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Homework 1 – The Cardiovascular System: The Heart

________ Which of the following is false with regard to a serous membrane?

(A) it is always wet,

(B) it forms a two layer “sack” around some organs

(D) its primary function is reducing friction,

(E) none of the above, these are all true.

________ When the digestive physiologist Pavlov rang a bell, he could get a dog to salivate because he had trained the dog that following the bell, food would be delivered. This action can be described as an example of a(n):

(A) extrinsic control of a negative feedback mechanism

(B) extrinsic control of a feedforward mechanism

(D) intrinsic control of a feedforward mechanism

(E) intrinsic control of a positive feedback mechanism.

_______ True or False. The lamina propria is simply the name for the areolar connective tissue found in mucous membranes.

______ The majority of the heart’s wall is composed of a layer of cardiac muscle called the:

(A) pericardium,

(B) mesometrium,

(D) myocardium

(E) epicardium

_____ Which of the following is false with regard to the internal lining of the heart chambers?

(A) it is classified as a mucous membrane

(B) it is most superficially lined with simple squamous epithelial cells

(D) its most superficial lining is known as the endothelium

(E) none of the above, these are all true with regard to the internal lining of the heart.

________ True or False. Overall, arteries and veins are differentiated by the fact that arteries carry oxygenated blood whereas veins carry deoxygenated blood.

________ True or False. Blood ejected from the left ventricle is bound for the lungs.

________ The bicuspid valve is also known as: (list all that apply)

(A) the right atrioventricular valve

(B) the pulmonary valve

(D) the mitral valve

(E) the left atrioventricular valve.

______The blood pressure in the pulmonary trunk is _?_ that in the aorta.

(A) less than

(B) more than

(D) highly variable and can’t be compared to

________ True or False. The volume of blood ejected by the left ventricle should be the same as the volume ejected by the right ventricle.

_______ The chordae tendineae:

(A) form the structural supports for the interventricular septum,

(B) help keep the ventricles from collapsing

(D) conduct electrical impulses to the ventricles

(E) keeps the electrical impulses of the atria separate from that of the ventricles.

_______ If the aortic valve in the heart was damaged, such that it failed to close properly:

(A) blood would accumulate in the left ventricle

(B) there would be a back flow of blood into the right ventricle

(D) blood pressure would increase in the lungs

(E) the right side of the heart would enlarge.

_______ The action potential of contractile cardiac muscle fibers lasts approximately as long as:

(A) an autorhythmic cardiac muscle fiber’s action potential

(B) a contractile cardiac muscle fiber contraction

(D) all of the above

(E) none of the above.

________ Approximately what percentage of cardiac muscle fibers can produce their own action potentials, i.e., are autorhythmic fibers? (A) 100%, (B) 50%, (C) 10%, (D) 1%, (E) none of

the above, no cardiac muscle fibers are autorhythmic.

________________ Starting from a point within the right brachial (arm) vein, a red blood cell will travel through the following vessels and chambers, in what order? (not all components are listed)

(A) left atrium

(B) superior vena cava

(D) pulmonary vein

(E) aorta

______ The sinoatrial node, without external stimuli, will fire at a rate of approximately _?_ beats per minute. (A) 120, (B) 100, (C) 60-80, (D) 40, (E) 0, there is no beating without external stimuli

________________ Place the following electrical conducting tissues of the heart in the correct order.

(A) atrioventricular node

(B) Purkinje fibers

(D) bundle of His,

(E) sinoatrial node.

________ True or False. The valve between the inferior and superior venae cavae and the atrium closes during atrial contraction.

________ In a normal functioning heart the atria contract _?_ the ventricles contract.

(A) at a faster rate than, (B) at a slower rate than, (C) at the same frequency as,

(D) at the same time as, (E) C & D

With regard to the heart sounds, the “lub” (1st sound) is produced by the ______, and the “dup” (2nd

sound) is produced by the _______.

(A) vacuum created by ejecting the blood, (B) opening of the semilunar valves, (C) closing of

pulmonary and aortic valves, (D) closing of the atrioventricular valves, (E) contraction of the aorta.

Label the deviations on the ECG below and place the following labels (the letters) at their

appropriate locations along the ECG (show whether the following “items” are at a pt. or over a range).

(A) dup (2nd heart sound), (B) passive ventricular filling, (C) isovolumetric (ventricular)

contraction, (D) the opening of semilunar valves, (E) the closing of atrioventricular valves

________ If scar tissue blocks the electrical conduction between the sinoatrial node and

atrioventricular node, the ventricles will: (A) contract at a faster rate than the atria, (B) contract

in synchrony with the atria, (C) contract less frequently than the atria, (D) will not contract.

________ Which of the following is not true of cardiac muscle?

(A) the cells have 1 or 2 nuclei, (B) the cells are connected by intercalated discs, (C) it is striated,

(D) the cells are interconnected by many gap junctions, (E) all of the above are true of cardiac muscle

_______ The hole connecting the right and left atria in utero (during fetal development) is called the:

(A) atrial foramen, (B) papillary foramen, (C) foramen pulmonar, (D) foramen ovale,

(E) anus foramis

What are the two equations for determining stroke volume? (hint, see next question)

What equation have we learned for determining cardiac output?

______________ What is the stroke volume of a patient with an end systolic volume of 70 mL and an

end diastolic volume of 142 mL? include units. (show your equation below)

______________ What is the average stroke volume of a patient with a cardiac output of 4.9 L/min

and a heart rate of 70 beats/min? include units. (show your equation below)

______________ What is the cardiac output of a patient with a stroke volume of 75 mL and a heart

rate of 85 beats/min? include units. (show your equation below)

_________ According to the Frank-Starling law, when the heart receives a greater blood volume:

(A) it will pump weakly to continue to produce the original stroke volume, (B) it will pump at the

original strength to increase stroke volume, (C) it will increase the strength of the pump and increase

stroke volume, (D) none of the above, the heart can not suddenly receive a greater blood volume.

________ True or False. High systemic levels of epinephrine lead to a large increase in cardiac output

by speeding up the heart rate and increasing stroke volume by improving myocardial contractility and

by enlarging the end diastolic volume through higher venous return.

Insert typical, healthy approximate values for the following characteristics (assume ~150 lb, 25 y.o.)

include units.

Stroke Volumerest _______________ COrest _______________ COmax ________________

Heart Raterest ______________ HRmax ________________ Blood Volume ______________