Week 7: Chp 28: Anatomy of the Heart

Question 1

What is the Heart?

Answer 1

a hollow, fist-sized organ

Question 2

What is the location of the heart?

Answer 2

• located in the thoracic cavity between the lungs in a space called the mediastinum
• it lies behind the sternum and rests on the diaphragm

Question 3

What is the heart contained in?

Answer 3

it is contained in a protective sac called the pericardium

Question 4

The pericardium has 2 layers

Answer 4

• the outer layer, the pericardial sac or parietal pericardium
• the inner layer, the epicardium or visceral pericardium

Question 5

Pericardial sac/ Parietal Pericardium

Answer 5

the outer layer of the pericardium

-a tough fibrous layer that turns inward at the base of the heart forming the inner layer, the epicardium

Question 6

Epicardium/ Visceral Pericardium

Answer 6

the inner layer of the pericardium

-covers the heart surface

Question 7

What is between the 2 layers of the Pericardium?

Answer 7

a pericardial cavity containing serous fluid that provides a lubricant that allows the heart to beat without friction

Question 8

The heart muscle wall is composed of how many layers?

Answer 8

3 layers

• epicardium (thin, outer layer)
• myocardium (thick, middle layer)
• endocardium (thin, inner layer)

Question 9

What is the muscular layer of the heart that is responsible for the mechanical, contractile function of the heart?

Answer 9

myocardium

Question 10

What layer of the heart lines the interior of the heart and heart valves and is continuous with the inner layer, or endothelium, of the blood vessels?

Answer 10

endocardium

Question 11

There are how many chambers within the heart?

Answer 11

4 chambers

• the right and left atria
• the right and left ventricles

Question 12

Blood Flow Through the Chambers of the Heart

Answer 12

1. The Right atrium receives deoxygenated blood from the systemic circulation through the great veins, the inferior and superior vena cava.
2. Blood flows from RA to the Right Ventricle (RV)
3. Blood is then delivered to the pulmonary circuit through the pulmonary artery
4. Newly oxygenated blood is returned to the Left Atrium via the pulmonary vein
5. Blood flows from the LA to the Left Ventricle (LV) and is then ejected into the aorta to the systemic circulation

Question 13

How many valves are in the heart?

Answer 13

4 valves

• Atrioventricular (AV) valves; tricuspid and bicuspid/mitral valve
• Semilunar valves; pulmonary and aortic valves

Question 14

Why is there a need for valves in the heart?

Answer 14

to facilitate a one-way flow

Question 15

Atrioventricular (AV) valves and their location

Answer 15

between the atria and ventricles on the left and right sides of the heart

• The AV valve between the right atrium and right ventricle is the tricuspid valve
• The AV valve between the left atrium and left ventricle is the bicuspid/mitral valve

Question 16

The Atrioventricular Valves Function

Answer 16

when open, the valves allow flow from the atria into the ventricle
-when the ventricles fill and the pressure within increases, the valves close to prevent retrograde flow back into the atria

Question 17

Chordae Tendineae

Answer 17

fibrous chords that connect the valves to muscle to prevent the valves from budging or turning inside out during ventricular contraction

Question 18

Semilunar Valves and their location

Answer 18

• between the ventricles and their respective arteries (Pulmonary and aortic valves)
• Pulmonary valve; between the right ventricle and pulmonary artery
• Aortic valve; between the left ventricle and the aorta

Question 19

The Semilunar valves function

Answer 19

control the flow of blood between the ventricles and the pulmonary artery or aorta

Question 20

The valves in the heart open and close in response to what?

Answer 20

changes in presssure

Question 21

What happens to the AV valves when ventricles are relaxed during filling or diastole?

Answer 21

-The AV valves are open, allowing blood to flow into the ventricles

Question 22

What happens to AV valves as the ventricles fill?

Answer 22

• The AV valves are forced upward and begin to close
• the pressure increase from ventricular contraction forces the AV valves fully closed, preventing backflow of blood into the atria

Question 23

When does the Semilunar valves open?

Answer 23

when the increase in pressure from ventricular contraction exceeds the arterial pressure in the pulmonary circuit or aorta, the semilunar valves open, allowing blood to flow to the pulmonary or systemic circulation