Unit 2: Cardiovascular system

Question 1

What are the three layers of the heart wall?

Answer 1

Endocardium, Myocardium, Pericardium

Endocardium: Inner lining; Myocardium: Muscle layer; Pericardium: Protective sac.

Question 2

What is the function of the endocardium?

Answer 2

Inner lining of heart chambers; prevents clotting.

Question 3

What is the function of the myocardium?

Answer 3

Responsible for pumping action.

Question 4

What is the function of the pericardium?

Answer 4

Protective sac that prevents friction.

Question 5

Describe the location of the heart within the thorax.

Answer 5

Inferior mediastinum, above diaphragm, behind sternum.

Question 6

What direction does the apex of the heart point?

Answer 6

Down, forward, and left.

Question 7

What direction does the base of the heart point?

Answer 7

Up, backward, and right.

Question 8

What are the four heart chambers?

Answer 8

Right atrium, Right ventricle, Left atrium, Left ventricle.

Question 9

What blood does the right atrium receive?

Answer 9

Deoxygenated blood from superior/inferior vena cava and coronary sinus.

Question 10

What is the function of the right ventricle?

Answer 10

Sends blood to the lungs via the pulmonary artery.

Question 11

What blood does the left atrium receive?

Answer 11

Oxygenated blood from the four pulmonary veins.

Question 12

What is the function of the left ventricle?

Answer 12

Pumps oxygenated blood into the aorta.

Question 13

What is the role of heart valves?

Answer 13

Prevent backflow of blood.

Question 14

What are the main types of heart valves?

Answer 14

AV valves (Tricuspid, Mitral/Bicuspid), Semilunar valves (Pulmonary, Aortic).

Question 15

What makes pacemaker cells unique?

Answer 15

Unstable resting potential; fire rhythmically without nervous input.

Question 16

How do pacemaker cells generate action potentials?

Answer 16

Use If channels for Na⁺ in / K⁺ out, then calcium influx causes depolarization.

Question 17

How does the autonomic nervous system regulate heart rate?

Answer 17

Sympathetic: ↑HR; Parasympathetic: ↓HR.

Question 18

What is the pathway of electrical conduction in the heart?

Answer 18

SA Node → Internodal pathways → AV Node → Bundle of His → Bundle branches → Purkinje fibers.

Question 19

Define systole in the cardiac cycle.

Answer 19

Ventricular contraction → blood ejection.

Question 20

Define diastole in the cardiac cycle.

Answer 20

Ventricular relaxation → chamber filling.

Question 21

What is Stroke Volume (SV) and its average value?

Answer 21

Volume ejected per beat (~80 mL).

Question 22

What is End-Diastolic Volume (EDV) and its average value?

Answer 22

Volume before contraction (~120 mL).

Question 23

What is Ejection Fraction (EF) and its calculation?

Answer 23

(SV/EDV) × 100 = ~67%.

Question 24

What is Cardiac Output (CO) and its average value at rest?

Answer 24

SV × HR = ~5 L/min.

Question 25

Define the Frank-Starling Law.

Answer 25

Greater ventricular filling → stronger contraction due to optimal sarcomere stretch.

Question 26

What are the types of blood vessels?

Answer 26

Arteries, Arterioles, Capillaries, Venules, Veins.

Question 27

What is the primary role of arteries?

Answer 27

Carry blood from heart under high pressure.

Question 28

What is the primary role of arterioles?

Answer 28

Regulate blood flow into tissues via diameter control.

Question 29

What is the primary role of capillaries?

Answer 29

Exchange nutrients and gases.

Question 30

What is the primary role of venules and veins?

Answer 30

Return blood to heart; act as reservoirs.

Question 31

How is blood pressure maintained in systemic circulation?

Answer 31

By elastic arteries and arteriolar resistance.

Question 32

What are the average values for systolic and diastolic pressure?

Answer 32

Systolic: ~120 mmHg, Diastolic: ~80 mmHg.

Question 33

What mechanisms assist venous return?

Answer 33

Venous valves, Skeletal muscle pump, Respiratory pump, Cardiac suction.

Question 34

What determines the direction of fluid movement in capillaries?

Answer 34

Hydrostatic pressure and oncotic pressure.

Question 35

What is Starling’s Equation?

Answer 35

Net pressure = Kf [(Pc + πIF) - (PIF + πc)]

Question 36

What causes edema?

Answer 36

↑ Capillary hydrostatic pressure, ↓ Plasma proteins, ↑ Interstitial protein.

Question 37

What is the role of the lymphatic system?

Answer 37

Returns interstitial fluid to blood circulation.

Question 38

What does lymph contain?

Answer 38

Water, plasma proteins, lipids, WBCs, debris.

Question 39

Where does lymph drain from the right upper body?

Answer 39

Right lymphatic duct.

Question 40

Where does lymph from the rest of the body drain?

Answer 40

Thoracic duct → enters at jugular–subclavian junction.

Question 41

What is the function of lymph nodes?

Answer 41

Filter lymph, trap pathogens, immune response sites.

Question 42

What are the three main receptor types involved in cardiovascular reflexes?

Answer 42

Baroreceptors, Chemoreceptors, Mechanoreceptors.

Question 43

Explain the baroreceptor reflex pathway for high blood pressure.

Answer 43

↑ BP → baroreceptors activate → medulla → ↓ sympathetic, ↑ parasympathetic → Vasodilation → ↓ HR → ↓ BP.