VPHY 3100 Exam 2 Study Guide
VPHY 3100 Exam 2 Study Guide VPHY 3100
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This 11 page Study Guide was uploaded by Lorin Crear on Saturday October 3, 2015. The Study Guide belongs to VPHY 3100 at University of Georgia taught by Dr. Li, Dr. Wells, Dr. Brown in Summer 2015. Since its upload, it has received 353 views. For similar materials see Elements of Physiology in Animal Science and Zoology at University of Georgia.
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Date Created: 10/03/15
Chapter 10 Sensory Physiology 0 Sensory cells 0 specialized epithelial cells that synapse With neurons 0 Information conveyed by sensory system 0 Modality of stimulus I What kind of sensory information is it o Intensity of stimulus I Encoded by frequency of action potentials I Greater intensity greater voltage of generator potentials local depolarizations of membrane greater frequency of action potentials 0 Time course of stimulus I Phasic receptors most common 0 Causes burst of action potentials When stimulus applied 0 Frequency of action potentials decreases as receptor adapts to stimulus 0 Smaller burst of action potentials When stimulus Withdrawn I Tonic receptors 0 Causes regular pattern of action potentials as long as stimulus endures 0 Location of stimulus o Receptive field of neurons 0 Center surround area immediately around center 0 Convergence of information from different receptive fields as it goes through medial lemniscal or lateral spinothalamic tract to brain 0 Somatosensory Perception 0 Receptor types 0 Cutaneous skin receptors I Touchpressure receptors 0 Free nerve endings light touch 0 Merkel s discs sustained touch and pressure 0 Ruffini endings sustained pressure 0 Meissner s corpuscles change in texture slow vibrations o Pacinian corpuscles deep pressure fast vibrations I Hotcold receptors I Nociceptors pain I Proprioceptors 0 Muscle spindles 0 Golgi tendon organs 0 Joint receptors 0 Visual perception 0 Anatomy Cornea clear part of sclera that allows light in at the front of the eye refracts light waves Iris colored portion of eye that adjusts pupil to let in moreless light Pupil black portion of eye Lens behind pupil further refracts light to project onto retina Retina thin tissue that covers back of eye contains photoreceptor cells GPCR to interpret incoming light waves interneurons and ganglia cells Fovea very small central pit of retina high concentration of cone receptors clearest picture if light hits here Optic nerve bundle of axons at back of eyeball optic disc blind spot of vision is where it meets the retina Vitreous humor clear gel that fills eyeball o Inversion amp reversal of the visual field Light waves are projected on the retina upside down and inverted left to right Each eyeball s visual eld split into left and right halves o All axons with right half of visual fields go to right side of brain 0 All axons with left half of visual fields go to left side of brain 0 Crossover occurs at optic chiasma o Transduction Photoreceptor cells PRCs 0 Sensory cells of visual system 0 Located in retina o Rods o Dimlight vision 0 Rhodopsins are lightreceptors GPCRs 0 Cones 0 Color vision 0 Photopsins are lightreceptors GPCRs 0 Vertical pathway within retina o PRCs 9bipolar cells 9 ganglion cells optic nerve 0 Light and impulses move in opposite directions 0 Anatomy of Retina Layers 0 Ganglion cells make up innermost layer closest to inside of eyeball o PRCs sit at the back of the retina o Exist at rest in depolarized state 40 mV due to dark current 0 Pigment epithelium in outer layer of retina keeps receptor cells healthy 0 When hit by light cisretinal which senses light will become transretinal which does not O O O O O o Transretinal dissociates from photoreceptors and makes it way to pigment epithelium Dark Current 1 9593 6 In 1 l 2 3 4 5 6 7 High concentration of cGMP secondary messenger in rods cGMP binds to ion channels Channels allow sodium and calcium to depolarize rod Glutamate released by rods in synapse with bipolar cells Glutamate interacts with metabotropic receptor on bipolar cell membrane IPSP Bipolar cell does not stimulate ganglion cell i ght cGMPdependent phosphodiesterase PDE activated by rhodopsin Dark current turned off by decrease of cGMP due PDE activity Hyperpolarization occurs in rod Rod releases less