The Heart

Question 1

Pericardium

Answer 1

Double layer of tough inélastic membranes

Question 2

Pericardial fluid

Answer 2

Secreted between the membranes, allowing them to move easily over each other

Question 3

Function of the pericardium and pericardial fluid

Answer 3

Protect the heart from over expansion caused by elastic recoil when it is beating very fast

Question 4

Cardiac muscle

Answer 4

• found only in the heart
• never fatigues
• does not tolerate lack of O2 or nutrients -> soon dies it supply is cut off
• myogenic

Question 5

Myogenic

Answer 5

Contraction initiated from within, no need for electrical stimulation

Question 6

Septum

Answer 6

• separates the two sides of the heart

* becomes rigid before the heart contracts; serges as a fulcrum for the action of the heart muscle

Question 7

Atria

Answer 7

• receive blood from the veins
• thin walled
• elastic; stretch as they collect blood
• adapted to receive blood under very low pressure

Question 8

Ventricles

Answer 8

• pump blood into the arteries
• very thick muscular walls
• allows strong contraction to create high enough pressure for the blood to travel to the destinations

Question 9

Aorta

Answer 9

• connected to the left ventricle

* carries oxygenated blood to all parts of the body except the lungs

Question 10

Vena cava

Answer 10

• connected to the right atrium

* brings deoxygenated blood back from the tissues of the body

Question 11

Pulmonary artery

Answer 11

• connected to the right ventricle

* carriers deoxygenated blood to the lungs

Question 12

Pulmonary vein

Answer 12

• connected to the left atrium

* brings deoxygenated blood back from the lungs

Question 13

Veins always

Answer 13

Deliver blood to the atria, from the body

Question 14

Arteries always

Answer 14

Take blood from the ventricles to the body

Question 15

Blood vessels of the heart

Answer 15

• coronary arteries
• cardiac veins
• supply the heart muscle with oxygen for cell respiration and waste removal

Question 16

Coronary arteries

Answer 16

• there are 3
• déliver some oxygenated blood from the left ventricle directly back
• blockage can lead to myocardial infarction, because the heart muscle is deprived of oxygen, so it dies

Question 17

Myocardial infarction

Answer 17

Heart attack

Question 18

Valves

Answer 18

• maintain unidirectional bloodflow
• valves closing = lub
• papillary muscle and tendinous cords
• semi-lunar valves
• vena cavae constrict during each heartbeat so that blood does not flow back into the veins

Question 19

Papillary muscles and tendinous cords

Answer 19

Prevent valves from turning inside out

Question 20

Semi-lunar valves

Answer 20

• prevent back-flow in the pulmonary artery and the dorsal aorta
• closure produces ‘dub’

Question 21

Papillary muscles

Answer 21

• do not move the valves

* increase the tension of the tendinous cords to resist blood’s powerful back pressure