waste through diffusion from the underlying dermis. The epidermis is composed of ______ types of cells. Five What are stem cells, what do they give rise to and where are they found? Stem cells are undifferentiated cells that give rise to keratinocytes. They are found in the stratum basale. The majority of epidermal cells are keratinocytes, which synthesize what? Keratin Melanocytes also occur only in the stratum _________; they synthesize the pigment ___________. Basale; melanin Tactile cells are the receptors for the sense of _________. Found in the stratum __________, they are associated with an underlying dermal nerve fiber. Touch; basale What are dendritic cells, where do they migrate from and where are they found? Dendritic cells are immune cells that migrate from bone marrow and are found in the stratum spinosum and stratum granulosum. The cells of the epidermis are arranged in four to five strata (five in thick skin). 1. Stratum basale: The innermost layer resting on the basement membrane. It consists of stem cells, keratinocytes, melanocytes, and tactile cells. 2. Stratum spinosum: Several layers of keratinocytes. As they are pushed upward by cell division, they flatten due to the accumulation of keratin filaments. Desmosomes bind the cells together, giving the layer a spiny appearance. 3. Stratum granulosum: Three to five layers of flat keratinocytes with dark-staining keratohyalin granules. 4. Stratum lucidum: A thin, translucent zone external to the stratum granulosum, seen only in thick skin. 5. Stratum corneum: Up to 30 layers of dead, scaly keratinized cells that form the surface layer. A keratinocyte’s life cycle begins in the stratum _______ and ends as what? Basale; it ends as a dead cell in the stratum corneum. Mitosis requires oxygen and nutrients, and epidermal cells acquire these from blood vessels in the _________. Can you briefly describe what happens as new keratinocytes push older ones toward the surface? What causes calluses or corns? Dermis. As new keratinocytes push older ones toward the surface, the older cells flatten, produce more keratin, and eventually die. Calluses or corns are caused by repeated pressure or friction, leading to thickened areas of the stratum corneum. In the stratum granulosum, four developments occur: 1. Keratohyalin granules release a protein that binds keratin filaments into coarse bundles. 2. Cells produce a layer of tough envelope proteins just beneath the plasma membrane. 3. Membrane-coating vesicles release a lipid mixture that waterproofs the surface of the cell. 4. The nuclei and organelles of the cells degenerate, and the cells die. An epidermal water barrier forms between the stratum granulosum and the stratum spinosum that prevents dehydration. Cells above the barrier die because they are cut off from nutrients below. The stratum corneum consists of layers of dead cells that exfoliate as tiny specks called dander. The dermis is a connective tissue layer beneath the epidermis. What is it composed of? Collagen, elastic and reticular fibers, fibroblasts, and other cells typical of fibrous connective tissue. What is embedded into the dermis? Hair follicles, sebaceous glands, sweat glands, nerve endings, and blood vessels. Skeletal muscles attached to dermal collagen fibers produce what? Facial expressions. What are the two zones of the dermis? How do they differ? 1. Papillary layer: Thin, superficial layer of areolar tissue with rich blood supply. 2. Reticular layer: Deeper, thicker layer of dense irregular connective tissue. The hypodermis, or subcutaneous tissue, has an indistinct boundary but contains more _________ and __________ tissue; it binds the skin to the underlying tissues. Areolar and adipose The hypodermis is the target for subcutaneous injections. Why? Because it is highly vascular and absorbs drugs quickly. Subcutaneous fat is hypodermis composed primarily of ________ tissue. This subcutaneous fat serves what purposes? Adipose; it provides energy storage, insulation, and cushioning. Hair and Nails What are some accessory organs of the skin and what are they composed of? Hair, nails, and cutaneous glands; they are composed of keratinized cells. What is a pilus? A pilus is a hair. Structurally, a hair has three zones along its length and three layers in cross section. Bulb: The swelling at the base where the hair originates. Root: The remainder of the hair within the follicle. Shaft: The portion above the skin surface. Where are the only living cells of the hair found? What is the tissue called around them? What does this tissue provide for the hair? In the bulb; the tissue around them is called the dermal papilla, which provides nutrients. In cross section, the innermost layer of