Circulatory System

Transport

Circulatory System

• Transports nutrients, oxygen, and other substances to all cells in the body

• These substances are transported in blood

• Blood flows through a network of tubes called blood vessels

• A pump, the heart, keeps blood flowing through the vessels

Circulatory System

• Humans have a double circulatory system– This means that blood needs to travel through

the heart twice on one complete journey through the body

DOUBLE Circ. System

• Blood on the left side of the heart came from the lungs

• We call it oxygenated blood, because it has oxygen in it

• Oxygenated blood is always colored RED

DOUBLE Circ. System

• The oxygenated blood then goes around the body, delivering oxygen to body cells

• This means the blood becomes deoxygenated

• Deoxygenated blood is colored BLUE

DOUBLE Circ. System

• When deoxygenated blood reaches the heart it gets pumped to the lungs.

• Because the lungs are so close, blood is pumped at a _____ pressure (force)

• When oxygenated blood reaches the heart it gets pumped to the rest of the body.

• Because the body cells can be far away, blood is pumped at a _____ pressure (force)

Circulatory System review1. What are 2 substances carried by the blood?2. Blood travels through tubes known as what?3. How many times does blood go through the

heart in one complete circuit?4. What kind of blood do we color red? Blue?5. Why is there a pressure difference in blood

going to the lungs, and going to the body?

Heart

• The function of the heart is to pump blood around the body.

• The heart is made of a special type of muscle called cardiac muscle.

• Your heart is about the same size as your fist.

• It pumps over 5,000 quarts of blood every day

Heart

• The heart is divided into four chambers.• The two upper chambers are known as

Atria (singular: atrium)• The two lower chambers are known as

Ventricles• The left and right sides of the heart are

completely separated by a septum.

HeartYouTube Video

Heart• It is very important that oxygenated and

deoxygenated blood DO NOT MIX.• This is achieved by having a septum that

separates the left and right side of the heart

• and…• By having valves that separate the atrium

from the ventricle

Heart Valves

Tricuspid Valve• Separates the right

atrium and ventricle• Has 3 parts or flaps

Bicuspid Valve• Separates the left

atrium and ventricle• Has 2 parts or flaps

Heart Valves

• Semilunar Valves

Prevents blood from flowing back into the ventricles

How does the heart get the nutrients and oxygen it needs?

• Blood does not spend enough time in the atria or ventricles to let oxygen and other nutrients fully diffuse to all the cells.

Coronary Arteries• On the outside of the heart are blood vessels

that supply the cardiac muscle with oxygen and nutrients.

• They are called Coronary Arteries

Coronary Arteries

• If a coronary artery gets blocked (by a blood clot, plaque, etc.) the cardiac muscles run short of oxygen.

• If they don’t have oxygen they can’t respire.

• This causes the heart to stop beating, otherwise known as a heart attack or cardiac arrest.

Coronary Heart Disease

• Blockage of the coronary arteries is called Coronary Heart Disease.

Coronary Heart Disease• Very common cause of death (25%)• There are several factors that increase a

person’s risk of getting this disease.– Diet– Smoking– Stress– Inactivity– Genes– And many others