The Heart
Structure of the Heart
Two parallel
independent systems
Two different “pumps”
Each @ atrium
(auricle) & ventricle
Designating right
cavity & left cavity
as if you were “wearing”
your heart
Heart Valve
replacement
Function of the Cavities
Right cavity takes in
oxygen poor blood
from the body
Pumps it to the lungs
Left cavity takes
oxygen rich blood from
the lungs
Returns it to the body
Functions of the Cavities
Atrium draws
blood in
from veins
Ventricle
pushes blood
away through
arteries
Differences Between the
Cavities
Right cavity takes in oxygen poor blood
from the body & sends it to the lungs
Left cavity takes oxygen rich blood from
the lungs and sends it to the body
through the aorta. Its wall is thicker
because it has to pump the blood
throughout the body
How the Heart Works
There are two stages in the heart beat
cycle
The diastole (relaxation)
The systole (contraction)
Diastole
In diastole the heart
relaxes and blood
goes into the two
auricles
Rising pressure in
each auricles opens
the tricuspid and
mitral valves and
blood flows into
the ventricles
Systole
Filled ventricles
contract and the mitral
and tricuspid valves
close
The filled ventricles
force the aorta and
pulmonary valves to
open
Blood is then pushed
into the arteries
Rate of Heartbeat
The heart is a muscle is a unique muscle.
It has the ability to contract
spontaneously at a regular rate of 80
beats per minute
That is what creates the pulse
Rate of Heartbeat
However this rate is influenced by two
nervous systems:
Sympathetic
Parasympathetic
Sympathetic
This controls your heart by fear, and
adrenaline.
For example when you get scared your
heart intends to beat faster.
Your heart is also affected by exercise
which is another aspect of the
sympathetic nervous system
Parasympathetic
This nervous system controls your heart
rate when you sleep
Your heartbeat is much slower when you
sleep then when you are awake because
of the function of this system
Heart Disease
The major form of heart disease is
atherosclerosis
In this condition fatty deposits called
plaques, composed of cholesterol and
fats, build up on the inner wall of the
coronary arteries
Heart Disease
Gradual narrowing of the arteries
throughout life restricts the blood flow to
the heart muscles.
Symptoms of this restricted blood flow
can include:
shortness of breathe
and a tightening pain in the chest
Heart Disease
A heart attack is caused when oxygen
supply to the heart is suddenly decreased
by:
plaque large enough to completely obstruct
the coronary artery
when part of the plaque breaks away and
lodges farther along the artery
How to Prevent Heart
Disease
Development of fatty plaque is due to
excessive intake of cholesterol and animal
fat and especially cigarette smoking
Evidence suggest that physical exercise
may help to prevent heart disease and
watching what you eat