A&P - Chapter 25 (Part 2) Flashcards
What is an example of steroid hormones?
Lipids
Are lipids soluble in water?
No
What help lipids to travel through blood plasma?
Soluble plasma proteins
What can steroid hormones easily cross?
The target cells phospholipid plasma membrane
What happens after a hormone is in the cell?
It binds to its specific receptor found in the nucleus
What does it form when a hormone binds to its specific receptor?
A hormone-receptor complex
When is protein synthesis activated?
When the steroid hormone binds to the receptor in the nucleus
What will the synthesized protein carry out?
The effects of the hormone
What is a non steroidal protein hormone referred to as?
The first messenger
What does the first messenger do?
Binds to a specific receptor in the target cells membrane
What do first messengers lead to?
A chemical reaction that activates substances in the cell known as secondary messengers
What are second messenger?
Are messengers that affect the cells activities
What is a common second messenger?
cAMP
What does cAMP do?
It acts to activate various enzymes
What happens to the effects of the nonsteroid hormones?
They are amplified by the cascade of reactions involved
What is hormone secretion controlled by?
Homeostatic feedback
- usually part of a negative feedback loop
Negative feedback
Mechanisms that reverse the direction of a charge in a physiological system
What is an example of negative feedback?
Insulin and blood sugar balance
Positive feedback
Mechanisms that amplify physiological changes
What are 2 examples of positive feedback?
- Oxytocin
2. Labour contractions
What feedback loop is more common?
Negative feedback
