the human body: an orientation i. an overview of anatomy and physiology a. anatomy- study of the...

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


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


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)


D. Organs1. Composed of at least two tissue types which work

togetherE. Organism

1. The sum total of all structural levels working in unison


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


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.


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


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.


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


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.


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.


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.


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

http://www.wisc-online.com/objects/index_tj.asp?objid=AP15405

the human body: an orientation i. an overview of anatomy and physiology a. anatomy- study of the...

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