Bio 251 Exam 1 Notes PDF

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08/27/20 Chapter 1: The Human Body Anatomy vs. Physiology Anatomy: the various structures of the body, and their relationship to one another ● Gross anatomy: structures visible to the naked eye ○ Regional vs. systemic anatomy ◆ Regional: examines all of the structures in a particular region of the body ● Can focus only on the thoracic ● Examines organs of different systems ◆ Systemic: examines the structures that belong to a single system ● Microscopic anatomy: structures that are microscopic ○ Cytology vs. histology ◆ Cytology: study of cells ◆ Histology: study of tissues ◆ Physiology: how these individual body parts work (or function) on a normal level ● Most often considered at the cellular/molecular level ● What an organ does to keep us alive under normal conditions Principle of Complementarity of Structure and Function ● What a structure can do is dependent on its form ● Physiology depends on anatomy ➔ Structural Organization of the Human Body 1) Chemical level ● Atoms combine to form molecules 2) Cellular level ● The smallest unit of life ● Cells will have very different functions based on where in the body they are found - this is what makes the physiological function of each organ unique 3) Tissue level ● Aggregations of living cells that carry out a similar function ● Four basic types: muscle, epithelial, nervous, and connective ● Each organ is composed of at least two tissue types 4) Organ level ● These tissues operate together to perform a certain function 5) Organ system level ● multiple organs work together to accomplish a purpose

6) Organismal level ● All organ systems working together to keep the organism alive Necessary Life Functions 1) Maintaining boundaries ● At the cellular level, and at the organismal level ○ At the cellular level there is the plasma membrane which will form a boundary that will separate the intracellular fluid from the extracellular fluid - ensures all the organelles stay together so that the cell can function ○ At the organismal level, the integument (skin) encloses the body as a whole and helps prevent desiccation and will prevent entry of pathogens or chemicals 2) Movement ● Cooperation of skeletal and muscular systems to coordinate actions ○ Can be conscious movements, or not ◆ Conscious = body movement produced by skeletal muscle tissue and bones; voluntary movement ◆ Involuntary movement = includes smooth muscle tissue and cardiac muscle tissue 3) Responsiveness (excitability) ● Sensing environmental changes and responding to them ● Nervous system is primarily involved with excitability ○ Also muscle tissue 4) Digestion ● Food is broken down to simple molecules to be absorbed to blood and delivered to various tissues ● Without this cells would run out of ATP 5) Metabolism - sum of all chemical reactions that take place in a cell and provide energy for vital processes and synthesis of various organic material; rate will depend on digestive and respiratory systems; controlled by hormones ● Catabolism, anabolism, and cellular respiration ○ Catabolic reaction = breaks down large complex structures into simpler structures ○ Anabolic reaction = build up large complex structures from simpler structures ○ cellular respiration = creation of ATP using oxygen and glucose 6) Excretion ● Removal of waste produced during digestive and metabolic functions ● Digestive, urinary, and respiratory systems are important for excretion

7) Reproduction ● Cellular level: cells must divide for organism to survive ● Organismal: production of offspring 8) Growth ● Increase in the number of body cells, or increase in size of individual cells themselves ● Building must occur faster than destruction ○ Anabolic have to exceed catabolic Survival Needs 1) Nutrients ● Brought into body by ingestion and absorption ● Include carbohydrates, fats, proteins along with vitamins and minerals ○ Carbohydrates = energy source ○ lipids/fats = very rich energy reserve ○ Proteins = are used for various structures ○ vitamins/minerals = necessary for chemical reactions in the body 2) Oxygen ● Cells can only survive a few minutes without oxygen 3) Water ● Provides environment for chemical reactions and serves as fluid base for secretions and excretion 4) Endothermy ● Body temperature must be maintained for chemical processes to occur 5) Atmospheric Pressure ● Breathing and gas exchange occur at an appropriate atmospheric pressure Homeostasis ◆ Homeostasis is the maintenance of the internal condition of the body despite a constantly changing external environment ● This maintenance is not a static state ● Accomplished by the work of virtually all organ systems Control of homeostasis ● Chiefly regulated by nervous system (neural impulses) and endocrine system (hormones) ○ central nervous system will send electrical impulses through the body and each impulse will carry a message to its destination organ ◆ Can cause an organ to increase or decrease its activity to help regulate homeostasis

