1. The Human Circulatory System

2. The Heart Located near the center of your chest Hollow structure
Composed almost entirely of muscle
About the size of your clenched fist

3. The Heart The heart contracts about 72 times per minute
Pumps about 70mL of blood with each contraction.

4. The Heart
The right and left sides of the heart are separated by a septum, or wall.
The septum prevents the mixing of oxygen rich and oxygen poor blood.

5. The Heart On each side of the septum are two chambers.
The upper chamber (receives blood) is the atrium.
The lower chamber (pumps blood out of heart) is the ventricle.

6. The Heart
The heart has a total of 4 chambers:
2 atriums
2 ventricles

7. Pathway of Blood
Deoxygenated blood passes from the right atrium into the right ventricle and then goes to the lungs.
From the lungs, blood moves back toward the heart into the left atrium to the left ventricle and then passes into the aorta to go to the rest of the body

8. Valves
As the heart contracts, blood flows into the ventricles and then out through the ventricles.
Flaps of connective tissue, called valves, are located between the atria and ventricles.
Blood moving keeps the valves open.
When the ventricles contract, the valves close which prevent blood from flowing back into the atria.

9. Blood Vessels
As blood moves through the circulatory system it moves through 3 types of blood vessels:
Arteries
Capillaries
Veins

10. Arteries Large vessels Carry blood from heart to tissues of body
Carry oxygen rich blood, with the exception of pulmonary arteries.
Thick walls-need to withstand pressure produced when heart pushes blood into them.

11. Capillaries Smallest blood vessels
Walls are only one cell thick and very narrow.
Important for bringing nutrients and oxygen to tissues and absorbing CO2 and other waste products.

12. Veins
Once blood has passed through the capillary systems it must be returned to the heart.
Done by veins
Walls contains connective tissue and smooth muscle.
Largest veins contain one way valves that keep blood flowing toward heart.
Many found near skeletal muscles. When muscles contract, blood is forced through veins.

13. Blood Pressure The heart produces pressure
The force of blood on the wall of the arteries is known as blood pressure.
Blood pressure decreases as the heart relaxes, but the rest of the circulatory system is still under pressure.

14. Blood Pressure
When blood pressure is taken, the cuff is wrapped around the upper portion of the arm and pumped with air until blood flow in the artery is blocked.
As the pressure in the cuff is relaxed, 2 numbers are recorded.
Systolic pressure- the first number taken, is the force felt in the arteries when the ventricles contract.
Diastolic pressure- the second number taken, is the force of the blood on the arteries when the ventricles relax.

15. Blood Composed of plasma and blood cells Types of Cells are:
Red Blood Cells
White Blood Cells
Platelets

16. Blood Plasma Straw colored 90% water
10% dissolved gases, salts, nutrients, enzymes, hormones, wastes, and proteins.

17. Blood Plasma proteins 3 Types: Albumins, globulins and fibrinogen.
Albumins and Globulins- transport substances such as fatty acids, hormones and vitamins.
Fibrinogen- Responsible for blood’s ability to clot

18. Blood Red Blood Cells Most numerous type Transport oxygen
Get color from hemoglobin
Disk shaped
Made in red bone marrow
Circulate for 120 days

19. Blood White Blood Cells
Guard against infection, fight parasites, and attack bacteria
Number of WBC’s increases when body is fighting
Lymphocytes produce antibodies which fight pathogens and remember them

20. Blood Platelets Aid the body in clotting Small fragments
Stick to edges of broken blood cell and secrete clotting factor to help form clot.

21. Blood Clotting Problems
Hemophelia
Genetic disorder that disrupts clotting
People must be very careful to avoid injury
Can be treated by injecting extracts that contain the missing clotting factor.