1. Internal Transport in Mammals
L2 Biology

2. Circulatory Systems Mammals have a closed system, with; a double pump
3 types of tubes
a liquid moving one way

3. Functions of the Circulatory System
Transports oxygen and nutrients from where it enters blood to all body cells
Transports carbon dioxide and other wastes from body to where they are removed
Transports hormones and antibodies around body
Prevents blood loss by clotting
Kills germs
Controls the amount of fluid in tissues
Helps control body temperature

6. The Heart A double pump to move blood through blood vessels
Left side stronger than right
Made from Cardiac Muscle
4 chambers: 2 atriums ( auricles) above and 2 ventricles below
4 valves, to stop backflow
Cardiac muscles contract due to electric impulses that pressurize the blood.

8. Blood flow in summary Left ventricle – aortic valve - aorta – body –
vena cava – right atrium (auricle) –
tricuspid valve – right ventricle – mitral
(bicuspid) valve - pulmonary artery – lungs
– pulmonary vein – left atrium (auricle) –
pulmonary valve - left ventricle … and so
on…

9. Heart beat (pulse rate) control
The heart beat and pulse rate is controlled by an electrical signal from the sinus node, located in the upper right atrium.
From the sinus node, the electrical signal spreads across the 2 atria, causing them to contract, and to push their load of blood into the ventricles. The signal then causes the 2 ventricles to contract and push the blood out of the heart towards the lungs and body tissue.
This signal controls the number and sequence of heart contractions and assures the heart works as efficiently as possible.

10. Blood vessels 3 main types:
Arteries: carry blood away from the heart, thick walled, under high pressure (arterioles link to capillaries).
Veins: carry blood back to the heart, thinner walls than arteries, larger internal diameter, valves stop back flow (venules link to capillaries).
Capillaries: smallest vessels, fluid leaks out of capillary walls to bathe the surrounding tissue cells to exchange gases, nutrients, wastes and kill germs

16. Blood

20. Blood Components
Red Blood Cells (RBC) – full of haemoglobin (an iron based molecule) which carries oxygen, disc shaped cells with no nucleus so cannot self-repair, made in bone marrow.
White Blood Cells (WBC) – protects body against disease, cells with a nucleus, no haemoglobin, can move through capillary walls into tissues, made in bone marrow.
Plasma – 90% water, part of blood that RBC, WBC, platelets, nutrients and wastes travel in, carbon dioxide dissolves in as bicarbonate.
Platelets – involved in blood clotting, also made in bone marrow