Structure of Human Blood

There are three types of human blood vessel: artery, vein, cappilary

Human blood vessels consists of 3 types:

1.Artery

• Carry oxygenated blood away from the heart to all parts of body except pulmonary artery

2.Cappilary

• Sites for exchange of respiratory gases, nutrients, and waste between blood
• The smallest blood vessels taht joints artery and vein

3. Vein

• Transport deoxygenated blood from all parts of body back to the heart except pulmonary vein

NOTES: 

• Artery branch out into smaller vessels called arterioles
• Arterioles branch to form cappilaries.
• Cappilary join with one another to form venules
• Venules join together to form vein

Function of Haemolymph

1)In insects,  the haemolymph  fills the entire body cavity called haemocoel.

2) A circulating system in insects is called open circulatory system.

3) Nutrients from digested foods and hormones diffuse from the haemolymph into the cells.

## HAEMOLYMPH DOES NOT TRANSPORT RESPIRATORY GASES BUT VIA THE TRACHEAL SYSTEM!!!

Functions of blood in Transport

1) Transport oxygen

• Transport from lungs which is alveolus to all part of body/cells
• In the lung, oxygen combines with haemoglobin, Hb to form oxyhaemoglobin then pumped to tissue
• In tissue, oxyhaemoglobin supplied for cellular respiration

                         

2) Transport of water to tissue

• to provide biochemical reactions
• 90% of water

3) Transport of carbon dioxide

4) Transport excretory waste products

• Deamination of excess amino acid occurs in liver to form urea
• From liver urea is transpoerted by blood to kidneys to be excreted

5)Transport of hormones

• Produces by the endocrine glands. For example: insulin and glucagon are carried by blood form pancreas to the liver

6) Transport of heat

• Regulate body temperature

7) Transport absorbd foor materials

• Soluble digested food, vitamins and mineral absorbed into the cappilaries of the villi in the small intestines. For examples: simple sugar (glucose), amino acid, vitamin B, ,mineral salts
• They are transported by hepatic portal vein from small intestines to liver then to heart
• Others food are absorbed into lacteals in villi. For examples: fatty acids, glycerol, vit A, D, E, K

Composition of Human Blood pt ii

B) Plasma

- Water: 90-92%
- Soluble solutes:

• Nutrients (glucose)
• Mineral ions (Na+, K+, Cl-)
• Dissolved gases (oxygen and carbon dioxide)
• Hormones (insulin)
• Wate products (urea and uric acid)
• Antibody
• Plasma protein (albuin, globulin, fibrinogen and prothrombin)