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 Anatomy
– the study of the
structure of body parts and their
relationships to one another
 Physiology
– the study of the
function of the body’s parts
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Physiology (function) is only explainable in
terms of the underlying anatomy (structure)
Anatomy & Physiology are inseparable
because function always reflects structure
Examples:
◦ Heart is able to pump blood (function) because it is
a thick, muscular organ with hollow tubes to
transport
◦ Bones provide support and structure (function)
because they contain hard mineral deposits
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Gross or Macroscopic – studies large body structures
seen with the naked eye (i.e. heart, lungs, kidneys)
◦ Systemic – gross anatomy of the body studied by system (ex.
Organs of cardiovascular system)
◦ Regional- gross anatomy of the body studied by region of
the body (ex. Organs located in abdomen)
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Microscopic- studies structures of the body too small
to be seen with the naked eyes
◦ Cytology – study of the cells
◦ Histology- study of tissues
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Developmental – studies changes in the body over
the course of a lifetime
◦ Embryology- changes in an individual from conception to
birth
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Chemical – atoms  molecules 
macromolecules  organelles
Cellular – cells are smallest unit of life
Tissues – groups of cells with similar functions
(epithelial, connective, muscle, nerve)
Organ – made up of different types of tissues
that work together to perform a specific
function
Organ system – consists of different organs
that work closely together
Organism – total of all structures working
together
Smooth muscle cell
Molecules
2 Cellular level
Cells are made up of
molecules.
Atoms
1 Chemical level
Atoms combine to
form molecules.
3 Tissue level
Tissues consist of
similar types of cells.
Smooth
muscle
tissue
Heart
Cardiovascular
system
Blood
vessels
Epithelial
tissue
Smooth
muscle
tissue
Connective
tissue
4 Organ level
Organs are made up
of different types
of tissues.
Blood
vessel
(organ)
6 Organismal level
The human organism
is made up of many
organ systems.
5 Organ system level
Organ systems consist of
different organs that
work together closely.
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Need to know basic structures and function for:
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Integumentary
Skeletal
Muscular
Lymphatic/Immune
Respiratory
Digestive
Nervous
Endocrine
Cardiovascular
Urinary
Reproductive
1.
Maintaining boundaries – the internal
environment remains distinct from the
external environment
◦ Cellular level – accomplished by plasma
membranes; selective permeability
◦ Organismal level – accomplished by the skin (i.e.
the integumentary system)
2.
Movement
 Locomotion (i.e. running, swimming) with help of
muscular and skeletal systems
 Propulsion of food, blood, urine (peristalsis)
 contractility – shortening of muscle cells
3.
Responsiveness – ability to sense changes in
the environment and respond to them
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4.
5.
Digestion – breakdown of ingested food to
absorb nutrients
Metabolism – all the chemical reactions that
occur in the body
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6.
Controlled by nervous system
Reflexes (ex. Pull hand away from hot stove, cut foot
on broken glass and pull back)
Catabolism- breaking down substances into simpler
building blocks
Anabolism- building more complex structures from
simpler substances
Excretion – removal of wastes from the body
7.
Reproduction
◦ Cellular – an original cell divides and
produces two identical daughter cells
(mitosis)
◦ Organismal – sperm and egg unite to
make a whole new person (reproductive
system)
8.
Growth – increase in size of a body
part or of the organism
 Increase # of cells
1.
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5.