○ Hormones are chemical messengers that cause a change in cellular activity when the cell binds to the hormone ◆ Each hormone can exert a different effect depending on the cell type or the receptor ● Variable: what is being controlled or regulated (ex. body temperature) ○ Receptor - specific structure that will receive information about the variable; will generate a message to be sent to the control center ○ Control center - responsible for interpreting the message and deciding what it is being told ○ Effector - an organ or structure that will carry out the response of the control center ◆ Homeostasis is controlled by negative feedback mechanisms or positive feedback mechanisms ● Negative feedback mechanisms: cause the variable to change in a direction that is opposite of the initial change to prevent severe changes in the body; used to reduce the intensity of a change in a certain direction and prevents sudden or severe changes that can be fatal or cause permanent damage ○ Ex: thermoregulation, hormones ● Positive feedback mechanism: cause the original change of the variable to be enhanced ○ Do not control events that require frequent, small adjustments ○ Ex: labor, blood clotting Imbalances in Homeostasis ● Aging often leads to homeostatic imbalance ○ Control systems become less efficient, making us more susceptible to disease ● Cascade of events caused by positive feedback mechanisms can overpower negative feedback mechanisms Anatomical Terms Position & Directional Terms ● Reference point: anatomical position ○ Right vs. left is always viewed in terms of the person being observed, not your own ● Directional terms: helps us explain one body part in relation to the others ◆ Regional terms: designate specific areas of the body within the axial and appendicular parts of the body

● Axial = forms the long axis of the body which includes the head and the vertebral column ● Appendicular = the appendages - the arms and legs Body Planes ● Sagittal: divides body into left and right ○ median/midsagittal plane divides the body exactly in half ● Frontal: divides body into anterior and posterior ○ Divides the body into the belly side to the back ● Transverse: divides body into superior and inferior parts Body cavities ● Most organs are found in one of the body cavities ○ Cavities will be closed meaning there is no hole leading into or out of the body and will serve to protect the organs within the particular cavity ● Dorsal body cavity: protects organs of the central nervous system (CNS) ○ Composed of the cranial cavity and spinal cavity ◆ Cranial cavity houses the brain ◆ Spinal cavity houses the spinal cord ● Ventral body cavity: houses visceral organs (deep body organs) ○ Composed of the thoracic cavity and the abdominopelvic cavity ◆ Thoracic cavity: chest which contains heart and lungs ◆ Abdominopelvic cavity: separated from thoracic cavity by diaphragm, contains digestive, urinary bladder, reproductive organs, rectum ○ Membranes ◆ Serous membrane: double-layered membrane covering internal organs (visceral serosa) -  layer will cling to the outside of the visceral organs - and the walls of the cavities (parietal serosa) - layer will cling to the body wall of the cavity - separated by thin layer of serous fluid which helps prevent excessive friction of the organs up against the body wall ● Pericardium, pleura, and peritoneum - concerned with the location ○ Pericardium = found in the pericardial cavity; visceral pericardium wraps around the heart and the parietal pericardium clings to the wall of the pericardial cavity

○ Pleura = serous membrane that is found in the pleural cavity which is anything associated with the lungs - visceral pleura wraps around the lungs and the parietal pleura clings to the wall of the pleural cavity ○ Peritoneum = serous membrane associated with the abdominopelvic organs Smaller body cavities ● Oral/Digestive cavities ○ Mouth is continuous with other digestive organs ◆ Mouth is usually called buccal cavity ● Nasal cavity ○ Within and posterior to nose, part of respiratory passageway ◆ Found in the skull ● Orbital cavity ○ Orbitals of skull ◆ Depressions in front of the skull where the eyes insert into the skull ● Middle ear cavity ○ Contains bones that help transmit sound vibrations to inner ear ◆ 3 ear bones; where most ear infections occur ● Synovial cavities ○ Associated with synovial joints → surround freely moveable joints of the skeletal system 09/01/20 Chapter 2: Chemistry Molecules, Compounds, & Mixtures ◆ Molecule: the combination of two or more atoms of the same   element ● Ex: O2 ◆ Compound: the combination of two or more atoms of different   elements ● Ex: NaCl (table salt) ◆ Mixtures: any substance containing two or more components physically intermixed ● Types of mixtures ○ 1) Solutions: homogeneous mixtures that can exist as a solid, liquid, or gas composed of very small particles that do not settle out (separate) ◆ Solvent i s the dissolving medium ● Water is the body’s primary solvent

