D2: Circulation and Respiration

D2-1: THE Cardiovascular System

September 2-3, 2010

I. Your Cardiovascular System

•This system consists of a collection of organs that transport blood throughout the body.

•“Cardio”-heart•“Vascular”-blood vessel

I. Your Cardiovascular System• The blood vessels carry

blood pumped by the heart.

• Your main blood vessels include:

▫ Arteries▫ Capillaries▫ Veins

II. The Heart

•As we discussed in our previous chapter, our heart is mostly made up of cardiac muscle tissue.

•In humans, our heart is about the size of our fist.

•Your heart also consists of fours separate chambers known as atria and ventricles.

II. The Heart•Each atrium is a part of the upper

chamber of the heart.

•Each ventricle is a part of the lower chamber of the heart.

•The right side of your heart pumps oxygen-poor blood to the lungs.

•The left side of your heart pumps oxygen-rich blood to the rest of your body.

II. The Heart

•Flap-like structures called valves are located between the atria and the ventricles and well as in places where large arteries are attached to the heart.

•As blood flows through the heart these valves open and close to prevent blood from going backwards.

II. The Heart• Why does your heart go

“lub-dub,” lub-dub”?

• The sound of a beating heart is caused by the valves closing.

II. The Heart• Let’s go through the flow

of blood found in Figure 3 on p. 31.

III. Blood Vessels

•Blood vessels are hollow tube structures that blood travels through.

•Veins=De-oxygenized blood•Artery=Oxygenized blood

•Capillaries=Small blood vessels

A. Arteries• A blood vessel that carries

blood away from the heart to the body’s organs.

• Have thick walls, which contain a layer of smooth muscle.

• Blood pressure is caused by your heart pumping blood.

• Your pulse is the rhythmic change your blood pressure.

B. Capillaries• A tiny blood vessel that

allows an exchange between blood and cells in other tissue.

• Blood cells give up oxygen and nutrients as they pass through.

• Body cells give up wastes and carbon dioxide.

• Capillaries are so small that blood cells must pass through single file.

C. Veins• A blood vessel that carries

blood back to the heart.

• Skeletal and Smooth muscles both push blood towards the heart.

IV. Two Types of Circulation

•Pulmonary Circulation:▫The Flow of blood from the heart to the

lungs and back to the heart through the pulmonary arteries, capillaries, and veins.

•Systemic Circulation:▫The flow of blood from the heart to all parts

of the body and back to the heart.

IV. Two Types of Circulation

•Here is the order of blood circulation beginning in the Right Ventricle.1. Right ventricle pumps blood into the

pulmonary artery (Oxygen-poor blood).2. This blood passes through capillaries

found in the lungs to take in oxygen.3. This oxygen-rich blood passes through

the pulmonary vein and back into the heart.

4. Pulmonary Circulation complete!

IV. Two Types of Circulation5. The Left Ventricle then pumps oxygen-rich

blood into the aorta. 6. The pressure pushes blood throughout body

passing oxygen to all of the body’s cells.7. As it passes through the capillaries, wastes

and carbon dioxide are carried away from the cells.

8. Oxygen-poor blood passes back through the main veins and returns to the Right atria.

9. Systemic Circulation complete. 10.REPEAT!

V. Cardiovascular Problems• Cardiovascular problems can be cause by

several different things including:▫Smoking▫High levels of cholesterol in blood▫Stress▫Physical Inactivity▫Poor eating habits▫Heredity

• Exercise and a proper diet can reduce these problems.

V. Cardiovascular Problems• Atherosclerosis

▫ Results when cholesterol builds up inside blood vessels.

▫ Platelets can often stick together, which can also lead to blockages.

▫ This narrows the blood vessels and makes them less elastic.

▫ This continued blockage can eventually lead to a heart attack.

V. Cardiovascular Problems• High Blood Pressure

▫ Hypertension Abnormally high blood

pressure.▫ This can lead to:

Heart attack Heart failure Kidney disease Stroke

Blood vessel in the brain becomes blocked or ruptures.

V. Cardiovascular Problems• Heart Attack

▫ Occurs when heart muscle cells die and part of the heart muscle is damaged.

▫ May result from a blockage in an artery or vein.

▫ If the heart does not receive oxygen, hearts cells quickly die and may stop.

• Heart Failure▫ Occurs when the heart

cannot pump enough blood to meet the body’s needs.

▫ Vital organs, such as the brain, lungs, and kidneys, may get damaged by lack of oxygen or a build-up of waste materials.