glutamate Bipolar cell is not inhibited Bipolar cell releases glutamate into synapse with ganglion cell Glutamate interacts with inotropic receptor on ganglion cell membrane EPSP 0 Convergence and receptor fields Ganglion cells typically harvest information from hundreds of PRCs No convergence at fovea where only cones Receptive eld made of central center and peripheral surround parts Ganglion cells most stimulated by contrast between center and surround Chapter 9 The Autonomic Nervous System 0 Autonomic vs Somatic Motor Systems Somatic affects skeletal muscle autonomic affects cardiac muscle smooth muscle and glands as well as blood vessels Autonomic nervous system is involuntary somatic nervous system is voluntary Presence of ganglia O I Neurons in somatic motor system run from spinal cord to effectors in skeletal muscle I Neurons in autonomic motor system synapse at ganglia on way from CNS to effectors o Somatic only sends excitatory impulses autonomic can send excitatory or inhibitory o Divisions of ANS 0 Both consist of preganglionic neurons cell bodies in CNS and postganglionic neurons cell bodies in PNS o Sympathetic I ght or ight I Chain of ganglia on either side of spinal cord 0 Most preganglionic fibers go here after passing through paravertebral ganglia 0 Those that innervate the adrenal medulla do not I Entire system activated as single unit 0 Parasympathetic I rest and digest I No chain of ganglia o Preganglionic fibers synapse With postganglionic fibers in terminal ganglia close to or Within target organs I Vagus Nerves 0 Primary route of parasympathetic innervation 0 Preganglionic fibers originate in medulla 0 Target organs heart lungs esophagus stomach pancreas liver intestines o Otto Loewi s experiment 0 Vagus nerve uses acetylcholine 0 Neurotransmitters of the ANS o Preganglionic fibers of both sympathetic and parasympathetic divisions are cholinergic release acetylcholine 0 Most sympathetic postganglionic fibers are adrenergic release norepinephrine 0 Most parasympathetic postganglionic fibers are cholinergic o Innervation o Tissues are innervated by both sympathetic and parasympathetic fibers 0 Divisions create antagonistic opposing signals that tissue must integrate 0 Sympathetic Adrenergic Innervation o Excitatory EPSP constrictionvesicle release 0 Inhibitory IPSP relaxationdilation o 4 types of receptors on target tissues all GPCRs I 11 0 excitatory 0 increased Ca2 concentration 0 increased Ca2 concentration 0 excitatory 0 increased cAMP concentration 0 inhibitory 0 increased cAMP concentration Chapter 11 Endocrinology o Hormones o Carried via blood 0 Regulate body metabolism growth and reproduction 0 Cellular Receptors o Enzymelinked receptors 0 Act through second messengers cAMP Ca2 kinases o Activated by insulin growth factors 0 Gproteincoupledreceptors 0 Act through second messengers cAMP Ca2 kinases o Activated by epinephrine norepinephrine epinephrine typically acts a hormone norepinephrine acts as a neurotransmitter o Intracellular receptors 0 Act as a transcription factor in the nucleus 0 Activated by steroids thyroid hormones o Pancreas o Islet of Langerhans comprises endocrine portion of pancreas 0 Alpha cells secrete glucagon I Released to increase blood glucose concentration I Promotes catabolism break down of macromolecules for energy 0 Beta cells secrete insulin I Released to decrease blood glucose concentration I Promotes anabolism storage of precursors to macromolecules I Insulin binds to Receptor Tyrosine Kinase RTK 0 Hepatocytes liver cells express GLUT2 transporters 0 Move glucose into liver When blood concentration is high 0 gt95 taken up by muscles and fat tissues 90 10 musclefat 0 Target tissues I Liver I Skeletal muscles I Adipocytes fat cells 0 Diabetes 0 High concentrations of circulating blood glucose 0 Type I Diabetes I Beta cells attacked by immune cells and produce notoo little insulin 0 Type II Diabetes I Target tissues develop resistance to insulin 0 HypothalamusPituitary Axis 0 master control of endocrine systems 0 Pituitary gland aka hypophysis o Controlled by hypothalamus o Anterior lobe aka adenohypophysis I Regulated hormonally I Releases all hormones other than ADH and oxytocin including o ACTH adrenocorticotropic hormone o Promotes secretion of glucocorticoids in adrenal cortex 0 tropic promotes appropriate growth of