Circulatory System

Circulation

• In the United States of America, what do we use to transport goods?– Roads, railroad tracks, and airline routes.

• Our body has a transportation system too which we call the circulatory system: where blood moves through our body.

Circulatory system• It is made of your heart, blood vessels, and

blood.• Blood vessels carries blood throughout the

body, which forms a closed circulatory system.• Closed circulatory system: is where blood

never leaves the blood vessels.

• What other organisms can you name that have a closed circulatory system?

Heart• Its like a double pump– Right side pumps blood

to the lungs– Left side pumps blood to

all other parts of the body

• Atrium (upper chambers): receive blood returning to the heart

• Ventricle (lower chambers): pump blood out of the heart

Heart Valves• Each valve in the heart is a thin, strong flap of

tissue that acts like a one-way door– Tricuspid: valve between the right atrium and right

ventricle– Bicuspid: valve between the left atrium and the left

ventricle– Semilunar valves: are found between the ventricles

and the blood vessels

• What is the job of the valves?– The valves open and close at different times to

prevent blood from flowing backward

Heart Valves

Heartbeat• What causes the sound of your heartbeat?– It is caused by the opening and closing of the

valves in the heart.

Blood Vessels

• 3 types of blood vessels:1. Arteries2. Veins3. Capillaries

Arteries• They are blood vessels that carries blood away from the heart.

• They are thick muscular walls that are strong and elastic.

• Each time the heat beats, blood is pushed through the heart under high pressure.– Therefore their strong elastic

walls allows them to stretch preventing the arteries from bursting

Veins• They are blood vessels that carry blood to the

heart.• They are less muscular and their pressure exerted

on veins are less than that of arteries.

Capillaries• They connect the smallest arteries and veins

together.• Microscopic blood vessels that are only 1 cell

thick.

Circulatory System Problems• 1 of the leading causes of death in the US.

1. High blood pressure• Caused by the narrowing of the arteries• Hardening of the arteries• Cholesterol (fatty substance) build up

2. Heart attack• Caused from narrow artery blockage• If the heart doesn’t get enough blood it begins to die

Circulation• Pulmonary Circulation: pathway of blood

between the heart and the lungs

Circulation cont.• Systemic Circulation: pathway of blood

between the heat and the rest of the body.

Blood• Functions:– Transportation of materials– Regulate body temperature– Maintain chemical balance– Protection against diseases

Parts of the blood

1. Plasma2. Red blood cells3. White blood cells4. Platelets

Plasma

• It is the liquid part of the blood, which is made up of 90% water.

• It carries dissolved vitamins, minerals, digested nutrients, wastes, and different kinds of proteins.

Red Blood Cells• Blood gets its color from 25 trillion red blood

cells.• Their job is to carry oxygen, which is done so

by a molecule called hemoglobin that is found on every red blood cell.

• Correction!!!!!!!!!!!– Blood without oxygen is dark red, but never blue.

White Blood Cells• They are cells that defend your body against

diseases.• You have only 1 white blood cell for every

1000 red blood cell• Phagocytes (white blood cells) surround

bacteria and digest them.• So why do we get pus when we get a cut?– Shows that our body is fighting the infection– Made up of dead white blood cells, bacteria, and

tiny pieces of dead tissue.

White Blood Cells

Platelets• They are the part of the blood that controls

clotting.• Clotting: prevention of blood loss• Platelets sick together at the site of a cut and

basically form a plug.

Blood Groups• Did you know that not every person’s blood is

the same?• Four blood types:

1. A2. B3. AB4. O

Blood Disorders• Anemia: is a disorder where blood can not carry

normal amounts of O2 to body cells.

• Leukemia: cancer of the blood, where the body produces millions of abnormal immature white blood cells.

Lymphatic System