Download The Human Body

The Human Body
What you need to know as a First
Aid Responder.
Why do I need to know this?
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To adequately assess a
victim’s condition and to
give effective first aid, a
first aider must be
familiar with the anatomy
and physiology of the
human body.
This knowledge provides
a solid cornerstone for
building the essentials of
quality victim assessment
and emergency first aid.
Which systems are most lifethreatening?
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Respiratory
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Circulatory
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Nervous
Other systems often affected:
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Skeletal system
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Muscular system
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Integumentary
system (Skin)
The Human Body
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The body can store food for several
weeks.
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The body store water to last several days.
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The body can only store enough oxygen
to last a few minutes. (4-6 minutes)
What can cut off the oxygen
supply?

Drowning
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Choking
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Smothering
The Respiratory System
Oxygen from air is made available to the
blood.
 Air enters the body through inhalation via
the nose or mouth.
 The nose provides a filtering of the air as
it enters the body.
 After passing through the nasal passages,
air enters the nasal portion of the pharynx
(throat).
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Respiratory System cont.
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From the back of the nose or the mouth, air
enters the throat or pharynx.
Pharynx – common passageway for food and air
Air then enters the trachea (windpipe)
From the trachea, air enters the bronchi into the
lungs.
The upper two inches of the trachea, just below
the epiglottis, is the larynx (voice box).
The larynx can be felt as the Adam’s Apple on
the front of the throat.
Lungs
The trachea branches into two main tubes
(bronchial tubes or bronchi) – one for
each lung.
 Each bronchus divides and subdivides
somewhat like branches of a tree –
bronchioles.
 At the end of each bronchiole is a tiny air
sac called alveoli enclosed in a network of
capillaries.

Lungs (cont.)
In the alveoli of the lungs, oxygen
combines with hemoglobin in red blood
cells to form oxyhemoglobin which is
carried to all parts of the body.
 Carbon dioxide and certain other waste
gases in the blood move across the
capillary walls into the air sacs and are
exhaled from the body.
 The lungs occupy most of the chest cavity.
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Mechanics of Breathing
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The passage of air into and out of the lungs is
respiration.
Inhalation is breathing in.
Exhalation is breathing out.
When the diaphragm contracts, the chest
expands drawing air into the lungs.
An exchange of oxygen and carbon dioxide
takes place.
When the diaphragm expands, it exerts pressure
on the lungs, causing air to flow out.
Respiratory Structures
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Respiratory structures in
infants and children are
smaller and more easily
obstructed than those of
adults.
The trachea is more
flexible.
Primary cause of cardiac
arrest in infants and
children is an uncorrected
respiratory problem.
Respiratory Rates

