Chapter 28 Flashcards
A chemical messenger secreted by cells of the endocrine system and transported through the blood stream to target cells with appropriate receptors where it elicits a response
Hormones
A chemical messenger that travels between a neuron and a neighboring neuron or the other target cell to transmit a nerve impulse
Neurotransmitter
Are hormones secreted near or far away from where they need to go?
Far from site of action
Do most nerve cells make direct contact with the cells they stimulate?
No
______ is usually synthesized and released very close to their site of action
Neurotransmitters
T or F
Hormones can carry out chemical reactions
False, signal inhibition/ activation of enzymes, proteins, etc
What are the three major types of hormones?
Amino acid derivatives
Polypeptides
Steroids
T or F
Steroids are polar so they can enter the cell directly via diffusion
False, they are Nonpolar which is why they can go through cell via diffusion
Can polypeptides and amine hormones pass through cell membranes? Why or why not?
No because they are water soluble so cannot pass through hydrophobic cell membrane
How to polypeptide and amine hormones deliver their messages?
Bonding noncovalently to receptors on cell surfaces
What is it called when a chemical messenger is released inside a cell after a hydrophilic hormone or neurotransmitter interacts with a receptor on the cell surface?
Second messenger (from polypeptide binding before)
The three membrane bound proteins that participate in the release of the second messenger is _____, ______, and an enzyme
- The receptor
- G protein
- Enzyme
What role does the G protein play in releasing the second messenger?
G protein activates the enzyme that participates in release of second messenger
What enzyme is responsible for degrading the neurotransmitter that remains in the synaptic cleft after a muscle contracts?
Acetylcholinesterase
What is this structure?
cAMP
This is _____ and it’s derived from tryptophan
Serotonin
