Part 1: An Overview Part 2: Maintaining Homeostasis ANATOMY & PHYSIOLOGY Part 1: An Overview Part 2: Maintaining Homeostasis

Anatomy & PHYSIOLOGY Anatomy = STRUCTURE Physiology = FUNCTION What does it look like? What is it made of? Physiology = FUNCTION What does it do? The structure of a body part is directly related to its function!

Levels of organization *Each level of the body is connected to the next level… Starting with the chemical level which includes:

Levels of organization Atoms  Molecules

Levels of organization Organelles  Cells

Levels of organization Tissues  Organs

Levels of organization Organ systems  Organism

All organ systems are interconnected!

Homeostasis defined: The body’s ability to maintain a relatively stable internal environment

Homeostatic control mechanisms Receptor: senses stimuli and sends info (input) to control center Control center: determines the set point; analyzes info and determines the appropriate response Effector: carries out the response (output) Efferent pathway provides feedback  positive or negative

Homeostasis can be controlled in 2 ways: 1) NEGATIVE feedback mechanism Most common Occurs when a pathway regulates itself by shutting off (inhibiting) the beginning of the pathway * Reverses original stimulus Ex: fever

Homeostasis can be controlled in 2 ways: 2) POSITIVE feedback mechanism Occurs when the original stimulus is increased Ex: labor (childbirth)

DISEASES/DISORDERS Acute: affects a person for a certain amount of time; usually temporary Ex: heart attack Chronic: remain for a long time and can get worse; usually no cure Ex: atherosclerosis (heart disease)

Diseases vs. disorders Both = disruption of homeostasis Disease: illness characterized by a particular set of signs and symptoms Disorder: abnormality of function

Signs vs. symptoms Symptom: subjective change in body function Sign: measureable condition

Examples Ex of SIGN: nausea, headache Ex: fever, rash, diarrhea