A&P - Chapter 22 (Part 2) Flashcards
What are the functions of the sympathetic nervous system? (3)
- Serves as the emergency/stress system
- Decreases non essential functions
- Controls visceral effectors during all types of stressful/strenuous events/activities
What is an example of a non essential function?
Digestion
What are 5 things that occur during the fight or flight response?
- Heart beats faster
- Most blood vessels constrict
- Sugar is released into the blood
- Respiration increases
- Pupils dilate
What does the parasympathetic preganglionic neurons have? (2)
- Dendrites
2. Cell bodies
Where are dendrites and cell bodies located in the parasympathetic preganglionic neurons?
In the gray matter of the CNS
- specifically in the brainstem and sacral segments of the spinal cord
- craniosacral NS
Where do axons of the parasympathetic preganglionic neuron extend?
They extend a considerable distance away from the CNS before synapsing with a postganglionic neuron
What 2 fibres make up the para/sympathetic ganglion?
- Cholinergic fibers
2. Adrenergic fibers
What leads to a single effector?
Having the parasympathetic preganglionic neurons and the postganglionic neurons synapse
What are the functions of the PNS? (3)
- Dominates control of most visceral effectors (organs) under normal every day conditions
- Usually involves response by only one organ
- Rest and digest
- repair and rejuvenate
Neurotransmitters
Chemicals by which neurons communicate across a synapse
How are each fibres (axons) of each division of the ANS classified?
According to the type of the neurotransmitter released by the axon terminal at the synapse
What do adrenergic fibres release?
Noradrenaline
What are most axons in adrenergic fibres?
Postganglionic sympathetic neurons
What do cholinergic fibres release?
Acetylcholine
What axons make up cholergic fibres? (2)
- Axons of the preganglionic sympathetic neurons
- a few are postganglionic - Axons of the preganglionic and postganglionic parasympathetic neurons
