Question 1

Which structure in the heart acts as the primary pacemaker, initiating the electrical impulses that trigger each heartbeat?

Accepted Answer

Sinoatrial (SA) node

Question 2

During the pacemaker potential phase of a cardiac pacemaker cell, which ion channels are primarily responsible for the gradual depolarization?

Accepted Answer

Slow Na$$^{+}$$ channels

Question 3

What is the correct sequence of structures that an electrical impulse travels through in the intrinsic conduction system of the heart?

Accepted Answer

SA node → AV node → Bundle of His → Bundle branches → Purkinje fibers

Question 4

A patient presents with a heart rate of 120 beats per minute. Which term best describes this condition?

Accepted Answer

Tachycardia

Question 5

Which part of the ECG corresponds to ventricular depolarization?

Accepted Answer

QRS complex

Question 6

If the end diastolic volume (EDV) is 120 mL and the end systolic volume (ESV) is 50 mL, what is the stroke volume (SV)? Use the formula $$SV = EDV - ESV.$$

Accepted Answer

70 mL

Question 7

Which homeostatic imbalance is most likely to result from a defective AV node that slows or blocks conduction to the ventricles?

Accepted Answer

Heart block

Question 8

Which of the following best describes the Frank-Starling Law of the heart?

Accepted Answer

The force of contraction and stroke volume increase in response to increased venous return

Question 9

A patient with persistent high blood pressure (aortic pressure \u003e90 mmHg) is at risk for which cardiac condition due to increased workload on the heart?

Accepted Answer

Congestive heart failure

Question 10

Which ion imbalance is most likely to cause cardiac arrest by altering the heart's electrical activity?

Accepted Answer

Hyperkalemia

Question 11

Which heart sound is associated with the closing of the semilunar (SL) valves?

Accepted Answer

Second sound (dup)

Question 12

A patient’s ECG shows an elevated S-T segment. What is the most likely clinical implication?

Accepted Answer

Cardiac ischemia

Question 13

Which phase of the cardiac cycle is characterized by ventricular contraction and ejection of blood?

Accepted Answer

Ventricular systole

Question 14

Which congenital heart defect involves mixing of oxygen-poor and oxygen-rich blood due to an opening between the atria?

Accepted Answer

Atrial septal defect

Question 15

Which hormone, released from the adrenal medulla, increases heart rate and contractility?

Accepted Answer

Epinephrine

Question 16

A patient with a heart murmur is found to have a valve that fails to close completely, allowing backflow of blood. What is this condition called?

Accepted Answer

Incompetent (insufficient) valve

Question 17

Which autonomic nervous system division decreases heart rate by hyperpolarizing pacemaker cells?

Accepted Answer

Parasympathetic nervous system

Question 18

If a trained athlete has a resting heart rate of 50 beats per minute and a stroke volume of 100 mL, what is their cardiac output? Use the formula $$CO = HR 	imes SV.$$

Accepted Answer

5000 mL/min

Question 19

Which of the following is a compensatory reflex that increases heart rate in response to increased venous return and atrial stretch?

Accepted Answer

Atrial (Bainbridge) reflex

Question 20

Which developmental structure allows blood to bypass the fetal pulmonary circulation by connecting the atria?

Accepted Answer

Foramen ovale

Chapter 18B: Cardiovascular System

Guida di studio - Domande di pratica

Study guide - Flashcard