Topic 3 Circulatory System: Human Heart

Question 1

• Human and bird hearts have 4 chambers, reptiles and amphibians have 3 chambers, fish have 2 chambers, and crocodiles and alligators have 4 chambers

Answer 1

Note

Question 2

• Fluid filled sac that surrounds the heart in order to protect and lubricate it for proper function

Answer 2

1. Pericardium

Question 3

• Chamber where deoxygenated blood enters via superior and inferior vena cava

Answer 3

2. Right Atrium

Question 4

• Blood is squeezed into this chamber through the right atrioventricular/tricuspid valve, which contracts and pumps blood into the pulmonary artery via pulmonary semilunar valve
  a. When ventricle contracts, the AV valve closes to prevent backflow, which produced the ‘lub’ sound
  b. Then ventricle relaxes the semilunar valve prevents backflow from pulmonary artery back into ventricles by closing, thus creating the ‘dub’ sound

Answer 4

3. Right Ventricle

Question 5

• Blood pathway from right side of heart to lungs, and eventually to left side of heart

Answer 5

4. Pulmonary Circuit

Question 6

• Blood flows from right and left pulmonary arteries -> arterioles -> capillaries of lungs -> collects in venules -> veins -> pulmonary veins -> left atrium

Answer 6

Note

Question 7

• Circulation pathway through body between left and right sides of heart

Answer 7

5. Systemic Circuit

Question 8

• After traveling through lungs, oxygenated blood enters left atrium via pulmonary veins

Answer 8

6. Left Atrium

Question 9

• After traveling through left AV/mitral/bicuspid valve, blood from left ventricle enters aorta through aortic semilunar valve into rest of body
  a. Aorta (largest vessel) -> arteries -> arterioles -> capillaries -> tissues get nutrients -> venules -> veins -> superior and inferior vena cava -> repeats
  b. The left AV valve prevents backflow into atrium and aortic semilunar valve prevents backflow to ventricle

Answer 9

7. Left Ventricle