PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT V, Exams of Physiology

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PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ How does velocity relate to cross sectional area in vessels? - CORRECT ANSWERS Inversely proportional velocity = 1/cross sectional area, capillaries have the highest cross sectional and surface area What component of circulation serve as a blood reservoir? - CORRECT ANSWERS veins What component of circulation are most distensible(dilated)? - CORRECT ANSWERS Veins What does distensible mean? - CORRECT ANSWERS the ability to be distended, extended, or dilated What component of circulation contains smooth muscle capable of dilating and constricting to alter flow or pressure? - CORRECT ANSWERS Arterioles: constriction increases arterial pressure but decreases capillary and venous pressure veins: constriction increases venous return (frank starling) What component of circulation contains no smooth muscle? - CORRECT ANSWERS Capillaries What component of circulation accounts for the highest degree of resistance flow? - CORRECT ANSWERS Arterioles What component of circulation accounts for about 2/3 of SVR? - CORRECT ANSWERS Arterioles What component of circulation allows exchange between fluid and solutes between blood and interstitial fluid? - CORRECT ANSWERS Capillaries How is arterial pressure regulated? - CORRECT ANSWERS by neuronal and hormonal impulses, independently of local blood flow and cardiac output, varies between a systolic value (120 mmHg) and diastolic value (80 mmHg) PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ What is mean arterial pressure? - CORRECT ANSWERS the average arterial pressure throughout one cardiac cycle, systole, and diastole The difference between systolic and diastolic pressures (increases or decreases) with the distance from the heart in the large arteries. - CORRECT ANSWERS increases. Compare laminar vs. turbulent flow - CORRECT ANSWERS - Laminar flow is a streamline flow where each layer of blood remains at the same distance from the wall. The central portion of blood stays in the center and has the highest velocity. - Turbulent flow is flow of blood in all directions with mixing due to eddy currents (flow around obstructions, rough surfaces, and sharp turns). and causes increased resistance Explain the following effects of flow velocity: vessel diameter, and viscosity on the tendency towards turbulent flow. - CORRECT ANSWERS - increase in velocity causes increase in turbulence - increase in vessel diameter causes increase in turbulence - increase in viscosity causes decrease in turbulence What is the meaning of viscosity? - CORRECT ANSWERS resistance of a fluid to change in shape Explain how vessel diameter, vessel length, and blood viscosity affect the resistance to blood flow. - CORRECT ANSWERS - As vessel diameter increases, resistance to flood flow decreases - As vessel length increases, resistance to blood flow increases - As blood viscosity increases, resistance to blood flow increases What is critical closing pressure? - CORRECT ANSWERS Internal pressure at which a passive blood vessel collapses and blood flow stops What are the 3 events of an aortic pressure wave in chronological order? - CORRECT ANSWERS systolic ejection, diastolic runoff, incisura PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ - increased venous tone (increases venous pressure) - increased arteriolar dilation (decreases TPR and allows more rapid flow from arteries to veins) Explain the venous pump and how valves are involved. - CORRECT ANSWERS The venous pump helps get blood back to the heart; movement or muscular tension causes blood squeezed in veins to go towards the heart. Venous valves allow direction of blood flow only towards the heart. What causes the venous pump and valves to fail? What happens when they fail? - CORRECT ANSWERS Standing sill causes the venous pump to not work and the feet vein pressure increases to 90 mmHg, resulting in edema. Valves may become incompetent creating varicose veins. What are varicose veins? - CORRECT ANSWERS big, twisty veins near the skin's surface that are caused by weakened valves Why does venous pressure in the lower body increase when standing up? - CORRECT ANSWERS Pooling of blood (compensated by baroreceptor reflex mechanism) and increased