Circulatory System

Question 1

List the 3 main Components Of the circulatory system:

Answer 1

Blood
Heart
Blood vessels - arteries, veins, capillaries

Question 2

State 4 main points about the blood component Plasma:

Answer 2

Largest component of blood (55%).
Mostly made of water, surrounding blood cells.
Helps maintain blood pressure & thermoregulation.
Contains substances: minerals, salts, proteins, hormones.

Question 3

What are platelets and their purpose?

Answer 3

Platelets assist with blood clotting.
Stimulated in response to damaged vessels.
Clotting factors in the blood coordinate the formation of platelets to change the blood from liquid to gel, forming a clot.

Question 4

State 2 points about Leuocytes?

Answer 4

Sub-divided into granulocytes and agranulocytes.

Each Leuocyte has its own particular function, playing an important role in the immune system.

Question 5

State a minimum of 5 facts about Erythrocytes.

Answer 5

No nucleus 
Cannot directly reproduce themselves 
Transport oxygen from the lungs, and carbon dioxide from around the body to the lungs. 
Haemoglobin = protein 
Formed in the bone marrow

Question 6

Provide a short definition for each, Arteries, veins and capillaries.

Answer 6

Arteries - oxygenated blood, carry blood away from the heart.
Veins - deoxygenated blood, carry blood towards the heart.
Capillaries - thin walled, link arteries to veins and carry either oxygenated or deoxygenated blood.

Question 7

Describe the position of the heart.

Answer 7

Lies within the thoracic cavity 
The point (apex) points downwards 
Lies to the left side of the thorax.
Lies at a slight angle pointing forward.
Around the 3rd and 7th rib.

Question 8

Describe the structure of the heart.

Answer 8

Made up of mostly muscle
Pericardium- sac that surrounds the heart - protects and keeps in place.
The epicardium- lines outer layer of heart.
The endocardium- lines inner walls of heart.
Two upper chambers (left/right atria).
Two lower chambers (left/right ventricles).

Question 9

How many chambers does the heart have?

Answer 9

4 chambers, separated by cardiac septum.

Question 10

State 5 points regarding the contraction of the heart.

Answer 10

Sino-atrial node (natural pacemaker)
Electrical current goes through the Bundle of HIS then to the purkinje fibres.
Systole pumps out the blood.
Diastole - point of relaxing.