1. Circulatory System
SBI 3U
Ms. Raper

2. Open circulatory system
Found in many insects
Blood returns to the heart via the movement of the animal’s body.
inefficient

3. Closed Circulatory System
Found in some invertebrates such as worms and in fish, reptiles, birds and mammals
Blood never leaves a system of tubes
Heart pumps blood around the body

4. William Harvey 1568 -1657 Was a physician trained in Italy.
Was the first to accurately describe the action of the heart pumping blood around the body.
He confirmed the presence of valves in the veins to prevent the backflow of blood.
He confirmed his theories by carrying out dissections.

6. Blood Vessels Arteries – carry blood AWAY from the heart.
Veins – carry blood back to the heart –
blood returns VIA the veins.
Capillaries – CONNECT arteries and veins, it is here that substances are loaded and unloaded into the
blood by diffusion.

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8. Arteries Thick elastic muscular walls Small lumen
Carry oxygenated blood (except pulmonary artery)
Carry blood away from the heart.

9. Veins Have thin walls Large lumen
Carry deoxygenated blood (except pulmonary vein)
Have valves to prevent backflow of blood
Carry blood back to the heart

11. Circulatory System

12. Blood vessels

13. Arteries Have a smaller lumen than veins Have thick Muscular walls.
Carry oxygenated blood (except the Pulmonary artery)
Have a pulse
Carry blood away from the heart
Have blood under high pressure
Blood is BRIGHT red
A cut artery spurts with the heart beat.
Main artery is the AORTA
Cross section through an artery.

14. Capillaries Connect arteries and veins. Are found in organs.
Are where substances are dropped off or picked up from the cells
Are only one cell thick.
Red Blood Cells must travel through in single file.
Low pressure
Cut capillaries ooze
Cross section of a capillary

15. Veins have thinner muscular walls than arteries,
Have a large lumen,
Have valves to prevent backflow of blood
Carry blood back to the heart
Carry deoxygenated blood (except the pulmonary vein)
Have blood that is DARK red.
Low pressure
A cut Vein will gushes.
Main vein is the VENA CAVA

16. Blood Vessels.

19. Exchange in Capillaries

20. Coronary Arteries

21. Peripheral Arteries

22. 3 parts to the Circulatory System
Cardiac - blood supply to and through the heart.
Pulmonary – blood flow through the lungs.
Systemic – blood flow through the body other than the lungs and heart.
Because blood flows through the heart twice for every complete circuit, it is referred to as a DOUBLE circulation.