Chapter 5
Anatomy, Physiology
and Pathophysiology
National EMS Education
Standard Competencies
Anatomy and Physiology
Integrates complex knowledge of the anatomy
and physiology of the airway, respiratory, and
circulatory systems to the practice of EMS
Pathophysiology
Applies comprehensive knowledge of the
pathophysiology of respiration and perfusion to
patient assessment and management
Introduction
• Anatomy refers to structure and components
of human body
– Gross anatomy: visible to naked eye
– Microscopic anatomy: visible through microscope
• Physiology examines body functions
• Pathophysiology studies body functions in an
abnormal state
Topographic Anatomy
• Planes and Lines
• Terms of Direction
• Terms of Movement
• Positions and Postures
The Integumentary System
(Skin): Anatomy
• Germinal layer of
epidermis produces
new skin cells
• Dermis contains sweat
glands, sebaceous
glands, hair follicles,
blood vessels,
specialized nerve
endings
• Mucous Membranes
The Integumentary System
(Skin): Physiology
• Functions
– Protect the body in the environment
– Regulate body temperature
– Transmit information from environment to brain
The Skeletal System: Anatomy
• Skeleton gives us our recognizable human
form, protects vital internal organs.
• Bones
• Tendons—connect muscles to bones
• Ligaments—connect bone to bone
• Cartilage—cushions between bones
– Lubricated by joint fluid (synovial fluid)
Overview of Bones (2 of 2)
Components of a long bone (humerus)
The Skeletal System:
Physiology
• Bones protect internal organs.
• Together with muscles, bones enable
movement.
• Bone stores minerals.
– Particularly calcium
• Bone plays role in forming blood cells and
platelets.
The Skeleton
• Axial
• Appendicular
• Joints
The Musculoskeletal System:
Anatomy
• Three types of
muscle:
– Cardiac
• Found only in the
heart
• Specially adapted
– Skeletal
– Smooth
• Involuntary
• In blood vessels,
intestines
The Musculoskeletal System:
Physiology
• Contraction and relaxation make movement
possible.
• A by-product of movement is heat.
• Muscles protect structures under them.
– For example, intestines are protected by rectus
abdominus muscles.
The Musculoskeletal System:
Anatomy (4 of 4)
The Respiratory System:
Anatomy
•
Nose
•
Mouth
•
Throat
•
Larynx
•
Trachea
•
Bronchi
•
Bronchioles
•
Lungs
•
Diaphragm
•
Muscles of chest wall
•
Accessory muscles of breathing
The Respiratory System:
Physiology
• Respiration
– Exchanges gases
• Ventilation
– Process of moving
air in and out of
lungs
• Breathing control
–
–
–
–
Medulla
Pons
Chemoreceptors
Carboxic drive
– Hypoxic drive
Acid-Base Regulation
• pH ranges from 0
(most acidic) to 14
(most basic).
• Normal pH of the
human body is 7.35
to 7.45.
• Buffer systems are
defenses against
acid-base changes
in the body.
Acid-Base Regulation
• Hydrogen ions combine with bicarbonate
ions to form carbonic acid
• Carbonic acid breaks down into carbon
dioxide and water
• As hydrogen ions are liberated in the body,
they combine with bicarbonate ions (action
of the buffer system) to resist pH changes in
blood
• H+ binds to HCO3- to form H2CO3
Acid-Base Regulation
• The body attempts to maintain a ratio of
HCO3:H2CO3 of 20:1
• As carbonic acid is manufactured by the
buffer system it breaks down into carbon
dioxide and water
• H2CO3 produces CO2 and H2O
Acid-Base Regulation
• The respiratory system is responsible for
maintaining appropriate levels of carbon
dioxide in blood
• As Carbon dioxide is generated,
chemoreceptors send messages to the
control centers of the brain
• Control centers respond by elevating the
respiratory rate
Acid-Base Regulation
• The kidneys are responsible for secreting
excess hydrogen ions or excess bicarbonate
ions in urine in order to maintain appropriate
acid-base balance
• If blood is acidic, the kidneys secrete
hydrogen ions
• If blood is alkaline, the kidneys secrete
bicarbonate ions
• Urine production is a relatively slow process
Acid-Base Abnormalities
• Metabolic
– Acidosis occurs when the body liberates more
hydrogen ions than the kidneys excrete
– Alkalosis occurs when the body absorbs more
bicarbonate than is eliminated by the kidneys
• Respiratory
– Acidosis occurs when the body fails to eliminate
carbon dioxide
– Alkalosis occurs when the body releases too
much carbon dioxide
Interpreting Blood Gases
• Acidosis = pH < 7.35
– Respiratory
• pCO2 > 45; If compensated, HCO3- > 26 mg/dl
– Metabolic
• HCO3- is < 22 mg/dl, pCO2 is normal
• Alkalosis = pH > 7.45
– Metabolic
• pCO2 < 35 and HCO3- is low
– Respiratory