capillary filtration What occurs if the baroreceptor reflex is blunted or absent? - CORRECT ANSWERS the baroreceptor reflex response compensates for the decreases in arterial pressure when one stands up, reduction in cerebral flow causes dizziness or fainting due to orthostatic hypertension - common side effect in alpha 1 blocking agents How might increased capillary filtration pressure lead to syncope? - CORRECT ANSWERS increased capillary filtration pressure is an elevated venous pressure that favors the movement of vascular fluid to the interstitium, it is a slower process, but fluid loss will reduce arterial pressure and may cause fainting if standing occurs for prolonged periods What is orthostatic hypotension? - CORRECT ANSWERS occurs when a patient goes from supine to standing and the arterial blood pressure drops drastically and results in syncope; occurs because of pooling of blood and increased capillary filtration pressure PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ Why does pooling of blood occur during orthostatic hypotension? - CORRECT ANSWERS increased venous pressure distend the veins in the lower body leading to rapid pooling of blood Why does an increased capillary filtration pressure occur during orthostatic hypotension? - CORRECT ANSWERS elevated venous pressure favors movement of vascular fluid to the interstitium, fluid loss results in lower arterial pressure What is syncope? - CORRECT ANSWERS fainting; passing out What are the two components of the mechanism of vasovagal syncope? - CORRECT ANSWERS intense, disturbing thoughts or emotions in the cerebral cortex may result in hypothalamic stimulation of parasympathetic activity to heart (decreasing heart rate) and sympathetic activity dilating peripheral vasculature in skeletal muscle (circulating EPI interacting with Beta 2 receptors) Describe the structure of the capillary wall. - CORRECT ANSWERS unicellular layer of endothelial cells surrounded by basement a membrane; 1 RBC width What are the functions of intercellular clefts? - CORRECT ANSWERS membrane pores between two adjacent endothelial cells, width of cleft is slightly smaller than the diameter of an albumin molecule. it allows water and water-soluble, small solutes can easily and rapidly diffuse through clefts. How do brain capillaries differ from systemic capillaries in terms of capillary wall structure and movement of water-soluble materials? - CORRECT ANSWERS there is a blood-brain barrier that has tight junctions between endothelial cells and allow water-soluble substances in through transport mechanisms, while capillaries have intracellular clefts allow water and water-soluble, small solutes to diffuse rapidly Describe how the concentration gradient determines a solutes movement across a capillary membrane. - CORRECT ANSWERS net diffusion rate is proportional to the concentration difference on the two sides of the membrane; solutes move passively from high to low concentration, a larger concentration gradient = faster movement, when gradient is gone all movement stops PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ Describe how permeability of a solute determines its movement across a capillary membrane. - CORRECT ANSWERS The size of molecules can affect permeability, the larger a solute the slower it diffuses. Lipid-soluble substances can move across the cell membrane. Water-soluble substances must use pores and be the right size to move across the membrane. How do interstitial fluid and plasma differ in solute concentration? - CORRECT ANSWERS ISF contains collagen fibers and proteoglycan filaments causing a gel like consistency. Plasma has the same concentration of substances except it contains plasma proteins What is the net fluid movement through the capillaries determined by? - CORRECT ANSWERS The 4 Starling forces What are the 4 Starling forces? - CORRECT ANSWERS 1. hydrostatic pressure in the capillary (Pc) 2. hydrostatic pressure in the interstitium (Pif) 3. osmotic pressure in the capillary- Plasma colloid osmotic pressure (πp) 4. osmotic pressure in the interstitium- ISF colloid osmotic pressure- (πif) What is capillary hydrostatic pressure and what is its net effect? - CORRECT ANSWERS A Starling force that effects net movement through the capillaries and is a positive value that favors filtration (fluid leaving capillaries going to