the hair is the _________, a core of loosely arranged cells and air spaces. Medulla The _______, external to the medulla, constitutes most of the hair. Cortex The __________, the outermost layer of a hair, is composed of layers of very thin, scaly cells that overlap like shingles with their free edges directed upward. Cuticle Nerve fibers called ________ receptors entwine each follicle and respond to hair movements such as when a hair is touched. Hair What are the piloerector muscles (pilomotor muscles or the arrector pili)? What nervous system controls the contraction of these muscles? They are bundles of smooth muscle cells that cause hair to stand on end (goosebumps); controlled by the sympathetic nervous system. Cutaneous Glands Sweat glands, or sudoriferous glands, are of two kinds: What are those two types? 1. Apocrine sweat glands  2. Merocrine (eccrine) sweat glands _________ sweat glands occur in the groin, anal region, axilla, and areola, and in mature males, the beard area, but they are absent or sparse in the axillary region of Koreans and Japanese. Apocrine They produce secretions by __________ in the same way as do merocrine glands, but their secretory part has a much larger lumen. Exocytosis The ducts of apocrine sweat glands lead into nearby ______ __________ rather than to the skin surface. Hair follicles _________ sweat glands are _______ glands that respond especially to stress and sexual stimulation; they do not develop until sexual maturity. Apocrine; scent The role of these glands is thought to be production of what? Pheromones What is bromhidrosis? The disagreeable body odor produced by bacterial action on fatty acids in apocrine sweat. ____________ (eccrine) sweat glands, the most numerous glands of the skin, produce watery perspiration. Merocrine Where are these glands found? All over the body, especially on the palms, soles, and forehead. These glands are simple tubular glands with a twisted coil in the dermis or hypodermis, and an undulating or coiled duct leading to a ______ ______ on the skin surface. Sweat pore Most sodium chloride is __________ as the secretion passes up the duct, but some remains, along with potassium ions, urea, lactic acid, and ammonia. Reabsorbed The majority of sweat is what? What is the pH of sweat? Water; pH ranges from 4 to 6. Excessive sweating can cause what? Dehydration and electrolyte imbalance. Sebaceous glands produce an oily secretion called sebum; they are flask-shaped, 7: Bone Tissue Tissues and Organs of the Skeletal System Define osteology. What is the skeletal system composed of? Osteology is the study of bones. The skeletal system is composed of bones, cartilages, and ligaments. The skeleton has at least six functions. What are those six? 1. Support: Provides structural support for the entire body. 2. Protection: Protects vital organs (e.g., brain, heart, lungs). 3. Movement: Facilitates movement by serving as points of attachment for muscles. 4. Electrolyte balance: Stores and releases minerals such as calcium and phosphate. 5. Acid-base balance: Buffers the blood against excessive pH changes. 6. Blood formation: Houses bone marrow, which produces blood cells. What type of tissue is bone, or osseous tissue? What is mineralization and what’s another name for it? What other tissue types are present in bone? Bone, or osseous tissue, is a connective tissue. Mineralization, also known as calcification, is the process of hardening the bone by depositing calcium salts. Other tissue types present in bone include marrow, cartilage, adipose tissue, nerves, and blood vessels. Bones have a variety of shapes correlated with their protective and locomotor functions. Flat bones: Thin, curved plates (e.g., skull, ribs, sternum). Long bones: Longer than they are wide, crucial for movement (e.g., femur, humerus). Short bones: Nearly equal in length and width, provide stability (e.g., carpals, tarsals). Irregular bones: Complex shapes (e.g., vertebrae, some skull bones). The general anatomy of bones can be observed in a _______ bone; flat bones have variations due to their shape. Long Describe the composition of a long bone. Be sure to pay attention to the terms compact, cancellous, and medullary cavity. Compact bone: Dense outer layer. Cancellous (spongy) bone: Lightweight, porous inner layer.  Medullary cavity: Central cavity containing bone marrow. What do the diaphysis and the epiphysis refer to? What are their purposes? Diaphysis: The shaft of a long bone, provides leverage and weight support. Epiphysis: The ends of a long bone, provides attachment for muscles and stability to joints. The joint surface where bones meet is covered with a layer of hyaline cartilage called the __________ cartilage, which enables a joint to move easily. Articular Blood vessels penetrate into the bone through minute holes called? Nutrient foramina What is the periosteum? What are the two layers? The periosteum is a sheath that covers the external surface of bones. It has two layers: 1. Fibrous layer: Outer layer of dense irregular connective tissue. 