Q: Which of the following equations correctly calculates cardiac output ($$CO) $$given a heart rate ($$HR) of 80 $$beats per minute and a stroke volume ($$SV) of 65 ml $$per beat?

$$CO = HR \times SV = 80 \times 65 = 5200\ \text{ml/min}$$

Q: Which of the following equations correctly calculates stroke volume ($$SV) $$given an end-diastolic volume ($$EDV) of 120 ml $$and an end-systolic volume ($$ESV) of 50 ml$$?

$$SV = EDV - ESV = 120 - 50 = 70\ \text{ml}$$

Question 1

Which of the following best describes the primary difference between the endocrine and nervous systems in terms of their method of communication and speed of response?

Accepted Answer

The endocrine system releases hormones into the bloodstream for slower, longer-lasting effects, while the nervous system uses neurotransmitters for rapid, short-lived effects.

Question 2

A patient presents with symptoms of anemia, including fatigue and elevated heart rate. Laboratory tests reveal decreased hemoglobin levels and increased reticulocyte count. Which of the following is the most likely cause of this patient's anemia?

Accepted Answer

Iron deficiency anemia due to inadequate dietary iron intake.

Question 3

Which of the following equations correctly calculates cardiac output ($$CO) $$given a heart rate ($$HR) of 80 $$beats per minute and a stroke volume ($$SV) of 65 ml $$per beat?

Accepted Answer

$$CO = HR 	imes SV = 80 	imes 65 = 5200\ 	ext{ml/min}$$

Question 4

During the cardiac cycle, which event is responsible for the first heart sound (S1, 'lub')?

Accepted Answer

Closure of the atrioventricular (AV) valves.

Question 5

A blood sample is treated with anti-A, anti-B, and anti-Rh antibodies. Agglutination occurs with anti-B and anti-Rh, but not with anti-A. What is the blood type of this sample?

Accepted Answer

B+

Question 6

Which of the following best explains why the left ventricle has a thicker wall than the right ventricle?

Accepted Answer

The left ventricle pumps blood to the entire body, requiring greater force to overcome systemic resistance.

Question 7

Which of the following is a function of albumin in blood plasma?

Accepted Answer

It maintains osmotic pressure, helping to retain water in the blood.

Question 8

A patient with deep vein thrombosis (DVT) develops sudden shortness of breath and chest pain. Which of the following best explains the likely complication?

Accepted Answer

A thrombus formed in the leg veins has broken off and lodged in the pulmonary vessels, causing a pulmonary embolism.

Question 9

Which of the following correctly describes the sequence of events in the intrinsic pathway of coagulation?

Accepted Answer

Activation of factor XII by exposed collagen, followed by a cascade activating factors XI, IX, and VIII, leading to formation of factor Xa.

Question 10

Which hormone is secreted by the kidneys and stimulates erythropoiesis in the bone marrow?

Accepted Answer

Erythropoietin (EPO)

Question 11

Which of the following best describes the mechanism of action for hydrophobic steroid hormones?

Accepted Answer

They bind to cytosolic or nuclear receptors and directly alter gene expression and protein synthesis.

Question 12

Which of the following equations correctly calculates stroke volume ($$SV) $$given an end-diastolic volume ($$EDV) of 120 ml $$and an end-systolic volume ($$ESV) of 50 ml$$?

Accepted Answer

$$SV = EDV - ESV = 120 - 50 = 70\ 	ext{ml}$$

Question 13

Which of the following is the universal donor blood type, and why?

Accepted Answer

O-, because it lacks A, B, and Rh antigens, minimizing risk of agglutination.

Question 14

Which of the following best describes the function of the AV node delay during the cardiac conduction pathway?

Accepted Answer

It ensures the atria have time to eject blood into the ventricles before ventricular contraction.

Question 15

Which of the following is a direct effect of atrial natriuretic peptide (ANP) released by the heart?

Accepted Answer

It lowers blood pressure by increasing sodium excretion and reducing blood volume.

Question 16

Which of the following best describes the role of platelets in hemostasis?

Accepted Answer

They form a platelet plug at the site of injury and release granules containing clotting factors.

Question 17

Which of the following correctly describes the function of the coronary circulation?

Accepted Answer

It supplies oxygen and nutrients directly to the myocardium, which cannot be reached by blood inside the heart chambers.

Question 18

Which of the following best explains the effect of sympathetic nervous system stimulation on cardiac output?

Accepted Answer

It increases cardiac output by increasing heart rate and contractility via release of norepinephrine.

Question 19

Which of the following is the correct formula for ejection fraction ($$EF) $$given a stroke volume ($$SV) of 70 ml $$and an end-diastolic volume ($$EDV) of 120 ml$$?

Accepted Answer

$$EF = \frac{SV}{EDV} 	imes 100 = \frac{70}{120} 	imes 100 = 58.3\%$$

Study Notes: The Endocrine System, Blood, and The Heart

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