interstitial space), forces fluid out of arterial end and allows fluid to reenter in at venous end, average value is 17.3mm Hg, net effect of increased Pc is increased fluid in ISF. values differ in lungs and kidneys What is ISF hydrostatic pressure and what is its net effect? - CORRECT ANSWERS A Starling force that effects net movement through the capillaries. if positive --> fluid forced in capillary, if negative--> fluid moves out of capillary into interstitial space, usually negative (0 to -3mm Hg) and favors filtration due to lymphatic pumping, Net effect when negative: lymphatic pumping What is plasma colloid osmotic pressure and what is its net effect? - CORRECT ANSWERS A Starling force that effects net movement through the capillaries, positive value and favors reabsorption (movement into capillaries), ≈28mm Hg, plasma proteins exert osmotic pressure (oncotic pressure) PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ Describe negative feedback of auto-regulation. - CORRECT ANSWERS exists to automatically adjust blood flow to match the tissue's metabolic needs Explain the vasodilator theory of autoregulation. - CORRECT ANSWERS low oxygen or nutrient --> release of vasodilating substances--> dilation of arterioles, meta-arterioles, and pre-capillary sphincters--> increase bloodflow --> washes out substance ending effects What are possible vasodilating substances? - CORRECT ANSWERS Adenosine (most important), Histamine, K+, low pH, High partial pressure of CO2, lactic acid, low concentrations of EPI How can changes in the partial pressure of O2 cause changes in arteriolar blood supply? - CORRECT ANSWERS low O2 reduces arteriolar tone, high O2 levels cause vasoconstriction (oxygen demand theory); in the absence of oxygen or other nutrients, vasodilator smooth muscles lose their tone and dilate so that blood flow increases Describe how blood flow to a tissue changes arterial perfusion pressure. - CORRECT ANSWERS blood flow to organ remains constant over a wide range of arterial perfusion pressures to limit the effect of changes in systemic arterial pressure, if the blood flow to a tissue is suddenly decreased, a compensatory vasodilation occurs to restore flow, local changes in vascular resistance compensate for the pressure changes - increase in pressure causes increase in blood flow momentarily, regulatory factors will return pressure to normal - at extremes the auto-regulatory mechanism cannot operate, flow is dependent on arterial pressure What arterial perfusion pressures will blood flow to a tissue remain constant at? - CORRECT ANSWERS 70-175 mm Hg What is the minimum pressure needed to keep small vessels from collapsing? - CORRECT ANSWERS 20-30mm Hg What is the myogenic theory? - CORRECT ANSWERS intrinsic contractile response to smooth muscle stretch PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ Explain the myogenic theory constrictor response. - CORRECT ANSWERS high arterial pressure stretch the arteriole and the arteriolar diameter increases. stretching causes vasoconstriction of the surrounding smooth muscle which reduces the diameter back to its original value reducing flow. the decreased flow protects capillaries from over-distention due to excessively high arterial pressure Explain the myogenic theory dilator response. - CORRECT ANSWERS decreased MAP is transmitted through the artery perfusing a tissue into the arterioles, the arteriolar diameter decreases due to the decreased distending pressure it is experiencing, when original pressure is restored, the arteriolar smooth muscle will dilate to allow a period of increased flow, the increased perfusion repays the oxygen debt that occurred during the occlusion Explain the metabolic theory for vasoconstriction and vasodilator responses. - CORRECT ANSWERS as arterial pressure increases, the amount of oxygen and nutrients delivered is in excess of demand and the vessels constrict to return flow to near normal; if arterial pressure suddenly decreases, oxygen demand exceeds supply and a vasodilator substance is released to help with vasodilation for more oxygen delivery Explain the metabolic theory- vasodilation response. - CORRECT ANSWERS sudden decrease in arterial pressure --> decrease in blood flow --> O2 demand more than supply--> increase production and accumulation of locally released vasodilators--> decreased local