Physiology Flash Cards

This Is For The Final In Physiology 502 At The University Of Michigan
 
Created Apr 26, 2010
by jkanners
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Side ASide B
What is homeostasis?
the maintanence of relatively stable conditions of the internal environment
What is the internal environment?
the extracellular fluid = plasma + interstitial fluid
What are homeostatic reflex arcs?
-stimulus response sequences involving negative feedback-responds to changes in variable
What are some variables regulated by the homeostatic reflex arc?
-body temp.-BP-arterial PO2 and PCO2-arterial pH-plasma glucose-plasma Na+, K+, Ca2+
What are the four functions of membranes?
1. form selective barrier2. detect chemical messengers at cell surface3. link adjacent cells...
What are two types of passive movement across membranes?
-diffusion - solute driven by concentration gradient-osmosis - water driven by osmolarity
What are the forms of mediated transport systems for movement across membranes?
-faciliated diffusion - movement requiring binding of molecule to transport protein, movement...
What is membrane potential?
-separation of charge across the plasma membrane-resting membrane potential: -70 mV-determined...
What is the equilibrium potential?
-for any ion-the membrane potential at which the net flux of the ion is 0-Nernst: E(ion) =...
How is the resting membrane potential determined?
-Goldman's equation, based on equilibrium potentials and their relative permeabilities-Vm =...
What are action potentials?
-all-or-none depolarization used to send signals over long distances-threshold (must depolarize...
What are synapses?
-sites of interaction between two neurons or a neuron and a target cells-ex: gland cell or...
What are some types of synapses?
-electrical: direct connections between cells via gap junctions (direct ion flow)-chemical...
What is the importance of the medulla oblongata?
cardiovascular, respiratory, swallowing and vomiting centers
What are some features of the autonomic nervous system?
-innervates smooth muscle, cardiac muscle and endocrine glands-sympathetic (NT = norepinephrine),...
What are teh four elementary attributes to any stimulus?
-type of stimulus (thermoreceptors, mechanoreceptors, photoreceptors, osmoreceptors, chemoreceptors)-intensity...
What are properties of light waves?
-visible light: wavelengths = 350-750 nm-reflection: light waves bounce off surface-refraction:...
What is the anatomy of the eye?
-3 concentric layers-outermost: sclera (white of eye), cornea (transparent)-middle: choroid...
How is light focused on the retina?
-waves pass through cornea and lens and bend-those striking perpendicular to surface will pass...
How do we focus light on different distances onto our retina?
-by changing the shape of the lens-zonular fibers are attached to the lens and ciliary muscle-ciliary...
What is accommodation?
-start with distant object, ciliary muscle relaxed, lens is flat, light is focused on retina-closer...
What is near-sightedness?
-cannot see objects far away-eyeball is too long for ability of lens to accommodate-object...
What is far-sightedness?
-cannot see near objects-eyeball is too short for ability of lens to accommodate-object focuses...
What are features of the retina?
-where photons of light are absorbed and converted to graded potentials and APs-two photoreceptors:...
Where are the rods and cones located?
-cones: primarily in center, fovea has highest density, greatest acuity-rods: in periphery,...
What are the important molecules for phototransduction?
-photopigment: cones (red, blue and green opsin), rods (rhodopsin)-retinal: light absorbing...
How does phototransduction occur in the dark?
-GTP to cGMP by guanylyl cyclase-cGMP binds channel and it opens-Na/Ca influx depolarizes cells;...
How does phototransduction occur in the light?
-photon absorbed by retinal/opsin, causes opsin to change shape and dissociate ("bleached")-activates...
How do the cells of the retina communicate?
-rods and cones generate graded potentials (light - less glutamate is released onto bipolar...
How does color vision work?
-three sets of cones absorb along different parts of spectrum, overlap is color vision-perception...
What are some of the effects of cortisol?
-steroid hormone, secreted by adrenal cortex, controlled by CRH and ACTH-anti-inflammatory,...
What are some of the effects of thyroid homrone?
-under control of TRH and TSH-iodine is required, T4 and T3 secreted by hyorid gland, some...
What are some of the factors affecting growth?
-environmental: adequate nutrition for substrates, adequate calorie intake, sickness and disease-hormones:...
What is the role of growth hormone?
