the human body: an orientation i. an overview of anatomy and physiology a. anatomy- study of the...
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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 another1. 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 Anatomya. Very small structures that can only be viewed with
a microscope b. Examples include:
Cytology- study of cellsHistology- study of tissues
Skeletal Muscle TissueBone 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 physiology1. 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 OrganizationA. 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 things3. 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. Organs1. Composed of at least two tissue types which work
togetherE. Organism
1. The sum total of all structural levels working in unison
The Human Body: An orientation
III. Maintaining LifeA. 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. Movementa. all activities promoted by muscular systemb. Locomotion (movement)c. Movement of substances through the
internal organs3. Responsiveness
a. the ability to sense and respond to changes in the environment
b. involves nervous system
The Human Body: An orientation
4. Digestiona. breakdown and delivery of nutrients
to the body5. 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 reactionsb. Involves several systems including digestive, urinary, and the respiratory system.
The Human Body: An orientation
7. Reproductiona. production of offspring (requires sperm and
egg)b. cellular reproduction (mitosis) - produces
identical cells for growth or repair8. Growth
a. increasing of cell size and numberB. Survival Needs
1. Nutrients (food)a. chemicals used for energy and cell buildingb. 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. Oxygena. required for chemical reactions (cellular
respiration) that release energy from food
C6H12O6 + 6O2 -------------------> 6CO2 + 6H2O + ~38 ATP
The Human Body: An orientation
3. Watera. makes up 60-80% of our body weightb. provides fluid base for secretions and
excretionsc. provides watery environment necessary for
metabolic reaction4. 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 Pressurea. 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 functioning2. Imbalance of homeostasis results in disease
a. as we age our body becomes less efficient and is less stable thus
increasing our risk for illnessesB. 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 orientation2. 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 informationiii. 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
Thermoregula-tion
Room Temperature Variable
The characteristic that is controlled
Body temperature
Thermometer Sensor
Detects the value of the variable
Nerve receptors
Thermostat
IntegratorCompares the actual value of
the variable to a pre-determined setpoint value
Brain (hypothalamus)
Furnace Effector
Instrument that has an effect on (changes) the variable
Muscles (shivering
The Human Body: An orientation
C. Feedback Mechanisms1. Negative feedback- “The output reverses the input.”
a. includes most homeostatic control systemsb. shuts off the original stimulus, or reduces its
intensityc. works like a household thermostatd. 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 AnatomyA. Special terminology used to
prevent misunderstanding where exact terms are used for; position, direction,
regions and structures1. Examples: Directional
terms- superior 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 Sections1. Sagittal- cut made along the lengthwise, or
longitudinal, dividing the body into right and left parts2. Frontal – cut made along a lengthwise plane that
divides the body into anterior and posterior parts3. Transverse- cut made along a horizontal plane that divides the body or organ into superior and inferior
parts
The Human Body: An orientationD. Body Cavities
1. Dorsal Body Cavity includes:a. Cranial cavity- space encased by the skullb. 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 regionii. Epigastric regioniii. Hypogastric regioniv. Right and Left Iliac regionsv. Right and Left Lumbar regionsvi. Right and Left Hypochondriac regions.
d. Pelvic Cavity- includes reproductive organs, bladder and rectum
Anatomy Directional Terms
TermTerm DefinitionDefinition ExampleExample
Superior Superior (cranial)(cranial)
Toward the head end or Toward the head end or upper part of a structure upper part of a structure
of the body; aboveof the body; above
The belly button is The belly button is superior to the knees.superior to the knees.
InferiorInferior(caudal)(caudal)
Away from the head end Away from the head end or toward the lower part or toward the lower part
of a structure of the of a structure of the body; belowbody; below
The nose is inferior to the The nose is inferior to the forehead.forehead.
AnteriorAnterior(ventral)(ventral)
Toward or at the front of Toward or at the front of the body; in front ofthe body; in front of
The breastbone is anterior The breastbone is anterior to the spine.to the spine.
PosteriorPosterior(dorsal)(dorsal)
Toward or at the back of Toward or at the back of the body; behindthe body; behind
The spinal cord is The spinal cord is posterior to the posterior to the
esophagus.esophagus.
Anatomy Directional Terms
MedialMedial Toward or at the mid-line Toward or at the mid-line of the body; of the body;
on the inner side ofon the inner side of
The heart is medial to the The heart is medial to the arm.arm.
IntermediateIntermediate Structure located Structure located between more medial between more medial and lateral structures.and lateral structures.
The collarbone is The collarbone is intermediate to the intermediate to the
breastbone and shoulder.breastbone and shoulder.
LateralLateral Away from the mid-line of Away from the mid-line of body; on the outer side ofbody; on the outer side of
The ribs are lateral to the The ribs are lateral to the breastbone.breastbone.
ProximalProximal Nearest the trunk, or Nearest the trunk, or closest to attachment of closest to attachment of
a limb to the body.a limb to the body.
The knee is proximal to The knee is proximal to the foot.the foot.
DistalDistal Farther from the origin of Farther from the origin of the body (trunk) or point the body (trunk) or point of attachment of a limb of attachment of a limb
to the body trunk.to the body trunk.
The wrist is distal to the The wrist is distal to the elbow.elbow.
SuperficialSuperficial Toward or at the body Toward or at the body surfacesurface
The skin is superficial to The skin is superficial to the skeletal muscles.the skeletal muscles.
DeepDeep Away from the body Away from the body surface; more internalsurface; more internal
The lungs are deep to the The lungs are deep to the skin.skin.
Regional Term Review
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