1 EXAM 1 STUDY GUIDE Explain the resting membrane potential and how it maintains balance by using Potassium and Sodium ions Na binds to the pump protein stimulating phosphorylation by ATP causing The shape change expels Na to the outside Extracellular K binds causing the pump protein to change shape release of the phosphate group Loss of phosphate restores original conformation of the pump protein K is released to cytoplasm and Na sites are ready to bind Na again Cycle repeats MEMBRANE POTENTIAL K diffuse down the concentration gradient out of the cell via leakage channels Loss of K results in a charge on the inner plasma membrane face K move into cell bc they are attracted to the charge on in the inner plasma membrane face A membrane potential is established when the movement of K out of the cell K movement into the cell The concentration gradient promoting K exit exactly opposes the electrical gradient for K entry More membrane potential Separation of oppositely charged particles ions across a membrane creates a membrane potential potential E measured as voltge Resting membrane potential RMP voltge measured in resting state in all cells o Ranges from 50 to 100 mV in diff cells o Results from diffusion and active transport of ions mainly K Sodium pumped out of cell using ATP and K into cell and you get a gradient High Sodium outside of cell and K inside cell Primary Active transport bc we use ATP directly If you use K or Na from gradient its secondary active transport using ATP indirectly create a membrane potential bc lots of K inside This creates a neg charge inside cell bc youre pumping out more positive than bringing in more positive The cell is really permeable to K K want to leave cell bc there is a concentration gradient So much in the cell that it wants to go down the gradient Na wants to get into the cell K will freely leave but not all leaves bc theres an electrical gradient Membrane becomes more negative as K leaves cell When the positive charge leaves it leaves negatively charged protein HOMEOSTASIS IN REFERENCE TO THERMOREGULATION AND NEGATIVE FEEDBACK LOOP body does something to cancel out a stimulus Homeostasis used for maintenance of a stable internal environment necessary for normal body fxing and to sustain life 2 Stimulus produces change in variable Change detected by RECEPTOR Output info sent along efferent pathway to activate EFFECTOR Response of effector feeds back to influence magnitude of stimulus returns Input info sent along afferent pathway to the control center BRAIN Negative feedback decreases the original stimulus or reduces intensity of variable to homeostasis original stimulus Positive feedback increases original stimulus to push the variable farther Only occurs in blood clotting milk let down birth of baby Body temperature goes up you have centers that tell the brain you are hot Set point is 37 degrees Hypothalamus in brain says the normal set point should be 37 degrees but its higher than that Brain in the output direction says to sweat bring bloodflow to skin Increase bloodflow to skeletal muscles directs away from core bc its too hot so blood can cool down Body temp goes down Called negative feedback bc the response by body cancels out the stimuli Primary way to maintain homeostasis negative feedback OSMOTIC PRESSURE movement of water Isotonic solution equal concentration of ions in solution and cell iso same tone shape bodies have osmolarity of 300 Hypertonic solution higher concentration of ions in solution than in cell cells shrink water moves out of cell Hypotonic solution lower concentration of ions in solution than in cell water goes into the cell cell expands NECESSARY LIFE FUNCTIONS Maintain boundaries Movement locomotion and movement of substances Growth increases cell size and of cells Responsiveness ability to sense changes and react Digestion breakdown and absorption of nutrients Metabolism chemical rxns within the body Excretion eliminates waste from metabolic rxns LEVELS OF ORGANIZATION Gross anatomy large structures easily observable Microscopic anatomy very small structures can only be viewed with microscope Cells smallest living unit Tissues collection of cells of same type Organs collection of 2 or more types of tissue put together into structures Organ systems collection of organs that work together to accomplish a that perform a specific fx particular task 3 BODY FLUID COMPARTMENTS Total body water all water in body Intracellular fluid inside cells Extracellular fluid outside cells includes plasma Plasma fluid blood is dissolved in matrix of connective tissue called blood Interstitial fluid cells surrounded by solution that bathes cells very similar to extracellular but does not include plasma FOUR TISSUE CLASSES Muscle Nervous Epithelial Connective BODY PLANES AND SECTIONS sagittal divides body or organ into left and right parts median or midsagittal divides body or organ into equal left and rights parts frontal divides body or organ into anterior ventral and posterior dorsal parts transverse or cross section divides body or organ into superior and inferior parts CHEMISTRY matter anything that takes up space and has mass composed of atoms molecules elements are fundamental units of matter energy capacity to do work used in cells to perform specific functions 4 main elements o carbon o oxygen o hydrogen o nitrogen atomic mass protons neutrons atomic number protons atoms of the same element share the same properties isotope elements can have atoms with diff masses Diff of neutrons CHEMICAL BONDS bond interaction bw 2 atoms many diff types of bonds Covalent bonds o Octet rule most atoms want 8 e s in outer shell o Single bond sharing 1 pair of e s 1 e from each atom o Double bond sharing 2 pairs of e s o Some are nonpolar electrically neutral some polar have a and charge 4 Ionic Bonds o Polar covalent bond results in regions of slight pos charge and regions of slight neg charge o Polar molecules can interact with ionic bonds Atoms may gain lose e s o o charged ions are cations lose an e o charged atoms are anions gain an e o o electrical forces hold ions together o o form when e s are transferred from 1 atom to another ions donate or accept e s so they can have 8 s in outer shell ions of opposite charges are electrically attracted to each other Hydrogen Bonds o charged regions on water molecules are attracted to the oppositely charged regions on nearby molecules o this attraction forms weak bonds called H bonds o weak
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