Blood and Circulation

Question 1

List the functions of blood. Be specific samANThA

Answer 1

Trans of Ox, nutrients to cells
Trans of CO and wastes away from cells
Trans chemical messengers to cells
Maintaining body temperature, water and ion concentration of bodily fluids
Protection against disease-causing micro-organisms
Clotting when vessels are damaged

Question 2

What’s blood made up of?

Answer 2

55% plasma

45% formed elements

Question 3

What’s the benefit of RBCs (erythrocytes) having no nucleus?

Answer 3

It allows more room for haemoglobin

Question 4

What is the scientific name for:

• White blood cells
• Platelets

Answer 4

WBCs - leucocytes

Platelets - thrombocytes

Question 5

How is oxyhaemoglobin formed?

Answer 5

When haemoglobin is able to combine with oxygen

Question 6

State the chemical formula for Oxyhaemoglobin

Answer 6

Haemoglobin + Oxygen HbO2

Question 7

How is carbominohaemoglobin formed?

Answer 7

When 22% of CO combines with haemoglobin

Question 8

Name the blood vessels and their function.

Answer 8

Arteries - carry oxygenated blood AWAY from the heart
Capillaries - carry blood BETWEEN cells
Veins - carry deoxygenated blood BACK to the heart

Question 9

Where are the atrioventricular valves located and what are other names for them?

Answer 9

They’re located between the Atrium and Ventricle.

Tricuspid and Bicuspid valves.

Question 10

What is the cardiac cycle?

Answer 10

The cardiac cycle refers to the sequence of mechanical and electrical events that repeats with every heartbeat.
Systole - contraction of heart muscles
Diastole - relaxation of heart muscles

Question 11

The muscles in the artery walls do NOT contract and relax to pump blood along the arteries. What is vasoconstriction and how does it relate to the above statement?

Answer 11

The muscles can contract to reduce the diameter of the artery, thus reduce blood flow to an organ. Such contraction is called vasoconstriction.

Question 12

What is vasodilation?

Answer 12

When the artery muscles relax to increase the blood flow to an organ.

Question 13

Why is blood pressure in the veins relatively low?

Answer 13

Because the blood loses most of its pressure as it flows through the tiny capillaries. The walls of veins are therefore much thinner than those in the arteries.

Question 14

List the differences between arteries and veins.

Answer 14

Arteries

• carry blood away from heart
• high blood pressure
• thick, muscular, elastic walls
• no valves

Veins

• carry blood towards the heart
• relatively low blood pressure
• thank, inelastic walls
• often have valves

Question 15

What is the process of blood clotting?

Answer 15

1) damage to blood vessel
2) blood vessel contracts to reduce blood loss
3) damage creates a rough surface (collagen), causing platelets to stick.
4) Activation of prothrombin
5) Prothrombin converts to thrombin
6) thrombin concerts fibrinogen to fibrin which forms a mesh which traps more platelet, resulting in a clot

Question 16

What is the main function of the lymphatic system?

Answer 16

• collect some of the fluid that escapes from the blood capillaries and return it to the circulatory system.
• defence against disease-causing organisms

Question 17

What does the lymphatic system consist of?

Answer 17

• a network of lymph capillaries

- lymph nodes

Question 18

Describe what occurs during atrial systole.

Answer 18

• period of contraction of the atria
• force flood into the ventricles
• black flow is prevented by valves
• increased blood pressure

Question 19

The cardiovascular system is composed of 2 circulatory paths. What are they?

Answer 19

Pulmonary - blood flow between the heart and lungs

Systematic - blood from the heart to the rest of the body

Question 20

List 3 ways carbon dioxide is transported in the blood

Answer 20

8% dissolves in plasma
22% as carbominohamoglobin
70% as bicarbonate ions

Question 21

List 2 ways oxygen is transported in the blood

Answer 21

3% dissolved in plasma

97% as oxyhaemoglobin

Question 22

To cater for such changes in oxygen and carbon dioxide levels, during exercise, for example, blood blow to and from the cells must be able to change. What 2 requirements need to be met?

Answer 22

• by changing the input of blood from the heart

- by changing the diameter of the blood vessels suppling the tissues