1. Ch. 1 – Characteristics of Life & Organization of the Human Body

2. What is the difference between Anatomy and Physiology?

3. A. Anatomy- study of the structures of an organism
-Examples of 4 subcategories:

4. 1. Gross anatomy- large, what you can see

5. 2. Microscopic anatomy - tiny
Cytology= study of cells
Histology=
tissues

6. 3. Developmental Anatomy
-structure of an embryo (embryology)

7. 4. Pathological anatomy- diseased structures

8. B. Physiology- study of the functions of an organism

9. What are the levels of organization in the human body?
-chemical (subatomic, atomic,
molecules, macromolecules)
-organelles
-cells (differentiated to perform unique functions) 100 Trillion!
-tissues
-organs
-organ system (see below)
-organism (human)

11. Virtually all processes in the body occur in order to maintain Homeostasis
What is Homeostasis?

12. Homeostasis- an organism’s maintenance of a relatively constant internal state within set ranges.
Examples:
Temp.=
~ °F
b.p.=
~ 120/80 mmHg
glucose=
~ mg/dl
Blood pH=
7.4
hydration=
~60% H2O
MANY, MANY more!

13. Homeostatic control mechanisms-
-known as a feedback control loop
-virtually all of the body’s organ systems can be involved
-there are three basic components:
-Sensor – senses a change (a “stimulus”)
-Integrator, (control center) – interpret the change
-Effector – responds to the change

15. EFFECTOR: the heart begins to beat faster thereby increasing pressure.
Example:
SENSOR: pressure sensor in the walls of the heart and major arteries senses low blood pressure and sends a signal to the brain.
INTEGRATOR: Medulla oblongata in the brain determines degree in which b.p. must be corrected and send a signal back to the heart.
EFFECTOR: the heart begins to beat faster thereby increasing pressure.

16. NEGATIVE feedback mechanism-
-creates a response that opposes the initial disturbance. (reverses the change)
-work to stabilize physiological variables
-are responsible for maintaining homeostasis

17. POSITIVE feedback mechanism-
-amplifies or reinforces the change that is occurring
CANCER! 
-can be harmful or disasterous
-very few normal positive feedback mechanisms
-childbirth, bloodclotting, a sneeze