-secreted from anterior pituitary; stimulates liver to release IGF-1, mediates growth effects...
What are the three types of muscle?
-skeletal: attached to bone via tendons, make up system of mechanical layers that develop force...
What are the proteins of skeletal and cardiac muscle?
-thin filament (actin - binding sites for troponin and myosin; tropomyosin - blocks myosin...
What is the functional unit of skeletal and cardiac muscle?
-sarcomere - repeating unit that shortens and/or generates force-Z line demarcates the sarcomere,...
What is an isotonic contraction?
-fiber shortens while load on muscle remains constant-load-velocity relationships - velocity...
What is an isometric contraction?
-fiber generates tension but does not shorten (or lengthen)-force-frequency relationship (increased...
What is a eccentric contraction?
-lenghtening-fiber generates tension but load is too great to shorten or isometrically contract,...
How is skeletal muscle energy metabolized?
-creatine phosphate - available for a few seconds, provides time for glycolysis and oxidative...
What is fatigue?
-not due to ATP depletion-contributing factors: decreased pH (increased acidity), build up...
What are the three skeletal muscle types?
1. slow oxidative fibers (hydrolyze ATP slower than fast fibers, most resistant to fatigue,...
Does skeletal muscle undergo hyperplasia (increased fiber mitosis and increased number of fibers)?
-NO!-strength training leads to hypertrophy (increased sarcomeres in parallel)-endurance training...
What are the differences in smooth muscle?
-fibers smaller than skeletal and cardiac-maximum tension per cross-sectional area is same-smooth...
What is the cross-bridge cycling for smooth muscle?
-inputs = nerves from PS/SNS, hormones, stretch, pacemaker cells (spontaneous APs)-intracellular...
What are the functions of the cardiovascular system?
-delivers nutrients to tissues (O2, glucose, fatty acids, aa's)-removes waste products (CO2,...
What is the flow of blood in the CV system?
-blood returns to right atrium via superior/inferior vena cava-right atrium to right ventricle...
What is cardiac output?
-volume of blood pumped by one ventricle per minute (about 5L/min); left = right under normal...
What are the different types of blood vessels?
-arteries: pressure reservoir, stretch as blood is pumped into them during systole, recoil...
What is the equation for flow?
flow = pressure/resistance-major determinant of R is radius (R = 1/r^4)
What are the pacemaker cells of the heart?
-located in SA node, AV node, and bundle of His-under tonic control of Sym and PS systems (basal...
What is an electrocardiogram?
-ECG; used to measure electrical currents through the heart-P wave = atrial depolarization,...
What is the cross-bridge cycling in cardiac muscle?
-regulated by Ca2+ binding to troponin-Ca2+ levels rise due to "calcium-induced calcium release"-membrane...
How does the sympathetic nervous system innervate cardiac muscle?
-SA/AV node - increase HR-ventricular muscle cells - increase contractility-arterioles...
How does the parasympathetic nervous system innervate cardiac muscle?
-SA/AV node - decreases HR
What is the Starling's Law of the heart?
-SV increases as EDV (end diastolic volume) increases-an increase in venous return will increase...
How can venous return be increased?
-sympathetic-mediated constriction-increased blood volume-skeletal muscle pump - contractions...
What are the periods of the cardiac cycle?
-systole: period of ventricular contraction-diastole: period of ventricular relaxation
What are the events of systole?
-atrium is relaxed, ventricle begins to contract-isovolumetric contraction occurs (pressure...
What are the events of diastole?
-ventricle begins to relax, aortic pressure greater than ventricular pressure, aortic valve...
What are some regulators of arteriolar diameter?
-local metabolites play a role-sympathetic activity-circulating EPI-circulating angiotensin...
How does arteriolar constriction and dilation affect bloodflow?
-constriction: increase pressure upstream and decrease pressure downstream-dilation: decrease...
What are some properties of capillary exchange?
-diffusion: major mechanism for exchange of nutrients, solutes and gases-bulk flow: shifts...
What is the baroreceptor reflex?
-senors that detect changes in arteriol BP, located in aortic arch and two carotid arteries-respond...
What is heostasis?
-blood clotting, involves platelets and clotting factors that circulate in blood in inactive...
How are clots formed?
-activation of clotting factors is a chain reaction (one factor activates the next), leading...
