The Transport System: Topic 6.2

Question 1

Label the structures of the human heart LOOK AT THE DIAGRAM YOU WHORE (and know the function of each).

Answer 1

Vena Cava - Delivers deoxygenated blood from the body to the right atrium
Right Atrium - Pumps deoxygenated blood through the tricuspid valve into the right ventricle
Right Ventricle - Pumps deoxygenated blood out of the heart, through the right semilunar valve and into the pulmonary artery
Pulmonary Artery - delivers deoxygenated blood to the lungs to become oxygenated
Pulmonary Vein - receives oxygenated blood from the lungs and delivers it to the left atrium
Left Atrium - pumps oxygenated blood out of the heart through the right semilunar valve and into the aorta
Aorta - pumps blood up and out of the heart carrying it around the body

Question 2

Outline how the heartbeat is increased (medulla, SA node, and epinephrine) to meet the demands of increased physical activity.

Answer 2

If CO2 levels rise as they would while exercising, the medulla sends a signal through a cranial nerve that causes the SA node to fire more often. The adrenal glands can also speed up the heartbeat by releasing epinephrine into the bloodstream

Question 3

Describe the pressure changes in the atria and ventricles that cause the AV and semilunar valves to open and close..

Answer 3

AV valve opens when pressure in the atria is higher than that of the ventricles and closes when it’s the opposite
SL valve opens when pressure in the ventricles is higher than that of the atria and closes when it’s the opposite

Question 4

Outline how the structure of arteries, veins, and capillaries are adapted to their function.

Answer 4

Arteries - High pressure, narrow lumen to maintain pressure, surrounded by 3 layer wall to prevent ruptures, muscle/elastic fibers to maintain pressure between heartbeats, high elasticity, outer layer of wall made of collagen to prevent rupturing
Veins - Wide lumen to decrease resistance and increase blood flow, thin wall so skeletal muscles can squeeze blood through, contains valves to prevent pooling and keep one way blood flow
Capillaries - One cell thick wall to minimize diffusion distance and increase diffusion rate, may contain pores or fenestrations, narrow diameter to increase SA/V ratio

Question 5

Outline the exchange of substances between the capillaries and tissues.

Answer 5

Exchange of substances is through diffusion. CO2 and wastes (such as urea) diffuse OUT of the tissues and into the blood whereas substances such as O2 and glucose diffuse INTO the tissues from the blood

Question 6

State the function of coronary arteries.

Answer 6

Coronary arteries branch off of the aorta and directly supply the heart with oxygen and glucose