1. 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
Cytology- study of cells
Histology- study of tissues
Bone Tissue
Skeletal Muscle Tissue

2. 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

3. 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)

4. 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

5. 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

6. 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.

7. 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 + 6O > 6CO2 + 6H2O + ~38 ATP

8. 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.

9. 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.

10. 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

11. Engineered Room Control
                                             
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
Integrator Compares 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

12. 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.

13. 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.

14. 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 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.

15. 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

16. 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

18. Anatomy Directional Terms
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.

19. 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.

20. 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