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Lecture 7Heart and Circulatory

System

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Lecture 7

1. Introduction

2. Blood

3. Blood Vessels & Blood Pressure

4. The Heart

5. Cardiovascular (Circulatory) System

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Circulatory System Function1. Transport System (gases, nutrients, hormones)

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Circulatory System Function2. Heat Distribution System

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Circulatory System Function

3. Heals wounds and fight off diseases

Homeostasis

Maintenance of a relatively constant internal

state under a much wider range of

environmental conditions.

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Blood

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Blood• The red fluid that circulates in our blood

vessels

• Primary Function -Transports Oxygen and

CO2 (waste)

• Main player in the body’s defense against

infection

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Hemopoietic Tissues

• Hemopoiesis – blood formation

• Bone Marrow, Spleen, Liver, and Kidneys

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BloodTwo main components to blood:

1. Blood Plasma

2. Blood Cells (Cellular Component)

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Blood Plasma

• Fluid component of the blood

• Makes up 55% to 60% of total blood volume

• About 92% is water (almost identical to sea

water)

• Other 8% is blood proteins and trace

materials

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Red Blood Cells

(Erythrocytes)95% of cellular component

Blood Cells

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Red Blood Cells

(Erythrocytes)

Hemoglobin MoleculesAbout 250 million /cell

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Red Blood Cells

(Erythrocytes)

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White Blood Cells

(Leucocytes)4% of cellular component

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White Blood Cells

(Leucocytes)4% of cellular component

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Platelets

(Thrombocytes)Less than 1% of “cellular component”

Not Cells!

Blood Types• Although all blood is made of the same plasma and

cells, not all blood is alike.

• Four major common blood types:

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Blood Types• Blood Type – “Antigens” on the surface of the red

blood cells. A antigens, B antigens

Blood Types

• Blood Type A – A antigens

• Blood Type B – B antigens

• Blood Type AB – both A and B antigens

• Blood Type O – NO antigens

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Blood Types• Antigens can trigger a patient's immune system to

attack transfused blood

ABO Blood Group System

Type O is the universal donor

Cannot receive A, B or AB blood

Type AB is the universal recipient

Type A can only receive

Type A and Type O

Type B can only receive

Type B and Type O

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Rh Factor

• In addition to the A and B antigens, there is a third

antigen called the Rh factor,

• Rh can be either present (+) or absent ( – )

• In general, Rh negative blood is given to Rh-

negative patients, and

• Rh positive blood or Rh negative blood may be

given to Rh positive patients.

Rh Factor

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Rh Factor

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The approximate distribution of blood types in the U.S. population

(distribution is different for specific racial and ethnic groups):

Blood Types

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Circulatory System Structure

Veins and Arteries

• Vein – a blood vessel that carries blood

toward (i.e. Back to) the heart

• Artery – a blood vessel that carries blood

away from the heart to the capillary

networks

• Capillary – site of exchange

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Blood Vessel Types

Arterial Portion

• Heart

• Artery

• Arteriole

• Capillary

Venous Portion

• Capillary

• Venule

• Vein

• Heart

About 70 % of the blood volume is found within the Venous portion

Aorta Vena Cava

Arterioles Venules

Capillaries

Blood Vessels

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Venous Valves

What is Blood Pressure?

Systolic

Pressure

Diastolic

Pressure

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Arteries Arteriole Capillary Venules Veins

Systolic

Diastolic

Blood Pressure VariationB

loo

d P

ressu

re (

mm

Hg

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Measuring Blood Pressure

Sphygmomanometer

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Blood Pressure