W3 - Autonomic NS (part of PNS) Flashcards
What 3 things do somatic innervate and what do they control?
Skin, skeletal muscle and joints - movement and posture
What 3 things does the ANS innervate and what does it do?
Internal organs, blood vessel and glands to maintain internal environment
What is the main organiser of the ANS and do ascending/descending connections carry this out?
Hypothalamus, descending
What is a description of homeostasis?
Dynamic balance between parasymp (rest/digest) and symp branches (fight/flight)
Not all structures are dually innervated (sweat glands only symp) but most are controlled by antagonistic para/symp divisions, give the example of the iris of the eye
Parasymp - contstriction of pupil, symp - dilation of pupil
Where do the parasympathetic nerves originate?
The cranio-sacral region
What cranial/sacral nerves are involved in the ANS?
Cranial - III, VII, IX, X and Sacral - 2, 3, 4
Where do sympathetic nerves originate?
Thoraco-lumbar region T1-L2
What maintains the internal visceral environment by relaying visceral info to CNS?
Visceral afferents
What two information types are relayed to the CNS by visceral afferents?
Physiological (good/normal) and pathophysiological (bad)
What three general stimuli do visceral afferents monitor?
Nociception, mechanical and chemical stimuli
Do symp/para usually relay nociceptive or physiological info?
Symp - nociceptive, Para - physiological
What two neurons do visceral motor efferent pathways consist of?
A lightly myelinated pre-ganglionic neuron and an unmyelinated post-ganglionic neuron
In the symp/para NS, are the pre-ganglioinic/post-ganglionic fibres shorter?
Symp - pre = shorter, Para - post = shorter
What NTM does a short pre neuron use in symp?
Acetylcholine
What NTM does a longer post neuron use in symp?
Noradrenaline
What NTM does a long pre neuron/short post neuron use in parasymp?
Both use acetylcholine
4 cranial nerves carry para info, what do they do?
III - pupil size, VII - saliva/tears production, IX- saliva production, X - every other para info in body (90%)
What parasympathetic axons do the vagus nerve carries?
Preganglionic
Where are the nuclei found in the sacral parasymp motor nerves in the SC and where do these axons project to?
Lateral horn, lower organs
Where are sympathetic preganglionic neurons located in the thoracolumbar SP before they project to the sympathetic chain ganglia through white ramus?
What do prevertebral ganglia contain?
Cell bodies of neurons that innervate abdominal and pelvic cavities
Which structure allows for a coordinated response from stimulus?
Sympathetic chain
What adrenal medulla controls hormones that initiate fight/flight, what are these two main HMs?
Adrenaline and noradrenaline
Sympathetic preganglionic fibres project directly/indirectly to cells of adrenal medulla to elicit a widespread symp response to stress?
Directly
