1. Unit J. Circulation and Blood .

2. Intro…
When you are unicellular there is no need for a transport system…
However when you are trillions of cells, a system to transport nutrients (glucose, amino acids) and remove wastes (carbon dioxide, ammonia) is required….

3. Functions of the Circulatory System:
Bring nutrients to the cells.
Take wastes away from the cells.

4. Circulatory System
Blood = the medium of transport (carries nutrients & wastes)
Blood vessels = pathway for blood
Heart = pump that will move blood through vessels
There are close to 100,000 km of blood vessels!

5. 5 type of blood vessels Arteries
Arterioles (smaller version of arteries)
Veins
Venules (smaller version of veins)
Capillaries – smallest!!!

6. Arteries (10% of blood) Carry blood AWAY from heart
Thick walls to withstand blood pressure
Elastic muscle fibers to withstand blood pressure
Highest blood pressure
Smooth muscle can regulate size

7. Arterioles Connects to arteries and capillaries Smaller than arteries
Can dilate or constrict which regulates blood pressure

8. Capillaries (5% of blood)
Narrow, microscopic tubes, blood cells will pass through single file!
Site of nutrient/ waste exchange
Thin walls (one cell layer thick!)allow for diffusion
Large surface area allows for greater exchange of gases and nutrients
Connect arterioles to venules

9. The blood flow across the capillary bed is regulated by a sphincter muscle on the arteriole side.

10. Capillary Bed

11. Venules
Connect together to form veins
Very thin walls

12. Veins (70% of blood) Carry blood BACK TO heart Thinner walls
Contain valves to prevent back flow
Lowest blood pressure
Use large muscles groups to help push blood back to heart

14. Blood vessels - compared

15. Pulmonary vs. Systemic
The cardiovascular system has 2 circuits with 2 functions:
Pulmonary = brings blood to/from the lungs
Systemic = brings blood to/from the body

16. 1. Pulmonary – from heart to lungs and back to heart
Right ventricle pushes deoxygenated blood out of the heart to the lungs
CO2 diffuses out, O2 diffuses in at the alveoli of the lungs
Oxygen-rich blood returns to the left atrium of the heart

17. 2. Systemic – from heart to EVERY cell of body and back to heart
Includes all blood vessels except those in the pulmonary system
The left ventricle of the heart pumps oxygenated blood to the cells
O2 diffuses out of blood, CO2 diffuses into blood
The vena cava returns deoxygenated blood back to the right atrium of the heart

19. A. In the pulmonary system
Oxygenated and Deoxygenated blood
A. In the pulmonary system
1. Arteries carry deoxygenated blood.
Veins carry oxygenated blood.
B. In the systemic system
1. Arteries carry oxygenated blood.
2. Veins carry deoxygenated blood.

21. Important Blood Vessels:
1. Pulmonary Circuit:

22. 2. Systemic Circuit - Arteries:

23. 2. Systemic Circuit - Veins:

24. Path of a blood cell
You should also be able to describe the flow of blood around the body through any major organ!

25. For example: Path of blood to kidneys
Left ventricle to aorta to renal artery to renal arterioles to capillaries to venules to renal vein to inferior venae cava to right atrium

26. For example: Path of blood to the intestines
Left ventricle to aorta to mesenteric artery to capillaries in the villi to venules to hepatic portal vein to liver hepatic vein to inferior venae cava to right atrium