target tissues as well as hormone secretion 0 TSH thyroidstimulating hormone o Promotes production and secretion of T3 and T4 hormones in thyroid gland 0 GHRH growth hormonereleasing hormone o Promotes tissue growth I Generally controlled by negative feedback inhibition 0 Posterior lobe aka neurohypophysis I Regulated by neurotransmitter release 0 Delivered via infundibulum contains hypothalamo hypophyseal tract I Releases ADH and oxytocin o ADH 0 Water reabsorption by kidneys 0 Oxytocin o Uterine contractions during labor 0 Contraction of mammary glands during lactation o Adrenal glands o Innervated by preganglionic sympathetic fibers that release acetylcholine o Adrenal medulla o Secretes epinephrine and norepinephrine 0 Produce ght or ight responses and increase glycogenolysis and lipolysis o Adrenal cortex 0 Secretes corticosteroids steroid hormones I Synthesized from cholesterol I Travel through bloodstream via carrier proteins I Bind to intracellular hormone receptors I Receptors form a dimer and travel to DNA inside nucleus to affect transcription I Most produce catabolic effects 0 Thyroid gland o Consists of spherical hollow sacs called follicles I Follicles are lined by follicular cells I Sac filled with uid known as colloid o Thyroid hormones I T4 amp T3 0 Secreted by follicular cells 0 Regulate body metabolism growth and development 0 Production 0 Tyrosinebased o Hypothalamus secretes TRH9anterior pituitary secretes TSH9thyroid gland secretes T3ampT4 o 4 and 3 refer to number of iodides attached to molecule I Iodides in colloid obtained from blood by follicular cells 0 T4 most commonly circulates but T3 is the active form 0 Target tissues 0 Liver promotes gluconeogenesis o Skeletal amp cardiac muscle bones brain promotes normal growth and development I Thyroid Hormones vs Steroid Hormones 0 Steroid hormones form HOMOdimers in nucleus in order to promote transcription thyroid hormones form HETEROdimers 0 Steroid hormones formed from cholesterol thyroid hormones formed from tyrosine 0 Steroid hormone receptor proteins reside in cytosol and shuttle to nucleus When bound to hormone in order to promote transcription thyroid hormone receptor proteins reside permanently in nucleus 0 Hypothalamopituitarythyroid axis negative feedback control I Increased concentrations of blood T4 decrease responsiveness of anterior pituitary to TRH and inhibit secretion of TRH by hypothalamus I Thyroid disease 0 Goiter abnormal growth of thyroid gland o Iodine insufficiency endemic goiter o HYPOthyroid condition 0 Low levels of I 9 Low levels of T4 production 9 low levels of circulating T4 9 no negative feedback to anterior pituitary 9 elevated TSH levels 9 increased trophic effects to thyroid gland 9 goiter o Graves disease toxic goiter autoimmune disease 0 HYPERthyroid condition 0 Antibodies mimic effects of TSH at thyroid gland 9 excessive T4 circulation in blood but antibodies not affected by negative feedback loop 9 goiter Chapter 12 Muscle Physiology 0 Muscle Cells 0 Skeletal Muscle I Sarcomere is smallest contractile unit striated striped appearance 0 Stripes due to overlapping of thin and thick filaments I Controlled by somatic motor neurons 0 Cardiac Muscle I Sarcomere is smallest contractile unit striated striped appearance I Autonomic motor neurons regulate strength and frequency of contraction 0 Smooth Muscle I No sarcomeres no striated appearance I Controlled by autonomic motor neurons 0 Skeletal Muscle 0 Organization of muscle tissue I Sarcomere smallest unit of muscle cell 0 Center of sarcomere tends to have greatest overlapping of filaments I Myofibril rod of repeating sarcomeres I Muscle fiber aka myofiber muscle cell bundle of myofibrils 0 Sarcolemma plasma membrane of muscle cell 0 Sarcoplasm cytoplasm of muscle cell 0 Sarcoplasmic reticulum specialized endoplasmic reticulum of muscle cells I Fasciculus bundle of muscle fibers I Muscle bundle of fasciculi o The motor unit I Comprised of single motor neuron and all muscle fibers cells it innervates I Typical motor neuron innervates 100 to 1000 muscle cells I One muscle comprised of multiple motor units 0 Neuromuscular junction I Specialized synapse between somatic motor neuron s axon terminal and motor end plate of skeletal muscle cell I Nerve terminals release acetylcholine and interact With nicotinic receptors on motor end plate 