vascular resistance --> increased blood flow --> increased O2 --> "wash out" of vasodilator substance --> vessel resumes to normal degree of tone Explain reactive hyperemia. - CORRECT ANSWERS blood supply blocked --> when flow is restored flow will be 4-7 times normal baseline --> duration of increased flow depends on O2 deficit What are the 2 explanations for reactive hyperemia? - CORRECT ANSWERS 2 mechanisms 1. vasodilators accumulate in the interstitial fluid --> increase flow (metabolic theory) 2. decreased arterial pressure --> less stretch --> re-perfusion --> dilator myogenic response allows increased flow to repay the O2 deficit Explain active hyperemia. - CORRECT ANSWERS increase in local metabolism of highly active tissue using up O2 and nutrients and causes the release of vasodilating substances --> increased blood flow up to 20 fold in exercising muscle PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ Which cells produce and secrete nitric oxide? - CORRECT ANSWERS endothelial cells What are the storage sites for nitric oxide in cells? - CORRECT ANSWERS nitric oxide is not stored, it is produced on demand What stimuli causes nitric oxide release? - CORRECT ANSWERS ACh, stretch, substance P, bradykinin What are the effects of nitric oxide on vascular tone? - CORRECT ANSWERS vasodilation, which decreases vascular tone What effects, if any, does nitric oxide have on platelet aggregation? - CORRECT ANSWERS no effect What cells produce and secrete prostacyclin? - CORRECT ANSWERS produced by endothelial cells from the precursor arachidonic acid through the cylcooxygenase pathway What are the effects of prastacyclin on vascular tone? - CORRECT ANSWERS promotes vasodilation which decreases tone What are the effects of prastacyclin on platelet aggregation? - CORRECT ANSWERS inhibits platelet aggregation What is the most potent endogenous vasocontrictor agent known? - CORRECT ANSWERS endothelin; ADH (vasopressin) is seconf most potent vasoconstrictor Which cells produce and secrete endothelin? - CORRECT ANSWERS produced and secreted by the endothelium What is the storage site in cells for endothelin? - CORRECT ANSWERS endothelin is not stored PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ Describe the effects on vascular tone by angiotensin II. - CORRECT ANSWERS acts on arterioles to increase TPR in conditions of severe hypotension, also involved in local regulation of blood flow in the kidney What substances (local and humoral) cause vasoconstriction? - CORRECT ANSWERS Endothelin, Thromboxane. Angiotensin II, Vasopressin, NE, EPI Describe the stimuli causing secretion of angiotensin II. - CORRECT ANSWERS secreted by the activation of RAAS Describe the effects on vascular tone by vasopressin. - CORRECT ANSWERS extremely potent endogenous vasoconstrictor; V1 receptions in the peripheral arterioles increase MAP, V2 receptors in the kidney increase water obsorption Describe the cellular sites of production, storage, and secretion for angiotensin II. - CORRECT ANSWERS produced by the activation of the RAAS, and it is not stored Describe the stimuli causing secretion of vasopressin. - CORRECT ANSWERS nerve impulse stimulation Describe the cellular sites of production, storage, and secretion for vasopressin. - CORRECT ANSWERS formed in the hypothalamus at the supraoptic nuclei, it is transported along axons to posterior pituitary, and stored in vesicles at these nerve endings Describe the site of formation and secretion for bradykinin. - CORRECT ANSWERS formed in the circulation, not stored anywhere Describe the storage sites in cells of bradykinin. - CORRECT ANSWERS not stored in any cells Describe the three major physiologic responses of bradykinin. - CORRECT ANSWERS arteriolar dilation via nitric oxide, increased capillary permeability, contraction of visceral smooth muscle PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ Describe the site of formation and secretion for histamine. - CORRECT ANSWERS released from mast cells in all tissues or from basophils in response to inflammation or allergic reaction Describe the storage sites in cells of histamine. - CORRECT ANSWERS granules Describe the three major physiologic responses of histamine. - CORRECT ANSWERS arteriolar dilations (via cAMP), increased capillary permeability, tissue edema, and contraction of visceral smooth muscle