• HCO3- > 26 mg/dl, pCO2 is normal
Ventilation (1 of 2)
• Tidal volume—air moved in a single breath
• Inspiratory reserve volume—deepest breath
you can take after normal breath
• Expiratory reserve volume—maximum
amount of air you can forcibly breathe out
after normal breath
Ventilation (2 of 2)
• Vital capacity—
amount of air
moved with
maximum
inspiration and
expiration
Characteristics of Normal
Breathing
• Normal rate and depth (tidal volume)
• Regular rhythm (pattern of inhalation and
exhalation)
• Good audible breath sounds on both sides of
chest
• Regular rise and fall movement on both
sides of chest
• Movement of abdomen
Compromised Breathing
Patterns in Adults
• Labored breathing
• Minute alveolar ventilation
< 4200 ml
• Muscle retractions
(clavicles, ribs)
• Pale or cyanotic (blue) skin
• Cool, damp (clammy) skin
• Tripod position
The Circulatory System:
Anatomy
• Heart
– Location
– Chambers, valves, accessory
structures
– Heartwall and Pericardium
• Blood vessels
– Types
– Circulatory pathways
• Blood
Heart Sounds
• Created by contraction and relaxation of
heart and flow of blood
• Heard during auscultation with stethoscope
• Normal heart sound: “lub-DUB”
• S1 and S2 are normal sounds, S3 and S4
are often not
– Also abnormal: murmurs, bruits, clicks, snaps
The Electrical Conduction
System
• Electrical stimulus controls
mechanical pumping action.
• Conduction system
components:
– Sinoatrial (SA) node
– Atrioventricular (AV) node
– Bundle of His
– Right and left bundle branches
– Purkinje fibers
Regulation of Heart Function
• Autonomic nervous system, endocrine
hormones, and heart tissue, control:
– Rate of contraction (chronotropic state)
– Rate of electrical conduction (dromotropic state)
– Strength of contraction (inotropic state)
• Baroreceptors respond to changes in
pressure.
• Chemoreceptors sense changes in chemical
composition of blood.
The Cardiac Cycle
• Process that creates the pumping of the
heart
– Systole
– Diastole
• Pulse pressure
• Afterload
• Stroke volume
• Cardiac output = stroke volume × heart rate
Blood Composition
• Plasma
• Red blood cells
– Hemoglobin
– Surface Antigens
• White blood cells (leukocytes)
– Fight infection
• Granulocytes (neutrophils, eosinophils, basophils)
• Agranulocytes (monocytes, lymphocytes)
• Platelets
The Circulatory System:
Physiology (1 of 2)
• Pulse is created by blood pumping out of left
ventricle into major arteries.
• Blood pressure is pressure blood exerts
against artery walls.
– Sphygmomanometer measures high/low points.
• Systemic vascular resistance is how dilated
or constricted the blood vessels are.
The Circulatory System:
Physiology
• Average adult has
about 5 L of blood
– Infants 300 mL,
children 2 to 3 L
• Central and
peripheral pulses
• BP = CO X SVR
The Lymphatic System
• Absorb fat from digestive tract, maintain fluid
balance, and fight infection
• Transports lymph
• Lymph nodes interspersed along course of
lymph vessels
• Lymph vessels absorb excess fluid and
return it to the central venous circulation
Cellular Transport Mechanisms
• Cell membrane is selectively permeable.
• Allows differences in concentrations inside
and outside cell
Cellular Transport Mechanisms
• Diffusion
– Movement of solutes from an area of high
concentration to an area of low concentration to
produce an even distribution of particles in the
space available
• Depends on:
– Permeability of membrane
– Concentration gradient
Cellular Transport Mechanisms
• Osmosis
– Movement of a solvent from an area of low
solute concentration to one of high concentration
• Osmotic pressure
• Facilitated diffusion
• Active transport
Body Fluid Balance
• Body fluid is
divided into:
– Intracellular fluid
(ICF)
– Extracellular fluid
• Intravascular fluid
(plasma)
• Interstitial fluid
• Fluid balance
maintains
homeostasis
• Regulated by
– Antidiuretic
hormone from
pituitary gland
– Thirst
• Fluid imbalance
can be lifethreatening
The Nervous System: Anatomy
and Physiology
• Components
• Central nervous system
• Peripheral nervous
system
The Central Nervous System
• Brain
• Spinal Cord
• Meninges
The Peripheral Nervous
System
• Divisions
– Somatic nervous system
– Autonomic nervous system has two parts:
• Sympathetic nervous system
• Parasympathetic nervous system
• Sensory and Motor Nerves
• Cranial and Spinal Nerves
The Endocrine System:
Anatomy and Physiology (1 of 2)
• Made up of glands located throughout body
• Glands
– Remove, concentrate, or alter materials from
blood
– Secrete them back into body
• Glands secrete proteins called hormones.
