Lesson Topic 1.1: Structural and Functional Organization of the Human Body Flashcards
Anatomy:
science that studies structure
Physiology:
science that studies body functions
Anatomy (structure) determines
physiology (functions)
4 basic types tissue:
epithelial
connective
muscular
nervous
Cellular:
cells containing organelles
Basic unit of life
Tissue:
groups of cells and surrounding material
Organ:
group of tissues performing a common function
System:
group of organs with a common function
Organism:
contains all systems of an individual
Homeostasis
Maintaining a stable internal environment
Homeostasis
Examples of variable factors
Body temperature
Blood pressure
Water and nutrient levels
Components of a Feedback System
Receptor: Recognizes the change and sends message = input (typically by nerve pathways) to:
Control Center: Evaluates input and sends output
Effector: Attempts to change the altered variable
(1) Receptor
A receptor is a body structure that monitors changes in a controlled condition and sends information called the input to a control center.
(2) Control Center
A control center in the body, for example, the brain, sets the range of values within which a controlled condition should be maintained, evaluates the input it receives from receptors, and generates output commands when they are needed.
(3) Effector
An effector is a body structure that receives output from the control center and produces a response that changes the controlled condition.
(a) Nearly every organ or tissue in the body can behave as an effector. For example, when your body temperature drops sharply, your brain (control center) sends nerve impulses to your skeletal muscles (effectors) that cause you to shiver, which generates heat and raises your temperature.
Negative Feedback Systems
Most homeostatic control mechanisms are negative feedback systems
“Negative” means “opposite” (not “bad”)
These systems reverse a change in the controlled variable, bringing it back to “normal”
Example: high blood pressure (BP) is detected and then lowered to normal BP
Positive Feedback Systems
Few homeostatic control mechanisms are of this type
These systems strengthen a change and must be shut down by an outside force.
Examples:
Contractions of uterus cause even more contractions (and more…) at child birth
Hormonal control of ovulation
Systems that control blood clotting
Disorder:
abnormality of structure/function
Disease:
specific illness characterized by signs and symptoms
Symptoms:
subjective changes not observable from outside a person. Examples: pain, headache, nausea
Signs:
observable or measurable changes. Examples: high BP, ankle swelling, fever
Aging and Homeostasis
Normal process that:
Includes a progressive loss in the ability to maintain homeostasis
Affects all body systems
Can be slowed down or minimized by healthy living
Anatomical position (Figure 1-5) pg. 13
Stands erect facing the observer, with head level and eyes facing forward, and palms facing forward
Head
Cephalic