2. Osteogenic layer: Inner layer containing bone-forming cells. Some collagen fibers of the outer layer are continuous with ________ that bind muscle to bone. Tendons Other collagen fibers of the outer layer penetrate into the bone matrix as ___________ fibers. Perforating (Sharpey’s) fibers Why is the osteogenic layer important? It is crucial for the growth and healing of bones. A thin layer of reticular connective tissue called the _____________ lines the internal marrow cavity, covers all surfaces of the spongy bone, and lines the canal system. Endosteum In children and adolescents, an epiphyseal plate of ________ cartilage separates the marrow spaces of the epiphysis and diaphysis. Hyaline What is the epiphyseal plate? It is a growth plate that allows for the lengthening of bones during development. In adults, what happens to the epiphyseal plate? It becomes an epiphyseal line as the cartilage is replaced by bone. The cranium is a typical flat bone, describe the sandwich-like arrangement seen in it. The cranium has an outer layer of compact bone, a middle layer of spongy bone (diploe), and an inner layer of compact bone. Define diploe. How does the diploe handle a moderate blow? Diploe is the spongy bone layer in flat bones. It can absorb shock and protect the inner compact bone layers. Both surfaces of a flat bone are covered with ____________, and the marrow spaces are lined with _____________. Periosteum; endosteum Histology of Osseous Tissue Bone, a connective tissue, consists of cells, fibers, and ground substance; there are four principal types of bone cells. 1. Osteogenic cells: Stem cells found in the endosteum and periosteum. 2. Osteoblasts: Bone-forming cells found on the bone surface. 3. Osteocytes: Former osteoblasts trapped in the matrix they deposited. 4. Osteoclasts: Bone-dissolving cells found on the bone surface. Osteoblasts are ______________ (do not divide), so differentiation of osteogenic cells is the only way new osteoblasts are generated. Nonmitotic Osteoblasts synthesize what? What stimulates osteogenic cells to multiply rapidly and generate increased numbers of osteoblasts? Osteoblasts synthesize the bone matrix. Stress and fractures stimulate osteogenic cells to multiply rapidly. Osteoblasts secrete what hormone and what does it stimulate? Osteocalcin, which stimulates insulin secretion by the pancreas and increases insulin sensitivity in adipocytes. Osteocytes are former ____________ that have become trapped in the bone matrix they deposited. Osteoblasts Define lacunae and canaliculi. Lacunae: Small cavities that house osteocytes. Canaliculi: Tiny channels that connect lacunae. Osteocytes have slender, fingerlike cytoplasmic processes that reach into the canaliculi, what do these processes do? They allow osteocytes to communicate and exchange nutrients and wastes. Neighboring osteocytes are connected by ______ junctions, allowing the passage of nutrients, wastes, and chemical signals. Gap Some osteocytes _______ bone matrix and others _______ it, contributing to the homeostasis of both bone density and blood concentrations of calcium and phosphate ions. Resorb; deposit Osteocytes are also strain sensors—what does this mean? They detect mechanical stress on the bone and signal bone remodeling. Osteoclasts are -______ cells found on the bone surface. Bone-dissolving Osteoclasts develop from bone marrow stem cells that give rise to ________ cells; thus, they have an independent origin from osteogenic cells, osteoblasts, and osteocytes. Blood The side of the cell facing the bone surface has a ruffled border, what does this help with? It increases the cell's surface area for bone resorption. Osteoclasts often reside in pits called? Resorption bays (Howship’s lacunae) Bone remodeling results from the combined action of _____________ and ______________. Osteoclasts and osteoblasts The matrix of osseous tissue is about one-third organic and two-thirds inorganic matter. Organic matter: Collagen fibers, glycosaminoglycans, proteoglycans, and glycoproteins. Inorganic matter: Hydroxyapatite (calcium phosphate), calcium carbonate, and other minerals. Bone is in a class of materials called a ____________, a combination of two structural materials—in this case, a ceramic and a polymer. Composite The polymer is __________, and the ceramic component is the ______________ and other minerals. Collagen; hydroxyapatite