Which stimuli cause histamine release? - CORRECT ANSWERS inflammation or allergic reaction What are histamines effects on vascular tone? - CORRECT ANSWERS cause arteriolar dilation, but also increases capillary permeability What is the formula for Pa? - CORRECT ANSWERS Pa (arterial pressure)= MAP = CO X SVR What is the formula for Cardiac Output? - CORRECT ANSWERS CO=SVxHR What major factor determines CO? - CORRECT ANSWERS Venous return What major factor determines SVR? - CORRECT ANSWERS arteriolar constriction What are the principal mechanisms that regulate Pa? - CORRECT ANSWERS -Acute, short term- CNS mediated- baroreceptor reflex response -chronic, long term- hormonally mediated renin-angiotensin-aldosterone system Describe the physiologic response to activation of the vasoconstrictor area of the medullary vasomotor center. - CORRECT ANSWERS neurons secrete NE and nerves from pressor area stimulate sympathetic vasoconstrictor nerves and cardiac nerves causing vasoconstriction , increased HR, and increased contractility -in arteries and arterioles. vasoconstriction increases SVR and Pa PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ - in veins, vasoconstriction increases venous return and cardiac output What is vasomotor tone? - CORRECT ANSWERS continuous slow firing maintaining a partial state of contraction in vascular smooth muscle, inhibition of tonic activity causes vasodilation Describe the functions of the medullary cardio-inhibitory center and the physiologic responses resulting from nerve impulses originating at this site. - CORRECT ANSWERS in the nucleus ambiguus and dorsal nucleus of vagus nerves; parasympathetic output stimulates the Vagus nerves decreasing HR and CO, there is little to no effect on SVR What effect on heart rate does excitatory impulses to the Vagus nerve have? - CORRECT ANSWERS lowers HR What is the vasodilator area? - CORRECT ANSWERS depressor area, stimulation inhibits vasoconstrictor area activity What controls the Vasomotor center(VC)? - CORRECT ANSWERS Hypothalamus stimulation causes inhibition of VC (lower BP) and stimulates cardioinhibitory center (decrease HR) What is the purpose and nature of activation of the baroreceptor reflex? - CORRECT ANSWERS rapid, minute-by-minute regulation of Pa; negative feedback mechanism What is the location of baroreceptors and pathways for nerve impulse transmission to the medullary area of the brainstem? - CORRECT ANSWERS initiated by stretch receptors located in the walls of the carotid sinus and aortic arch What is the pathway and operation of a baroreceptor reflex for increased Pa? - CORRECT ANSWERS increased Pa stretches the walls of the carotid sinus and aorta; stimulates "sensor" cells mediating the baroreceptor response, this results in increased frequency of firing of afferent signals from the carotid sinus and aortic arch to the medullary area, causing decreased sympathetic tone, vagal stimulation, and decreased Pa What is the pathway and operation of a baroreceptor reflex for decreased Pa? - CORRECT ANSWERS decreased stretch on carotid sinus baroreceptors causing decreased firing rate of PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ What is the response of the RAAS on the cardiovascular system during hemorrhage? - CORRECT ANSWERS increases Pa during hemorrhage Explain the compensatory response to acute hemorrhage. - CORRECT ANSWERS blood loss decreases Pa, BOTH decrease baroreceptor and RAAS activation which increases perfusion What is the physiological role and effects of atrial natriuretic peptide (ANP)? - CORRECT ANSWERS ANP is a hormone released when atrial distention occurs causing salt and water excretion and volume contraction to prevent runaway effects of the RAAS What is the central venous compartment? - CORRECT ANSWERS the volume of blood enclosed by the right atrium and the great thoracic veins (vena cava) What is venous return (VR)? - CORRECT ANSWERS the rate at which blood returns to the central venous compartment from the peripheral veins What is central venous pressure (CVP)? - CORRECT ANSWERS Venous blood pressure within the right atrium How is CVP related to right atrial pressure and what are the resting values? - CORRECT ANSWERS At rest CVP=RAP=0 mm Hg What is the peripheral venous compartment? - CORRECT ANSWERS large veins outside of the thorax What is peripheral venous pressure (Ppv)? - CORRECT ANSWERS usually about 7mm Hg- caused by various compression points in large veins as they enter the thorax What is the mean systemic filling pressure (Psf)? - CORRECT ANSWERS -about 7mm Hg -the pressure in only the systemic circuit, ignoring the heart and pulmonary circulation -also called mean circulatory filling pressure -measure of filling pressure that creates force to propel blood to RA PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ What happens to the VR curve when RAP is increased? - CORRECT ANSWERS decreased VR- oppose blood to RA What happens to the VR curve when RAP is decreased? - CORRECT ANSWERS VR stays the same due to plateau; negative pressure causes a collapse of veins entering the chest If not flow exists in the circulatory system, what happens to VR and RAP? - CORRECT ANSWERS VR = 0 L/min, RAP = 7 mmHg What happens to the VR curve when blood volume is increased? - CORRECT ANSWERS increased VR What happens to the VR curve when sympathetic stimulation is increased? - CORRECT ANSWERS increased VR What effect does increasing RAP have on the CO curve? - CORRECT ANSWERS CO increases; Frank Starling mechanism = more blood returning to heart, causes a larger force of contraction What effect does an increase in sympathetic stimulation have on the CO curve? - CORRECT ANSWERS activates beta 1 receptors in the heart causing increased HR and FOC, resulting in increased CO What effect does an increase in positive inotropic agent have on the CO curve? - CORRECT ANSWERS shifts the CO curve upwards; positive inotropic agent caused an increase in FOC of the cardiac muscle with increased SV, together these increase CO What effect does left ventricular failure have on the CO curve? - CORRECT ANSWERS Any level of ventricular failure decreases CO What effect does an increased blood volume have on the CO curve? - CORRECT ANSWERS the CO curve is not affected; only the circulation is affected What is the equilibrium point? - CORRECT ANSWERS where normal CO and VR curves intersect; CO = VR; CVP is the same for both the heart and circulation PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ What is the effect of the positive inotropic agent on the equilibrium point? - CORRECT ANSWERS CO is increased, VR curve is not affected; new equilibrium point is at a lower value of RAP What is the effect of increased blood volume on the equilibrium point? - CORRECT ANSWERS shifts the VR curve upwards and increased MSFP, CO curve is not affected; at the new equilibrium point, both CO and RAP are increased What is the effect of sympathetic stimulation on the equilibrium point? - CORRECT ANSWERS increase in CO shifts the CO curve upwards, VR curve shifts upwards What is the effect of exercise on the equilibrium point? - CORRECT ANSWERS an increase in HR increases CO, CO curve shifts to the right What is the hemodynamic change in all known cases of chronically elevated CO? - CORRECT ANSWERS decreased SVR What are examples of diseases causing chronically elevated CO? - CORRECT ANSWERS Beriberi- thiamine deficiency, hyperthyroidism, anemia What factors do not affect CO? - CORRECT ANSWERS sleep, moderate change in environmental temperature What factors increase CO? - CORRECT ANSWERS anxiety, excited, eating, exercise, high temperatures, pregnancy, epinephrine What factors decrease CO? - CORRECT ANSWERS sitting or standing in supine position, rapid arrhythmias, heart disease What is the major factor controlling blood flow through skeletal muscle during rest and exercise? - CORRECT ANSWERS sympathetic tone PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ Explain the process of auto-regulation in regulating skeletal muscle blood flow during exercise. - CORRECT ANSWERS accumulation of vasodilator metabolites helps for vasodilation to be able to occur as an auto-regulatory response Why does MAP need to increase during exercise? - CORRECT ANSWERS it increase blood flow to certain areas How are the CO and VR curves affected by exercise? - CORRECT ANSWERS CO curves are shifted to the left (up) and VR curves are shifted upwards How does exercise effect HR? - CORRECT ANSWERS increases HR How does exercise effect SV? - CORRECT ANSWERS increases SV How does exercise effect CO? - CORRECT ANSWERS increases CO How does exercise effect Pa? - CORRECT ANSWERS slightly increased Pa How does exercise effect