Adults
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Children
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Infants
12 - 20 breaths per minute
15 – 30 breaths per minute
25 – 50 breaths per minute
Signs of Inadequate Breathing
Rate of breath outside
normal ranges
 Cool or clammy skin
 Pale or cyanotic
(blue-gray) color
 Nasal flaring
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Increased Breathing Rate
Can occur with
increased exertion –
hard muscular work
 Carbon dioxide
increases in blood and
oxygen needs to be
taken in – increases
heart rate and
respiration.
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The Circulatory System
Made up of the blood, heart, and blood
vessels (arteries, veins, capillaries)
 Carries nutrients and other products from
the digestive tract in its plasma, and
oxygen from the lungs in its hemoglobin.
 Transports wastes produced by the cells
to the lungs, kidneys, and other excretory
organs for removal from the body.
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Heart
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Contracts and relaxes to pump blood through
the vessels to the body.
A powerful, hollow, muscular organ
The size of a man’s clenched fist
Shaped like a pear
Located in the left center of the chest, behind
the sternum.
Divided into two chambers, atria (upper) and
ventricles (lower)
The Heart
Check valves are
located between each
atrium and its
corresponding
ventricle
 Opening and shutting
of these valves at just
the right time in the
heartbeat keeps the
blood from backing
up.
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The Heart
At each beat (contraction) the heart
pumps blood rich in carbon dioxide and
low in oxygen from the right ventricle to
the lungs and returns oxygen-rich blood to
the left atrium of the heart.
 The left ventricle pushes blood rich in
oxygen freshly obtained to the rest of the
body and returns oxygen-poor blood to
the right atrium.
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The Heart
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At each relaxation of
the heart, blood flows
into the left atrium
from the lungs and
into the right atrium
from the rest of the
body.
Blood Vessels
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Arteries – elastic, muscular tubes that
carry blood away from the heart.
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Veins –thin tubes that carry blood to the
heart.
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Capillaries – fine vessels that connect
arteries and veins – key to gas exchange.
Normal Heart Rates
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Adults -
60 to 100 beats per minute
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Children - 80 to 100 beats per minute
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Toddlers - 100 to 120 beats per minute
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Infants - 120 to 140 beats per minute
Major locations for Pulse
Carotid - neck
 Femoral - thigh
 Radial - wrist
 Brachial – upper arm
 Posterior tibial - ankle
 Dorsalis pedis – top of foot
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Blood Pressure
A measure of the
pressure exerted by
the blood on the walls
of the flexible
arteries.
 Low blood pressure –
hypotension
 High blood pressure hypertension
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Blood
Plasma – liquid portion of blood, 90%
water, carries food materials to body cells,
carries waste materials of cells to organs
to be released
 Red blood cells – gives blood color, carries
oxygen to the organs
 White blood cells – body’s defense, fight
infection
 Platelets – blood clotting
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Blood (cont.)
A hemorrhage is profuse bleeding.
 Perfusion is circulation of blood through
an organ or structure.
 Hypoperfusion is the inadequate
circulation of blood through an organ or
structure.
 The average adult male has about six
quarts (12 pints) of blood.
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Shock
Also known as hypoperfusion – a state of
profound depression of the vital processes
of the body
 Symptoms: pale, cyanotic (bluish),
clammy, cool skin, rapid pulse, rapid
breathing, restlessness, anxiety, mental
dullness, nausea, vomiting, reduction in
total blood volume, low or decreasing
blood pressure, subnormal temperature
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Nervous System
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Complex collection of neurons (nerve
cells) that coordinate the work of all parts
of the body and keep the individual in
touch with the outside world.
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Neurons receive stimuli from the
environment and transmit impulses to
nerve centers in the brain and spinal cord.
The Nervous System
Once nerve cells have been destroyed, the
body cannot regenerate them.
 Some limited nerve repair is possible,
however, as long as the vital cell body is
intact.
 If a nerve fiber is cut or injured, the
section attached to the cell body remains
alive, but the part beyond the injury
withers away.
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The Nervous System
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Branches of the nervous system include:
* central nervous system
* peripheral nervous system
* autonomic nervous system
The CNS
Consists of the brain and spinal cord.
 Serves as the controlling organ of the
body.
 The brain enables us to think, judge, and
act.
 The spinal cord is a major communication
pathway between the brain and the rest of
the body.
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The Brain
The most highly
specialized organ in
the body.
 Weighs about three
pounds on average.
 Richly supplied with
blood vessels.
 Requires considerable
oxygen to perform
effectively.
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The Brain
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Has three main subdivisions:
*cerebrum – 75% of cranial cavity
*cerebellum – small brain
*medulla oblongata - brain stem
The Brain
Cerebrum is divided into two hemispheres
and is known as the “gray matter” .
 Cerebrum controls sensation, thought,
association memory.
 At back of the cerebrum – in the occipital
lobe – is the sight center of the brain.
 The temporal lobes deal with smell and
hearing.
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The Brain
The cerebellum’s main function is to
coordinate muscular function.
 The medulla oblongata controls
involuntary functions of the body.
 CSF – cerebrospinal fluid is a clear, watery
solution similar to blood plasma. It
circulates throughout the brain and spinal
cord serving as a protective cushion and
exchanges food and waste materials.
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The Brain
The total quantity of CSF in the brainspinal cord system is 100 to 150 ml, with
several liters produced daily.
 CSF is constantly being produced and
reabsorbed.
 Brain damage usually coordinates with the
opposite side of the body being affected.
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Spinal Cord
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A soft column of nerve
tissue continuous with
the lower part of the
brain that is enclosed in
the bony vertebral
column.
Thirty-one pairs of spinal
nerves branch from the
spinal cord.
Damage to the cord is
almost always
irreversible.
Spinal Cord
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Damage to the
lumbar spine causes
paralysis and loss of
sensation in the legs
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Damage to the
cervical cord causes
paralysis and loss of
sensation in the arms
as well as the legs.
Peripheral Nervous System
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Consists of the sensory
and motor nerves.
The sensory nerves carry
sensations, such as smell,
touch, heat, and sound
from the body to the
brain and spinal cord.
The motor nerves carry
information from the
brain and spinal cord to
the body.
Autonomic Nervous System
Consists of a group of nerves that control
heart rate, digestion, sweating, and other
automatic body processes.
 If a nerve is cut or seriously damaged,
disrupting the connection between the
brain and the body, the body part will not
be able to work. This loss can be
permanent.
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Nervous System
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Fortunately, the CNS
is well protected
against injury.
* bony structures
* meninges
* cerebrospinal
fluid