Transcript File - CORE Charter FFA and Agriculture Program

Introduction to the Heart and
Circulatory System
Have a Heart!
Secretariat
How Big is the Heart?
• A human heart is about 10.5 ounces
• The average Thoroughbred horse heart weighs 9
pounds
– Secretariat: Could finish the quarter mile race
at speeds of 49 MPH
(Man O War only maxed out at about 40 MPH)
– Upon autopsy found that his heart weighed
about 22 pounds!
• Found to be a genetic factor carried on the X
chromosome of the mare
• Not a mutation because the heart was in
correct proportion
Functions of the Circulatory System
• Transports oxygen, nutrients, and other
essential compounds to all cells.
• Transports CO2 and other wastes away
from cells for elimination from the body.
• Helps maintain Homeostasis of body cells.
Three Main Parts
• Heart
• Blood Vessels
• Blood
Heart
• The Main Pump
• The heart is divided into 4 chambers that
are connected by valves
– Valves are flap-like structures that allow blood
to only flow in one direction
– The audible sounds heard in the heart (Lubdub) are actually the valves closing
• When a valve is not working properly the
sound will be different creating a “Murmer”
The Chambers of the Heart
• There are 4 chambers divided into “upper”
and “lower” chambers
• There are two hemispheres of the heart;
the right and left side, divided by the
septum
Atria
– Upper Chambers of the Heart
– Right Atrium:
• Receives blood from the vena
cava as it returns to the heart
– Left Atrium:
• Receives blood returning to the
heart from the pulmonary veins
Ventricles
• The lower chambers of the heart
• Right Ventricle:
• Receives blood from the right atrium
and pumps it to the pulmonary artery
• Left Ventricle:
• Receives blood from the left atrium
and pumps it to the aorta
The Heart
The Heart Diagram
• Using your heart
diagram, fill in
the missing
answers
Blood Flow through the Heart
• De-oxygenated
blood flows from
the vena cava into
the right atrium
• The right atrium
empties its
contents into the
right ventricle
Blood Flow Continued
• De-oxygenated
blood is pumped
into the pulmonary
artery
• The pulmonary
artery carries
blood to the lungs
where it picks up
oxygen
• The blood is
returned to the
left atrium by the
Flow of blood through the heart!
Un-oxygenated blood enters through the
vena cava
right atrium
through the
tricuspid valve into the right ventricle
through the pulmonary artery (away)
to the
lungs to get oxygen back through the
pulmonary vein
into the left atrium
through the mitral valve into the left
ventricle
out the aorta
Pericardium
• Fluid filled sac
around the heart
• Function
– Keeps the heart
in the chest
cavity
– Prevents the
heart from over
expanding
– Limits heart
motion
• Pericardial Membranes
– Fibrous
• Outer fibrous
sac
– Parietal
• Lies between
visceral and
fibrous
– Visceral
• Outer layer of
the wall of the
heart
Heart Wall
• Epicardium
– Outer layer of the wall of the heart
– Provides protection
• Myocardium
– Muscular middle layer of the heart
– Stimulates heart contractions to pump blood
from the ventricles and relaxes to allow the
atria to receive blood
• Endocardium
– Inner layer of the heart
– Participates in the contraction of the heart
Heart Health
• Oh My! Maybe I
should lay off of the
corn!
• Because swine and
humans are so
compatible, heart
valves are
commonly used
from pigs to repair
those in humans!
Are you Ready Doctor?
• http://www.pbs.org/wgbh/nova/eheart/transpl
antwave.html