1. Unit #1 Wellness & Homeostasis “Homeostasis”
Biology 30S
Unit #1 Wellness & Homeostasis
“Homeostasis”

2. Homeostasis
“Homeo” means same “stasis” means state
The Body’s ability to maintain its internal environment within acceptable ranges despite the changing external environment
The body’s ability to maintain “normal” physiological conditions

3. Homeostatic Conditions: (1) Body Temperature
Homeostatic mechanisms must allow the body to maintain the following condititions:
The body must maintain an internal temperature of approximately 37 degrees Celsius
This is maintained by a homeostatic mechanism called Thermoregulation

4. The body must maintain a constant water balance
78% of the human body is made up of water
A 1% drop in fluid body mass causes thirst
A 5% drop causes extreme pain and collapse
A 10% decrease often results in death
Water balance is maintained by a homeostatic mechanism called Osmoregulation

5. The body must maintain an internal blood pressure of
120/80 kPa
The body must maintain a blood pH level near 7.4
Blood glucose (blood sugar) levels must be maintained at concentrations around 100mg/ml
(3) Blood Pressure (4) Blood pH (5) Blood Glucose

6. (6) Respiratory Gasses
Oxygen (O2) and Carbon Dioxide (CO2) levels must be balanced in the cells and bloodstream
These levels are maintained by a homestatic mechanism called Respiration

7. (7) Waste Management
The ability of the body to remove harmful wastes is essential to maintaining homeostasis
Often cellular metabolism results in the production of harmful waste
Organs such as the liver, lungs, kidneys, skin and stomach help the body regulate and reduce waste levels in the body

8. (8) Immunity (9) Repairs Death
Homeostatic mechanisms regulate the body’s response to pathogens
Homeostatic mechanisms regulate the body’s ability to repair injuries and “heal”
The failure of Homeostasis (more or less)