The Body’s Transport System

The Body’s Transport SystemThe Circulatory System

The Circulatory System• The Cardiovascular

System carries needed substances to cells and carries waste products away from cells.– Consists of the

heart, blood vessels, and blood.• Blood contains cells

that fight disease (white blood cells).

• Blood vessels carry blood to every part of your body.

• Blood moves oxygen and nutrients to cells and carries carbon dioxide and other wastes away from the cells.

• Blood carries carbon dioxide to the lungs, and we lose it when we exhale.

The Heart• The heart is a hollow, muscular

organ that pumps blood throughout the body.– It pushes blood through the blood

vessels every time it beats.• The heart has four chambers with

two on the right and two on the left.– The two sides are separated by a wall

called the septum.

The Heart• The four chambers

are divided between two atria on the top and two ventricles on the bottom.– The atria receive

blood coming into the heart, and the ventricles pump blood out of the heart.

The Heart• In the right atrium,

there are a group of cells that send signals to make the heart contract called the pacemaker.

• The atria are separated from the ventricles by valves (flaps of tissue that prevent blood from flowing backward).

The Heart• The heartbeat makes a lub-dub

sound, which is caused by the opening and closing of the heart valves.– When the valves between the atria and

the ventricles close, the lub sound is made.

– When the valves between the ventricles and the blood vessels close, it makes the dub sound.

KWL: Circulation

k w l

Pathway of BloodRight

Side of the Heart

Lungs

Left Side of the Heart

Cells of the Body

Coronary Circulation• Coronary

Circulation is the flow of blood to and from the tissue of the heart.

• When the coronary circulation is blocked, oxygen and nutrients cannot reach all the cells of the heart and can result in a heart attack.

Pulmonary Circulation• Pulmonary

Circulation is the flow of blood through the heart to lungs and back to the heart.

Systemic Circulation• Systemic Circulation

is the flow of blood to all of your organs and body tissues, except the heart and lungs.

Blood Flows Through Two Loops• Loop One: To

the Lungs and back to the Heart– Blood from the

body goes into the right atrium then to the right ventricle and to the lungs to receive oxygen.

• Loop Two: To the Body and back to the Heart– Blood from the

lungs goes into the left atrium to the left ventricle to the aorta (largest artery in the body), and it circulates throughout the arteries and capillaries in various organs.

Blood Vessels - Arteries

• Arteries are blood vessels that carry blood away from the heart.

• Arteries have thick, elastic walls made of connective tissue and smooth muscle tissue.

• The pulse is caused by alternating expansion and relaxation of the artery wall.

Blood Vessels - Veins• Veins are blood vessels that carry blood

back to the heart.• Veins have one-way valves that keep blood

moving toward the heart.• The two major veins return blood from your

body to your heart are the superior vena cava and the inferior vena cava.

• The superior vena cava returns blood from your head and neck.

• The inferior vena cava returns blood from your abdomen and lower body.

Blood Vessels - Capillaries• Capillaries are microscopic blood

vessels that connect arteries and veins.

• The walls of capillaries are only one cell thick and is where oxygen is dropped off and carbon dioxide is picked up.

Blood Vessels

Blood Pressure• What causes blood pressure?

– Blood exerts a force against the walls of the blood vessels.

– The force is caused by contraction of the ventricles in the heart.

• Measuring Blood Pressure– Measured with a shygmomanometer.– The first number represents the contraction

of ventricles.– The second number represents the

relaxation of ventricles.