When bones are deficient in calcium salts (the ceramic component), they are what? Soft and bend easily. The protein component gives bone what? Describe how a bone would be without it. Flexibility and tensile strength; without it, bones would be brittle and shatter easily. The ratio of minerals to collagen varies in different parts of the skeleton in response to tension and compression. Compact bone is studied using slices that have been dried, cut with a saw, and ground to translucent thinness, revealing details of the matrix. These histological sections show onion-like concentric _________ arranged around a _________ (haversian or osteonic) canal and connected to each other by ____________. Lamellae; central; canaliculi What constitutes an osteon? A central canal and its concentric lamellae. Describe perforating (Volkmann) canals. They are transverse or diagonal passages that connect central canals. How are the collagen fibers arranged in the matrix? What does the arrangement enhance? They are arranged in a helical pattern, enhancing the bone's strength and resilience. How do nutrients and waste enter and leave bone? Through the blood vessels in the central and perforating canals, and via diffusion through the canaliculi. What is circumferential lamellae? Lamellae that run parallel to the bone surface, encircling the entire bone. What is interstitial lamellae? Remnants of old osteons found between newer osteons. Spongy bone consists of a lattice of delicate slivers of bone called spicules and thin plates called __________; the term spongy refers to its appearance, not its hardness. Trabeculae Spongy bone is covered with ___________ and permeated by spaces filled with bone marrow. Endosteum Central canals are not needed, what is this? Because the trabeculae are thin Bone Development Define osteogenesis. What are the two methods of bone development? Osteogenesis, or ossification, is the process of bone formation. The two methods of bone development are: 1. Intramembranous ossification 2. Endochondral ossification Intramembranous ossification produces what bones? Development includes four stages, what are the four stages and can you briefly describe each one? Intramembranous ossification produces flat bones of the skull, clavicles, and part of the mandible. The four stages are: 1. Ossification centers form: Mesenchymal cells cluster and differentiate into osteoblasts. 2. Calcification: Osteoblasts secrete osteoid, which calcifies. 3. Formation of trabeculae: Osteoid is laid down between blood vessels, forming a network of trabeculae. 4. Development of periosteum: Mesenchyme condenses on the external surface, forming the periosteum. What is endochondral ossification? Most bones of the body develop in this way, and the process includes six stages, what are the six stages and can you briefly describe each one? Endochondral ossification is the process by which bone forms by replacing hyaline cartilage. The six stages are: 1. Formation of bone collar: Around the diaphysis of the hyaline cartilage model. 2. Cavitation of the hyaline cartilage: Within the cartilage model. 3. Invasion of internal cavities: By the periosteal bud and spongy bone formation. 4. Formation of the medullary cavity: As ossification continues; appearance of secondary ossification centers in the epiphyses. 5. Ossification of the epiphyses: When completed, hyaline cartilage remains only in the epiphyseal plates and articular cartilages. 6. Growth in length and remodeling: Continues through adolescence. Ossification occurs throughout life with the growth and remodeling of bones. The epiphyseal plate is the region in which bone ___________ takes place. Elongation The epiphyseal plate consists of _________ cartilage in the middle, with a _________ zone on each side. Hyaline; transition The transitional zone, facing the marrow cavity, is called the __________. Metaphysis Cartilage converts to bone in a five-stage process. 1. Zone of reserve cartilage: Resting hyaline cartilage. 2. Zone of cell proliferation: Chondrocytes multiply and line up in rows. 3. Zone of cell hypertrophy: Chondrocytes enlarge. 4. Zone of calcification: Minerals deposited in the matrix. 