– Regulate mood, growth and development,
metabolism, sexual development, much else
The Endocrine System:
Anatomy and Physiology (2 of 2)
The Pituitary Gland and the
Hypothalamus
• Pituitary gland is called “master gland.”
– Its secretions control those of other endocrine
glands.
– Secretes growth hormone, thyroid-stimulating
hormone, adrenocorticotropin hormone,
gonadotropic hormones, ADH, oxytocin
• Hypothalamus is main link between
endocrine system and nervous system.
The Thyroid Gland
• Large gland at base of neck
• Manufactures and secretes hormones that
have role in growth, development,
metabolism
• Secretes calcitonin
– Helps maintain normal calcium levels in blood
• Parathyroid glands
– Located in thyroid
– Secrete parathyroid hormone
The Pancreas
• Organ of both the endocrine system and
digestive system
• Produces insulin and glucagon
• Insulin causes uptake and metabolism of
sugar, fatty acids, amino acids.
• Glucagon stimulates breakdown of glycogen
to glucose.
– Also stimulates liver and kidneys to produce
glucose
The Adrenal Glands
• Located on top of each
kidney
• Secrete:
– Sex hormones
– Hormones vital in maintaining
water and salt balance
– Adrenaline (mediates “fightof-flight” response)
– Epinephrine and
norepinephrine
The Reproductive Glands and
Hormones
• Gonads are
ovaries in women
and testes in men.
• Ovaries produce
estrogen and
progesterone.
• Major female
hormones
• Developing fetus
manufactures hCG
– Estrogen
– Progesterone
– Human chorionic
gonadotropin
(hCG)
• Testosterone is
produced by
testes.
– And to smaller
extent by adrenal
glands and ovaries
The Digestive System:
Anatomy
The Digestive System:
Physiology (1 of 2)
• In succession, different secretions (primarily
enzymes) are added to food by:
– Salivary glands
– Stomach
– Liver
– Pancreas
– Small intestine
The Digestive System:
Physiology
• Converts food into basic sugars, fatty acids,
amino acids
• These products cross wall of intestine and
travel through portal vein to liver
• Liver further processes and stores or
transports to heart
• Circulatory system then nourishes all cells
The Urinary System: Anatomy
and Physiology (1 of 2)
• Controls discharge of waste filtered from
blood by kidneys
• Functions
– Controls fluid balance in body
– Filters and eliminates wastes
– Controls pH balance
The Urinary System: Anatomy
and Physiology (2 of 2)
• Components
–
–
–
–
Kidneys
Ureters
Urinary bladder
Urethra
• This example
shows the male
urinary system.
The Genital System: Anatomy
and Physiology
• Controls reproductive processes by which
life is created
• Male genitalia lie outside pelvic cavity.
– Except for prostate gland and seminal vesicles
• Female genitalia lie inside pelvic cavity.
– Except for clitoris and labia
The Male Reproductive System
and Organs
• Testicles,
epididymis, vasa
deferentia, penis
• Functions
– Reproduction
– Production of
sex hormones
– Penis is also
part of urinary
system
The Female Reproductive
System and Organs
• Ovaries, fallopian tubes, uterus, cervix,
vagina
• Functions
– Reproduction
– Production of sex hormones
Life Support Chain (1 of 2)
• Body’s cells require:
– Oxygen
• Brought by respiratory and circulatory systems
– Nutrients
• Food broken down by digestive system into
glucose
• Brought by circulatory system
– Removal of wastes
• Removed by circulatory system
Life Support Chain (2 of 2)
• Aerobic metabolism uses oxygen.
– Only possibility for some cells (eg, heart, brain)
• Anaerobic metabolism does not use oxygen.
– Most cells can operate without oxygen for 1 to 3
minutes.
– Lactic acid is a by-product.
• Converted back to useful energy source once
oxygen becomes available
Pathophysiology (1 of 4)
• Study of functional changes that occur when
body reacts to disease
• Airway patency
– Can be impaired by blocked airway
– Muscles of breathing can be impaired.
– Decreased level of consciousness can impair
ventilation.
Pathophysiology (2 of 4)
• Respiratory compromise
–
–
–
–
Can be caused by decrease of oxygen in air
Fluid in alveoli can prevent gas exchange.
Cells will move to anaerobic metabolism.
Body can adapt to mild, gradual compromise.
– Severe or prolonged compromise can cause
death.
Pathophysiology (3 of 4)
• Shock
– Condition in which perfusion is inadequate to
organs and tissue
– Hypovolemic shock results from lack of blood
volume (as from trauma).
– Cardiogenic shock results from heart
inefficiencies.
– Distributive shock results from issues regarding
dilation and constriction of blood vessels.
Pathophysiology (4 of 4)
• Alteration of cellular metabolism
– In strenuous exercise, demand for glucose
exceeds supply.
– Body burns fats and turns them into glucose.
– This process is inefficient, but body can sustain
for a while.
– If there are breathing or perfusion problems,
however, process can cause damage or death.