Unit 1.Lec 6-Cardiac Muscle Physiology

Question 1

Structure of the Heart

Answer 1

2 Pumps (R&L) comprised of Muscular Chambers (Atria & Ventricles) seperated by valves

Question 2

Explain the movement of blood in the heart?

Answer 2

Deoxy blood from SVC, IVC and coronary sinus enters the RA–>then enters the RV through the tricupsid valve–>Deoxy blood in RV goes to pulmonary artery through the pulmonary valve–>(Blood goes to the lungs)–>Oxy blood enters LA through the pulmonary vein—> LA to LV through mitral valve–> LV to aorta through aortic valve

Question 3

Why are walls of the left ventricle thicker than the right ventricle?

Answer 3

LV pumps out more blood and requires more pressure

Question 4

What part of the heart facilitates blood filling?

Answer 4

Right atrium

Question 5

List the Heart valves (3)

Answer 5

• Tricupsid valve
• Mitral valve
• Aortic valve
• Pulmonic valve

Question 6

How do heart valves open and close and what occurs at each step?

Answer 6

• Valves open and close in a coordinated way
• OPEN: Ejecting blood (either atria to ventricle or ventricle to systemic)
• CLOSE: Filling atria/ventricle

Question 7

What is the movement of valve opening based on?

Answer 7

Based on pressure differences btw atrai and ventricles

Question 8

What does muscle contraction of the heart closely follow?

Answer 8

The wave of depolarization (excitation) throughout the heart

Question 9

Define stroke volume

Answer 9

The amount of blood ejected from the heart, based on systolic/diastolic volume

Question 10

Explain End Diastolic Volume (EDV)

Answer 10

Amount of blood sitting in the ventricles before contractions

Question 11

Explain Systolic End Volume (SEV)

Answer 11

Amount of blood left in the LV or RV after its empty (after contractions)