1. Circulatory System

2. Functions of Circulatory System
Brings oxygen, nutrients, and hormones to cells
Fights infection
Regulates body temperature

3. Structures of Circulatory System
Heart
Blood
Blood Vessels:
Arteries
Capillaries
Veins

4. Heart Location: near center of chest Composed of: muscle (myocardium)
4 chambers: 2 Atria, 2 Ventricles
Contracts ~ 72 times a minute
Pumps ~ 70 milliliters of blood with each contraction
During an average lifetime, the human heart will beat more than 2.5 billion times

5. Heart
Give a tennis ball a good, hard squeeze. You're using about the same amount of force your heart uses to pump blood out to the body. Even at rest, the muscles of the heart work hard--twice as hard as the leg muscles of a person sprinting.

6. Blood Human body contains 4-6 liters
Connective tissue containing dissolved substances and specialized cells
45% cells
55% plasma
90% water
10% gases, salts, nutrients, enzymes, hormones, waste products, and plasma proteins

7. Blood Functions Collects Regulate body temp Fight infection
oxygen from lungs
Nutrients from digestive tract
Wastes from tissues
Regulate body temp
Fight infection
Form clots to repair damaged vessels

8. Blood Cells Red (erythrocytes)
Most numerous 1 ml of blood = ~ 5 million RBCs
Transport oxygen
Get color from Hemoglobin (iron-containing protein that binds oxygen)
Shaped like disks w/ thick edges
Produced from red bone marrow
Circulate ~ 120 days before being destroyed in liver & spleen

9. Blood Cells White (leukocytes) Platelets
Less abundant (700 RBC to 1 WBC)
“army” of circulatory system
Attack foreign substances
Platelets
Clots blood
Repairs damaged vessels

10. Figure 37-10 Blood Clotting
Section 37-2
Break in Capillary Wall
Blood vessels injured.
Clumping of Platelets
Platelets clump at the site and release thromboplastin. Thromboplastin converts prothrombin into thrombin..
Clot Forms
Thrombin converts fibrinogen into fibrin, which causes a clot. The clot prevents further loss of blood..

11. Blood Vessels Arteries Large (“super highways”)
Carry blood away from the heart
Carry O2 rich blood (exception: pulmonary artery)

12. Blood Vessels Capillaries Smallest (“side streets and alleys”)
Exchange of nutrients, oxygen, carbon dioxide, and waste
Veins
Return blood to heart
Muscles help force blood through veins against gravity

13. Figure 37-5 The Three Types of Blood Vessels
Artery
Vein
Connective tissue
Smooth muscle
Endothelium
Valve
Venule
Arteriole
Capillary

14. Path of Blood Flow Start in the heart: Leaves heart:
Left Atrium (through mitral valve)
Left ventricle (through aortic valve)
Leaves heart:
Aorta
Body/Capillaries

15. Path of Blood Flow Returns to Heart: Leaves Heart: Veins
Vena Cava (inferior and Superior)
Right atrium (through tricuspid valve)
Right ventricle (through pulmonary valve)
Leaves Heart:
Pulmonary artery (goes to lungs)
Through pulmonary veins to left atrium

16. The Circulatory System
Section 37-1
Capillaries of head and arms
Capillaries of abdominal organs and legs
Inferior vena cava
Pulmonary vein
Capillaries of right lung
Superior vena cava
Aorta
Pulmonary artery
Capillaries of left lung

17. Word Bank Left Atrium Left Ventricle Right Atrium Right Ventricle
Pulmonary Artery
Pulmonary Veins
Aorta
Vena Cava