The Cardiovascular SystemWarm-up:

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Why the Blood Circulates• Your heart pumps blood to your body’s cells 24 hours

a day, even when you’re asleep.• Your heart accomplishes the following important

tasks:• Carries oxygen from the lungs to body cells.• Absorbs nutrients from food and delivers nutrients to

body cells.• Carries carbon dioxide, a waste gas, from your cells back

to your lungs to be exhaled.• Delivers other waste products to the kidneys for removal

from the body.• Helping the white blood cells fight disease by attacking

infectious organisms.

The Cardiovascular System• The cardiovascular system consists of the heart, blood, and

blood vessels.

• How far do you think your blood vessels would stretch, if laid out end to end?• 60,000 miles

• That’s enough to circle the earth two and a half times.

How Blood Circulation Works• The HeartThe Heart• It is the muscle that makes the cardiovascular system work.• The heart has four chambers:• The two top chambers are called atria.• The two lower chambers are called ventricles.

• Valves between the atria and ventricles allow blood to flow through the chambers.

• At the top of the right atrium is an area of muscle that acts as a pacemaker for the heart called the sinoatrial node.

• Electrical impulses stimulate the atria to contract, forcing blood into the ventricles.

• These electrical impulses travel through the heart to an area between the two ventricles, to stimulate them to contract, pumping blood out of the heart.

How Blood Circulates Cont.• Pulmonary circulation:Pulmonary circulation:• Process by which blood moves between the heart and

the lungs.

• During this process:

• #1 - blood that has lost oxygen travels back from the body picking up carbon dioxide and wastes;

• #2 – This blood then travels back through the right side of the heart;

• #3 - The heart then pumps the blood to the lungs;

Pulmonary circulation cont.

• #4 - In the lungs the carbon dioxide is dumped off and the blood is reloaded with fresh oxygen.

• #5 – The freshly reloaded blood travels back to the left side of the heart;

• #6 - The heart then pumps fresh oxygenated blood out to the rest of the body.

• http://youtu.be/oZ1_TAwCUWw

Blood Components

• It is the fluid that delivers oxygen, hormones, and nutrients to the cells and carries away wastes.

• Blood is made up of:• PlasmaPlasma – the fluid in

which other parts of the blood are suspended. • 55% of blood volume• Mainly water, but it

also contains nutrients, proteins, salts, and hormones.

• Red Blood CellsRed Blood Cells

• Make up 40% of normal blood.

• Contain hemoglobin – the oxygen-carrying protein in blood.

• Hemoglobin contains iron that binds with oxygen in the lungs and releases the oxygen in the tissues.

• Hemoglobin also combines with carbon dioxide.

Blood Components Continued• White Blood Cells White Blood Cells • Protect the body against infection.• Some white blood cells surround and ingest the

organism causing disease.• Others form antibodies that provide immunity against a second

attack from that specific disease.• Other types fight allergic reactions.

• PlateletsPlatelets• Types of cells in the blood that cause

blood clots to form.• When the wall of a blood vessel tears,

platelets collect at the tear. • They release chemicals that produce small thread-like fibers

that trap nearby cells and help form a clot.• The clot blocks the flow of blood and dries to form a scab.

Blood Vessels• Carry blood throughout the body.

• There are three main types of blood vessels:• ArteriesArteries – blood vessels that carry oxygenated blood

away from the heart.

• Arteries branch into progressively smaller vessels arterioles.

• Arterioles deliver blood to the capillaries.

• CapilCapillarieslaries – small vessels that carry blood from arterioles and to small vessels called venules, which empty into veins.

• Form a vast network throughout tissues and organs in the body.

Blood Vessels• VeinsVeins – blood vessels that return blood to the heart.

• Walls are thinner and less elastic than the arteries.

• Many veins have valves that help prevent the back flow of blood that is pumped back to the heart.

• When surrounding muscles contract they help exert pressure on the vein walls, helping to move blood against gravity to the heart.

• http://youtu.be/CjNKbL_-cwA

Maintaining Your Circulatory System• Many cardiovascular system problems appear later in life.

However you can reduce your risk of this problems later in life by making healthy decisions throughout your life.

• Some helpful behaviors that should become regular habits for a healthy heart:• Eat a well-balanced diet

• Maintain a healthy weight for your body type

• Participate in regular aerobic exercise for at least 150 minutes a week.

• Avoid tobacco smoke and using tobacco products.

• Avoid illegal drug use

• Get regular medical check ups.

Blood Pressure• Blood pressureBlood pressure – a measure of the amount of force that the

blood places on the walls of blood vessels, particularly large arteries, as it is pumped through the body.• A blood pressure reading includes 2 numbers.

• The 1st measures your systolic pressure – the maximum pressure as your heart contracts to push blood into your arteries.

• The 2nd/bottom number measures your diastolic pressure – the pressure at its lowest point when your ventricles relax.

• What is considered a healthy blood pressure?

• 120/80 or below

• What is considered to be high and places strain on the heart?

• 140/90 and above• http://www.ehow.com/video_4398719_why-blood-pressure-

important.html

Cardiovascular System Problems• Some cardiovascular problems are inherited; others result from

illness, diet, or aging.

• Congenital heart defectsCongenital heart defects

• Conditions of the heart that are present at birth.

• Septal defect – whole in septum allowing oxygenated blood to mix with oxygen-depleted blood.

• AtherosclerosisAtherosclerosis

• Caused by the narrowing and stiffening of the arteries due to fatty deposits accumulating in their walls. Can lead to a heart attack.

• Heart murmursHeart murmurs

• Unusual sounds produced by turbulent blood flow may be do to a heart valve defect.

• Heart attackHeart attack

• Also known as a myocardial infarction.

• Occurs when an area of cardiac muscle is deprived of blood, and therefore oxygen, due to a blockage in an artery.

• The most common cause is iron deficiency.

• ThrombosisThrombosis

• The partial or total blockage of an artery, vein, or even the heart can occur when a clot (thrombus) forms due to a circulatory problem.

• Caused by fatty build up or inflammation of the blood vessel.

• LeukemiaLeukemia

• Form of cancer in which white blood cells are produced excessively and abnormally.

• Causes one to be susceptible to infection.

Heart Disease

• http://youtu.be/3cW8__wFXDA

• http://youtu.be/JtFV1EGI3B4

Assignment

•Blood Flow Diagram

DUE TOMORROW