Cardiovascular System 2

Question 1

Outline the organisation of the CV system and the heart

Answer 1

Pulmonary circuit
- Carries blood to and from gas exchange surfaces of lungs

Systemic circuit
- Carries blood to and from the rest of body

Question 2

Describe the anatomy of the heart

Answer 2

• Great veins and arteries at the base
• Pointed tip is apex
• Coronary sulcus
  
  • Divides upper atria from ventricles
• Interventricular sulcus
  
  • Separate R & L ventricles

Question 3

Identify the layers of the heart wall

Answer 3

Outer layer - Epicardium (visceral layer of serous pericardium)
- Made from epithelial tissue

Middle layer - Myocardium (cardiac muscle tissue)

 - Bulk of heart tissue
 - Provides pumping action

Inner layer - Endocardium
- Continuous with endothelial lining of great vessels

Question 4

Describe the blood flow through the heart

Answer 4

• Right atrium receives deoxygented blood from systemic circulation via
  
  • Superior vena cava (SVC)
  • Inferior vena cava (IVC)
  • Coronary sinus
• Right atrium to Right Ventricle through AV valve
• Right ventricle to pulmonary trunk & pulmonary arteries
• Then into pulmonary circulation
• Blood passes through lungs
• Returns to heart through 4 pulmonary veins
• Pulmonary veins into Left atrium
• Left atrium to Left ventricle through AV valve
• Then pushed into systemic circulation via aorta
• Aorta branches into two different directions of systemic circulation

Question 5

Describe the coronary circulation

Answer 5

Circulation of blood in the blood vessels that supply the heart muscle (myocardium)

Coronary arteries

 - branch from ascending aorta
 - fill upon diastole
 - carry oxygenated blood to the myocardium

Pulsatile blood flow
Little flow during systole

Question 6

Atrioventricular (AV) valves

Answer 6

AV valves stop backflow of blood from ventricles into atria.

Lie between atria and ventricles

 - Right AV - known as tricuspid
 - Left AV   - known as bicuspid (mitral)

Cusps supported and linked by chordae tendinae to papillary muscle

Pressure in atria > pressure in ventricles
- Valves will open and blood flows into ventricles

Pressure in ventricles > pressure in atria
- Valves close and blood flows into aorta or PA

Question 7

Semilunar Valves

Answer 7

Semilunar valves stop backflow of blood from aortic & pulmonary trunks into ventricles.

Between ventricles & major arteries (aorta & PA)

Prevent blood flowing back into heart

Pulmonary semilunar valve
- At base of pulmonary arterial trunk

Aortic semilunar valve
- At base of aorta

No valves between veins and atria