Visceral nervous system and efferent pathway

Question 1

How is somatic and visceral function relayed to hypothalamus?

Answer 1

• Somatic - thalamic nuclei
• Visceral - mesencephalic nuc and medullary reticular formation

Question 2

What does the nuc of the solitary tract in medulla do for the hypothalamus?

Answer 2

• Principal visceral sensory nuc that receives organized input from major organ systems by the glosso and vagus nerves
• Nuc processes visceral, cardio, resp and gustatory info

Question 3

What is an important contribution to the hypo from the tel?

Answer 3

• Prefontal cortex- from the hippocampus via fornix
• Arrangement enables emotional inputs to be related to and coordinated with visceral and somatic info

Question 4

What are the pathways in the hypothalamus?

Answer 4

• Axonal pathways from hypo extend to BS and SC by direct routes of by pathways in reticular formation
• Hypo regions control visceral efferent neurons- pregang symp and parasymp neurons
• Caudal hypo regions control symp fxn
• Cranial hypo regions control parasymp fxn
• Other projections provide feedback to forebrain routed through rostral thalamuc nuclei

Question 5

How is the hypophysis attached?

Answer 5

• By the infundibulum to the hypothalamus

Question 6

What are the part of the hypophysis?

Answer 6

• Neurohypophysis- outgrowth of brain, vasopressin and oxytocin by supraoptic and paravent nuc
• Adenohypophysis - develops from oral ectoderm

Question 7

Where are the cell bodies of preganglionic neurons of symp?

Answer 7

Located in lateral column of the SC gray matter between first thoracic and middle lumbar segments

Question 8

Where are the cell bodies of postganglionic neurons of symp?

Answer 8

Found in paravertebral ganglia of the symp chain or in the subvertebral ganglia on the aorta
- Both are close to SC

Question 9

Where are the cell bodies of preganglionic neurons of parasymp?

Answer 9

Restricted to BS, nuclei of oculomotor, facial, glosso, and vagus nerves or to the lateral gray matter columns of the sacral segments of the SC

Question 10

Where are the cell bodies of postganglionic neurons of parasymp?

Answer 10

Located within the small ganglia in close proximity to or actually incorporated within walls of the organs they supply

Question 11

What are the NT of symp and parasymp neurons?

Answer 11

• Symp: norepinephrine
• Parasymp: acetylcholine

Question 12

What is the limbic system?

Answer 12

Series of forebrain structures that control somatic and visceral behavior associated with strong emotions

Question 13

What is the cortical part of the limbic system?

Answer 13

• Ring at the medial surface of the cerebral hemi including cingulate and supracallosal gyri, piriform and hippocampus

Question 14

What is the subcortical part of the limbic system?

Answer 14

• Hypothalamus, septal area, amygdala, habenular nuc and dorsal part of mesencephalic tegmentum

Question 15

Parasymp oculomotor nucleus

Answer 15

• Lies in the midbrain with motor nuc of third CN
• parasymp pregang fibers come from main trunk of nerve within orbit and constitute the oculomotor root of ciliary gang
• Postgang fibers proceed as short ciliary nerves
• Penetrate sclera to form the ciliary plexus from which parasymp fibers extend to ciliary and pupillary sphincter muscles

Question 16

Parasymp facial nerve

Answer 16

• Originates in rostral parasymp salivatory nuc of medulla
• Pregana fibers incorporated in main facial trunk, run through somatic geniculate gang and leave in chorda tympani and greater petrosal nerve
• CT joins with lingual nerve from which parasymp fibers emerge to synapse within the mandibular gang
• Postgang fibers supply mandibular and sublingual salivary glands

Question 17

Greater petrosal never and deep petrosal nerve (symp) constitute what nerve?

Answer 17

• Nerve of pterygoid canal- leads to pterygopalatine gang
• Postgang parasymp fibers join lacrimal nerve en route to lacrimal gland and other branches of max nerve and then to glands in nasal and palatine mucosa

Question 18

Parasymp of glosso nerve

Answer 18

• Originates from middle parasymp nuc in medulla
• Pregang fibers pass through somatic ganag of this nerve before joining tympanic plexus
• Proceed to synapse in otic gang
  -Postgang fibers are carried via pterygoid n and communicating branch of the auriculotep nerve to parotid gland

Question 19

Parasymp of vagus nerve

Answer 19

• Vagus is mainly parasymp fibers distal to recurrent laryngeal nerve
• Pregang parasympathetic fibers synapse in small ganglia along plexuses