FIRST AID AND EMERGENCY
CARE
LECTURE 3
ANATOMY AND PHYSIOLOGY
Respiratory System
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UNDERSTANDING VITAL BODY FUNCTIONS
FOR FIRST AID
In order for the service member to learn to
perform first aid procedures, he must have a
basic understanding of what the vital body
functions are and what the result will be if they
are damaged or not functioning.
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1.
2.
3.
4.
THE RESPIRATORY SYSTEM
COMPONENTS OF THE RESPIRATORY
SYSTEM
The Airway
The neuromuscular system
The Alveoli
The vascular system, arteries, capillaries &
veins
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The Airway
Upper airway: Consists of Nose and mouth,
Pharynx, Larynx
Lower airway: Consists of Trachea, Bronchi
(right and left), Bronchioles
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The Neuromuscular System
Respiratory centre in the brain
Nerves
Muscles of respiration, These are:
1. Diaphragm
2. Intercostal muscles
3. Some muscles in the neck and shoulder
girdle
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Chest cage, protect the lungs and the heart. It
surrounded by the spine at the back, the
sternum in front, and the ribs around
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The Alveoli
They are minute air sacs, millions in number.
They are made of a very delicate thin membrane
of one cell layer forming a fine network. The
capillaries are on the outer side of the alveoli
where exchange of gases takes place.
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Pulmonary Vessels
They are arteries that carry dark-colored blood
with low oxygen levels from the heart to the fine
network of capillaries where Oxygen (O2) is
picked-up by the blood and Carbon Dioxide
(CO2) is expelled out of the alveoli. The
oxygenated blood is then carried out to the left
side of the heart by the veins to be distributed to
the various body organs and tissues.
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All artery carry oxygenated blood except
pulmonary artery
All vein carry deoxygenated blood except
pulmonary vein
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PHYSIOLOGY OF RESPIRATION
The function of the respiratory system is to pickup oxygen from the air and expels carbon
dioxide into the air.
Metabolism is a continuous process which
needs oxygen to function and as a result of this
process, carbon dioxide is produced.
The Cardiovascular system transports oxygen
from the lungs to the cells and transports carbon
dioxide from the cells to the lungs for elimination.
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The Breathing Process
All humans must have oxygen to live.
Through the breathing process, the lungs draw
oxygen from the air and put it into the blood.
The heart pumps the blood through the body to
be used by the cells that require a constant
supply of oxygen. Some cells are more
dependent on a constant supply of oxygen than
others. For example, cells of the brain may die
within 4 to 6 minutes without oxygen. Once
these cells die, they are lost forever since they
do not regenerate. This could result in
permanent brain damage, paralysis, or death.
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The breathing mechanism is controlled and
influenced by the respiratory centre in the brain
and primarily the rate and depth of breathing is
stimulated by carbon dioxide in the arterial
blood.
As the level rises, the respiratory centre sends a
continuous parade of signals via the nerves to
respiratory muscles.
This will result in an increasing rate and depth of
breathing until the level of carbon dioxide falls,
then the breathing rate and depth are returned
to normal.
This is known as feedback mechanism between
carbon dioxide level and the rate and depth of
breathing.
Gas
Inspired Air
Expired
O2
21%
16%
CO2
0.03%
4%
N2
79%
79%
Humidity
Less
More
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During respiration, 5% of oxygen passes from
atmospheric air into the blood through alveolar
and capillary walls and 4% of carbon dioxide is
eliminated from the blood into the expired air.
Inspiration is an active process while expiration
is a passive process.
Respiration
Respiration occurs when a person inhales
(oxygen is taken into the body) and then exhales
(carbon dioxide [CO2] is expelled from the
body).
THE CARDIOVASCULAR SYSTEM
The Cardiovascular System composed of:
1. The Heart
2. The blood vessels (Arteries, Capillaries, Veins)
THE HEART
 Fist-sized organ situated in the center of the
chest between the sternum and the spine and
above the diaphragm
 It is surrounded by the lungs except in small
area in front of the heart known as the bare area
and the area against the spine
 It has a hollow tough muscular wall surrounded
by the pericardium
 It is divided into right and left sides and each
side has two chambers (right atrium and right
ventricle, and left atrium and left ventricle)
THE VASCULAR SYSTEM
 The cardiovascular system composed of:
 Arteries: Thick-walled, carrying blood from the
heart under high pressure.
 Capillaries: Thin network of one cell layer.
 Veins: Thin-walled vessels that carry blood
under low pressure back to the heart.
PHYSIOLOGY OF THE HEART
 Heart pumps blood from the right ventricle into
the pulmonary artery to the lungs to purify the
blood and from the left ventricle into the aorta to
distribute blood to the rest of the body.
 Arteries carry blood away from the heart
 Veins carry blood back to the heart
 Exchange of gases takes place in the capillary
system throughout the body.
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FUNCTIONS OF THE CARDIOVASCULAR
SYSTEM
To purify the blood through the pulmonary
capillary system
To provide oxygenated blood and nutrient to all
tissues, through the systemic capillary system.
The heart beats 60-80 beats/minute during rest
The amount of blood pumped by a single beat
and known as the stroke volume is ~70ml.
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The heart pumps ~5 liters/minute
Cardiac output is equal to stroke volume
multiplied by heart beats/min. That is to say
70x70=4900 (5 liters/min).
The heart can beat faster, up to 180-200
beats/min during exercise, so it is capable of
pumping up to 35 liters per minute.
BLOOD SUPPLY TO THE MYOCARDIUM
 Two coronary arteries, right and left, originate
from the first part of the aorta.
 They are divided into several branches which
encircles the heart to supply the myocardium.
 The coronary arteries are end arteries. There is
no venous coronary artery.
Heart Beats at Rest
Heart beat/minute = 70x1 = 7
Heart beat/hour
= 70x60 = 4,200
Heart beat/day
= 4200x24 = 100,800
Heart beat/year
= 100,800x365 = 6,792,00
Volume pumped/min
= 5lit
Volume pumped/hour = 5x60 = 300 lit
Volume pumped/day = 300x24 = 7200 li
Volume pumped/year = 7200x365 lit =
2,628,000lit