Chapter 25 Flashcards
Second greatest controling system of the body
Endocrine system
Performs same general functions as
Nervous system
Endocrine system functions
Communication
Integration
Control
Neuroendocrine system
Both systems working together
;glands in the endocrine secrete _____ into ____
Hormones into blood
Horomones are _______ and _________
Slow and long lasting
Generally horomones are not stored in the endocrine glands T/F
T
Classification of horomones by function (3)
Tropic
Sex
Anabolic
Classification by chemical structure
Steroidal hormones (lipid or fat-soluble) Non-steroidal (amino acid/protein)
Tropic hormones target ….
Other endocrine glands and stimulate their growth and secretion
Sex hormones target…
Reproductive tissue
Anabolic hormones stimulate…
Anabolism in target cells
Hormones have specific _________ that they affect
Target cells
General principles of hormone action (2)
Hormones signal a cell by binding to the target cells specific receptors in a lock and key mechanism
Different hormone-receptor interactions produce different regulatory changes within the target cell through chemical reactions
Types of combined hormone actions
Synergism
Permissiveness
Antagonism
Synergism
Combinations of hormones acting together have a greater effect on a target cell than the sum of the effects they would have working alone
Permissiveness
A small amount of one hormone allows a second one to have its full effects on a target cell
Antagonism
One hormone produces the opposite effects of a nother hormone; used to “fine tune” the activity of target cells with great accuracy
Steroid hormones are _____ in water and can _______ cross plasma membranes
Not soluble
Easily
After a steroid hormone is in the cell, it binds to its specific receptor found in the nucleus, forming a ___________. The model of hormone action is known as __________ or _______
Hormone receptor complex
Mobile-receptor model or nuclear receptor model
What happens when the hormone binds to the receptor in the nucleus
Protein synthesis is activated
Steroid hormones regulate cells by regulating
Production of specific hormones
Responses to steroid hormones can be ________
From 45 mins to several days
Non-steroidal proteins are ______
Protein hormones (made from A.A.)
Protein hormones cant penetrate the cell membrane without
A messenger/ carrier
The non steroidal protein hormone is refered to at ___________, which binds in target cells membrane
First messenger
The binding of first messengers in the cell membrane leads to activating _____
Second messenge
What is a common second messenger
.. cAMP
Second messengers do what
Affect the cell’s activities
The second messenger model can also be called
Fixed membrane-receptor model
Second messenger mechanisms operate _______ than primary messengers
Much quicker
Oxytocin is an example of a _________ feedback system
Positive
Target cells sensitivity depends on
Number of receptors it has for that hormone
More hormones= greater effect
The # of hormone receptors can change due to cell ____________
Growth/ repair
Up regulation is
Receptors are synthesiszed faster than they are broken down = increased sensitivity
Down-regulation
Receptors are broken down faster than they are synthesized/ replaced = decreased sensitivity
Prostagladinds
Aka tissue hormones
- Powerful substances found in a wide variety of body tissues (not typical hormones!)
- Unique group of lipid/fatty-acid based hormones
- Often produced in a tissue and diffuse only a short distance to act on cells in that tissue (not transported in the blood to distant tissues organs as ‘regular’ endocrine hormones are)
- 9 structural classes: PGA to PGI
- Influence many body functions, e.g. respiration, BP, G-I secretions, inflammation, reproduction