◆ Solute i s dissolved in solvent ● Usually present in smaller amounts ◆ Ex: saline solutions (water + NaCl) ○ Concentration of solution can be described using: ◆ A) Percent solution: amount of solute (mass or volume) is expressed as a percentage of the total solution volume (usually expressed as a liquid but sometimes as a mass); can be used for solid-liquid, solid-solid, and liquid-liquid ● How to calculate: total mass of solute (g) ○ % Solution = total mass of volume (ml) x 100 Example: Hospitals use a 0.9% saline solution to replenish fluids and electrolytes. How much sodium chloride (NaCl) would need to be added to 1000 ml of water to produce this solution? ◆ B) Molarity (mol/L): the number of moles of a substance per liter of solution ● Reminder: a mole of any element or compound is equal to its molecular weight ● How to calculate: M oles solute ○ M = Liters of solution ● Example: What is the molarity of a solution formed from 10.45 g glucose dissolved in water to make a total volume of 550 ml? ● Example: Calculate the mass of glucose required to make a 0.5 M solution with a total volume of 325 ml. ○ 2) Colloids: heterogeneous mixtures composed of large solute particles that do not settle out ◆ Can undergo sol-gel transformation → mixture can change from a fluid state to more solid state (and back again!) ● Ex: cytosol (semi-fluid mixture found in all living body cells) of cells changes consistency depending

on certain cell activities (cellular division, change in shape, etc.) ○ 3) Suspensions: heterogeneous mixture composed of large solute particles that do settle out ◆ Ex: blood contains a fluid portion (called plasma) with various cell types (red blood cells, white blood cells, & platelets) suspended in it Chemical Bonds ◆ Reminder: chemical bonds occur when chemical substances are held together by the attraction of atoms to each other through sharing or exchanging electrons ● Electrons that are farthest from the nucleus have the greatest potential energy and are most likely to be involved in forming and breaking bonds Types of bonds: ● 1) Ionic bond: transfer of electrons to or from one atom to another, such that charged particles (ions) are formed ○ Anions: accept the electron, becomes negatively (-) charged ○ Cations: donates the electron, becomes positively (+) charged ○ Ex: NaCl ● 2) Covalent bonds: atoms involved in this bond share some electrons in a common orbital ○ Can be single, double, or triple ○ Polar vs nonpolar molecules Nonpolar molecules: atoms in covalent bond share electrons equally, are electrically balanced ● Ex: electrons in CO2 share electrons equally Polar molecules: atoms in covalent bond do not share electrons equally, with one atom being an “electron hog” ● Ex: oxygen (electronegative) strongly attracts electrons from hydrogen (electropositive) in H2O ● 3) Hydrogen bonds: occur when hydrogen atom that is already covalently bonded to another atom is attracted by another “electron hungry” atom ○ Too weak to form molecules, but can be structurally important ○ Ex: oxygen in H2O pulls hydrogen from another H2O molecule ◆ This forms surface tension Chemical Reactions ◆ Occur when chemical bonds are formed, broken, or rearranged Types of reactions: ● 1) Synthesis reaction: formation of bonds between atoms or molecules to form larger, more complex structures

○ Are endergonic → contains more energy after formation ◆ Product will have more free energy than the reactants ○ Ex: anabolic reactions in the body ● 2) Decomposition reaction: bonds are broken to create smaller molecules or individual atoms ○ Are (mostly) exergonic → release energy when bond is broken ◆ Product will have less free energy than the reactants ○ Ex: catabolic reactions in the body Inorganic Compounds & Homeostasis ◆ 1) Water: makes up most of body mass and most of the volume of individuals cells ● Importance in homeostasis: ○ A) Universal solvent ◆ Transport → water carries nutrients, respiratory gases, metabolic waste, etc. ◆ Water can surround some charged structures (ex: large proteins) to prevent interactions with other charged particles ○ B) Heat capacity is high - the amount of heat needed to raise the body temperature by 1 degree Celsius ◆ Can absorb and release large amounts of heat with little change to its own temperature ◆ Importance: prevents overheating from sun exposure, exercise, etc. ○ C) Protection ◆ Water-based body fluids provide a “cushion” for internal organs ◆ Importance: prevents damage to organs ○ D) Heat of vaporization is high ◆ Large amount of heat must be absorbed to break bonds & cause evaporation ◆ Importance: sweating is extremely effective in cooling the body ○ E) Reactive ◆ Water is used in several chemical reaction in the body ● Hydrolysis reaction vs. dehydration  synthesis ○ Hydrolysis reaction: water is added to a compound to break the bonds of a particular substance

