1. Human Circulatory System

2. Importance of Circulatory System
Transports nutrients to cells, wastes away from cells, and chemical messengers from cells in one part of the body to distant cells
Distributes heat throughout the body
Defends against invading organisms that could cause disease

3. Structure of Circulatory System
Composed of a four chambered heart that pumps ~ 5 L of blood through 96,000 km of blood vessels that come in contact with every one of the 60 trillion cells in your body

4. Three Types of Blood Vessels
Arteries
carry blood away from the heart to the rest of the body
are thick-walled to withstand pressure
subdivide into small arteries called arterioles

5. Three Types of Blood Vessels
Veins
return blood from the body tissues to the heart
are thin-walled
contain valves that allow a one-way flow of blood
subdivide into small veins called venules

6. Three Types of Blood Vessels
Capillaries
connect arterioles to venules
walls are single cell thick
exchange of O2, CO2, nutrients and wastes occur between blood and body cells through the capillary walls

7. ARTERY
arteriole
capillary
venule
VEIN

8. Questions from Text

9. The Heart
is a double pump separated by a muscular wall called the septum
the right side contains oxygen-poor blood and pumps it to the lungs
the left side contains oxygen-rich blood and pumps it to the cells of the body

10. The Heart, cont’d is divided into 4 chambers:
2 upper, thin-walled atria (atrium - sing.) which act as holding chambers
2 lower, thick-walled ventricles which pump the blood
is covered and protected by a tough membrane called the pericardium

11. Arteries
Superior vena cava
Aorta
Rt pulmonary artery
Left pulmonary artery
Rt pulmonary veins
Left pulmonary veins
Pulmonary arteries trunk
Semilunar valve
Left atrium
Right atrium
Atrioventricular valve
Semilunar valve
Atrioventricular valve
Left ventricle
Right ventricle
Septum
Inferior vena cava

12. The Double Pump
The right side of your heart pumps oxygen-poor blood to the lungs, dumps off CO2, picks up O2 and returns it to the heart – this is called pulmonary circulation.
The left side of your heart pumps oxygen-rich blood to all your body cells, dumps off O2, picks up CO2 and returns it to the heart – this is called systemic circulation.

13. The Path of Blood: Pulmonary Circulation
The right atrium collects oxygen-poor blood from the superior and inferior vena cavas
From the right atrium, blood flows into the right ventricle, where it is pumped into the pulmonary arteries.
The pulmonary arteries take the blood to the lungs to dump CO2 and pick up O2.
This oxygen-rich blood returns to the heart via the pulmonary veins to the left atrium.

14. Superior vena cava
Rt pulmonary artery
Semilunar valve
Right atrium
Atrioventricular valve
Right ventricle
Inferior vena cava
Rt pulmonary veins
Arteries
Aorta
Left pulmonary artery
Left pulmonary veins
Pulmonary arteries trunk
Left atrium
Left ventricle
Septum

15. The Path of Blood: Systemic Circulation
The left atrium passes oxygen-rich blood to the left ventricle.
The left ventricle pumps blood into the aorta which branches into arteries and arterioles that go to all body parts.
Arterioles connect with capillaries where O2 and nutrients are delivered and CO2 and wastes are picked up..

16. The Path of Blood: Systemic Circulation, cont’d
Capillaries run into venules which run into veins, which return blood to the heart.
The superior vena cava collects blood from the upper body and the inferior vena cava collects blood from the lower body.
This oxygen-poor blood is emptied into the right atrium of the heart.

17. Superior vena cava
Rt pulmonary artery
Semilunar valve
Right atrium
Atrioventricular valve
Right ventricle
Inferior vena cava
Rt pulmonary veins
Arteries
Aorta
Left pulmonary artery
Left pulmonary veins
Pulmonary arteries trunk
Left atrium
Left ventricle
Septum

18. Blood Flow Animation