Download Lesson 1: Circulatory System

Chapter 3: Lesson 1
Circulatory System
I. Circulatory System (Also known
as the transportation system)
A. It brings food and oxygen to body
cells and removes cells’ wastes
B. It includes 3 parts
1. Heart
2. Blood
3. Blood vessels
C. Blood
1. Made up of 4 parts
a. Plasma- straw colored; carries food to your
cells from digestive system
b. Red blood cells- carry oxygen to your body’s
cells
c. White blood cells- work hard to protect
body from germs and other harmful things.
d. Platelets- cause blood clots to form to stop
cuts from bleeding.
D. Types of Blood Vessels
1. Arteries
a. carry blood away from your heart to other
parts of your body.
b. branch out into smaller tubes to carry blood
with lots of oxygen
2. Capillaries
a. smallest kind of blood vessel
b. some can be so narrow, the cells move through
in a single file line
3. Vein
a. carry blood back to the heart
b. have valves (flaps) that open and close to let
blood flow in one direction
Cycle of the Circulatory System
1. Blood with CO2 enters the right atrium
through a vein.
2. Blood with CO2 continues to the right
ventricle
3. The valve between the right atrium and right
ventricle closes.
4. Blood (CO2) is pumped through an artery to
the lungs
5. Blood with oxygen (from the lungs) enters the
left atrium through a vein.
6. Blood with O2 travels from the left atrium to
the left ventricle.
7. The valve closes between the left atrium and
the left ventricle.
8. Blood with O2 is pumped out the aorta to the
rest of the body.
9. The cycle repeats from Step 1-8.