Lecture 7 Flashcards
(14 cards)
What is the ANS?
The autonomic nervous system
What does an ANS do?
The ANS conveys all of the central nervous system efferent outputs to the body and is responsible for regulating physiological functions largely outside the influence of voluntary control.
What are the two divisions of the ANS?
The parasympathetic division which tends to regulate basal activity.
The sympathetic division which tends to respond to stressful situations.
Where does the ANS convey information to?
The neuro-effector junction
What parts of the spinal cord do parasympathetic signals tend to stem from?
The sacral spinal cord and the cervical region
Where do the sympathetic signals tend to stem from?
The thoracic and lumbar spinal cord regions
In parasympathetic systems is the pre-ganglionic fibre longer?
Yes, they extend into the tissue
In sympathetic systems is the pre-ganglionic fibre longer?
No, it is very short
Give 5 key characteristics of parasympathetic nerves
Origin in the lateral horn of the medulla and sacral regions of the spinal cord
They have long myelinated preganglionic fibres
They have short unmyelinated postganglionic fibres
Ganglia located in the tissues that the postsynaptic fibres innervate
Have actions that oppose the sympathetic nervous system
Give five key features if the sympathetic nerves
Origin in the lateral horn of the lumbar and thoracic spinal cord
They have short myelinated preganglionic fibres
They have long unmyelinated post ganglionic fibres
Ganglia located in the paravertebral chain close to the spinal cord
Have actions that oppose the parasympathetic nervous system
What are the principal neurotransmitters in the ANS?
Acetylchoine
Noradrenaline
Are all pre-ganglionic neurones cholinergic in the ANS?
Yes
What neurotransmitters do parasympathetic postganglionic neurones use?
Acetyl choline
In the ANS what does the release of ACh lead to the activation of in the postganglionic neuron?
The nicotinic ACh receptors which are ligand-gated ion channels
