Exam I Answer Key Flashcards

1
Q

If a person’s systolic pressure is 120 mm Hg and his mean arterial pressure is 90 mm Hg, what is his diastolic pressure?

A

Mean pressure = diastolic pressure + 1/3 pulse pressure; and pulse pressure (P) = systolic pressure (S) - diastolic (D) so
Mean = D + 1/3 (S-D)

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2
Q

If a person has a cardiac output of 4.9 liters/min, a heart rate of 70 beats/min, and an end-diastolic volume of 130 milliliters/beat, what is his end-systolic volume?

A

CO = (HR)(SV) = (HR)(EDV - ESV)

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3
Q

Ventricular ejection occurs when

A

The AV valves are closed and Semilunar valves are open

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4
Q

The drop in pressure from one end of a vessel to the other end of that same vessel is directly proportional to

A

The resistance in that vessel. ABSOLUTE pressure would be related to how far from the pump the vessel is. The cross-sectional area of that part of the circulatory tree only influences the velocity of the blood.

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5
Q

What is always true about large diameter blood vessels?

A

They have thicker walls than small diameter vessels in which the blood pressure is similar

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6
Q

A local reduction of pH in the tissues of the gut cause

A

Vasodilation of gut arterioles. Relaxation of precapillary sphincters in capillaries of gut tissue.

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7
Q

As you go from rest to exercise what happens to your heart?

A

End-diastolic volume stays the same or could decrease if the HR is very high. Stroke volume rises. End-systolic volume falls b/c greater ejection due to increased contractility.

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8
Q

Metarterioles

A

Are part of channels that connect arterioles to venules, and provide a pathway for blood to bypass a capillary bed if the precapillary sphincters are closed

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9
Q

What assists in the return of blood to the heart?

A

Skeletal muscles that squeeze veins during their contraction. Differences in abdominal and thoracic pressures during the respiratory cycle. One-way valves in the veins. Gravity in those veins that lie Above the heart.

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10
Q

As your metabolism increases

A

The average velocity of your blood increases b/c cardiac output rises (more blood moves through circuit/min) so it has to go faster. The production of lymph increases b/c blood pressure rises. The flow (ml/min) of blood increases.

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11
Q

Name the double-layered serous membrane that surrounds the heart

A

Pericardial sac (Pericardium)

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12
Q

This plasma protein, produced by the liver, becomes a structural component of blood clots

A

Fibrinogen

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13
Q

Fibers that attach between the AV valves and the papillary muscles, which serve to anchor the valves and keep them for everting during systole

A

Chordae Tendinae

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14
Q

Name the chemical released by thrombocytes that causes vasoconstriction

A

Seratonin

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15
Q

Name the internal lining of the heart which is continuous with the heart valves

A

Endocardium

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16
Q

In the fetus, umbilical veins are part of the _____ circuit, and they carry blood that is relatively _____ in oxygen content

A

Systemic & High

17
Q

In which tissue does blood flow (ml/min) remain unaltered as you move from rest to heavy exercise

A

Brain

18
Q

Lymph is identical to

A

Interstitial fluid

19
Q

T/F: Lipid soluble solutes such as oxygen and carbon dioxide diffuse through the cells membranes of capillaries, whereas water soluble solutes such as glucose and amino acids diffuse through fenestrations and clefts (e.g. pores) in the capillary wallls

A

T

20
Q

T/F: At any point in time, the volume of blood in the systemic circuit exceeds the blood volume in the pulmonary circuit, but the stroke volumes of the left and right ventricles are equal

A

T

21
Q

T/F: In the contractile cells of the heart, the influx of calcium through slow, voltage-dependent calcium channels is matched by the outflow of potassium causing a plateau in the action potential and creating a prolonged refractory period

A

T

22
Q

T/F: Plaque buildup can reduce the effective diameter of coronary arteries by as much as 60% without effecting flow very much, because the major source of resistance in the coronary circulation is downstream of the arteries

A

T

23
Q

T/F: Starling’s Law of the Heart states that the strength of contraction is proportional to the number of cross bridges formed

A

F; it’s about the degree of stretching

24
Q

T/F: Because veins interconnect much more freely than do arteries (i.e. venous anastomoses are common), the occlusion of a venous channel rarely blocks flow from a tissue

A

T

25
Q

T/F: A sudden drop in blood pressure will be sensed by baroreceptors in the aortic arch and carotid arteries, and via the vasomotor area of the medulla will lead to an increase in venous tone

A

T

26
Q

T/F: Pulse pressure is highest in the blood vessels with the greatest diameter, because they offer less resistance to flow than small vessels

A

F; ones closest to the heart do. Large veins have no pulse

27
Q

T/F: There is no longer a distinction between systolic and diastolic pressure (i.e. there is no pulse) by the time the blood has reached the venules

A

T

28
Q

The relatively-long length of the systemic circuit, compared to the pulmonary, is reflected in

A

Relatively-thin walls of the right ventricle compared to the left ventricle b/c it must exert more pressure to overcome greater resistance in long circuit

29
Q

The left atrium acts

A

As a reservoir to collect blood during ventricular systole

30
Q

The site for the pacemaker for cardiac contractions

A

Right atrium

31
Q

Red blood cells (test)

A

Are destroyed after their approximate 3 to 4 month life span
Lack a nucleus
Are produced in the red bone marrow when progenitor cells are stimulated by the hormone erythropoietin (sometimes called hemopoietin)

32
Q

Name the correct order of structures in the electrical conduction pathway in the heart

A

SA node, AV node, AV bundle (of His), bundle branches, Purkinje fibers