○ Dehydration synthesis: removal of water to form bonds to create a particular substance ◆ Importance: chemical reactions stop with little/no water availability ◆ 2) Salts: dissociate in solution to form electrolytes ● Importance: electrolytes Na+ and K+ allow for muscle contraction and transmission of nerve impulses, Fe+ used to carry O2, etc. ◆ 3) Acids & Bases: also form electrolytes ● Acids: release H+ ions in solution ○ Cause pH to drop ● Bases: release OH- ions in solution ○ Cause pH to increase ● Importance: many chemical reactions in the body take place at a certain pH, blood pH is optimal at 7.2-7.4 ● Potential problem: high/low pH disrupts cellular activity, hydrogen bonds, etc. ○ Solution? Buffers! ◆ Weak acids release some (but not all) H+ when pH becomes too basic ● Are weak because they only partially dissociate ◆ Weak bases tie up excess H+ when pH becomes too acidic ◆ Result: buffers prevent large changes in pH that could cause excessive damage in the body Organic Compounds & Homeostasis ◆ Organic molecules found in the body contain carbon ● Why? It is electroneutral → it neither gains nor loses electrons, can form molecules of various shapes (long chains, rings, etc.) Macromolecules: polymers that are made up of several smaller, identical subunits called monomers ● Macromolecule formation involves dehydration synthesis ○ H from one monomer and OH from second monomer are removed ◆ Result: monomers form a covalent bond, water is released at the site of bond formation ● Macromolecule breakdown involves hydrolysis ○ Water is added to break covalent bond between monomers Types of Macromolecules ◆ 1) Carbohydrates: sugars and starches ● Monomer: monosaccharide

○ Monosaccharides can form disaccharides, polysaccharides ◆ Disaccharides and polysaccharides must be hydrolyzed to be used by cell ● Are physically too large to pass through the cell membrane ● Hydrolysis reactions take place in the digestive tract ○ General formula: CH2O ◆ Ex: glucose = C6H12O6 ○ Importance: pentose sugar deoxyribose   found in DNA, glucose is blood sugar, etc. ● Major functions: ○ Fast, easy-to-use energy source ○ Cell-cell interactions → carbohydrates attached to cell surface, used to communicate ◆ Carbohydrates are attached to the exterior of the plasma membrane ○ Structural (very small amount) ◆ 2) Lipids ● Types of lipids ○ A) Triglycerides ◆ Monomer: fatty acids and glycerol ◆ Varieties: ● Saturated → contain only single covalent bonds, molecules packed closely together; typically solid at room temperature; bad for your health ○ Ex: fat found in meat products ● Unsaturated → contain 1 or more double covalent bonds, molecules more spread out ○ Ex: most plant-based oils ● Trans fat → oil fats that have a H added at sites of double bonds ○ Ex: doughnuts, cookies ● Omega-3 fatty acids → oil fat found in cold-water fish ○ Ex: krill oil, fish oil capsules ◆ Major functions: protection, insulation, fast & easy accessible energy storage ○ B) Phospholipids

◆ Modified triglycerides with 2 fatty acid chains and a phosphate group ● Fatty acid chains are hydrophobic ● Phosphate “head” is hydrophilic ○ Polar heads face the outermost portion of the cell ● Nonpolar tails are hydrophobic ◆ Major functions: used to build cell membranes (phospholipid bilayer) ○ C) Steroids ◆ Most important steroid for life: cholesterol ● Ingested in eggs, meat, cheese ● Liver produces cholesterol ◆ Major functions: structural component of cell membranes, is “base” used by body to form other steroids (steroid hormones - testosterone & estrogens, corticosteroids) ◆ 3) Proteins ● Monomers: amino acids ○ Amino acids linked together by peptide bonds ○ Sequence in which amino acids is ordered leads to large variety of protein functions ◆ Any disruption in the order of amino acids will lead to either a decrease in the function of the protein or a complete loss of function of the protein ● Structure determines function! ○ Fibrous proteins → form long strands that can link together to form long, stable structures ◆ Function(s): provide mechanical support & tensile strength, some contractile ability ◆ Ex: collagen, muscle ○ Globular proteins → compact, spherical in shape ◆ Chemically active ◆ Function(s): transport molecules, immune defenses, regulation of growth & development, etc. ● Enzymes: biological catalysts ○ Function: catalysts lower the activation energy of chemical reactions ○ Varying degrees of specificity

◆ Some only catalyze 1 reaction, others can catalyze multiple reactions ○ Importance: without enzymes, most reactions in the body would either not occur or would occur too slowly to sustain life ◆ 4) DNA & RNA ● Importance: store, transmit, and help express genetic information ● Monomer: nucleotides ● Deoxyribonucleic Acid (DNA) ○ Double-stranded structure with pentose sugar deoxyribose ○ Bases: Adenine (A), Guanine (G), Thymine (T), Cytosine (C) ○ Replicates itself prior to cell division → all resulting cells carry same genetic information ○ Importance: stores genetic information in the form of genes (or genome) in the nucleus of the cell ● Ribonucleic Acid (RNA) ○ Single-stranded structure with sugar ribose ○ Bases: Adenine (A), Guanine (G), Cytosine (C), Uracil (U) ○ Function: uses “instructions” from DNA for protein synthesis Organic Compounds & Homeostasis (continued) ◆ ATP & ce...