The Circulatory System

Video Introduction(22min)

The Body’s Transport System• Made up of the heart, blood and a series of

blood vessels.• Jobs:

1. Delivers nutrients and oxygen to the body cells.2. Carries carbon dioxide and other wastes away

from the body cells.3. Protects the body from disease and infection.

The Heart• Cardiac muscle– Involuntary like smooth muscle– Reacts quickly & Striated like skeletal muscle– Doesn’t tire

• Only rests between beats

• Approximately the size of your fist.• Located slightly to the left of your sternum.• Pumps approximately 5 L of blood per minute.• Heartbeat is controlled by a special tissue –

pacemaker.– Sends out signals to the heart muscle that controls

contractions.

The HeartAorta

PulmonaryArtery

PulmonaryVein

Left Atrium

Valves

Left Ventricle

Superior Vena Cava Pacemaker

PulmonaryArtery

PulmonaryVein

Right Atrium

Right VentricleValves

Inferior Vena Cava Septum

The Heart• Your heart is made up of four chambers:– Two upper chambers – Atrium (Atria = singular)– Two lower chambers - Ventricles

• The heart is also split into left and right sides– separated by a thick wall of tissue – Septum• Blood will never cross between the two sides.

• As we discuss the heart from now on, YOU will become the doctor and THE HEART will be the patient laying on the operating table.– Left becomes Right and Right becomes Left!!!!!!!

Divisions & Chambers

Upper Chambers –Atrium

Lower Chambers –Ventricles

Right Side Left Side

Flow of BloodBlood returning to the heart from the

head.

Blood returning to the heart from the

body.

Blood leavingthe heart -to

the head.

Blood leavingthe heart -to

the body.

Blood going tothe lungs

Blood going tothe lungs

Blood going backto the heart from

the lungs

Blood going backto the heart from

the lungs

Myths about the Color of Blood

• Is blood really blue?– NO – blood is NOT blue!!!!!! BLOOD IS RED!!!!!– Blood can either be:• high in oxygen, brighter red color, or • low in oxygen, darker red color. (purple)

– The skin changes the way blood looks in the veins to make it look bluer in color.

Right Side

I. The Patient’s Right Side of the Heart

Blood is returning to the heart from it’s trip around the body.

Returns to the heart through the Vena Cava

Condition of the blood:o High in Carbon Dioxideo Low in Oxygen

Right Side

1. Right Atrium (RA)– Collecting chamber for

blood returning to the heart from the body.

2. Right Ventricle (RV)– Pumping chamber –

sends blood to the lungs.

– A valve separates the two chambers and prevents blood from flowing backwards.

1.

2.

Right Side

3. Blood leaves the heart, through the pulmonary arteries.– Drops off waste gas

carbon dioxide.– Picks up new supply of

oxygen.

4. Returns to the heart through the pulmonary veins.

3.

4.

3.

4.

Left Side

I. The Patient’s Left Side of the Heart

Blood is returning to the heart from it’s trip to the lungs.

Condition of the blood:o High in Oxygeno Low in Carbon Dioxide

Left Side5. Left Atrium (LA)– Collecting chamber for

blood coming back to the heart from the lungs.

6. Left Ventricle (LV)– Pumping chamber –

pumps blood to the rest of the body.

– Six times more powerful than the right ventricle.

5.

6.

Leaving the Heart

7. Blood leaves the heart through the largest and strongest blood vessel in the body – Aorta

7.

To the Head/Upper Body

To the Lower BodyPump Your Blood – Happy Days

(4:09 min)