Flashcards in Exam II: The Autonomic Nervous System Deck (21):
What are the three components of the nervous system?
Nerves (pathways of communication)
What are the two major sections of the Autonomic Nervous System?
What are the 2 key neurotransmitters of the Autonomic NS?
Where is acetylcholine released from?
Cholinergic nerve fibers
All efferent fibers leaving the CNS are ____.
Describe how ACh is made
ACh is made from acetyl-CoA using an enzyme called choline 0-acetyltransferase.
It is synthesized in the mitochondria
After made, it is transfered to neuronal terminal by a choline transporter and stored as "quanta" in vesicles in nerve terminals
What does Acetylcholinesterase (AChE) do?
Breaks down ACh into choline and acetate
_____ release norepinephrine
Adrenergic nerve fibers
Where are adrenergic nerve fibers found?
Make up the postganglionic neurons of sympathetic nervous system
What are the actions of norepinephrine? (HINT: 5 actions)
1. Increase HR and BP
2. Mobilize energy stores
3. Increase blood flow to skeletal muscle
4. Divert blood flow from skin and internal organs
5. Dilate pupils and bronchioles
What are the 3 termination methods of adrenergic action?
1. NE metabolized by catalytic enzymes
2. Diffusion away from receptor site
3. Reuptake into terminal by norepinephrine transporter (NET) or other cells
What are the two types of Cholinergic receptors?
What are the three types of Adrenergic receptors?
1. Alpha 1 and Alpha 2
2. Beta 1 and Beta 2
What are two drugs that inhibit NET?
Which organ system is the major target of the Autonomic Nervous System?
Why is there a control function of the autonomic system? (2 reasons)
1. To prevent system from overstimulation
2. Maintain effector organ functions within a narrow window of tolerance
What 3 mechanisms control autonomic nervous system?
1. Presynaptic regulation
2. Postsynaptic regulation
3. Other integrated systems
2 examples of presynaptic regulation
alpha2 receptors: when activated by NE, they decrease the amount of NE released from that same nerve cell (autoreceptor)
Beta receptors facilitate the release of more NE
Two mechanisms of postsynaptic regulation
1. Up or down regulate receptors
2. Action of one receptor is affected by action of other receptors
What controls the iris radial muscle?
alpha 1 receptors