Blood and blood vessels

Group H

The main blood vessels connected to the heart are the

• arteries, veins, and capillaries.

During blood circulation, the arteries carry blood away from the heart. The capillaries connect the arteries to veins. Finally, the veins carry the blood back to the heart.

Arteries

• The inner layer of the arteries is very smooth so that the blood can flow easily with no obstacles in its path.

• The walls of the arteries are muscular to help the heart pump blood.

• The arteries deliver the oxygen-rich blood to the capillaries.

Capillaries

• The capillaries are very thin and fragile.

• The exchange of oxygen and carbon dioxide takes place through the thin capillary wall.

Veins

Veins are something like arteries but not as strong because they transport blood at a lower pressure. The veins transport waste-rich blood back to the lungs and heart.

• The valves inside the veins are important so that waste rich blood move in the proper direction.

Function of blood

• Blood carries oxygen from the lungs and nutrients from the digestive tract to the body’s cells. And carries away waste products.

• Helps keep your body at the right temperature

• Carries hormones to the body’s cells

• Sends antibodies to fight infection

• Contains clotting factors to help the blood to clot and the body’s tissues to heal

Components of blood :

• Plasma

• Red blood cells

• White blood cells

• Platelets

Plasma

-Fluid part of blood-Carries carbon dioxide, hormones and

waste

Red blood cells

-Contain haemoglobin which carries oxygen-Made in the bone marrow. The more you train the more red blood cells are made.-Carry oxygen to heart

White blood cells

-An important part of the immune system, they produce antibodies and destroy harmful microorganisms-Made in the bone marrow

Platelets

-Clump together to form clots-Protect the body by stopping bleeding When exercising blood does the following things:-Transports nutrients and waste-Delivers oxygen to the working muscles-Removes heat (temperature regulation)-Dilutes/carries away lactic acid (acidic balance)