The Circulatory System

Circulatory System

• The human circulatory system consists of the heart, a series of blood vessels, and the blood that flows through them.

The Heart – about the size of your cliched fist• Pericardium – protective sac the heart is enclosed in

• Myocardium - thick middle muscle layer of the heart; pumps blood through the circulatory system

• Atrium - upper chamber of the heart that receives and holds blood that is about to enter the ventricle

• Ventricle - thick-walled, muscular, lower chamber of the heart that pumps blood out of the heart

• Pulmonary Circulation - pathway in which the right side of the heart pumps blood to the lungs

• Systemic Circulation - pathway in which the left side of the heart pumps blood to all of the body except the lungs

• Valves - flap of connective tissue between an atrium and a ventricle, or in a vein, that prevents backflow of blood

Circulation of Blood Through the Heart

1. Vena Cava2. Right Atrium3. Right

atrioventricular (AV) tricuspid valve

4. Right Ventricle5. Pulmonary

Semilunar Valve

6. Pulmonary Artery

7. Lungs8. Pulmonary

veins9. Left Atrium10. Left

Atrioventricular (AV) bicuspid valve

11. Left Ventricle12. Aortic

Semilunar Valve

13. Aorta14. To all the cells

of the body

Circulation

• 4 chambered Heart

• 3 loop system circulatory system

Heartbeat

• Pacemaker - small group of cardiac muscle cells in the right atrium that “set the pace” for the heart as a whole; also known as the sinoatrial node

Circulation System• Aorta - large blood vessel in mammals through

which blood travels from the left ventricle to all parts of the body except the lungs

• Artery - large blood vessel that carries blood from the heart to the tissues of the body. – High Pressure, can contract and expand

• Capillary - smallest blood vessel; brings nutrients and oxygen to the tissues and absorbs carbon dioxide and waste products– Thin so nutrients can be passed to cells or

waste material absorbed• Vein - a blood vessel that returns blood to the

heart. – Low pressure, no muscles in walls

Circulatory System

• One-way Valves

• Exercise

Blood Pressure

• Systolic – first number, measures the pressure on the arteries when the ventricles are contracted

• Diastolic – second number, measures the pressure on the arteries when the ventricles are relaxed

• Normal blood pressure 120/80

Questions

1. List the structures of the circulatory system.

2. Compare the functions of the three types of blood vessels in the circulatory system.

3. Describe the path of blood circulation through the body.

4. How is heartbeat controlled?

5. Explain how regular exercise can promote good circulation.

Blood

Blood CompositionComponent Scientific Name Properties

Red Blood Cells Erythrocytes •Carry hemoglobin and oxygen.

•No nucleus

•Avg. Life 120days

•Formed in bone marrow

•Recycled by Liver

White Blood Cells Leukocytes •Fight infection

•Formed in Bone marrow

•Die fighting infection (pus)

Plasma None •Liquid portion of blood. (90%) water

•Contains:•Clotting factors•Hormones•Antibodies•Dissolved gasses•Nutrients & wastes

Platelets Thrombocytes •Clot blood

•Formed in bone marrow by megakaryocytes

Blood Composition

Red Blood Cells

• Red blood cells transport oxygen.

• Mature RBC have no nuclei.

• Last for about 120Days

White Blood Cells

• Produce in Red Bone Marrow

• No Hemoglobin; Contains Nucleus

White Blood Cells

Clotting

• Thromboplastin, prothrobin, thrombin, fibrinogen, and fibrin are all clotting proteins found in blood plasma

• Mechanism– Thromboplastin & Ca+ ions

are released by damages cells & stimulates the

– Conversion of prothrombin thrombin & stimulates

– Conversion of Fibrinogen Fibrin (clot)