Part 2 of Chapter 6: The human circulatory system <3🫀

Question 1

What is blood circulation?

Answer 1

• Blood circulation is the action when blood transports oxygen and nutrients to all parts of the body and transports waste materials out of the body by flowing continuously around the body in a closed system.

Question 2

What is the human circulatory system?

Answer 2

• The human transport system is known as the human circulatory system.
• The human circulatory system consists of the heart, different types of blood vessels and blood.

Question 3

What are the 3 main types of blood vessels?

Answer 3

1. Arteries
2. Veins
3. Capillaries
   The relation of blood vessels:
   - The arteries branch to form smaller vessels that are known as arterioles which branch further to form blood capillaries.
   - The capillaries then merge (together) as they leave an organ or tissue to form venules.
   - The venules then join together to form veins.

Question 4

What are arterioles?

Answer 4

• Arterioles are the smaller vessels that are formed when the arteries branch out and they also branch out to form blood CAPILLARIES AFTERWARDS (so it is in the middle of arteries and capillaries.)
  Arteries –> arterioles —> capillaries

Question 5

What are venules?

Answer 5

• Venules are formed when capillaries merge after they leave an organ or tissue, and they also join to form veins. (so, it is in the middle of capillaries and veins)
  Capillaries –> Venules –> Veins

Question 6

What does the pulmonary artery and vein transport?

Answer 6

• The pulmonary arteries transport deoxygenated blood to the lungs from the heart.
• The pulmonary veins transport oxygenated blood from the lungs, back to the heart.

Question 7

What does the aorta transport?

Answer 7

• The aorta transports oxygenated blood from the heart to the rest of the body.

Question 8

What does the upper and lower vena cavae transport?

Answer 8

• The upper and lower vena cavae transport deoxygenated blood to the rest of the body to the heart.

Question 9

What does the hepatic artery and hepatic portal vein transport?

Answer 9

• The hepatic artery and the hepatic portal vein transport oxygenated blood to the liver.
• The deoxygenated blood leaves the liver through the hepatic vein.

Question 10

What is the hepatic vein?

Answer 10

• The hepatic vein is the vein where deoxygenated blood leaves the liver.
  (Check page 58 revision guide for diagram)

Question 11

What does the renal artery transport?

Answer 11

• The renal artery transports oxygenated blood to the kidneys and deoxygenated blood leaves the kidneys through the renal vein.

Question 12

What is the renal vein?

Answer 12

• The renal vein is the vein where the deoxygenated blood leaves the kidneys.

Question 13

What are the structures of the arteries?

Answer 13

Arteries have:
- Thicker muscular walls with more elastic tissue to withstand (take on) higher blood pressure.
- Smaller lumen that is relative to the diameter of the blood vessel
- Valves are absent in the arteries.

Question 14

What are the structures of the veins?

Answer 14

Veins have:
- Thinner muscular walls with little elastic tissue.
- Larger lumen that is relative to the diameter.
- Valves that close to prevent the backflow of blood are present.

Question 15

What are the structures of the capillaries?

Answer 15

Capillaries have:
- One cell-thick wall with no muscular or elastic tissue.
- Larger lumen that is relative to the diameter.
- Extensive branching increases the total cross-sectional area and this slows down blood flow and gives it more time for the exchange of substances.

Question 16

What are the functions of the arteries?

Answer 16

Function of the arteries:
- Carries blood away from the heart
- Carried oxygenated blood, EXCEPT for pulmonary arteries which carry deoxygenated blood from the heart to the lungs.

The flow of arteries:
- Higher blood pressure
- Blood moves in spurts, giving rise to the pulse.
- Blood flows rapidly.

Question 17

What are the functions of the veins?

Answer 17

Function of the veins:
- Carries blood towards the heart
- Carried deoxygenated blood, EXCEPT for pulmonary veins which carry oxygenated blood from the lungs to the heart.

The flow of veins:
- Lower blood pressure
- No pulse.
- Blood flows slowly.

Question 18

What are the functions of the capillaries?

Answer 18

Function of the arteries:
- Link arteries to veins
- Its partially permeable walls allow for the quick diffusion of oxygen, nutrients, and waste materials.

The flow of capillaries :
- Blood pressure is reduced as blood flows from the arterial end to the venous end
- No pulse.
- Blood flows slowly.

Question 19

What is tissue fluid and interstitial fluid found in?

Answer 19

• Tissue fluid or interstitial fluid is found in the tiny spaces between tissue cells.

Question 20

Where does dissolved food substances and oxygen diffuse into?

Answer 20

• Dissolved food substances and oxygen diffuse from the blood in the capillaries into the tissue fluid and then into the tissue cells.

Question 21

How does metabolic waste products diffuse from the tissue cells into the blood?

Answer 21

• Metabolic waste products diffuse for the tissue cells into the tissue fluid and then through the capillary walls and into the blood which transports the waste products to the excretory organs for removal.

Question 22

What is the purpose of the rate of blood flow in capillaries being slow?

Answer 22

• the rate of blood flow in capillaries is slow to allow more time for cellular respiration, therefore increasing the efficiency of the exchange of materials between the blood and the tissue cells.

Question 23

Why do red blood cells alter their shape?

Answer 23

• Red blood cells alter their shape as they flow through the blood capillaries because their diameter is reduced so that they can easily pass through the blood capillary lumen (1), and their surface area is increased to speed up the absorption or the release of oxygen (2).