2.2
THE CIRCULATORY SYSTEM
Circulatory System Functions:
-transports gases between
the lungs and the cells
-delivers nutrients to all cells
in the body and removes
waste products
Anatomy of the Heart
Superior
Inferior
The Pump - The Heart
-drives the circulatory
system.
-pumps blood to the cells
and back to the heart.
The Blood Vessels of the Circulatory system
-The main vessels: arteries and veins
-The vessels closest to the cells are tiny, and are called capillaries.
Blood Vessels: Arteries
Arteries
-are thick-walled,
-elastic
-carry oxygen-rich blood away
from the heart to all body cells
-When the heart squeezes, a
high pressure environment is
created in the vessels and
pushes blood through them
Atherosclerosis
-Narrowing and hardening of the arteries
due to build up of plaque (cholesterol)
-Causes high blood pressure
-stroke or heart attack can result if arteries
become completely blocked
Blood Vessels: Veins
Veins
-are thin-walled
-inelastic
-valves keep blood from
flowing backward as it is
carried toward the heart
-when the heart squeezes, the
valves open and close when
the heart relaxes
Blood Vessels: Capillaries
Capillaries
-the smallest vessels in the body
-site of oxygen and carbon dioxide exchange between the blood and
cells
-they connect arteries and veins
Blood flow through the Heart
1.The superior and inferior Vena
Cava fills the Right Atrium with
Carbon Dioxide rich blood
2.The AV valve opens
3. Right Ventricle fills with the
Carbon dioxide rich blood
The carbon dioxide rich blood
gets pushed through the
pulmonary arteries back to the
lungs for gas exchange
1.The pulmonary vein delivers
oxygen rich blood to the left
atrium
2.The AV valve opens
3.Left ventricle fills with Oxygen
rich blood that gets pushed
through the aorta to all parts of
the body
4.Exchange of gases/nutrients/
waste occurs at the capillaries
Heart Sounds
“LUB DUB”
LUB is the closing of the AV valves
DUB is the closing of the Semi Lunar Valves
LISTEN to your heart: http://www.fi.edu/learn/heart/monitor/heartbeat.html
Blood Components
•
An adult body holds
approximately 5 L of blood, 3L
is plasma, the remaining 2L is
made up of hematocrit (RBC,
WBC, Platlets)
Components:
1.
Red Blood Cells (RBC) – carry
oxygen/carbon dioxide around
the body
2.
White Blood Cells (WBC) –
needed for immune defence
3.
Platlets – needed for repair
4.
Plasma – fluid portion of the
blood
Homework
1. What causes your heart sounds?
2. A murmur is a conditions in which your heart valves do
not close properly. How would this affect your heart
sounds?
3. What is the difference between an artery and a vein?
4. A) what is the name of the major artery in the body?
5. B) what is the name of the major vein in the body?
6. What is the role of capillaries?
7. What allows red blood cells to carry oxygen?
8. Using the diagram provided on a handout, begin with
blood entering the heart at the pulmonary vein and
create a flowchart that shows the pathway blood takes
through the heart.