Nutrients – needed for energy and cell
building (food: carbs, proteins, lipids)
Oxygen – necessary for metabolic reactions
(releases energy from food in cell respiration)
Water – provides the necessary environment
for chemical reactions
Normal body temperature – necessary for
chemical reactions to occur at life-sustaining
rates (37 Celsius; 98.6 Fahrenheit)
Atmospheric pressure – required for proper
breathing and gas exchange in the lungs
KEY CONCEPT: All survival needs must be
present to maintain life BUT must be in
appropriate amounts…excesses and deficits
may be harmful
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Homeostasis – ability to maintain a relatively
stable internal environment in an everchanging outside world
◦ Does not mean “unchanging” or “static” but rather a
“dynamic state of equilibrium”, or balance, where
conditions may vary but within narrow stable limits
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Variables-factor or event being regulated in
the body
The three interdependent components of
control mechanisms respond to changes in
variables:
◦ Receptor – monitors the environment and responds
to changes (stimuli) in it; DETECTS CHANGE
◦ Control center – receives input from receptor,
determines the set point at which the variable is
maintained; and determines appropriate response
◦ Effector – receives directions from control center
and provides the means to respond to stimuli
3
Input:
Information
sent along
afferent
pathway to
Control
center
Receptor (sensor)
4 Output:
Information sent
along efferent
pathway to
Effector
2 Change
detected
by receptor
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Stimulus:
Produces
change
in variable
Variable (in homeostasis)
Response of
effector feeds
back to
influence
magnitude of
stimulus and
returns variable
to homeostasis
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Negative Feedback= depresses or shuts off the
original stimulus
◦ Causes the variable to change in the opposite direction of the
original change
◦ Return to norm or “ideal” value
◦ Most homeostatic control mechanisms are negative feedback to
prevent sudden, severe changes in body
◦ Examples: regulation of body temperature & heart rate
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Positive Feedback= enhances the original stimulus
so the activity is amplified (waterfall effect)
◦ Causes the variable to change in the same direction as the
original disturbance
◦ Usually control infrequent events such as labor contractions or
blood clotting
Set
point
Control center
(thermostat)
Signal
wire turns
heater off
Receptor-sensor
(thermometer in
Thermostat)
Heater
off
Effector
(heater)
Response;
temperature
drops
Stimulus:
rising room
temperature
Balance
Response;
temperature
rises
Stimulus:
dropping room
temperature
Heater
on
Set
point
Effector
(heater)
Receptor-sensor
(thermometer in
Thermostat)
Signal
wire turns
heater on
Control center
(thermostat)
NEGATIVE FEEDBACK
POSITIVE FEEDBACK
Disturbance of homeostasis or the
body’s normal equilibrium
 Overwhelms the usual negative
feedback mechanisms allows
destructive positive feedback
mechanisms to take over
 Often results in disease
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◦ Pathology: study of disease conditions
that occur
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Special terminology is used to prevent
misunderstanding when discussing the body
Exact terms are used for:
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Position
Direction
Regions
Structures
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Provides standard frame
of reference when using
directional terms to
describe the body
Body erect, feet slightly
apart, palms facing
forward, thumbs point
away from body
“standing at attention”
but with palms forward
and hands out
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Allow us to explain where one body structure
is in relationship to another
Superior (Cranial)– toward the head
Inferior (Caudal) – away from the head
Anterior (Ventral) – toward the front of the body
Posterior (Dorsal) – toward the back of the body
Medial – toward the midline
Lateral–away from the midline
**Right and left refer to
those sides of the person
being viewed…NOT
those of the observer
SUPERIOR
SUPERIOR
The mouth is
INFERIOR to the
eyes
INFERIOR
INFERIOR
The forehead
is SUPERIOR
to the nose
The heart is
POSTERIOR
to the
sternum
The sternum is
ANTERIOR to
the spine
The heart is
MEDIAL to the
arm
MEDIALLATERAL
The arms are
LATERAL to
the chest
LATERALMEDIAL
Proximal – closer to the trunk of the
body
 Distal – farther from the trunk of the
body
 Superficial (External) – toward the
body surface
 Deep (Internal) – away from the body
surface