5. Zone of bone deposition: Chondrocytes die, and osteoblasts deposit bone matrix. The growth of cartilage from within the metaphyses is called ____________ growth; _________ can result from a failure of cartilage to grow in the long bones. Interstitial; dwarfism Growth stops when all the __________ is depleted; the site of the original epiphyseal plate is marked with a line of spongy bone called the epiphyseal ______. Cartilage; line Bones continually grow throughout life in diameter and thickness through a process called _____________ growth that deposits new tissue at the surface. Appositional Appositional growth is similar to intramembranous ossification; how so? Both processes involve the addition of new layers of bone matrix on the surface. They lay down matrix in layers parallel to the surface, not in cylindrical osteons; this process produces ________________ lamellae. Circumferential As a bone increases in diameter, its marrow cavity does what? Expands Bones are continually remodeled throughout life by the ___________ of old bone and ___________ of new, replacing about _____% of skeletal tissue per year. Resorption; deposition; 10% Wolff’s law of bone states what? Bone grows and remodels in response to the forces placed upon it. This phenomenon is an example of the complementarity of _____ and __________. Form and function Bone remodeling results from the action of osteo_____ and osteo______. Osteoclasts and osteoblasts On average, how are the bones of athletes and people engaged in manual labor different from the bones in sedentary people? They have denser and stronger bones due to the greater mechanical stress placed on them. Physiology of Osseous Tissue Mineral deposition is a crystallization process in which _______, __________, and other ions are taken from the blood plasma and deposited in bone tissue, mainly as crystals of hydroxyapatite. Calcium, phosphate How does this process happen? Osteoblasts produce collagen fibers that spiral the length of the osteon. These fibers become encrusted with minerals that harden the matrix. Define ectopic ossification. The abnormal calcification of tissues. What is arteriosclerosis? Hardening of the arteries due to calcification. What is a calculus? A calcified mass in an otherwise soft organ, such as the lungs. Mineral resorption is the process of what? Dissolving bone and releasing minerals into the blood. How does this process happen? Osteoclasts secrete hydrochloric acid to dissolve bone minerals and enzymes to digest the collagen. What does calcitonin do? It lowers blood calcium levels by inhibiting osteoclast activity and stimulating osteoblasts. What does parathyroid hormone do? It raises blood calcium levels by stimulating osteoclast activity, promoting calcium reabsorption by the kidneys, and enhancing the effects of calcitriol. Bone Disorders What causes a stress fracture? A break caused by abnormal trauma to a bone. What is a pathologic fracture and what is it due to? A break in a bone weakened by disease, such as osteoporosis or cancer. Fractures are also classified according to the direction of the fracture line, whether the skin is broken, and whether the bone is cracked or broken into pieces. An uncomplicated fracture heals in ____ to ____ weeks, but complex fractures and fractures in the elderly take longer; the healing process occurs in four stages. What are those four stages? Can you briefly describe them? 8 to 12 weeks 1. Hematoma formation: Blood clot forms at the fracture site. 2. Soft callus formation: Collagen and fibrocartilage form a soft callus. 3. Hard callus formation: Osteoblasts deposit a temporary bony collar around the fracture. 4. Bone remodeling: Osteoclasts remove small bone fragments, and osteoblasts deposit spongy bone, which is then converted to compact bone. Treatment of fractures involves reducing the _____________ of broken bones and ______________ the bone during healing. Displacement; immobilizing In closed reduction, the bone fragments are manipulated how? Without surgery. What happens to the bone in an open reduction? The bone fragments are surgically exposed and fixed with plates, screws, or pins. What does a cast do? It stabilizes and immobilizes the bone during healing. Several other bone disorders exist, the most common of which is ________________. Osteoporosis 8: The Skeletal System Overview of the Skeletal System Axial Skeleton: Forms the central supporting axis of the body. Includes the skull, vertebral column, and thoracic cage. Appendicular Skeleton:  Includes the limbs and girdles (pectoral and pelvic girdles). Bone Count: Adults typically have 206 bones. At birth, there are around 270 bones. The number of bones decreases as separate bones fuse during childhood. Fusion is usually complete by early adulthood. Sesamoid Bones: Small bones that form within tendons in response to stress. Example: Patella (kneecap). Extra Skull Bones: Some people have extra bones called sutural (or wormian) bones. Bone Markings: Bones exhibit various anatomical features such as ridges, spines, bumps, depressions, canals, pores, slits, and cavities. Many of these markings can be felt on your own body. The Skull Composition: The skull is composed of 22 bones. Sutures are immovable joints that