The Heart and the Flow of Blood

Question 1

What role does the heart play in the circulatory system?

Answer 1

The heart provides the driving force of the circulatory system, to push blood through the vessels.

Question 2

Describe the composition of a mammalian heart.

Answer 2

Mammal hearts have four chambers, two sides, each with an atrium (upper chamber) and a ventricle (lower chamber). Each side are separate pumps, that work simultaneously. The heart has a muscular wall called the septum that separates the left and right sides. The heart is composed of cardiac muscle tissue.

Question 3

Describe the flow of blood through the body and the heart.

Answer 3

Deoxygenated bloods moves into the heart via the superior and inferior vena cava. It moves into the right ventricle from where it is pumped into the pulmonary artery to the lungs. There, blood is oxygenated, and will then return to the heart, in the left atrium through the pulmonary veins. It then moves through the left ventricle to reach the aorta from where it is distributed to the rest of the body.

Question 4

Why is the left ventricle much bigger and thicker than the right ventricle?

Answer 4

Because the left ventricle has to pump blood to all areas of the body, whereas the right ventricle only has to pump blood to the lungs.

Question 5

What is systemic circulation?

Answer 5

It is the pumping of oxygenated blood to all parts of the body, and the return of deoxygenated blood to the heart.

Question 6

What is pulmonary circulation?

Answer 6

The pathway of blood from the heart to the lungs and back to the heart.

Question 7

Outline the characteristics of the pulmonary circuit.

Answer 7

It has a lower blood pressure than the systemic circuit.

The pulmonary artery is high in carbon dioxide and low in oxygen, vice versa for pulmonary vein.

Question 8

Outline the characteristics of the systemic circuit.

Answer 8

Blood pressure decreases as it travels away from the heart and back towards the heart.
The pulse decreases along the arteries to the capillaries.

Question 9

Describe how substance exchange occurs at capillaries.

Answer 9

At the capillaries O2 and nutrients diffuse out into the tissues and CO2 and other wastes diffuse in from the tissues

Question 10

Describe what occurs at the blood flow in the kidneys.

Answer 10

Blood flow through the kidneys loses urea and excess salts and water
(O2 decreases and CO2 increases due to active transport of nutrients)

Question 11

Describe what occurs in the blood flow in the intestines.

Answer 11

Blood flow through the intestines collects the products of digestion.
(O2 decreases and CO2 increases due to active transport of nutrients)