Physiology Unit 3 Multiple Choice

Which of the following describes the effect of end- diastolic volume on stroke volume? (a) A decrease in end-diastolic volume creates a vacuum drawing more blood into the ventricle increasing stroke volume. (b) An increase in end-diastolic volume stretches ventricular muscle cells to lengths greater that optimum, decreasing stroke volume. (c) A decrease in end-diastolic volume allows cardiac muscle to relax, conserving energy for the next contraction, thereby increasing stroke volume of that next contraction. (d) A decrease in end-diastolic volume allows ventricular muscle cells to relax more during diastole, allowing more blood to return to the heart increasing stroke volume. (e) An increase in end-diastolic volume stretches ventricular muscle cells to lengths closer to optimum, increasing the strength of contraction and thereby increasing stroke volume.

During intense (heavy) exercise, the initial ability of oxidative phosphorylation to provide enough ATP for the sudden demand of increased force generation by the skeletal muscle is _____________, ___________ until oxygen delivery and other mechanisms come up to speed. (a) enhanced : fatty acids (b) enhanced : substrate-level phosphorylation (c) inadequate : fatty acids (d) enhanced : glucose (e) inadequate : substrate-level phosphorylation

The repeated oscillating interaction between actin and myosin by skeletal muscle cell is called what? (a) Z line interaction (b) crossbridge cycling (c) titin cycling (d) the sliding-filament model (e) sarcomeric facilitation

What is the regulatory protein component of the thin filament that binds to calcium, thereby initiating skeletal muscle contraction? (a) actin (b) myosin (c) titin (d) troponin (e) tropomyosin

Release of an inorganic phosphate from myosin molecule directly results in which of the following? (a) power stroke (b) breaking of the actin myosin complex (c) development of rigor (d) cocking of the myosin head (e) binding of actin to myosin

During the cross-bridge cycle, ATP binding to myosin causes which of the following? (a) myosin head to interact with calcium channels, triggering calcium release from SR (b) the myosin head to swing forward pulling actin toward the M line (c) the myosin head to be in its high-energy form (d) the myosin head to detach from actin (e) the myosin head to attach to actin

The time between the occurrence of an action potential in skeletal muscle and the onset of tension is called what? (a) latent period (b) contraction phase (c) synaptic delay (d) relative refractory period (e) relaxation period

The sequence of events that links the muscle's action potential to changes in skeletal muscle force development is called what? (a) the sliding-filament model (b) oxidative phophorylation (c) crossbridge cycling (d) excitation-contraction coupling (e) myoaction coupling

The period of ventricular contraction is called ___________, whereas the period of ventricular relaxation is called_________. (a) action potential : refractory period (b) action potential: graded potential (c) systole : diastole (d) V fib : A fib (e) diastole : systole

As skeletal muscle is further stretched beyond the length where optimum force is developed, (a) thin filaments are pulled away from the thick filaments, thereby reducing actin's ability to interact with myosin (b) thick filaments overlap one another, thereby reducing their ability to interact with actin. (c) amount of calcium released by the sarcoplasmic reticulum is reduced as length increases. (d) thick filaments are pulled away from one another, thereby reducing their ability to interact with actin. (e) thin filaments overlap one another, thereby reducing their ability to interact with myosin.

Which of the following is the correct order of muscle fiber recruitment, from first to last? (a) slow oxidative : fast glycolytic : fast oxidative (b) fast glycolytic : slow oxydative : fast oxidative (c) fast glycolytic : fast oxidative : slow oxidative (d) fast oxidative : fast glycolytic : slow oxidative (e) slow oxidative : fast oxidative : fast glycolytic

Which of the following is NOT an accurate description of specific muscle fiber types? (a) Slow oxidative fibers are the smallest diameter fibers. (b) Fast glycolytic fibers are the largest diameter fibers. (c) Fast glycolytic fibers produce their ATP by glycolysis. (d) Slow oxydative fibers are quick to fatigue. (e) Fast oxidative fibers have a high mitochondrial density.

Which of the following adaptations does NOT generally occur with aerobic exercise? (a) an increase in the number of myofibrils per muscle fiber (b) an increase in the aerobic capacity of muscle (c) an increase in the number of mitochondria per muscle fiber (d) an increase in the blood supply to the muscles (e) a conversion of fast glycolytic fibers to fast oxidative fibers

Which skeletal muscle fiber type has most its energy come from substrate-level phosphorylation? (a) slow (b) fast (c) intermediate (d) oxidative (e) glycolytic

What is an increase in the number of active motor units that would increase the force developed by a skeletal muscle called? (a) summation (b) length tension relationship (c) recruitment (d) tetanus (e) treppe

Which of the following components of an ECG represent ventricular repolarization? (a) P wave (b) QRS complex (c) T wave (d) PQ interval (e) TQ segment

Which of the following factors determines preload? (a) peripheral resistance and tension (b) end-diastolic volume and end-systolic volume (c) parasympathetic activity of the ventricles (d) heart rate and venous return (e) the pressure in the aorta and the lungs

The speed with which the skeletal muscle generates force is determined primarily by (a) type of myosin and its ATPase present. (b) speed of which myosin strand moves. (c) troponin. (d) the amount of energy available. (e) tropomyosin.