connect skull bones. Cavities: The largest cavity is the cranial cavity, which encloses the brain. Other cavities include the orbits (eye sockets), nasal cavity, oral cavity, middle and inner ear cavities, and paranasal sinuses. Foramina: Foramina (sing. foramen) are holes that allow passage for nerves and blood vessels. Cranium: Forms the cranial cavity and protects the brain. Composed of eight bones: frontal, parietal (2), temporal (2), occipital, sphenoid, and ethmoid. Meninges:  The brain is separated from the cranial bones by three membranes called meninges. The thickest and toughest is the dura mater. Foramen Magnum: The cranium has an opening called the foramen magnum where the spinal cord enters. Frontal Bone: Extends from the forehead back to the coronal suture. Joins the frontal bone to the parietal bones. Parietal Bones: Form most of the cranial roof and part of its walls. Bordered by four sutures: sagittal, coronal, lambdoid, and squamous. Temporal Bones: Form much of the lower wall and part of the floor of the cranial cavity. Can be felt just above and anterior to each ear. Four parts: squamous, tympanic, mastoid, and petrous. Zygomatic Process: Forms part of the zygomatic arch (cheekbone). Mandibular Fossa: Site where the mandible articulates with the cranium. External Acoustic Meatus: Tympanic part is a ring of bone that borders the ear canal opening. Styloid Process: Resembles a stylus (writing implement). Mastoid Process: Filled with small air sinuses that are subject to infection (mastoiditis). Occipital Bone: Forms the rear of the skull and much of its base. Foramen magnum allows passage of the spinal cord. Occipital condyles are smooth knobs on either side of the foramen magnum. Sphenoid Bone:  Complex shape with a thick medial body and outstretched greater and lesser wings. Lesser wing contains the optic canal. Superior orbital fissure serves as a passage for nerves supplying the eye muscles. Sella Turcica: A saddle-like structure that houses the pituitary gland. Ethmoid Bone: Located between the eyes. Contributes to the medial wall of the orbit, the roof and walls of the nasal cavity, and the nasal septum. Perpendicular plate forms the superior part of the nasal septum. Cribriform plate forms the roof of the nasal cavity. Crista galli is a median blade that forms an attachment point for the dura mater. Olfactory bulbs rest in depressions on either side of the crista. Cribriform foramina allow passage for olfactory nerves. Facial Bones Facial Bones: 14 bones: maxillae (2), palatine bones (2), zygomatic bones (2), lacrimal bones (2), nasal bones (2), inferior nasal conchae (2), vomer, and mandible. Maxillae: Largest facial bones forming the upper jaw. Alveolar processes are bony points between teeth. Each tooth root is inserted into a deep socket called an alveolus. Infraorbital foramen is a gash in the floor of the orbit. Palate: Forms the roof of the mouth and floor of the nasal cavity. Consists of a bony hard palate and a fleshy soft palate. Palatine processes are horizontal extensions of the maxilla. Cleft palate is a congenital defect where the palatine processes fail to fuse. Palatine Bones:  Located in the posterior nasal cavity. Each has an L shape formed by a horizontal and perpendicular plate. Zygomatic Bones: Form the angles of the cheeks. Lacrimal Bones: Form part of the medial wall of each orbit. Smallest bones of the skull. Inferior Nasal Concha: Largest of the three nasal conchae. Vomer: Forms the inferior part of the nasal septum. Resembles a plow. Mandible: Strongest bone of the skull and the only one that can move. Mastication is the process of chewing. Mandible has a horizontal body and a vertical ramus. Temporomandibular joint (TMJ) is formed where the mandible articulates with the temporal bone. Auditory Ossicles and Hyoid Bone Auditory Ossicles: Three bones in each middle-ear cavity: malleus, incus, and stapes. Hyoid Bone: Slender bone between the chin and larynx. Does not articulate with any other bone. Serves as an attachment point for muscles of the tongue, larynx, and pharynx. Infant Skull Fontanelles: Soft spots on an infant's skull where bones have not yet fused. Joined only by fibrous membranes.  