B7.2. Transport in mammals

 (0654) Coordinated Sciences 2023/2024

Subheadings and Key concepts

• the Circulatory system
• the heart
• coronary heart disease (CHD)
• investigating physical activity on pulse + heart rate
• blood vessels
• components of blood

07. Human Transport pdf

#78 Summary of human transport

Mammals have a double circulatory system, in which blood is moved through vessels by the regular contraction and relaxation of cardiac muscles in the wall or the heart.

# 77 Functions of lymphatic system

Credit: Adam

The lymphatic system is a collection of lymph vessels and glands. It has 3 main roles:

• Fluid balance: return tissue fluid to the blood

• Protection from infection: produce white blood cells lymphocytes

• Absorption of fats: transport digested fats from villi to blood stream

#76 Immune system - antibody production, tissue rejection & phagocytosis

The immune system is the body's defence against disease and foreign bodies, under the form of antibody production, tissue rejection and phagocytosis. 

#75 Blood clotting

When an injury causes a blood vessel wall to break, platelets are activated. They change shape from round to spiny, stick to the broken vessel wall and each other, and begin to plug the break. 

# 74 Blood cells - structure and functions

Blood consists of cells floating in plasma. 
Most of the cells are red blood cells. 
A much smaller number are white blood cells.

There are also fragments formed from special cells in the bone marrow, called platelets. 

# 73 Blood composition and Plasma

If blood is allowed to stand without clotting, it separates out into 4 components: plasma, red blood cells, white blood cells and platelets.

The plasma and red blood cells play an important role in the transportation of substances, around the body.

White blood cells and platelets are part of the body's immune system.

# 72 Arteries, veins and capillaries - structure and functions

There are 3 main kinds of blood vessels – arteries, veins and capillaries. 

• Arteries carry blood away from the heart. They divide again and again, and eventually form very tiny vessels called capillaries. 
• The capillaries gradually join up with one another to form large vessels called veins. 
• Veins carry blood towards the heart.

#71 Effect of exercise on heartbeat and causes of coronary heart disease

A heartbeat is a contraction. Each contraction squeezes blood to the lungs and body. The heart beats about 70 times a minute, more if you are younger, and the rate becomes lower the fitter you are.

# 70 Structure and function of the heart

The function of the heart is to pump blood around the body. The right side pumps blood to the lungs and the left side pumps blood to the rest of the body. 

# 69 Transport in humans - the circulatory system

The main transport system of human is the circulatory system, a system of tubes (blood vessels) with a pump (the heart) and valves to ensure one-way flow of blood.

Its functions:

• To transport nutrients and oxygen to the cells.
• To remove waste and carbon dioxide from the cells. 
• To provide for efficient gas exchange.