Lesson 3: The Circulatory System

Hook: Interesting Facts Science

There are 97,000km of blood vessels in every human

The aorta, which is largest artery located in the body, is about the diameter of a garden hose

The risk of cardiovascular disease is twice as high in women that snore regularly compared to women who do not snore

The right lung of a human is larger than the left one. This is because of the space and placement of the heart

The average life span of a single red blood cell is 120 days

The Circulatory System: Functions

The circulatory system is the transport system of the body.

Four main functions:

1. Transport of O2 and CO2.

2. Distribution of nutrients and transport of wastes.

3. Maintenance of body temperature.

4. Circulation of hormones.

The Circulatory System: Structure

There are 3 components of the circulatory system:

1. A fluid which carries materials (blood).

2. Spaces throughout the body where the fluid moves (blood vessels).

3. A pump to push fluid through spaces (heart).

The Circulatory System: Vessels

Arteries carry blood away from the heart, to the body.

Veins carry blood from the body, to the heart.

The Circulatory System: Vessels

Movement of Oxygenated Blood Through Vessels:

Large Smaller Smallest

Heart Arteries Arterioles Capillaries Tissues

Movement of Deoxygenated Blood Through Vessels:

Small Larger Largest

Tissues Capillaries Venules Veins Heart

The Circulatory System: Circuits

The circulatory system is actually two systems in one.

1.The Pulmonary Circuit

The right side of the heart pumps blood to the lungs.

The blood picks up oxygen from the lungs and returns it to the left side of the heart.

The Circulatory System: Circuits

2. The Systemic Circuit

The left side of the heart pumps oxygenated blood to the body’s system.

The blood returns to the right side of the heart without oxygen (deoxygenated).

The Circulatory System: The Heart

The mammalian heart is a double pump separated by a wall of muscle called the septum.

The heart consists of 4 chambers:

Left atrium and right atrium (upper chambers of the heart).

Left ventricle and right ventricle (lower chamber of the heart).

The Circulatory System: The Heart

The atria receive blood from the body.

The ventricles pump blood to the body.

Recall:

Pulmonary Circuit: Right ventricle pumps to the lungs; left atrium receives blood from the lungs.

Systemic Circuit: Left ventricle pumps to the body; right atrium receives blood from the body.

The Circulatory System: The Heart

Blood Flow Review (Complete on work sheet)

Body Superior/Inferior Vena Cava Right Atrium Right Ventricle

Pulmonary Artery Lungs Pulmonary Vein Left Atrium Left Ventricle

Aorta Body

Blue: Deoxygenated bloodSuperior Vena Cava brings blood from the top of the body, Inferior

Vena Cava brings blood from the bottom of the body – largest vein in the body; Pulmonary Artery is the only artery in the body to

carry deoxygenated blood.Red: Oxygenated blood

The Aorta is the largest and strongest artery in the body; Pulmonary Vein is the only vein in the body to carry oxygenated blood.

Blood Flow Summary

Review: The Human Heart

No Notes - Blood Movement in the Heart

Deoxygenated blood from the body’s veins enters the right atrium of the heart.

It is then passes a valve and moves into the right ventricle.

From the right ventricle it is pumped to the lungs to receive oxygen and lose carbon dioxide

Blood Movement in the Heart

The oxygen rich blood then flows into the left atrium.

Passing another valve it moves into the left ventricle.

The blood is then pumped to the rest of the body through the aorta and into the arteries.

Oxygen is carried throughout the body.

Summary: Blood Flow in the Heart

Heart Attack

If too much cholesterol is ingested than plaque may build up

When excessive plaque builds up the artery may be clogged.

If the artery is clogged then little oxygen will move to the heart = Heart attack.

If lack of oxygen moves to the brain = Stroke

Method of Treatment: Angioplasty

Video on Angioplasty

Blood Pressure

Blood pressure is the amount of pressure exerted by the heart on the blood. It varies between a maximum (systolic) and minimum (diastolic) pressure

Systolic pressure is the pressure exerted when the heart is pumping blood

Diastolic pressure is the pressure associated with the filling of the heart with blood

High and Low Blood Pressure

People with high blood pressure are said to have hypertension

People with low blood pressure are said to have hypotension

In Class Assignment - Homework

Read pages 195-200. Page 202: #1-5.

Read pages 203-206. Page 207: #1-3, 6-9.

Complete the Circulatory System Review Sheet