Cardio/Respiratory Systems

Question 1

Which vessels are the opposite to all others in terms of which carry oxygenated and deoxygenated blood?

Answer 1

Pulmonary artery and vein

Question 2

What are the functions of the cardiovascular system?

Answer 2

Carries and distributes nutrients
Carries and removes waste
Hormone circulation
Transports immune cells and blood coagulation factors
Maintains body temperature

Question 3

What is the structure of the heart?

Answer 3

Endocardium (endothelium)
Myocardium (muscle)
Epicardium (epithelium)

Question 4

What is the structure of blood vessels?

Answer 4

Tunica intima (endothelium)
Tunica media (muscle/elastic tissue)
Tunica adventitia (connective tissue)

Question 5

How does blood flow through the heart and lungs?

Answer 5

Blood enters the right hand atrium from systemic circulation vein (deoxygenated)
Blood flows through tricuspid valve into right ventricle (pulmonary valve closed)
Blood flows through pulmonary valve into pulmonary vein (tricuspid valve closed)
Blood flows through pulmonary circulation, becoming oxgenated and returns to heart via pulmonary artery into left atrium
Blood flows into left ventricle through mitral valve (aortic valve closed)
Blood flows through aortic valve into aorta and into systemic circulation (mitral valve closed)

Question 6

What do atrioventricular valves do?

Answer 6

Prevent backflow of blood from ventricles into atria

Question 7

What do semilunar valves do?

Answer 7

Prevent early outflow of blood into blood vessels from ventricles

Question 8

What are the reasons for differences in the make up of arteries, veins and capillaries?

Answer 8

Arteries have large lumens to allow for large amounts of blood flow and thicker walls with muscular and elastic tissue so they can contract to move blood along
Veins have large lumen to allow for large amounts of blood flow and thinner walls with valves to prevent backflow. Walls are thinner due to reduced blood pressure compared to arteries.
Capillaries have small lumen and thin endothelial walls to decrease blood pressure, allowing slowing of blood flow to increase transfer time of nutrients, gases and waste and easy transfer.

Question 9

What happens on inspiration?

Answer 9

Diaphragm contracts, moving down
External intercostal muscles are pulled up and contract
Thoracic cavity expands allowing for lungs to expand
Alveoli experience reduced pressure so air enters

Question 10

What happens on expiration?

Answer 10

Diaphragm relaxes, moving up
External intercostal muscles are pushed down and relax
Thoracic cavity reduces making lungs shrink
Alveoli experience increased pressure so air leaves

Question 11

What 4 properties allow for gas exchange via the alveoli?

Answer 11

Large surface area
1 layer of epithelial cells
reduced surface tension (caused by surfactants - mostly phospholipids)
pressure gradients

Question 12

What is the partial pressure of oxygenated and deoxygenated blood?

Answer 12

Oxygenated: 100mmHg
Deoxygenated: 46mmHg

Question 13

What do oxygen and carbon dioxide bind to in the blood?

Answer 13

Oxygen: Iron on haemoglobin
Carbon dioxide: Amine groups on amino acids on polypeptides

Question 14

How much oxygen is bound to haemoglobin?
Where is the rest?

Answer 14

97%
Remainder is dissolved within the blood plasma

Question 15

How much carbon dioxide is bound to amine groups?
Where is the rest?

Answer 15

23%
Remainder is either dissolved into plasma (7%) or diffuses into plasma as a bicarbonate ion (70%)

Question 16

How does the partial pressure of oxygen affect haemoglobin’s affinity for both oxygen and carbon dioxide?

Answer 16

Increased partial pressure = higher affinity for oxygen
Decreased partial pressure = higher affinity for carbon dioxide