PP? - CORRECT ANSWERS PP increased due to increase in SV How does exercise effect SVR? - CORRECT ANSWERS SVR or TPR decrease due to vasodilation What is the major factor controlling blood flow through skeletal muscle during rest? - CORRECT ANSWERS sympathetic input- tonic vasoconstrictor nerves secrete NE What is the major factor in controlling blood flow through skeletal muscle during exercise? - CORRECT ANSWERS local autoregulation What happens to cutaneous circulation in response to exercise? - CORRECT ANSWERS initially decreased but eventually increases 4 fold due to vasodilation and heat production PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ When exercising only a few muscles, how does the body respond? - CORRECT ANSWERS sympathetic stimulation over the whole body, vasodilation only in active muscles What is the normal core body temperature? Is rectal or oral temperature measurement more accurate? - CORRECT ANSWERS 97-99 degrees F orally, +1 degree F rectally; rectal temperature usually provides best correlation with core temperature, oral underestimates by 1 degree F What are the types of heat loss? - CORRECT ANSWERS radiation, conduction, convection, evaporation Describe radiation heat loss. - CORRECT ANSWERS Radiation is transfer of heat through electromagnetic waves through space - no direct contact needed Most common form of heat loss (60%) Describe conduction heat loss. - CORRECT ANSWERS heat loss through direct contact Describe convection heat loss. - CORRECT ANSWERS Convection is a process by which heat is transferred to air Describe evaporation heat loss. - CORRECT ANSWERS the process of losing heat through the conversion of water to gas (evaporation of sweat) Describe the diunral rhythm of the body core temperature. - CORRECT ANSWERS peak in body temperature late afternoon/early evening, body temperature is lowest during early more/dawn; there is a normal daily variation of 1.8 degrees F in adults and up to 2.5 degrees F in children What are the structures of cutaneous circulation? - CORRECT ANSWERS venous plexus, skin capillaries, arteriovenous anastomoses Explain the function of the venous plexus in cutaneous circulation. - CORRECT ANSWERS continuous venous plexus exists in the subcutaneous tissues and is supplied by blood flow PHYSIOLOGY EXAM 2 QUESTIONS AND ANSWERS LATEST UPDATE 2024/2025 ALL ANSWERS 100% CORRECT VERIFIED BEST EXAM SOLUTION RATED A+ from the skin capillaries; in the body's most exposed areas, blood is supplies to the venous plexus directly form arteriovenous anastomoses Explain the function of the skin capillaries in cutaneous circulation. - CORRECT ANSWERS supply the venous plexus in the subcutaneous tissues Explain the function of the arteriovenous anastomoses in cutaneous circulation. - CORRECT ANSWERS supplies blood directly to the venous plexus in the body's most exposed areas such as the hards, feet, and ears Where is the temperature regulatory center located? - CORRECT ANSWERS posterior hypothalamus Explain the mechanisms for the stimulation, formation, and secretion of sweat. - CORRECT ANSWERS stimulation of pre-optic neurons in hypothalamus sends impulses through the ANS nerves to the spinal cord and then through sympathetic fibers to the sweat glands in the skin Compare the osmolarity of sweat with plasma. - CORRECT ANSWERS the sweat appearing at the skin's surface is always hypotonic in relation to the plasma How does the salt concentration vary with the rate of sweat secretion? - CORRECT ANSWERS low rate of sweat secretion = low salt concentration in sweat (5 mEq/L), high rate of sweat secretion = high salt concentration in sweat (50-60 mEq/L) How does aldosterone affect sweat? - CORRECT ANSWERS increases the rate of active Na+ reabsorption from the duct to minimize the loss of salt in the sweat when the plasma salt levels are already low; extreme sweating can deplete the ECF of salt Explain the time course and process for acclimatization to a hot environment. - CORRECT ANSWERS new arrival to hot environment (unacclimatized) makes the body temp increase, cause weakness, and relatively low rate of sweating with low salt concentration; after acclimatization over several days to weeks, increased work tolerance with only small increases in body temperature due to earlier onset and increased rate of sweating, salt concentrations may be higher