8: Transport in Humans

Question 1

Why do small organisms not need a transport system?

Answer 1

The substances are transported throughout their body by diffusion or streaming of the cytoplasm.

Question 2

Why do large multicellular organisms need a transport system?

Answer 2

Cells in different parts of the body are far away from each other. Diffusion is too slow and becomes inefficient. Therefore, to ensure the supply of useful substances to target cells and removal of waste from the body, a transport system is developed in them.

Question 3

What are the systems included in the human transport system?

Answer 3

Circulatory system, lymphatic system

Question 4

What are the three main parts of the human circulatory system and their functions?

Answer 4

Blood: it carries useful substances and waste to and from body cells.
Blood vessels: they form a system of tubes that distribute blood throughout the body; the smallest blood vessels allow exchange of materials between blood and body cells.
Heart: it acts as a pump to give the force to drive blood throughout the body.

Question 5

What are the four components of blood?

Answer 5

Plasma, red blood cells, white blood cells, blood platelets

Question 6

What are the properties and functions of plasma?

Answer 6

Plasma contains mostly water with various substances dissolved or suspending in it.
It is the medium for transporting substances throughout the body, and it helps distribute heat throughout the body to maintain body temperature.

Question 7

List 7 substances that the plasma transports.

Answer 7

Water, carbon dioxide (both as a gas and in the from of hydrogen carbonate ions), nutrients, urea, hormones, antibodies, and fibrinogen.