Intramembranous ossification takes place later. Most fontanelles ossify by 1 year of age. The largest, the anterior fontanelle, is still evident 18 to 24 months after birth. The Vertebral Column and Thoracic Cage Functions of the Vertebral Column: Supports the skull and trunk. Allows for movement. Protects the spinal cord. Absorbs stresses produced by walking, running, and lifting. Provides attachment for limbs, thoracic cage, and postural muscles. Structure: Consists of a chain of 33 vertebrae with intervertebral discs of fibrocartilage between them. Vertebral Groups: 1. Cervical (7 vertebrae) 2. Thoracic (12 vertebrae) 3. Lumbar (5 vertebrae) 4. Sacral (5 vertebrae, fused in adults) 5. Coccygeal (4 vertebrae, fused in adults) Shape and Curvatures: The vertebral column has an S-shape with four bends: cervical, thoracic, lumbar, and pelvic. In newborns, the vertebral column is C-shaped. The S-curve develops as the child begins to lift its head and walk, allowing for better balance and weight distribution. Cervical curvature develops when the baby starts to lift its head. Lumbar curvature develops when the child begins to walk. Vertebra Features: The most obvious feature is the vertebral body, which bears weight. Vertebral foramina form the vertebral canal, through which the spinal cord passes.  The spinous process is directed posteriorly and downward. Spinous and transverse processes provide attachment points for muscles and ligaments. Intervertebral foramen allows passage for spinal nerves. Intervertebral Discs: Consist of a nucleus pulposus (inner gelatinous core) and anulus fibrosus (outer ring of fibrocartilage). Discs help with shock absorption and flexibility. A herniated disc occurs when the nucleus pulposus protrudes through the anulus fibrosus. Regional Differences: Cervical vertebrae (C1–C7) are small and allow for head movement. C1 (atlas) articulates with the occipital bone, allowing for nodding. C2 (axis) allows for head rotation. The dens (odontoid process) of C2 can cause fatal injury if damaged. Atlas and cranium form the atlanto-occipital joint. Atlas and axis form the atlantoaxial joint. Cervical vertebrae have transverse foramina for vertebral arteries. Thoracic Vertebrae: T1–T12 correspond to the 12 pairs of ribs. Features include costal facets for rib attachment, spinous processes that angle downward, and larger bodies than cervical vertebrae. Lumbar Vertebrae: L1–L5 are larger and thicker, supporting more weight. Sacrum: In children, consists of five separate vertebrae (S1–S5) that fuse by age 26. Anterior sacral foramina allow passage for nerves and blood vessels. Auricular surface articulates with the hip bones, forming the sacroiliac joint. Coccyx: Usually consists of four (sometimes five) coccygeal vertebrae, which fuse by age 20-30. Can be fractured by a fall or during childbirth. Thoracic Cage: Consists of the thoracic vertebrae, ribs, and sternum. Encloses and protects the heart and lungs. Plays a role in breathing by expanding and contracting. Sternum: Composed of three regions: manubrium, body, and xiphoid process. Improper chest compressions can drive the xiphoid process into the liver, causing fatal hemorrhage. Ribs: 12 pairs with no difference between sexes. True ribs (1–7) attach directly to the sternum. False ribs (8–12) attach indirectly or not at all. Floating ribs (11–12) do not attach to the sternum. The Pectoral Girdle and Upper Limb Pectoral Girdle: Consists of the clavicle and scapula. Sternoclavicular joint: clavicle and sternum. Acromioclavicular joint: clavicle and scapula. Glenohumeral joint: scapula and humerus. Clavicle: S-shaped with sternal (medial) and acromial (lateral) ends. Commonly fractured due to its subcutaneous position. Scapula: Triangular plate overlying ribs 2–7. Suprascapular notch allows passage for a nerve. Anterior surface: subscapular fossa. Posterior surface: spine, supraspinous fossa, infraspinous fossa. Acromion articulates with the clavicle. Glenoid cavity articulates with the humerus, forming the shoulder joint. Upper Limb Regions: 1. Brachium (arm): humerus. 2. Antebrachium (forearm): radius and ulna. 3. Carpus (wrist): 8 carpal bones. 4. Manus (hand): 5 metacarpals and 14 phalanges. Humerus: Head articulates with the glenoid cavity. Common fracture site: surgical neck. Deltoid tuberosity: insertion for deltoid muscle. Distal end: capitulum (lateral condyle) articulates with radius, trochlea (medial condyle) articulates with ulna. Pits: olecranon fossa (posterior), coronoid fossa (anterior medial), radial fossa (anterior lateral). Radius: Discoidal head at proximal end. Spins on the capitulum and radial notch of ulna. Radial tuberosity: insertion for biceps brachii muscle. Ulna: Trochlear notch wraps around the trochlea of the humerus. Radius and ulna connected by interosseous membrane, allowing for pronation and supination. The Pelvic Girdle and Lower Limb Pelvic Girdle Composition: Composed of two hip bones (coxal bones) and the sacrum. Joints: Each hip bone is joined to the vertebral column at the sacroiliac joint. The two hip bones are joined to each other at the pubic symphysis, which consists of the interpubic disc and the adjacent region of each hip bone. Pelvis Structure: The greater (false) pelvis is between the flare of the hips.  