An increase in venous return would result in a(n) (a) increased end-systolic volume. (b) increased end-diastolic volume. (c) decreased end-systolic volume. (d) increase mid-systolic volume. (e) decreased end-diastolic volume.

Given end-diastolic volume = 130 mL and end-systolic volume = 55mL, what is the stroke volume and ejevtion fraction? (a) SV = 80 mL, EF = 0.61 (b) SV= 75 mL, EF = 0.58 (c) SV = 75 mL, EF = 0.42 (d) SV = 180 mL, EF = 0.38 (e) SV = 180 mL, EF = 0.61

What converts the myosin head into the high-energy state? (a) the hydrolysis of ATP (b) the condensation of ATP (c) binding to titin (d) binding to actin (e) binding to ATP only

When an action potential is generated within a motor neuron, (a) the muscle cell of the motor unit will occasionally contracted. (b) only select muscle cells within the motor unit are stimulated to contract. (c) all of the muscle cell of the motor unit is stimulated to contract. (d) every muscle cell of the motor unit is stimulated to contract. (e) the muscle cells from a neighboring motor unit will contract.

Cardiac output is determined by what two variable? (a) end-diastolic volume and end-systolic volume (b) preload and afterload (c) heart rate and stroke volume (d) heart rate and end diastolic volume (e) stroke volume and end diastolic volume

In what phase of the cardiac cycle does ventricular pressure exceed aortic pressure? (a) atrial contraction (b) ventricular filling (c) isovolumetric contraction (d) isovolumetric relaxation (e) ventricular ejection

Blood is ejected from the left ventricle once pressure within the (a) ventricle is greater than pressure within the aorta. (b) ventricle is less that pressure within the aorta. (c) ventricle is greater that pressure within the pulmonary artery. (d) ventricle is less than pressure within the pulmonary artery. (e) muscles of the pulmonary semilunar valve relax

What two major regions of the heart contain a concentration of pacemaker cells? (a) sinoatrial node and bundle of His (b) sinoatrial node and atrioventricular node (c) sinoatrial node and Purkinje fibers (d) bundle of His and Purkinje fibers (e) bundle of His and atrioventricular node

Closure of the atrioventricular valve occurs when (a) pressure inside the ventricular is less than pressure inside the atrium. (b) the valve contracts. (c) pressure inside the ventricle is greater than pressure inside the atrium. (d) the atrium contracts. (e) the papillary muscle contract.

What is occurring during ventricular ejection? (a) AV and semilunar valves are open as blood is leaving the ventricles. (b) AV valves are open and the semilunar valves are closed as ventricular pressure is increasing. (c) TAV valves are open and the semilunar valves are open as blood us leaving the ventricles. (d) AV and semilunar valves are closed as ventricular pressure is increasing. (e) AV valves are closed and the semilunar valves are open as blood is leaving the ventricles.

The T-Q segment is the time from the end of the T wave to the beginning of the QRS complex which measures the time (a) of atrial systole. (b) between heartbeats. (c) of ventricular systole. (d) of atrial diastole. (e) of ventricular diastole.

Which of the following is the correct conduction pathway through the heart? (a) AV node, SA node, AV bundle, bundle branches, Purkinje fibers (b) SA node, AV node, bundle branches, AV bundle, Purkinje fibers (c) SA node, AV node, AV bundle, bundle branches, Purkinje fibers (d) Purkinje fibers, AV bundle, bundle branches, SA node, AV node (e) AV node, SA node, bundle branches, AV bundle, Purkinje fibers

Closure of the atrioventricular valve occurs when (a) the papillary muscles contract (b) the valve contracts (c) pressure inside the ventricle is greater than pressure inside the atrium (d) pressure inside the ventricle is less than pressure inside the atrium (e) the atrium contracts

In what phase is the cardiac cycle when AV valves are open and semilunar valves are closed? (a) atrial contraction (b) ventricular filling (c) isovolumetric contraction (d) isovolumetric relaxation (e) vetricular ejection