What are the functions of the respiratory system?
-ventilation (movement of air between atmosphere and lungs)-gas exchange (transfer of O2 and...
How are pressures involved in inspiration and expiration?
-at rest between breaths, Patm = Palv = 0-during inspiration, Palv < Patm, during expiration,...
What is active expiration?
-contraction of abdominal muscles and expiratory intercostals to push diaphragm up and pull...
What is compliance?
-expandability of lung, determined by amount of elastic tissue and surface tension-compliance...
What is tidal volume?
-amount of air entering lungs during resting inspiration and passive expiration-functional...
What is anatomic dead space?
-volume of the conducting zone in which no gas exchange takes place-some inspired air remains...
What are the two ventilation equations?
-minute ventilation = TV x frequency-alveolar ventilation = (TV - VD) x frequency (more accurate...
What is the airway resistance?
-not limiting to airflow-factors that affect airway resistance: lateral traction (resistance...
What diseases affect airway resistance?
-asthma - chronic inflammation reduces airway diameter, amking smooth muscle hypersenitive...
How does gas exchange work?
-diffusion of gases occurs down a partial pressure gradient-at lungs, O2 moves from atmosphere...
What is hyperventilation? What is hypoventiliation?
-hyper: indicates a state in which ventiliation is elevated compared to metabolism, arterial...
How is oxygen transported?
-bound to Hb, binds to iron atom in heme portion-22% is unloaded into the tissues-if O2 delivery...
How is carbon dioxide transported?
-10% dissolved in plasma, 30% bound to globin portion of Hb, 60% as bicarbonate ions (carbonic...
What is rhythmic breathing?
-pacemaker cells in medulla oblongata send output to motor neurons of inspiratory muscles;...
What inputs into the respiratory system of the medulla oblongata?
-inputs from higher center (cortex, pons)-receptors in lungs and airways (stretch receptors,...
How does exercise affect breathing?
-moderate exercise - chemoreceptor input not involved with increased ventiation (ventilation...
What are some functions of the kidney?
-maintain salt and water balance-eliminate metabolic wastes and foreign substances-regulate...
What are the two regions of the kidney? What is the functional unit?
-renal cortex (outer region), location of all renal corpuscles (glomeruli, Bowman's capsules)-renal...
What are the four basic renal processes?
-filtration (bulk flow movement from glomerular capillaries to Bowman's space)-reabsorption...
How is glomerular filtration rate determined?
-if filtered load > amount excreted = net reabsorption-if filtered load < amount excreted...
How is glucose handled in the kidneys?
-gluose transporters on apical and basolateral membranes in proximal tubule-co-transported...
How is sodium handled in the kidneys?
-reabsorbed by proximal tubule, asecnding limb of loop of Henle, distal tubule and collecting...
How is water reabsorbed in the kidneys?
-by proximal tubule, descending loop of Henle and collecting duct-passive, downhill through...
How are sodium and water reabsorption of the kidneys regulated? **(study this section of notes)
-water: hormones (ADH), sensors - osmoreceptors in hypothalamus, volume receptors in large...
How is the excretion of potassium by the kidneys regulated?
-effect of aldosterone (increases K+ secretion)-increased plasma [K+] directly stimulates aldosterone...
How does the kidney play a role in acid-base balance?
-reabsorbs filtered bicarbonate-adds new bicarbonate and secretes H+ and excretes H2PO4--adds...
How does renal failure develop and how is it treated?
-hyperkalemia, acidosis, proteinuria, anemia, wate product build up in blood, high BP, problems...
What are the four layers of the GI tract wall?
1. mucosa (layer of polarized epithelial cells in contact with luminal contents, secretory...
What are some secretions made by the stomach?
-neck cells (mucus)-cheif cells (pepsinogen and gastric lipase)-parietal cells (HCl and intrinsic...
How are stomach secretions regulated?
-stimulated by cephalic phase and gastric phase stimuli (stomach distension, chyme pH, chyme...
What is the motility of the stomach?
-peristalsis-basic electrical rhythm (set by pacemaker smooth muscle cells in stomach wall)-force...
What are some of the secretions of the SI?
-CCK and secretin-regulated by pH, distension, osmolarity, peptides and fats in duodenum
How does digestion and absoprtion occur in the SI?
