Transcript The Circulatory System

The Circulatory System
A & P - Mr. Carlson
Major Structures of the
Circulatory System
•
•
•
•
•
•
Heart
Blood Vessels
Blood
Lymph Nodes
Lymph
Lymph Vessels
www.google.com
The Heart
• The heart is the central
organ of the
cardiovascular system.
• Beats more than 2.5
billion times in an
average lifespan.
• Lies within the thoracic
cavity, behind the
sternum, and between
the lungs.
www.google.com
Heart Parts
• The pericardium is a
tough sac-like membrane
that surrounds the heart
and functions to secrete a
fluid that reduces friction
as the heart beats.
• The septum vertically
divides the heart into two
sides.
• Right side pumps blood to
lungs.
• Left side pumps blood to
other parts of the body.
www.google.com
Heart Chambers
• The heart is divided
into upper & lower
chambers.
• Each upper chamber is
called an atrium.
• Each lower chamber is
called a ventricle.
• There are four total
chambers.
www.google.com
Heart Valves
• Atrioventricular valves
separate each atrium from
each ventricle.
• AV valves consist of flaps
of tissue that open in only
one direction.
• The AV valve on the right
is called the tricuspid
valve.
• The AV valve in the left is
called the mitral valve.
www.google.com
Heart Valves
• Semilunar valves separates
the ventricles from large
blood vessels on each side
of the heart.
• SL valves are also one-way
valves.
• The SL valve on the right is
known as the pulmonary
valve.
• The SL valve on the left is
known as the aortic valve.
www.google.com
Patterns of Circulation
• The heart and blood vessels from one continuous,
closed system of circulation.
• This system also consists of two primary
subsystems:
• Pulmonary Circulation – Blood travels between
heart and lungs.
• Systemic Circulation – Blood travels between the
heart and all other body tissues.
Circulation of Blood in the Heart
• Deoxygenated blood from the body returns via the
superior & inferior vena cava to the right atrium.
• The right atrium pumps blood through the tricuspid
valve to the right ventricle.
• The muscles of the right ventricle contract and force
the blood into the pulmonary arteries, which lead to
the lungs.
• In the lungs, carbon dioxide diffuses out and oxygen
diffuses into the blood.
Circulation of Blood in the Heart
• Oxygenated blood from the lungs returns via the
Pulmonary Veins to the left atrium.
• From the left atrium, blood passes through the
mitral valve into the left ventricle.
• Contraction of the muscular walls of the left
ventricle force the blood into a large blood vessel
called the aorta.
• From the aorta, blood is distributed to the rest of the
body except the lungs.
Whew!!!
Have you had enough yet?
I didn’t even include the SL
Valves in the last description!
Almost there!
Control of the Heartbeat
• The heart consists of muscle cells that contract in waves.
When the first group of muscle cells is stimulated it sets off a
chain reaction that travels across the heart.
• The sinoatrial (SA) node is a group of specialized heartmuscle cells located in the right atrium that is stimulated
first.
• The SA node is called the pacemaker because it regulates the
rate of contraction of the entire heart.
• The atrioventricular (AV) node is located in the septum
between the atria and relays the electrical impulse to the
muscle cells that are located in the ventricles.
Heart Disease
• The end result of untreated
heart disease is a heart
attack.
• Heart disease is one of the
leading causes of death in
the United States.
• Elevated cholesterol levels is
a major factor in creating
heart disease.
• The CDC estimates the
number of americans that
are overweight or obese is
currently at 61%.
www.google.com