The volume of blood that is pumped by the heart every minute is determined by the equation (a) EF = EDV - ESV (b) CO = HR x SV (c) MAP = CO x TPR (d) T = PR/2 (e) SV = EDV - ESV

During which phase of the cardiac cycle are all four heart valves open? (a) isovolumetric contraction (b) isovolumetric relaxation (c) ventricular filling (d) ventricular ejection (e) none

The portion of osmotic pressure exerted by _________ in the blood is known as colloid osmotic pressure (or oncotic pressure). (a) steroids (b) large ions (c) proteins (d) small ions (e) lipids

Sympathetic nerves have what effect on systemic arterioles? (a) neither vasodilation or vasoconstriction, but may cause vasospasm (b) vasospasm (c) vasodilation (d) vasoconstriction and vasospasm (e) vasoconstriction

The hormone ADH (vasopressin) acts in the short term to ______ and in the long term to ________ thereby increasing mean arterial pressure. (a) vasocontrict arterioles : decrease urine flow (b) vasodilate arterioles : decrease urine flow (c) decrease urine outflow : vasocontrict arterioles (d) increase urine outflow : vasodilate arterioles (e) vasodilate arteroles : increase urine outflow

The opening and closure of the atrioventricular and semilunar valves is driven by (a) contraction and relaxation of the valve (b) contraction of the ventricle and atria that pull the valves into place (c) contraction of the valves (d) contraction of muscles attached to the valves (e) differences in pressure across the valve

During isovolumetric relaxation, (a) AV and semilunar valves are open and ventricular pressure is decreasing. (b) AV and semilunar valves are closed and ventricular pressure is increasing. (c) AV and semilunar valves are closed and ventricular pressure is decreasing. (d) AV valves are open, the semilunar valves are closed, and ventricular pressure is decreasing. (e) AV and semilunar valves are open and ventricular pressure is increasing.

The high compliance of veins allows them to (a) rapidly change central venous pressure with small changes in blood volume. (b) act as pressure reservoirs (c) provide driving force for the movement of blood through the vasculature during diastole. (d) accommodate large volumes of blood with little change in pressure. (e) hold only small volumes of blood.

What is the driving force for blood flow through the systemic circuit? (a) mean arterial pressure (b) total peripheral resistance (c) pulse pressure (d) cardiac output (e) perfusion pressure

An increase in heart rate can be mediated through which of the following? (a) a decrease in parasympathetic nervous activity only (b) a decrease in sympathetic activity only (c) an increase in sympathetic activity only (d) an increase in parasympathetic activity and a decrease in sympathetic activity (e) a decrease in parasympathetic activity and an increase in sympathetic activity

Which of the following structures contains high pressure baroreceptors? (a) aortic arch only (b) carotid sinus only (c) right atrium only (d) both the aortic arch and carotid sinus (e) aortic arch, right atrium, and carotid sinus

A decrease in afterload will lead to which of the following? (a) decrease cardiac output (b) increased stoke volume (c) decreased heart rate (d) decreased stroke volume (e) increased heart rate

Which of the following would decrease mean arterial pressure? (a) increase in venous return (b) increase in heart rate (c) increase in total peripheral resistance (d) increase in arteriole diameter (e) increase in stroke volume

The long-term regulation of arterial blood pressure involves the (a) release of hormones over a period of minutes (b) stimulation of an increase in urine flow through the kidneys (c) control of peripheral resistance (d) control of blood volume by the kidneys (e) immediate change in activity of the nervous system

What is bulk flow of fluid from inside a capillary into interstitial fluid called? (a) excretion (b) absorption (c) filtration (d) adsorption (e) secretion

The increase in stroke volume that occurs during exercise is caused primarily by a(n) (a) increase in venous return (b) increase in end-diastolic volume (c) decrease in peripheral resistance (d) decrease in end-systolic volume (e) increase in myocardial contractility

Which of the following equations correctly relates flow, pressure, and resistance? (a) pressure = flow x resistance (b) flow = pressure - resistance (c) flow = pressure + resistance (d) flow = pressure x resistance (e) resistance = flow x pressure

Mean arterial pressure can be increased by all of the following EXCEPT (a) decreasing end-diastolic volume (b) increasing venous return (c) increasing sympathetic activity (d) increasing blood volume (e) increasing heart rate

Under normal conditions, which Starling forces favor filtration? (a) interstitial fluid hydrostatic pressure and plasma oncotic pressure (b) capillary hydrostatic pressure and interstitial fluid hydrostatic pressure (c) capillary hydrostatic pressure and plasma oncotic pressure (d) capillary hydrostatic pressure and interstitial fluid osmotic pressure (e) interstitial fluid hydrostatic pressure and interstitial fluid osmotic pressure