1. The Nervous System & Homeostasis
Homeostasis Notes
pg. 42
The Nervous System & Homeostasis

2. Homeostasis is the ability or tendency of an organism to maintain stable internal conditions.

3. Homeostasis = Regulating internal environment

4. If an organism does not maintain homeostasis, it becomes sick or diseased.
When an organism has a disease, it will make adjustments to how it functions in order to restore homeostasis.
If it cannot restore homeostasis, the organism might die.

5. Homeostasis
An organism maintains homeostasis by making small adjustments to how it functions. This way, it maintains a balanced internal environment.
The internal environment conditions are not always exactly the same. The actual conditions inside the body slightly fluctuate above and below the optimal condition.
* Ex. The optimal human body temperature is 98.6 F. However, our body temperatures can range from 97.7 – 99.5 degrees F and still be considered normal.
In humans and other animals, organs work together to maintain homeostasis. Organs increase or decrease their function to change how the body works.

6. How does the body maintain Homeostasis?
An organism monitors and responds to internal and external stimuli in order to maintain homeostasis.
In humans, the nervous system is responsible for monitoring internal conditions and detecting changes in the external environment.
When the nervous system detects a change, it responds by sending signals to the organs. These signals cause the functions of the organs to change.
The nervous system works closely with the endocrine system to respond to stimuli and maintain homeostasis.

7. The Nervous and Endocrine Systems
The nervous system is the network of nerve cells and fibers that transmits nerve impulses between parts of the body.
The endocrine system is the collection of glands that produce hormones that regulate metabolism, growth and development, tissue function, sexual function, reproduction, sleep, and mood, among other things
The nervous system can signal glands of the endocrine system to respond to release hormones.
Hormones help regulate many life processes in an organism. Hormones signal cells and/or organs to increase or decrease their function in order to maintain homeostasis.

10. Vocabulary: Physiological = in your body

11. Goosebumps
Vestigial (left-over) trait from when our ancestors had more hair to hold up and to make a difference in temperature.

12. The body does more than just sweat or shiver in response to temperature change