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37–1 The Circulatory SystemA. Functions of the Circulatory SystemB. The Heart

1. Circulation Through the Body2. Circulation Through the Heart3. Heartbeat

C. Blood Vessels1. Arteries2. Capillaries3. Veins

D. Blood PressureE. Diseases of the Circulatory System

1. High Blood Pressure2. Consequences of Atherosclerosis3. Circulatory System Health

Section 37-1

Section Outline

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Questions to be answered• What are the structures of the

circulatory system?  

• What are the three types of blood vessels in the circulatory system?

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Vocabulary to know for the chapter

• myocardium atrium ventricle pulmonary circulation systemic circulation

valve pacemaker aorta artery capillary vein atherosclerosis

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37–1 The Circulatory SystemA. Functions of the Circulatory System• The human circulatory system consists of the heart, a series of blood vessels, and the blood that flows through them

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B. The Heart• A picture of the structures of the Heart is found on page 944 in your book• Myocardium – thick layer of muscle that the powerful contractions pump blood through the circulatory system.

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Section 37-1

Figure 37-3 The Structures of the Heart

Right Ventricle

Right Atrium

Left Atrium

Inferior Vena CavaVein that brings oxygen-poor blood from the lower part of the body to the right atrium

Tricuspid ValvePrevents blood from flowing back into the right atrium after it has entered the right ventricle

Pulmonary ValvePrevents blood from flowing back into the right ventricle after it has entered the pulmonary artery

Pulmonary VeinsBring oxygen-rich blood from each of the lungs to the left atrium

Superior Vena CavaLarge vein that brings oxygen-poor blood from the upper part of the body to the right atrium

AortaBrings oxygen-rich blood from the left ventricle to the rest of the body

Pulmonary ArteriesBring oxygen-poor blood to the lungs

Aortic ValvePrevents blood from flowing back into the left ventricle after it has entered the aorta

Mitral ValvePrevents blood from flowing back into the left atrium after it has entered the left ventricle

Left Ventricle

Septum

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1. Circulation Through the Body Pulmonary circulation – pathway of oxygen-poor blood that pumps from heart to lungs Systemic circulation – pathway oxygen rich blood is pumped from the heart to rest of the body

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Section 37-1

Figure 37-2 The Circulatory System

Capillaries of head and arms

Capillaries of abdominal organs and legs

Inferior vena cava

Pulmonary veinCapillaries of

right lung

Superior vena cava

Aorta Pulmonary artery

Capillaries of left lung

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2. Circulation Through the Heart Valves – flaps of connective tissue between atria and the ventricles Creates one way traffic of blood

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3. Heartbeat Two networks of muscle fibers in the heart, one in the atria and the other in the ventricles Pacemaker – the nodes that start heart muscle contraction The Sinoatrial node starts the wave for the heart muscle contraction

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Sinoatrial (SA) node

Atrioventricular (AV) node

Conducting fibers

Contraction of Atria Contraction of Ventricles

Section 37-1

The Sinoatrial Node

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C. Blood VesselsAorta – the first of a series of blood vessels that carry the blood on its round trip through body and back to the heart

1. Arteries Arteries - large vessels that carry blood form the heart to the tissues of the body Most of the time filled with oxygen-rich blood

2. Capillaries Capillaries are the smallest of the blood vessels. The walls can be 1 cell thick Bring nutrients and oxygen to the needed areas and absorb waste products and carbon dioxide3. Veins Veins – vessels that return blood back to the heart many are located between skeletal muscle this way every time you contract you push blood back to the heart

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Section 37-1

Figure 37-5 The Three Types of Blood Vessels

Capillary

Connective tissue

Connective tissue

Smooth muscle

Smooth muscle

Endothelium

Endothelium

Valve

Venule

Endothelium

Arteriole

VeinArtery

E. Diseases of the Circulatory SystemAtherosclerosis – condition in which fatty deposits called plaque build up on the inner walls of the arteries. This can cause a blockage in the blood vessels causing a heart attack of stroke

1. High Blood PressureA.K.A hypertention, forces the heart to work harder and might wear out quicker2. Consequences of AtherosclerosisBlood clots, can be seen blood shot eyes

Heart attackStroke

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3. Circulatory System HealthCardiovascular diseases are easier to prevent that to cureExercise, control weight, reduce stressDiet of low saturated fat and cholesterolCardiovascular diseases are also reduced by not smoking

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