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The elbow is
PROXIMAL to the
wrist
The knee is
DISTAL to
the thigh
The skin is
SUPERFICIAL to
the skeletal
The lungs
are DEEP to
the skin
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Regions
◦ Axial – includes the head, neck,
and trunk
◦ Appendicular – consists of
appendages or limbs, which
attach to the body’s axis
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Sagittal – vertical plane that divides the body into
right and left parts
◦ Midsagittal or medial – sagittal plane that lies on the
midline
◦ Parasagittal- offset/parallel to the midline
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Frontal or coronal – vertical plane that divides the
body into anterior (front) and posterior (back) parts
Transverse or horizontal (cross section) –
horizontal plane that divides the body into superior
and inferior parts
Oblique section – cuts made diagonally
◦ (seldom used)
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Body Cavities are spaces closed to exterior of
body within the body that contain organs, or
viscera
2 Main Sets:
◦ Dorsal cavity- protects the nervous system; 2
subdivisions
 Cranial cavity – within the skull; encases the brain
 Vertebral/Spinal cavity – runs within the vertebral
column; encases the spinal cord
 Cranial and spinal cavity are continuous with one
another; posterior to ventral cavity
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Ventral cavity is located anterior to the dorsal
cavity
Ventral Cavity- Contains the internal organs
(viscera); 2 subdivisions
◦ Thoracic
 superior to the abdominopelvic cavity
 Contains lungs (pleural cavity), heart (pericardial cavity), and
mediastinum (trachea + esophagus)
 Surrounded by ribs and muscles of the chest
◦ Abdominopelvic – Most vulnerable because there are no
bones to protect the organs here
 Separated from thoracic by diaphragm
 Contains abdominal cavity (stomach, intestines, spleen, liver)
and pelvic cavity (bladder, rectum, some reproductive
organs)
Cranial cavity
(contains brain)
Thoracic
cavity
(contains
heart
and lungs)
Dorsal
body
cavity
Diaphragm
Vertebral cavity
(contains spinal
cord)
Abdominal cavity
(contains digestive
viscera)
Key:
Pelvic cavity
(contains bladder,
reproductive organs,
and rectum)
Dorsal body cavity
Ventral body cavity
(a) Lateral view
Key:
Cranial
cavity
Dorsal body cavity
Ventral body cavity
Vertebral
cavity
Thoracic
cavity
(contains
heart
and lungs)
Superior
mediastinum
Pleural
cavity
Pericardial
cavity within
the mediastinum
Diaphragm
Abdominal cavity
(contains digestive
viscera)
Abdominopelvic
cavity
Ventral
body cavity
(thoracic
and
abdominopelvic
cavities)
Pelvic cavity
(contains bladder,
reproductive organs,
and rectum)
(b) Anterior view
Figure 1.9b
Parietal serosa -lines internal body cavity walls;
folds over on itself to form visceral serosa
 Visceral serosa- covers the internal organs;
wraps each individual organ
 Serous fluid -separates the 2 layers of serosa
(parietal and visceral); allows organs to slide
without friction
Function:
- Provide protection to organs
- Reduce friction between organs and cavity walls
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Figure 1.10a
Figure 1.10b
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Oral and digestive – mouth and cavities of the
digestive organs
Nasal –located within and posterior to the nose
Orbital – house the eyes
Middle ear – contains bones (ossicles) that transmit
sound vibrations
Synovial – joint cavities
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The nine abdominopelvic regions include:
Right hypochondriac region
Epigastric region
Left hypochondriac region
Right lumbar region
Umbilical region
Left lumbar region
Right iliac region
Hypogastric region
Left iliac region
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X-ray: directs short wavelength
electromagnetic waves at the body
◦ Dense structures appear light (absorb x-ray), while
hollow organs and fat appear dark (absorb less)
 Used for bones and tumors
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CT (computed tomography): uses x-rays;
produces cross-sectional images of the body
◦ Used for brain and abdomen
◦ CAT scan type of CT
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PET (positron emission tomography): used to
observe metabolic processes
◦ A form of nuclear medicine; patient is given an
injection of radioisotopes
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Sonography (ultrasound): uses sound waves
to create an image of body organs
◦ Imaging of choice in obstetrics
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MRI (magnetic resonance imaging): used to
image soft tissue structures
◦ Uses a huge magnet; distinguishes the water
content of body tissues