Download Anatomy Directional Terms

The Human Body: An orientation
I. An Overview of Anatomy and Physiology
A. Anatomy- study of the structure and shape of the body parts and
its relationships to one another
1. Gross Anatomy
a. Large easily observable structures visible to the naked
eye such as the heart, lungs, and kidney.
b. Examples include:
Surface Anatomy- internal structures as they
relate to the overlying skin surface. For example,
identifying muscles and a nurse finding a blood
vessel to draw blood from.
2. Microscopic Anatomy
a. Very small structures that can only be viewed with a
microscope
b. Examples include:
Cytology- study of cells
Histology- study of tissues
Bone Tissue
Skeletal Muscle Tissue
The Human Body: An orientation
B. Physiology- Study of how the body and its parts function to carry out
their life sustaining activities.
1. Physiology is best explained when the underlying chemistry,
physics and anatomy are understood.
2. Topics are specific for the system:
Renal Physiology, Cardiovascular physiology
C. Relationship between anatomy and physiology
1. The structures (anatomy) determine what functions
(physiology) take place. This principle is the core concept in
helping you understand the systems of the body we will be
learning throughout the year.
2. Example: Nerve cells are long and thin (structure) in order
to conduct messages (function) quickly throughout the body
The Human Body: An orientation
II. Levels of Structural Organization
A. Chemical Level
1. Atoms combine to form molecules such as water,
proteins, or sugar.
B. Cells
1. Molecules combine to form cells
2. Cells are the smallest units of all living things
3. Cells vary widely in size and shape, reflecting their
unique function in the body.
C. Tissues
1. Groups of similar cells that have a common function
2. Four basic types of tissue include:
a. Epithelium- lining, covering and glandular
tissue (skin)
b. Connective- supports and connects body parts,
most abundant tissue in body (ligaments,
tendons)
c. Muscle- movement (muscle tissue)
d. Nervous- internal communication (neurons)
The Human Body: An orientation
D. Organs
1. Composed of at least two tissue types which work together
E. Organism
1. The sum total of all structural levels working in unison
The Human Body: An orientation
III. Maintaining Life
A. Necessary Life functions
1. Maintaining boundaries
a. “inside” remains distinct from “outside”
b. Example: -cells have the plasma
membrane that separates the inside of the cell
from the outside
-Body uses the integument (skin)
2. Movement
a. all activities promoted by muscular system
b. Locomotion (movement)
c. Movement of substances through the internal
organs
3. Responsiveness
a. the ability to sense and respond to changes in
the environment
b. involves nervous system
The Human Body: An orientation
4. Digestion
a. breakdown and delivery of nutrients to
the body
5. Metabolism- all chemical reactions within the
body
a. Includes breaking down substances,
producing energy through cellular
respiration, and building molecules to
make body structures.
b. Metabolism depends on the digestive
and respiratory systems to distribute
needed substances throughout the body.
6. Excretion
a. elimination of waste from metabolic
reactions
b. Involves several systems including
digestive, urinary, and the respiratory
system.
The Human Body: An orientation
7. Reproduction
a. production of offspring (requires sperm and egg)
b. cellular reproduction (mitosis) - produces
identical cells for growth or repair
8. Growth
a. increasing of cell size and number
B. Survival Needs
1. Nutrients (food)
a. chemicals used for energy and cell building
b. includes carbohydrates (fuel for body cells),
proteins (building material of the body), lipids
(insulation and energy), vitamins and minerals
(required for chemical reactions and oxygen
transport in the blood)
2. Oxygen
a. required for chemical reactions (cellular
respiration) that release energy from food
C6H12O6 + 6O2 -------------------> 6CO2 + 6H2O + ~38 ATP
The Human Body: An orientation
3. Water
a. makes up 60-80% of our body weight
b. provides fluid base for secretions and excretions
c. provides watery environment necessary for
metabolic reaction
4. Body Temperature
a. must be maintained around 98°F
-if body temperature is too high, proteins break
down and chemical reactions do not take place
5. Atmospheric Pressure
a. exchange of gases (carbon dioxide and oxygen) in
lungs depends on atmospheric pressure. At high
altitudes the atmospheric pressure is lower and the
air is thinner making gas exchange more difficult.
The Human Body: An orientation
IV. Homeostasis
"Homeostasis: How stuff works"
A. Maintenance of a stable internal environment = a
dynamic state of equilibrium
1. Homeostasis must be maintained for normal
body functioning
2. Imbalance of homeostasis results in disease
a. as we age our body becomes less
efficient and is less stable thus increasing
our risk for illnesses
B. Homeostatic control
1. A stimulus (stress) that disrupts homeostasis
creates a feedback response. The nervous and
endocrine systems are the chief systems in
communicating and maintaining homeostasis within
the body.
