Physiology, Physiology, quiz 8

How much of a change in the membrane potential is necessary for the summation of postsynaptic potentials to results in an action potential being generated? Answers: a. +30 mV b. -55 mV c. +10 mV d. +15 mV

+15 mV

Circulatory tree

A branching networkfrom ventricle to atrium Arteries ⇨ capillaries ⇨ veins Few large vessels Many small vessels

Absolute and relative refractory periods are important aspects of which of the following? Answers: Action potentials Resting potentials Equilibrium potentials Graded potentials

Action potentials

Which of the following neuronal processes transmits an action potential? Answers: a. Axon b. Dendrite c. Cell body d. Glia

Axon

Arterioles

Lead to capillaries Narrow = provide the most resistance No elastic tissue, some muscle Control BP and flow Mostly sympathetic innervation

Lymphatic system

Lymph capillaries: very porous Lymphatic vessels: valves: one-way flow contractile Fluid returned at large veins

Veins and venules

Not as muscular or elastic Distensible Sympathetic innervation

Which factor/s can be changed quickly and locally?

Pressure gradient Vessel length Viscosity Vessel radius

The myocardium would be the thickest in the ________. Answers: a. right atrium b. right ventricle c. left ventricle d. left atrium

c. left ventricle

Which of the following is unique to cardiac muscle cells? Answers: a. Only cardiac muscle has a high concentration of mitochondria. b. Only cardiac muscle contains a sarcoplasmic reticulum. c. Only cardiac muscle has gap junctions. d. Only cardiac muscle is capable of autorhythmicity

d. Only cardiac muscle is capable of autorhythmicity

In relaxed muscle, the myosin-binding site on actin is blocked by ________. Answers: a. troponin b. titin c. tropomyosin d. myoglobin

tropomyosin

Which of the following is least able to cross the blood-brain barrier? Answers: a. glucose b. sodium ions c. water d. white blood cells

white blood cells

Which of the following voltages would most likely be measured during the relative refractory period? Answers: a. -80 mV b. +30 mV c. 0 mV d. -45 mV

-80mV

The muscles of a professional marathon runner are most likely to have ________. Answers: a. 40 percent fast-twitch muscle fibers and 60 percent slow-twitch muscle fibers b. 20 percent fast-twitch muscle fibers and 80 percent slow-twitch muscle fibers c. 50 percent fast-twitch muscle fibers and 50 percent slow-twitch muscle fibers d. 80 percent fast-twitch muscle fibers and 20 percent slow-twitch muscle fibers

20 percent fast-twitch muscle fibers and 80 percent slow-twitch muscle fibers

The muscles of a professional sprinter are most likely to have ________. Answers a. 20 percent fast-twitch muscle fibers and 80 percent slow-twitch muscle fibers b. 40 percent fast-twitch muscle fibers and 60 percent slow-twitch muscle fibers c. 80 percent fast-twitch muscle fibers and 20 percent slow-twitch muscle fibers d. 50 percent fast-twitch muscle fibers and 50 percent slow-twitch muscle fibers

80 percent fast-twitch muscle fibers and 20 percent slow-twitch muscle fibers

Large/elastic arteries

> 10 mm wide Usually named Fast flow No innervation

What is the correct definition of a cation? Answers: a. A cation is an ion that can have a positive or negative charge. b. A cation is a negatively charged ion. c. A cation is a positively charged ion. d. A cation is an ion that cannot have a charge.

A cation is a positively charged ion.

Nicotine will excite the post-ganglionic neurons of the _____________ autonomic nervous system. Answers: a. Parasympathetic b. Both sympathetic and parasympathetic c. Sympathetic

Both sympathetic and parasympathetic

How are potassium ions typically moved out of a neuron when the membrane is at rest? Answers: Potassium ions are stable and do not move when a membrane is at rest. The sodium-potassium pump moves potassium ions out of the cell. Concentration gradients move potassium ions out of the cell. Electrical gradients move potassium ions out of the cell.

Concentration gradients move potassium ions out of the cell.

Cardiac cycle

Cycle = repetition L & R sides are synchronized L & R volumes are the same (but pressures differ) left side is higher pressure

Select the main parts of a neuron Answers: a. Dendrite b. Axon c. Cell body

Dendrite, Axon, Cell body

Diverting blood

Digestive tract, kidneys and skin: Normally receive more thanthey need; can toleratereduced flow Brain and heart: Most metabolically active Cannot tolerate reduced flow

Capillary function

Exchange materials between blood and tissues 1. Through endothelial cells by simple diffusion or using transporters: gases, small organic molecules 2. Through endothelial cells using vesicles 3. Between endothelial cells by simple diffusion 4. Between cells by bulk flow (filtration)

Preganglionic neurons secrete ACh. Their receptors are always nicotinic. Thus, post-ganglionic neurons can be: Answers: a. Excited only b. Either excited or inhibited c. Inhibited only

Excited only

Which of the following statements is true? Answers: a. Fast fibers have a small diameter. b. Fast fibers have many mitochondria. c. Fast fibers have large glycogen reserves d. Fast fibers contain loosely packed myofibrils.

