1. The Circulatory System
The body’s
transport
system:

2. Functions: Transportation:
oxygen and nutrients etc are distributed to body cells.
carbon dioxide and wastes are taken away from the cell.
Maintenance of body temp & chemical balance.
Circulation of hormones, components of the immune system etc.

3. Structures: Fluid which carries materials to be transported (blood)
Blood Vessels or tubes for the blood to move through (arteries, veins, capillaries)
A Pump that pushes the fluid through the blood vessels (heart)

4. 1. Blood Vessels Arteries: - carry blood away from the heart
- thick and elastic walls (high pressure)
- usually high O2, low CO2 (except pulmonary)
Veins: - carry blood to the heart
- thin and slightly elastic walls
- contain flap-like valves to prevent backflow
- usually low O2, high CO2 (except pulmonary)
Capillaries: - tiny blood vessels one cell thick
- microscopic network of blood vessels at all tissues
- allows exchange of materials between cells & blood
Artery
Vein

6. 2. THE HEART

7. The Incredible Heart Muscle
Great Strength :
Pumps 4-5 L of blood through ~ km of blood vessels.
High Endurance:
Beats on average 72 beats / minute, ~ beats / day
During a lifetime, could fill an ocean tanker full of blood TWICE
Size:
Size of your fist & weighs ~ 300 grams
Pace Maker:
Makes its own ‘electricity!’
Coordinates the beating of heart cells

8. The Incredible Heart - Double Pump
Right Side Pump:
Pumps blood that is low in oxygen to the lungs to pick up oxygen.
Deoxygenated blood from the body drains into the right atrium via the vena cava (large veins.)
Blood goes from the right atrium to the right ventricle which pumps the blood to the lungs via the pulmonary artery.

9. The Incredible Heart Pump
Left Side Pump:
Pumps blood that is high in oxygen to the body to give oxygen to body cells (for cell respiration)
Oxygenated blood from the lung enters the left atrium via the pulmonary veins.
Blood goes from the left atrium to the left ventricle which pumps the blood to the body via the aorta (largest artery in the body).

11. THE HEART

12. 3. Blood Major blood component: Plasma (55%):
Liquid part of blood
contains dissolved material
Red Blood Cells (RBC - 44%):
Contains haemoglobin that carries oxygen
White Blood Cells (WBC – 1%):
Immune system (WBC engulf invaders/ produce antibodies)
Platelets (< 1%):
Cell fragments needed to clot blood

13. Branches of the Circulatory System
Systemic circuit: Blood goes from the heart to the rest of the body and back to the heart. Includes:
Cardiac circuit: blood goes to the heart muscle (coronary arteries & veins)
Hepatic-Portal: transports blood from digestive tract to liver then to heart
Renal: carries blood to, and from the kidneys
Pulmonary circuit: Blood goes from the right side of the heart to the lungs & back to left side of the heart (pulmonary arteries & veins)

15. Heart Cycle: Diastole: Heart fills with blood Systole: Heart pumps
The heart muscles relax
Atria collects blood & drains it into ventricles
Systole: Heart pumps
Ventricles contract
Blood is pumped out of the heart
Heart Sounds: Lubb – Dubb - Closing of the heart valves
Ventricles contract & increase in pressure causes the AV valve to close shut  Lubb sound
Ventricles relax, causing blood to rush in from Atria
Decrease in pressure as blood flows in, causing semilunar valves to shut  Dubb sound