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Complete Final Exam Review 31 whole pages of notes, including many diagrams ! prof can ask some detailed questions, so they are detailed notes

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University of Waterloo
BIOL 273
Katherine Wood

Introduction physiology: study of the structure and function of a living organism and its component parts Tissue Types 1. Epithelial- protect internal environment, regulate the exchange of materials a) exchange rapid exchange of material b) transporting selective transport of material c) ciliated provide transport in airways and female reproductive tract d) protective e) secretory synthesize and release products into the external environment/blood 2. Connective structural support & barriers, extensive ECM, contains proteoglycans, collagen, elastin, fibrillin and fibronectin a) loose elastic b) dense strength (tendons and ligaments) c) adipose contains adipocytes d) blood e) supporting dense (cartilage and bone) 3. Muscle contract to produce force and movement a) skeletal body movement b) smooth substances into/out of body c) cardiac moves blood from heart 4. Neural carry info. From one part of the body to another, very little ECM a) neurons electrical or chemical info. b) glial cells suppot neurons homeostasis: maintenance of a relatively stable internal environment; involves automatic control acclimatization: environmentally induced change in physiological function with no genetic change circadian rhythms: daily biological rhythms ex. Sleep, menstrual cycle Cell-to-Cell Communication 1. Gap junctions occur via connexons (protein channels), can open and close 2. Contact-dependent interaction between membrane molecules, found in immune cells and during development 3. Local communication via paracrine (act on neighbouring cells) and autocrine (act on the cell producing them) signals ex. Histamine 4. Long-distance communication use chemical and electrical signals (neurohormones, neurotransmitters), used in nervous and endocrine system 1. Receptors trans-membrane or glycoproteins a) extracellular hydrophilic, bind ligand b) trans-membrane - hydrophobic c) intracellular hydrophilic, activate cellular response agonist: activates receptor and response, not necessarily at the same level antagonist: binds but inhibits the response Control and Integration 1. Local or Long-distance Control local: effects are exerted on neighbouring cells reflex: reaction is controlled from elsewhere steady state: a system in which a particular variable is not changing and energy is constantly added ex. Internal body temperature stimulus sensor/receptor afferent pathway integrating centre efferent pathway target/effector response Negative feedback: opposes or removes the signal, returning the variable to its original state, oscillation around a set-point Positive feedback: reinforces stimulus, further from the set-point (not homeostatic) ex.labour Feedforward control: predicts that change is about to happen, starts the response loop before stimulus to prevent change and have less oscillation ex. Smell of food up-regulation: increases the response to a stimulus down-regulation: decreases the response to a stimulus Neurophysiology Components of the Nervous System 1. Central Nervous System brain&spinal cord nuclei: clusters of neuronal bodies tracts: bundles of axons forming a pathway 2. Peripheral Nervous System consists of nerves (bundles of axons of sensor & motor neurons) receptors: cells specialized to convert stimuli into electrical signals ganglia: clusters of neuronal cell bodies 3. Receptors convert stimuli into electrical signals, transmit info to afferent neurons 4. Afferent (sensory Neurons transmit to CNS, cell bodies outside CNS, transmit to interneurons 5. Interneurons inside CNS, 96% of all neurons, transmit to efferent neurons 6. Efferent (motor) Neurons inside CNS, carry out the message for a response Cells of the Nervous System 1. Neurons generate electrical pulses over long distances a) Soma (cell body) contains nucleus, keeps cell functioning b) dendrites receive info, transmit electrical signals towards soma c) axon send out info, transmit electrical signals away from soma d) axon terminal connection between neuron and other cells; presynaptic pseudounipolar: somatic sensory neurons, axon and dendrites fuse during development bipolar: smell/vision sensory neurons, contain a single axon and dendrite anaxonic: interneuron, axon is hard to identify multipolar (CNS): highly branched with numerous dendrites, no long axon multipolar (efferent): 5-7 dendrites, single long axon 2. Glial Cells -50:1 ratio of glial to neurons, communicate with nearby cells using chemical and electrical signals; aid in nerve impulse conduction, maintain ECM around neurons a) PNS Glial Cells Schwann cell: wrap around axons, forms myelin (layers of membrane), gap junctions between layers Satellite cell: non-myelinating Schwann cells, support soma, maintain ECM b) CNS Glial Cells oligodendria: CNS version of Schwann, myelinate axons astroglia: star-shaped, make contact with blood vessels and neurons to transfer nutrients, maintain homeostatis in ECM microglia: small, specialized immune cells, remove damaged cells and foreign invaders ependymal cells: epithelial, create a selectively permeable barrier Electrical Properties of Neurons electrical principles Coulombs Law (strength is proportional with distance) Nernst Equation: used to calculate the electrical potential of the cell needed to generate an equilibrium state cell at rest inside is electronegative (-90 to -70mV) so ions with a positive equilibrium will want to move in the cell and ions with a negative equilibrium potential will want to move out membrane potential: the electrical and chemical gradients caused by the distribution of ions across the cell membrane is a source of potential energy concentrations of ions equilibrium potential for K+ is about -90mV and +60mV for Na+ Goldman equation: takes into account the permeability of each ion; change ion permeability you change the membrane potential -cell is 40x more permeable to K+ than Na+ -ions DO leak out but Na+/K+ ATPase pump offsets (3 Na+ out for 2 K+ in) 1. Gated Channels a) Mechanical found in sensory neurons, open in response to physical forces b) Chemical respond to ligands c) Voltage respond to changes in voltage 2. Transmission of electrical signals depolarization: a decrease in the membrane potential difference, cell becomes less negative ex. Less permeable to K+, Na+ entry, Ca2+ entry hyperpolarization: an increase in the membrane potential difference, cell becomes more negative ex. Cl- entry, K+ exit change total number of protein channels slow, requires transcription etc. open or close existing protein channels fast, requires a change in protein channel conformation -Na+ contributes minimally to the resting potential but is critical in generating changes that cause electrical signals Signals generated by neurons short distance: graded potentials (increase/decrease) long-distance: action potentials (on/off) Graded Potentials and Action Potentials Graded Potentials -depolarizing or hyperpolarizing -occur in dendrites or cell body of neurons -triggered by opening/closing of ion channels
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