Circulatory System

Question 1

Circulatory System Components

Answer 1

Blood
Heart
Blood Vessels (Arteries, Veins, Capillaries)

Question 2

Composition of Blood

Answer 2

PLASMA (Top Layer)- Makes up about 55% of its overall content, surrounding and carrying blood cells, helps maintain blood pressure.
THROMBOCYTES (Middle Layer)- Also known as Platelets, assist with blood clotting and are stimulated in response to damage vessels.
LEYCOCYTES (Middle Layer)- Buffy coat layer, sub divided into granulocytes (grains) and agranulocytes (No grains). Every Leycocytes has a particular function, all play a part of the immune system.
ERYTHROCYTES (Bottom layer)- Also known as red blood cells, have no nucleus. They transport oxygen and carry carbon dioxide back to the lungs. Do this by a protein called Haemoglobin. Formed in the bone marrow.

Question 3

The Heart - Purpose

Answer 3

To pump blood around the body.
Systemic Circulation- Function of the heart to pump blood around the body.
Pulmonary Circulation- Function of the heart to pump blood to the lungs to be oxygenated.

Question 4

The Heart - Position

Answer 4

The heart lies within the thoracic cavity.
The point or apex points downwards.
Lies to the left side of the thorax near the sternum.
Around the 3rd to 7th rib.
Lies at a slight angle pointing forward.

Question 5

The Heart- Structure

Answer 5

Heart is made up of large muscles- Myocardium.
Pericardium- Serious sac that surrounds the heart, purpose is to protect and keep it in place.
Epicardium- Lines the outer layer of the heart.
Endocardium- Lines the inner walls of the heart.
There are four chambers in the heart, separated by cardiac septum.
Two upper chambers are:
- The right Atrium
- The left Atrium
Twp lower chambers are:
- The right ventricle
- The left Ventricle
Left value is called the Mitral value (Bicuspid)
Right value is called the Tricuspid value
Between the atrium and ventricles are the atrioventricular valves.

Question 6

Blood Flow

Answer 6

Blood flows a specific route through the heart and can only flow in one direction.
The blood entering the chambers does not supply the myocardium.
The coronary arteries serve the myocardium its blood supply.
Values are present to stop the back flow of blood.
L- left
O- Oxygenated
R- right
D- deoxgenated

Question 7

Open Circulatory System

Answer 7

Pump like heart structure, Haemolymph is pumped out of vessels.
The Haemolymph bathes the organs and is not directly pumped into them. The flow then makes its way back to the pump via passive flow.
Less energy to function.
Examples:
Snails
Grasshoppers