Fast fibers have large glycogen reserves

Which of the following statements is false? Answers: Graded potentials are always hyperpolarizing, whereas action potentials are always depolarizing. Graded potentials are proportional to the magnitude of the stimulus, whereas action potentials are "all-or-none." Refractory periods are not associated with graded potentials, but are associated with action potentials. Graded potentials are always decreasing, whereas action potentials are always non-decreasing.

Graded potentials are always hyperpolarizing, whereas action potentials are always depolarizing.

Parasympathetic

Metabotropic receptor Closes Ca++ channels Opens K+ channels

Sympathetic

Metabotropic receptor Opens Ca++ channels Opens Na+ channels

Pacemakers

Modified cardiac muscle Non-contractile Membrane potential never rests: depolarizes spontaneously

The resting potential for a particular neuron is measured to be -60 mV. Which of the following distributions of ions could NOT produce this measurement? Answers: a. More anions than cations on both sides of the cell membrane b. More anions than cations on the outside of the membrane, more cations than anions on the inside of the membrane c. More cations than anions on the outside of the membrane, more anions than cations on the inside of the membrane d. More cations than anions on both sides of the cell membrane

More anions than cations on the outside of the membrane, more cations than anions on the inside of the membrane

Capillaries

Narrowest; slowest flow No innervation (control?) No smooth muscle (except at pre-capillary sphincter) Thin walls; endothelium only

Which term describes the cell membrane potential of a neuron at rest? Answers: Polarized Depolarized Hyperpolarized Repolarized

Polarized

Action potentials are characterized by which of the following? Answers: a. Rapid depolarization b. Depolarization or hyperpolarization c. Slightly negative polarization d. Repolarization

Rapid depolarization

Pacemakers

SA node: main, fastest

Parasympathetic autonomic nerve system targeted organs can be: Answers: a. Either excited or inhibited b. Excited only c. Inhibited only

Selected Answer: a. Either excited or inhibited

Which of the following neurotransmitters is associated with inhibition exclusively? Answers: a. GABA b. glutamate c. acetylcholine d. norepinephrine

Selected Answer: a. GABA

What is the target of an upper motor neuron? Answers: a. lower motor neuron b. skeletal muscle c. muscle d. cerebral cortex

Selected Answer: a. lower motor neuron

Which structure predominates in the white matter of the brain? Answers: a. myelinated axons b. neuronal cell bodies c. ganglia of the parasympathetic nerves d. bundles of dendrites from the enteric nervous system

Selected Answer: a. myelinated axons

Which term describes a bundle of axons in the peripheral nervous system? Answers: a. nerve b. ganglion c. tract d. nucleus

Selected Answer: a. nerve

A channel opens on a postsynaptic membrane that causes a negative ion to enter the cell. What type of graded potential is this? Answers: a. repolarizing b. hyperpolarizing c. non-polarizing d. depolarizing

Selected Answer: b. hyperpolarizing

What type of receptor requires an effector protein to initiate a signal? Answers: a. ionotropic receptor b. metabotropic receptor c. cholinergic system d. biogenic amine

Selected Answer: b. metabotropic receptor

Which of the following statements is false? Answers: a. Slow fibers contain the pigment myoglobin. b. Slow fibers contract for extended periods. c. Slow fibers contain a large number of mitochondria. d. Slow fibers have a small network of capillaries.

Slow fibers have a small network of capillaries.

Saltatory conduction refers to which of the following? Answers: The conduction of an action potential along a demyelinated axon. The conduction of a graded potential along a demyelinated axon. The conduction of an action potential along a myelinated axon. The conduction of a graded potential along a myelinated axon.

The conduction of an action potential along a myelinated axon.

Which of the following statements describes smooth muscle cells? Answers:a. They primarily use anaerobic metabolism. b. They have a rapid onset of contractions. c. They cannot exbihit tetanus. d. They are resistant to fatigue.

They are resistant to fatigue.