The Human Body: An orientation
2. Three components of a feedback system
a. Receptor- sensor that monitors and responds to
changes in the environment (sends message to control
center)
b. Control Center- (usually spinal cord, brain or endocrine
organ) receives information from the receptor and
sends orders to the effectors organs
i. determines set point (normal levels)
ii. analyzes information
iii. determines appropriate response
c. Effector- body structure which receives the message
from control center and produces a change or response
Click to enlarge
Click to enlarge
Engineered Room Control
Feedback Loop
Human Body
Thermoregulation
Room Temperature
Variable
The characteristic that is
controlled
Body temperature
Thermometer
Sensor
Detects the value of the
variable
Nerve receptors
Thermostat
Integrator
Compares the actual value of
the variable to a predetermined setpoint value
Brain
(hypothalamus)
Furnace
Effector
Instrument that has an effect
on (changes) the variable
Muscles (shivering
The Human Body: An orientation
C. Feedback Mechanisms
1. Negative feedback- “The output reverses the input.”
a. includes most homeostatic control systems
b. shuts off the original stimulus, or reduces its intensity
c. works like a household thermostat
d. Here’s a common example: Let’s say you decide to
down four Krispy Kreme doughnuts. Soon after, your
body begins to break down the doughnuts and sugars
flood into the blood stream; your blood sugar levels
spike upward disrupting homeostasis. The rising
glucose levels stimulate the insulin producing cells of
the pancreas to release insulin into the blood. Insulin
stimulates the cells of your body to take up glucose. As
the cells take glucose out of the blood, glucose levels
begin to drop and signal the pancreas to stop producing
insulin. Blood glucose levels are now back to their set
point.
The Human Body: An orientation
2. Positive Feedback- “The output reinforces the input.”
a. increases the original stimulus to push the variable
farther, the change that proceeds occurs in the same
direction as the initial disturbance.
b. In the body this occurs in blood clotting as the
injury continues to stimulate the buildup of platelets
until clotting occurs. Another example is childbirth, as
the contractions cause the baby to move into the birth
canal the response causes more contractions to occur
until the baby is born.
The Human Body: An orientation
V. The Language of Anatomy
A. Special terminology used to prevent
misunderstanding where exact terms are
used for; position, direction, regions
and structures
1. Examples: Directional termssuperior means toward the head
end
Regional Terms- brachial refers
to the arm
B. Anatomical position- body is erect with
feet parallel and arms hanging at the
sides with the palms facing forward.
The Human Body: An orientation
C. Body Planes and Sections
1. Sagittal- cut made along the lengthwise, or longitudinal,
dividing the body into right and left parts
2. Frontal – cut made along a lengthwise plane that divides
the body into anterior and posterior parts
3. Transverse- cut made along a horizontal plane that
divides the body or organ into superior and inferior parts
The Human Body: An orientation
D. Body Cavities
1. Dorsal Body Cavity includes:
a. Cranial cavity- space encased by the skull
b. Spinal cavity- runs within the vertebral column
2. Ventral Body Cavity includes:
a. Thoracic Cavity- includes lungs, heart, and is
protected by the rib cage (ends at diaphragm)
b. Abdominopelvic Cavity- stomach, liver, intestines.
This cavity can be broken into six distinctive regions:
i. Umbilical region
ii. Epigastric region
iii. Hypogastric region
iv. Right and Left Iliac regions
v. Right and Left Lumbar regions
vi. Right and Left Hypochondriac regions.
d. Pelvic Cavity- includes reproductive organs, bladder
and rectum
Anatomy Directional Terms
Term
Definition
Example
Superior
(cranial)
Toward the head end or
upper part of a structure
of the body; above
The belly button is superior
to the knees.
Inferior
(caudal)
Away from the head end or
toward the lower part of a
structure of the body;
below
The nose is inferior to the
forehead.
Anterior
(ventral)
Toward or at the front of
the body; in front of
The breastbone is anterior
to the spine.
Posterior
(dorsal)
Toward or at the back of
the body; behind
The spinal cord is posterior
to the esophagus.
Anatomy Directional Terms
Medial
Toward or at the mid-line
of the body;
on the inner side of
The heart is medial to the
arm.
Intermediate
Structure located between
more medial and lateral
structures.
The collarbone is
intermediate to the
breastbone and shoulder.
Lateral
Away from the mid-line of
body; on the outer side of
The ribs are lateral to the
breastbone.
Proximal
Nearest the trunk, or
closest to attachment of a
limb to the body.
The knee is proximal to the
foot.
Distal
Farther from the origin of
the body (trunk) or point of
attachment of a limb to the
body trunk.
The wrist is distal to the
elbow.
Superficial
Toward or at the body
surface
The skin is superficial to the
skeletal muscles.
Deep
Away from the body
surface; more internal
The lungs are deep to the
skin.
Regional Term Review
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