The Endocrine System Flashcards
Hormones control what?
Reproduction
Growth and development
Maintenance of wanter, nutrient balance of blood
Regulation of metabolism and energy balance
Mobilizing body’s defenses against stressors
What does the word “hormones” mean?
“To arouse” (alters cellular activity)
Define hormones
Chemical substances secreted by endocrine cells into extracellular fluids to regulate activity of other cells in the body.
What are hormones produced by?
Specialized cells and organs.
What is the affect of hormones?
Target cells or target organs
What happens in hormone transmission?
Blood moves hormones to target sites.
What are the effects of hormones?
- Change in permeability (go through) of plasma membrane (allow more or less to enter or leave the cell
- Make proteins or enzymes
- Activate or inactivate enzymes
- Stimulate growth of cells
- Promotes secretion (getting rid of stuff) activity
Hormone levels in blood are mostly maintained by positive or negative feedback?
Negative
What does a stimulus or low hormone levels in blood trigger?
The release or more hormones.
What happens to hormone release once an appropriate level in blood is reached?
Hormone release stops.
Function of the endocrine system:
Uses chemical messengers (hormones) that are released into the blood.
What is feedback mechanism?
A loop in which a product feeds back to control its own production.
What is negative feedback/ an example?
Keeps the concentration of a hormone within a narrow range (brings things to normal if they become extreme). Ex: thyroid
What is positive feedback regulation/ an example?
When a product feeds back to increase its own production. Ex: milk production
How are most hormones regulated?
By feedback mechanisms.
