Lesson 6

Question 1

2. What are the three elements that make up ‘formed elements’? What two types of molecules are found in plasma?

Answer 1

The three elements that make up formed elements are red blood cells, white blood cells and platelets. Plasma contains both organic and inorganic molecules dissolved in water.

Question 2

3. What are the three main functions of blood?

Answer 2

3.​The three main functions of blood are:
​i)​ transport
​ii) defense
​iii)regulation

Question 3

4. List the substances blood transports to the tissues. List the substances that blood transports away from tissues.

Answer 3

Blood transports oxygen from the lungs and nutrients from the digestive system to the body’s tissues. Blood transports carbon dioxide, a by-product of cellular respiration, to the lungs and waste products that are the result of cellular metabolism to the kidneys, for elimination from the body.

Question 4

5. What are pathogens?

Answer 4

Pathogens are microscopic infectious agents, such as bacteria and viruses

Question 5

6. Describe three ways in which the various components of the blood defend the body.

Answer 5

Various components of the blood defend the body by the following mechanisms:
​i) blood cells that surround and destroy pathogens
​ii) blood cells that produce antibodies that destroy pathogens
​iii)platelets and plasma protein that cause blood clotting preventing blood loss

Question 6

7. List three ways in which the blood helps regulate the body.

Answer 6

7.​Blood regulates the body by:
​i) regulating body temperature
​ii) maintaining salt/water balance
​iii)regulating pH levels in the body

Question 7

8. How does the blood help regulate body temperature?

Answer 7

8.​Blood helps regulate body temperature by picking up heat mostly from active muscles and transporting it about the body. When the blood is too warm, blood vessels in the skin dilate and heat is released.

Question 8

9. What is the function of salts and plasma in the blood?

Answer 8

9. Salts and plasma proteins in the blood help keep the liquid content of blood high, in other words, maintaining the salt/water balance of blood.

Question 9

10. What substances help the blood regulate Ph balance?

Answer 9

The blood’s pH or acid/base balance is maintained by buffers in the blood

Question 10

11. What is plasma and what is it formed of?

Answer 10

Plasma is the liquid portion of blood. The main component of plasma is water which represents 92% of plasma. The remaining 8% of plasma contains the following: various inorganic salts (ions); small organic molecules such as the nutrients glucose and amino acids and waste products such as urea; large organic molecules such as hormones and the plasma proteins; gases mostly CO2.

Question 11

12. List he three major types of plasma proteins and the function of plasma proteins.

Answer 11

12.​The three major types of plasma proteins are:
​i) albumins
​ii) globulins
​iii)fibrinogen
​Plasma proteins help balance the pH of blood, maintain osmotic pressure, transport large molecules, fight infection and clot blood.

Question 12

1. What are the two layers that blood separates into and describe the contents of each? List the percentages of total blood volume each represents.

Answer 12

Blood separates into two layers. The bottom layer is referred to as formed elements. The top layer is referred to as plasma. The formed elements represent 45% of blood volume and plasma represents 55% of blood volume.