Circulatory system

Question 1

Functions of the blood

Answer 1

Transportation - red blood cells carry oxygen to cells
Carbon dioxide back to lungs, nutrients around the body, hormones, waste materials.
Defence - White blood cells fight disease, engulf bacteria. Lymphocytes produce antibodies
Regulation - regulates body heat by absorbing it from the liver and muscles and transports it round the body.
Clotting - platelets clot a damaged area. Prevents excess blood loss and protects against microbe entry.

Question 2

Structure and function of plasma.

Answer 2

90% water also contains blood proteins, mineral salts, food substances, waste materials, gases, enzymes, hormones, antibodies. Renews cellular fluid, maintains pH at 7.4, makes blood viscous, provides energy to cells, protects chemical reactions.

Question 3

Structure and function of red blood cells (erythrocytes)

Answer 3

Minute discs. Red colour comes from haemoglobin mixed with oxygen, Made in bone marrow. Function to carry oxygen to cells and remove carbon dioxide from cells

Question 4

Structure and function of white blood cells (leucocytes)

Answer 4

No colour, have a nucleus and bigger than red blood cells. 1 to every 600 red ones. Fight infection.

Question 5

Structure and function of thrombocytes.

Answer 5

Platelets are formed in the red bone marrow smaller than red blood cells. Function in blood clotting.

Question 6

Structure and function of arteries

Answer 6

Carry blood away from the heart. Carry oxygenated blood apart from the pulmonary artery. Blood travels at a higher pressure. Eventually form smaller vessels called arterioles. Contain no valves. Lie deeper in the body.
Have thicker muscular walls.

Question 7

Structure and function of veins

Answer 7

Carry blood to the heart from the body. Carry deoxygenated blood except pulmonary vein. Travels at lower pressure. Eventually form smaller vessels called venules. located in between muscles, and contain valves that stop blood flowing backwards. Lie more superficially in the body. Have thinner muscular walls.

Question 8

Structure and function of capillaries

Answer 8

Narrow blood vessels which have very thin walls, just one cell thick. Substances can pass through. Exchange oxygen and nutrients for carbon dioxide and wastes within all cells and tissues. Forms the link between arterioles and venules.

Question 9

What are the three levels of the walls of the heart called?

Answer 9

Pericardium, myocardium and endocardium.

Question 10

How many chambers does the heart have and what are they called?

Answer 10

Four, two upper chambers called the right and left atriums and two lower called the right and left ventricles.

Question 11

What does systole mean?

Answer 11

When the cardiac muscle in the heart contracts it is referred to as systole.

Question 12

What does diastole mean?

Answer 12

When the cardiac muscle relaxes.

Question 13

where does the oxygenated blood enter the heart?

Answer 13

The oxygenated blood enters the body in to the left atrium of the heart through the pulmonary veins.

Question 14

How does the deoxygenated blood enter back into the heart?

Answer 14

Via the superior and inferior vena cava into the right atrium of the heart.

Question 15

What is blood pressure?

Answer 15

The level of pressure exerted on the walls of the arteries as blood flows through them.

Question 16

Factors that affect blood pressure

Answer 16

Age, weight, exercise, stress, gender and diet

Question 17

What is the difference between the pulmonary and systemic circulatory system.

Answer 17

Pulmonary system - transports blood from the lungs to the heart and back again. Systemic system transports blood from the heart to the rest of the body and back again.