Within neurons, ions move by active and passive transport. Answers: True False

True

Conduction

Via electrical synapses SA node AV node AV bundle Bundle branches Purkinje fibers

Which of the following is a positive inotrope? Answers: a. Ca2+ b. K+ c. Both Na+ and K+ d. Na+

a. Ca2+

Most blood enters the ventricle during ________. a. atrial diastole b. ventricular systole c. atrial systole d. ventricular systole

a. atrial diastole

The first heart sound represents which portion of the cardiac cycle? Answers: a. closing of the atrioventricular valves b. atrial systole c. closing of the semilunar valves d. ventricular systole

a. closing of the atrioventricular valves

The ________ layer secretes chemicals that help to regulate ionic environments and strength of contraction and serve as powerful vasoconstrictors. Answers: a. endocardium b. myocardium c. epicardium d. pericardial sac

a. endocardium

The cardiovascule centers are located in which area of the brain? Answers: a. medulla oblongata b. mesencephalon (midbrain) c. cerebrum d. pons

a. medulla oblongata

Which valve separates the left atrium from the left ventricle? Answers: a. mitral b. tricupsid c. pulmonary d. aortic

a. mitral

Ventricular relaxation immediately follows ________. Answers: a. ventricular repolarization b. ventricular depolarization c. atrial depolarization d. atrial repolarization

a. ventricular repolarization

A sprinter would experience muscle fatigue sooner than a marathon runner due to _______________. Answers: a. glycolysis in the muscles of the marathon runner b. aerobic metabolism in the muscles of the sprinter c. anaerobic metabolism in the muscles of the sprinter d. anaerobic metabolism in the muscles of the marathon runner

anaerobic metabolism in the muscles of the sprinter

Which of the following properties is not common to all three muscle tissues? Answers: a. excitability b. at rest, uses shielding proteins to cover actin-binding sites c. elasticity d. the need for ATP

at rest, uses shielding proteins to cover actin-binding sites

In a healthy young adult, what happens to cardiac output when heart rate increases above 160 bpm? Answers: a. There is no way to predict. b. It decreases. c. It remains constant. d. It increases.

b. It decreases.

Which component of the heart conduction system would have the slowest rate of firing? Answers: a. bundle branches b. Purkinje fibers c. atrioventricular node d. atrioventricular bundle

b. Purkinje fibers

Which primitive area of the heart will give rise to the right ventricle? Answers: a. truncus arteriosus b. bulbus cordis c. sinus venosus d. primitive ventricle

b. bulbus cordis

The two tubes that eventually fuse to form the heart are referred to as the ________. Answers: a. bulbus cordis b. cardogenic tubes c. cardiogenic region d. primitive ventricle

b. cardogenic tubes

Of the three germ layers that give rise to all adult tissues and organs, which gives rise to the heart? Answers: a. ectoderm b. mesoderm c. endoderm d. placenta

b. mesoderm

Which portion of the ECG corresponds to repolarization of the atria? Answers: a. P wave b. none of the above: atrial repolarization is masked by ventricular depolarization c. QRS complex d. T wave

b. none of the above: atrial repolarization is masked by ventricular depolarization

Which chamber initially receives blood from the systemic circuit? Answers: a. left ventricle b. right atrium c. right ventricle d. left atrium

b. right atrium

What happens to preload when there is venous constriction in the veins? Answers: a. It decreases b. There is no way to predict c. It increases d. It remains constant

c. It increases

The force the heart must overcome to pump blood is known as ________. Answers: a. stroke volume b. preload c. afterload d. cardiac output

c. afterload

Which of the following is not important in preventing backflow of blood? Answers: a. AV valves b. chordae tendineae c. endocardium d. papillary muscles

c. endocardium

The cardiac cycle consists of a distinct relaxation and contraction phase. Which term is typically used to refer ventricular contraction while no blood is being ejected? Answers: a. quiescent b. diastole c. isovolumic contraction d. Systole

c. isovolumic contraction

Which element is important in directly triggering muscle contraction? Answers: a. chloride (Cl-) b. sodium (Na+) c. potassium (K+) d. calcium (Ca++)

calcium (Ca++)

According to the sliding filament model, binding sites on actin open when ________. Answers: a. creatine phosphate levels rise b. ATP levels rise c. calcium ion levels rise d. acetylcholine levels rise

calcium ion levels rise

Muscle relaxation occurs when ________. Answers: a. calcium ions are actively transported into the sarcoplasmic reticulum b. calcium ions diffuse into the sarcoplasmic reticulum c. calcium ions diffuse out of the sarcoplasmic reticulum d. calcium ions are actively transported out of the sarcoplasmic reticulum

calcium ions are actively transported into the sarcoplasmic reticulum

Cardiac muscles differ from skeletal muscles in that they _____________. Answers: a. contained intercalated discs b. are striated c. utilize aerobic metabolism d. contain myofibrils