-digestion: brush border enzymes for protein and carbs, enzymes secreted from pancreas for...
What is the motility of the SI?
-segmentation: mixing contractions, slow movement of chyme toward ileum-migrating myoelectric...
What are the secretions of the LI?
-K+-HCO3-
How does absorption occur in the LI?
-Na+-Cl--water
What is the motility of the LI?
-some segmentation-mass movement (peristalsis)-gastrocolic reflex (food/chyme in stomach and...
What are the secretions of the pancreas and how are they regulated?
-enzymes: stimulated by CCK, potentiated by secretin-trypsinogen, chymotrypsinogen, procarboxypeptidase,...
What are the secretions of the liver and how are they regulated?
-bile and HCO3--hepatic portal blood bile salt concentration regulates liver production of...
What is the digestive process of carbs?
-begins in mouth with salivary amylase-stops in stomach (salivary amylase inactivated by acid)-completed...
What is the absorption process of carbs?
-glucose and galactose by active transport coupled to Na+ absorption across apical membrane-fructose...
What is the digestive process of protein?
-none in mouth-begins in stomach with pepsinogen secretion - activatedto pepsin by acid - breaks...
What is the absorptive process of protein?
-aa's absorbed by active transport coupled to Na+ across apical membrane and facilitated diffusion...
What is the digestive process of lipids?
-none in mouth or stomach-occurs in SI: emulsfication (motility mixes and breaks up big fat...
What is the absorptive process of lipids?
-free fatty acids and monoglycerides diffuse across apical membrane and are taken up by ER-more...
What are some features of the absorptive state?
-food in GI tract and being absorbed-glucose and aa's levels high, triglyceride levels high,...
How does insulin stimulate liver during absorptive state?
-liver: glucose to ATP, glycogen, fatty acids, alpha-glycerol-phosphate-aas to protein or alpha-ketoacids-production...
How does insulin stimulate adipocytes during absorptive state?
-stimulation of glucose uptake and triglyceride production-increased numbers of glut-4 transporters...
How does insulin stimulate skeletal muscle during absorptive state?
-stimulation of glucose uptake-increased number of glut-4 transporters on membrane-increased...
What are some features of the postabsorptive state?
-no food in Gi tract-plasma glucose falling, aa's initally fall then remain stable as released...
How do various hormones affect the postabsorptive state?
-EPI levels increase - increased glycogenolysis and gluconeogenesis by liver, increased glycogenolysis...
What catabolic activities occur in liver in postabsorptive state?
-glycogenolysis and gluconeogenesis and release of glucose to plasma - substrates = lactate...
What catabolic activities occur in adipocytes in postabsorptive state?
-breakdown of triglycerides to fatty acids and glycerol-fatty acids released to circulation...
What catabolic activities occur in skeletal muscle in postabsorptive state?
-glycogenolysis and release of pryuvate and lactate to travel to liver-protein breakdown to...
What catabolic activites occur in brain cells in postabsorptive state?
-continued uptake of glucose for energy-if ketone levels build up enough in blood (prolonged...
What catabolic activites occur in all cells except CNS in postabsorptive state?
-decreased uptake of glucose and aas-increased uptake and utilization of fatty acids for energy...
What are the two types of diabetes mellitus? What is the treatment for diabetes?
-type 1: insulin deficient, requires insulin-type 2: insulin resistant, treatment involves...
What is diabetic ketoacidosis?
-develops when blood ketone body levels are highly elevated becomes ketone bodies are acidic
How are the basal metabolic rate and metabolic rate regulated?
-TH is major determinant, starvation decreased TH secretion which decreases BMR and decreases...
How do hypothyroidism and hyperthyroidism affect BMR?
-hypo: decrease BMR (sometimes results in weight gain), cold intolerance due to decreased heat...
What are inhibitors of hunger/signals for satiety?
-distension of stomach and duodenum-neural feedback from stomach-CCK from SI-neural feedback...
What are stimulators of hunger?
-low plasma glucose-Ghrelin from stomach
What are some characteristics of leptin?
-secreted by fat cells (adipocytes)-decreases hunger by decreasing neuropeptide Y (NPY) in...
What is obesity?
-multifactorial disorder (sedentary lifestyle, abnormal feeding behavior, neurogenic abnormalities,...


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