Circulatory System

Question 1

Functions of Blood

Answer 1

1. Transporting oxygen and nutrients to the cells of the body
2. Transporting carbon dioxide and other waste products away from the cells
3. Transporting chemical messengers called hormones to the cells
   maintaining the pH of body fluids
   distributing heat and maintaining body temperature
   maintaining water content and ion concentration of body fluids
   protecting against disease-causing micro-organisms
   clotting when vessels are damaged, thus preventing blood loss.

Question 2

Structure of Blood

Answer 2

• Blood is composed of plasma and formed elements.
• Plasma makes up ~ 55% of blood volume
• Formed elements make up ~ 45% of blood volume and consist of red blood cells, white blood cells and platelets.

Question 3

Plasma

Answer 3

• Mixture of water with dissolved substances such as sugar and salts
• The function of plasma is to transport the components of blood, including cells, nutrients, wastes, hormones, proteins and antibodies, throughout the body.

Question 4

Erythrocytes

Answer 4

• AKA- Red blood cells
• Account for 40-45% of bloods volume
• Cells are a biconcave shape- flattened in the middle on both sides. Red blood cells do not contain a nucleus.
• Their function is to transport oxygen from the lungs to the cells throughout the body.

Question 5

Leucocytes

Answer 5

• AKA white blood cells
• Play an important role in protecting the body from infection.
• Larger than red blood cells, but only make up ~1% of blood.

Question 6

Thrombocytes

Answer 6

• AKA Platelets
• Small fragments of cells.
• When a blood vessel is injured, the platelets adhere to the lining and form a scaffold for the coagulation of the blood to form a clot.