The lesser (true) pelvis is below the greater pelvis. Separated by a round margin called the pelvic brim. The opening circumscribed by the brim is called the pelvic inlet. The lower margin of the lesser pelvis is called the pelvic outlet. Hip Bone Features: 1. Iliac Crest: The superior crest of the hip. 2. Acetabulum: The hip socket. 3. Obturator Foramen: A large round-to-triangular hole below the acetabulum. Fusion of Childhood Bones: The adult hip bone is formed by the fusion of three childhood bones: ilium, ischium, and pubis. Ilium: The largest bone, extends from the iliac crest to the center of the acetabulum. Greater sciatic notch below the posterior inferior spine, named for the sciatic nerve that passes through it. Auricular surface joins with the sacrum to form the sacroiliac joint. Ischium: The inferoposterior portion of the hip bone. Ischial tuberosity supports the body when sitting. Pubis: The most anterior portion of the hip bone. Has a superior and inferior ramus and a triangular body. Bodies of the pubis meet at the pubic symphysis. Pubis and ischium encircle the obturator foramen. Sexual Dimorphism: The pelvis is sexually dimorphic, meaning it has differences between males and females, typically related to childbirth. Lower Limb Regions: 1. Femoral Region (Thigh): Femur. 2. Crural Region (Leg): Tibia and fibula.  3. Tarsal Region (Ankle): Tarsal bones. 4. Pedal Region (Foot): Metatarsals and phalanges. Femur: The longest and strongest bone of the body. Hemispherical head articulates with the acetabulum in a ball-and-socket joint. Greater and lesser trochanters for muscle attachment. Epicondyles and Supracondylar Lines: Medial and lateral epicondyles are the widest points at the knee. Attachments for thigh and leg muscles and knee ligaments. Patella: A large sesamoid bone (kneecap). Cartilaginous at birth, ossifies at 3 to 6 years of age. Tendons and Ligaments: Tendons connect muscle to bone. Ligaments connect bone to bone. Tibia: Located on the medial side of the leg. The only weight-bearing bone of the crural region. Sharp angular anterior border (shin). Ankle Knobs: Medial malleolus (part of the tibia). Lateral malleolus (part of the fibula). Fibula: A slender strut that helps stabilize the ankle. Joined to the tibia by an interosseous membrane. Ankle and Foot: Bones in proximal and distal groups similar to the wrist. Largest tarsal bone is the calcaneus (heel bone). Second largest and most superior tarsal bone is the talus.  9: Joints Joints and Their Classification 1. Define joint: A joint, also known as an articulation, is a connection between two bones in the skeletal system. 2. What is arthrology? Arthrology is the study of joints, their structure, function, and classification. 3. The study of musculoskeletal movement is ______________, a branch of biomechanics, which deals with a broad variety of movements and mechanical processes of the body. The study of musculoskeletal movement is kinesiology, a branch of biomechanics. 4. The name of a joint is derived from what? Can you give some examples? The name of a joint is often derived from the bones involved in the joint. Examples: Temporomandibular joint: Named after the temporal bone and the mandible. Sternoclavicular joint: Named after the sternum and the clavicle. 5. What are the four main categories of joints? The four main categories of joints are: 1. Bony joints (synostoses) 2. Fibrous joints (synarthroses) 3. Cartilaginous joints (amphiarthroses) 4. Synovial joints (diarthroses) 6. A _______ joint, or synostosis, is an immovable joint formed when the gap between two bones ossifies. A bony joint, or synostosis, is an immovable joint formed when the gap between two bones ossifies. 7. Bony joints can form by ossification of either _______ or ______________ joints. Bony joints can form by ossification of either fibrous or cartilaginous joints. 8. Can you give an example? An example of a bony joint is the fusion of the left and right halves of the frontal bone in the skull. 9. The epiphyses and diaphyses of long bones are jointed by _____________ joints that become synostoses in early adulthood. The epiphyses and diaphyses of long bones are jointed by cartilaginous joints that become synostoses in early adulthood. 10. A ____________joint (synarthrosis or synarthrodial joint) has adjacent bones that are bound by collagen fibers. There are three kinds of fibrous joints: sutures, gomphoses, and syndesmoses. A fibrous joint (synarthrosis or synarthrodial joint) has adjacent bones that are bound by collagen fibers. There are three kinds of fibrous joints: sutures, gomphoses, and syndesmoses. 11. What is a suture? A suture is a t