OBJECTIVE
Without reference, identify at least four out
of six principles about anatomy and
physiology as they relate to general medical
equipment.

Circulatory System
 Functions
 Respiration
Oxygenated blood is delivered from the
lungs to the body
Carbon dioxide enriched blood is carried
from the body to the lungs
 Nutrition - erythrocytes carry food
absorbed from the intestines to the tissue
cells
• Protection
Leukocytes fight infection
Thrombocytes aid in the clotting process
to stop bleeding
• Excretion - waste products are removed
from the cells and carried to kidneys for
filtration and removal
• Regulation
Temperature - the circulation of
blood in the body acts similar to
the circulation of anti-freeze in a
combustion engine
Hormone distribution
 Two main divisions
• Pulmonary - refers to the
respiratory functions of the
circulatory system (oxygenation and
de-oxygenation of blood)
• Systemic - refers to the distribution
of nutrients throughout the body
 Heart – a four chambered muscular pump
about the size of a fist that lies tilted to the
right in the chest with the apex (pointed
end) resting on the top diaphragm and the
base (broad end) on the top
 The pericardium is a sac like structure
surrounding the heart that contains a fluid
which cushions and lubricates the heart
 The right atrium is the chamber that
collects de-oxygenated blood from the
body
 The right ventricle is the pumping
chamber that sends de-oxygenated blood
to the lungs for oxygenation
 The left atrium is the chamber use for
collecting oxygenated blood from the
lungs
 The left ventricle is the pumping chamber
that sends oxygenated blood to the body
 Layers of the Heart
The outer layer is the epicardium
The middle layer which is comprised of
muscle tissue is the myocardium
The inner layer lining the camber walls is
the endocardium.
 The sinoatrial node is the impulse
generating (pacemaker) tissue located in
the right atrium
 The atrioventricular node conducts the
normal electrical impulse from the atria to
the ventricles, located between the atria
and ventricles
 The bundle of hiss is the small band of
specialized cardiac muscle fibers that
maintain the normal sequence of the
heartbeat by conducting energy from the
right atrium to the ventricles
 Purkinje fibers – conducts the pacemaker
stimulus along the inside walls of the
ventricles to all parts of the heart
 Myocardial cell activity
 Polarization
Heart cells are charged (polarized)
negatively in the resting state
» Negatively charged interior
» Positively charged surface
No physical response, only electrical
activity
 Depolarization
When electrically stimulated, the heart
cells become positively charged
(depolarized)
The physical response of the cells to
depolarization is contraction of the heart
 Repolarization
Following contraction, the electrical
realigning of the heart cells to their
polarized state
Returns to resting state
 Electrical activity of the heart cells
 Produces approximately -90 mv of
electricity in the resting state (polarized)
 +20 to +40 mv of electricity when fully
depolarized
 Passes through the heart and is picked up
by external skin electrodes and recorded
as an electrocardiogram
 Blood vessels
• Arteries - thick walled, elastic vessels
which carry blood away FROM the heart
 Arterioles - small branches of arteries
which control blood flow by constriction
and dilation
• Capillaries - smallest blood vessels with
walls only one cell thick. All exchanges
of food and oxygen occur here
• Veins - large, thin walled, nonmuscular vessels which carry blood
back to the heart. Veins also contain
valve to prevent back flow
 Venules - small beginning branches of
veins
 Blood
• Cellular portion makes up about 45% of the
blood volume
Red blood cells (RBC) - carry oxygen
White blood cells (WBC) - fight infection
Platelets - aid in coagulation
• Liquid (plasma) portion makes up about
55% of the blood volume
Acts as a support for the cellular
portion of the blood
Contains dissolved nutrients and
chemicals
 Major arteries
 Pulmonary - connects the right ventricle
with the lungs
 Aorta - carries blood from the left
ventricle to the body
 Coronary (right and left) - first branch
from the aorta, supplies the heart muscle
with blood
 Femoral - supplies the legs
 Brachial - supplies the arms
 Carotid - supplies the head
Coronary Artery
 Major veins
 Superior vena cava - returns blood from
the head, arms and upper chest
 Inferior vena cava - returns blood from the
legs, abdomen and lower chest
 Most veins have the same name as their
corresponding artery
Vein Viewer – uses infrared
and projector to view veins in
real time

Respiratory system
 Terms
 External respiration is the exchange of
gases between an organism and its
environment
 Diffusion is the gaseous exchange of air in
the alveoli of the lungs with the blood
 Internal respiration is the exchange of air
in the capillaries with body cells
 Structures of the respiratory system
• Nasal cavity
Warms and moistens the air entering the
body
Lined with cilia to remove dust and
foreign particles (aided by mucous)
• The Pharynx is the pathway for breathing
as well as a muscular tube for the passage
of food
• The larynx is known as the organ of sound
(voice box)
 Trachea (windpipe)
 A rigid tube constructed of
cartilaginous rings
Lined with cilia to acts as a filter
Runs anterior to the esophagus from the
larynx to where it branches
 Bronchial tree
Bronchi – a branching set of tubes from
the trachea which leads to the lungs
Bronchioles – smaller branches of
bronchi which conduct air into the lungs
 Alveoli
Small sac like structures at the end of the
bronchioles
Alveoli sacs are surrounded by capillaries
Separation between the sacs and capillaries
is very thin
Oxygen and carbon dioxide readily diffuse
between air and the blood in the capillaries
This is the only place gas exchange takes
place in the body
 Lungs
The primary organ for respiration
Consists of two cone shaped organs
Divided into lobes – the right lung has
three lobes and the left lung has two
lobes
The pleura is the membrane which
surrounds the lungs
» Each lung has its own pleura
» Filled with pleura fluid to reduce
friction
 Muscles of respiration
The diaphragm is a dome shaped
muscle which forms the floor of the
thoracic cavity
» The main muscle of respiration
» Contraction causes inspiration by
moving down and enlarging the cavity
Intercostal muscles are located between
the ribs; contraction causes inspiration
 Phases of respiration
Inspiration
» Fresh air is taken into the lungs
» Oxygen diffuses in the blood and
carbon dioxide diffuses into the air
Expiration – air is expelled