9 EPSP o ExcitationContraction Coupling I Transformation of electrical signal action potential in muscle cell into contraction of sarcomeres I Anatomy of a myofiber 0 Sarcoplasmic reticulum SR Surrounds myofibrils as a network of interconnected tubules Terminal cistemae enlarged areas of SR surrounding Ttransverse tubules 4 5 o Ttubules Continuous With sarcolemma Wrap around myofibrils at regular intervals Sodium channels carry action potential from neuromuscular junction across sarcolemma and through Ttubules Action potentials activate voltage gated dihydropyridine receptors DHPRs on Ttubules DHPRs force open ryanodine receptors RyRs they re physically attached to on terminal cisternae of SR RyRs open and allow Ca2 to pass into sarcoplasm Ca2 stimulates contraction of sarcomeres o Sliding filament model of contraction Anatomy of sarcomere 0 Thin filaments actin Gactin spheres With myosin binding sites Myosin binding sites blocked in relaxed muscle by tropomyosin protein Troponin proteins sit on tropomyosin 0 Thick filament myosin Composed of long rods with head groups Head groups I Exist in either cocked or exed position relative to actin 0 Only binds to actin in cocked position I Only bind to actin in presence of Ca2 o Zones H zone I Middle of sarcomere I Just thick filaments With no overlap I Gets shorter during contraction A band I Defined by length of thick filament I band I Ends of sarcomere I Just thin filaments With no overlap I Gets shorter during contraction Z disc I Center of each I band I Mark the ends of each sarcomere I Contraction Z discs moving closer together 9 shortening of myofibrils 9 shortening of muscle cells I Crossbridge cycle 1 6 7 8 Myosin head in cocked position bound to ADP and Pi inorganic phosphate that was previously hydrolyzed for energy Ca2 circulating in sarcoplasm causes conformational change in troponin Tropomyosin moves to uncover myosinbinding sites on Gactin Myosin head binds to actin Pi is released causing myosin head to change from cocked to exed position causing power stroke ADP is released and replaced by ATP ATP binding causes myosin head to detach from actin ATP is hydrolyzed and myosin head returns to cocked position 0 Muscle Contraction I Twitch smallest unit of contraction response of muscle to one action potential I Muscle responses Summation Unfused incomplete tetanus Fused complete tetanus Individual twitches cannot be distinguished Not a natural physiological state 0 Muscles amp Energy I Production of ATP in muscles Aerobic respiration oxidative phosphorylation in mitochondria Anaerobic respiration glycolysis and fermentation to lactate For bursts of heavy activity Phosphocreatine For bursts of heavy activity I Use of ATP in muscles I Fatigue Myosin ATPases create contraction Ca2ATPases create relaxation Causes Depletion of muscle glycogen stores Lactic acid accumulation from anaerobic respiration Impaired EC coupling decreased release of Ca2 0 Effects Decreased force production Reduced rate of rise of force Longer time to relax 0 Motor Unit Types I Slow Type I 0 Slow high oxidative capacity 0 Smaller diameter amp less myosin 9 less forceful contractions o Fatigueresistant I Fast FatigueResistant Type HA 0 Fast high oxidative capacity 0 Medium diameter amp more myosin 9 intermediate forcefulness I Fast Fatigable Type IIX 0 Fast low oxidative capacity relies more on anaerobic respiration 0 Large diameter amp more myosin 9 greatest force 0 Fatigue quickly 0 Neural control of skeletal muscle I Muscle spindle apparatus proprioceptor 0 Sensory receptor 0 Located on intrafusal muscle fibers specialized fibers that detect amount and rate of change in muscle length 0 Muscle stretch 9 spindle stretch 9 stimulation of sensory neurons 0 Increased length of muscle 9 increased action potential frequency I Lower motor neurons 0 0tmotoneurons innervate extrafusal type that engage in contraction muscle fibers 0 ymotoneurons innervate intrafusal muscle fibers I Corticospinal pyramidal tract I Extrapyramidal tract 0 Knee jerk re ex monosynaptic stretch re ex 1 Striking of patellar ligament stretches tendon and quadriceps femoris muscle 2 Spindle is stretched activating sensory neuron 9 Sensory neuron activates umotoneuron 4 0tmotoneuron stimulates extrafusal muscle fibers to contract knee jerk
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