Download - St. William the Abbot School

Notes Chapter 16 – The Circulatory System
The cardiovascular system carries needed substances to cells
and carries waste products away from cells. Blood also
contains cells that fight disease.
The heart is a muscular organ that pumps blood through blood
vessels of the cardiovascular system.
The heart is about the size of your fist. It works over and over
again without getting tired like other muscles do.
The right and left side of the heart is separated by a tissue
called the septum.
The heart has 4 chambers, 2 upper and 2 lower.
Chambers of the heart
>Right atrium- blood enters the heart here
>Left atrium
>Right ventricle
>Left ventricle
Blood moves through valves between the atria and the
ventricles. The valves make sure that blood only flows in one
direction.
Blood flows in a 2 loop system. In the first loop, blood travels
from the heart to the lungs and then back to the heart. In the
second loop, blood is pumped from the heart throughout the
body and then returns again to the heart.
Blood entering the right atrium has little oxygen and a lot of
carbon dioxide. It is dark red in color. This blood travels into
the right ventricle and then goes to the lungs by way of the
pulmonary artery.
The blood travels to the lungs where it receives oxygen and
becomes bright red in color.
The blood travels back to the heart by way of the pulmonary
vein and enters the left atrium. It passes to the left ventricle
and then to the largest artery, the AORTA. The blood is rich in
oxygen and goes to all parts of the body.
Then the cycle begins again!
Blood Vessels
Artery-carries blood AWAY from the heart
Veins- carry blood to the heart
Capillaries- small vessels where materials are exchanged
between blood and body’s cells
Your pulse measures your heartbeat. The average pulse is 7080 beats per minute at rest.
The coronary artery carries blood to the heart and is located on
the outside of the heart.
Blood pressure is measured with a machine called a
sphygmomanometer. This is the cuff that the doctor places on
your arm and pumps up with air.
Parts of the blood
Red blood cells-made mostly of hemoglobin, an iron containing
protein
White blood cells- fight infections
Platelets- helps the blood to clot
Plasma- the liquid part of blood
There are 4 blood types
A, B, AB, and O
Diseases of the Heart
Heart Attack- the muscle is damaged, blood flow is blocked
Hypertension- high blood pressure
Atherosclerosis- is a hardening of the arteries wall, usually due
to cholesterol, a wax-like substance that clogs the arteries.
BE SURE YOU KNOW THE DIAGRAMS ON PAGES 536 AND 546
IN YOUR TEXT BOOK