contained intercalated discs

During which phase of a twitch in a muscle fiber is tension the greatest? Answers :a. contraction phase b. repolarization phase c. resting phase d. relaxation phase

contraction phase

Question 9 In which septum is it normal to find openings in the adult? Answers: a. interventricular septum b. interatrial septum c. all of the above d. atrioventricular septum

d. atrioventricular septum

The influx of which ion accounts for the plateau phase? Answers: a. chloride b. potassium c. sodium d. calcium

d. calcium

The earliest organ to form and begin function within the developing human is the ________. Answers: a. brain b. stomach c. lungs d. heart

d. heart

Which of the following lists the valves in the order through which the blood flows from the vena cava through the heart? Answers: a. aortic semilunar, pulmonary semilunar, tricuspid, bicuspid b. bicuspid, aortic semilunar, tricuspid, pulmonary semilunar c. mitral, pulmonary semilunar, bicuspid, aortic semilunar d. tricuspid, pulmonary semilunar, bicuspid, aortic semilunar

d. tricuspid, pulmonary semilunar, bicuspid, aortic semilunar

The pulmonary trunk and aorta are derived from which primitive heart structure? Answers: a. primitive ventricle b. sinus venosus c. bulbus cordis d. truncus arteriosus

d. truncus arteriosus

Muscle fatigue is caused by _____________. Answers: a. buildup of ATP and lactic acid levels b. buildup of ATP and pyruvic acid levels c. exhaustion of energy reserves and buildup of lactic acid d. exhaustion of energy reserves and buildup of pyruvic acid levels

exhaustion of energy reserves and buildup of lactic acid

The correct order for the smallest to the largest unit of organization in muscle tissue is ________. Answers: a. myofibril, muscle fiber, filament, fascicle b. muscle fiber, fascicle, filament, myofibril c. fascicle, filament, muscle fiber, myofibril d. filament, myofibril, muscle fiber, fascicle

filament, myofibril, muscle fiber, fascicle

Cardiac output

heart rate x stroke volume

Preload

is the amount of blood in the ventricles at the end of atrial systole just prior to ventricular contraction

End Systolic Volume (ESV)

is the amount of blood remaining in each ventricle following systole

Afterload

is the force the ventricles must develop to effectively pump blood against the resistance in the vessels (Total peripheral resistance)

Smooth muscles differ from skeletal and cardiac muscles in that they ________. Answers: a. are under voluntary control b. lack actin c. lack myosin d. lack myofibrils

lack myofibrils

From which embryonic cell type does muscle tissue develop? Answers: a. satellite cells b. myotube cells c. myoblast cells d. ganglion cells

myoblast cells

Drug X blocks ATP regeneration from ADP and phosphate. How will muscle cells respond to this drug? Answers: a. by using ADP as an energy source b. by absorbing ATP from the bloodstream c. by using glycogen as an energy source d. none of the above

none of the above

What aspect of creatine phosphate allows it to supply energy to muscles? Answers: a. ATPase activity b. phosphate bonds c. carbon bonds d. hydrogen bonds

phosphate bonds

Stroke volume

s the amount of blood pumped by each ventricle

The cell membrane of a muscle fiber is called ________. sarcolemma Answers: myofibril b. sarcoplasma c. sarcolemma d. myofilament

sarcolemma

Thin and thick filaments are organized into functional units called ________. Answers: a. T-tubules b. myofilaments c. sarcomeres d. myofibrils

sarcomeres

Which cell type helps to repair injured muscle fibers? Answers :a. myoblast cells b. satellite cells c. myotube cells d. ganglion cells

satellite cells

If cardiac muscle cells were prevented from undergoing aerobic metabolism, they ultimately would ________. Answers: a. stop contracting b. start contracting c. undergo glycolysis d. synthesize ATP

stop contracting

Muscle that has a striped appearance is described as being ________. Answers: a. elastic b. nonstriated c. excitable d. striated

striated

Depolarization of the sarcolemma means ________. Answers: a. the inside of the membrane has become less negative as sodium ions accumulate b. the outside of the membrane has become less negative as sodium ions accumulate c. the inside of the membrane has become more negative as sodium ions accumulate d. the sarcolemma has completely lost any electrical charge

the inside of the membrane has become less negative as sodium ions accumulate

During muscle contraction, the cross-bridge detaches when ________. Answers a. calcium ions bind to troponin b. the myosin head binds to an ATP molecule c. calcium ions bind to actin d. the myosin head binds to an ADP molecule

the myosin head binds to an ATP molecule

F = ΔP/R

⇧ Pressure Gradient ⇩ Resistance ⇧ Flow