The Visceral Nervous System

1
The Visceral Nervous System

• ??????? ?????
• ???

2
The Visceral Nervous System

• Composition
• Visceral motor nerves (autonomic nervous system)
• Sympathetic part ???
• Parasympathetic part ????
• Visceral sensory nerves

3
Visceral motor nerves
4

5
Main differences between somatic motor and
visceral motor n.
Somatic Visceral
Effectors Skeletal muscles Cardiac, smooth muscles and glands
Kind of fibers One Two sympathetic and parasympathetic
From lower center to effect require Single neuron Two neurons preganglionic neuron (fiber) and postganglionic neuron (fiber)
Fibers Thick myelinated Preganglionic thin myelinated postganglionic unmyelinated
Distributive form Nerve trunk Nerve plexuses
Control Voluntary (consciousness) Involuntary (unconsciousness )
6
Sympathetic part ???

• Lower center located in lateral gray horn of
  spinal cord segments T1L3
• Sympathetic ganglia
• Paravertebral ganglia ???
• Prevertebral ganglia ???

7
Paravertebral ganglia ???

• Arranged on either side of vertebral column
• Consist of 1922 of oval-shaped ganglia
• Three cervical
• 1012 thoracic
• 4 lumbar
• 23 sacral
• Ganglion impar???? unpaired on the anterior face
  of coccyx

8
(No Transcript)
9
Sympathetic trunk ???

• Formed by paravertebral ganglia and
  interganglionic branches
• Lie on either side of vertebral column from base
  of skull to coccyx
• The trunks of two side unite in front of the
  coccyx at a small swelling, the ganglion impar

10
Prevertebral ganglia ???

• Lie anterior to vertebral column and near the
  arteries for which they are named
• Celiac ganglion ?????
• Aorticorenal ganglion ?????
• Superior mesenteric ganglion ???????
• Inferior mesenteric ganglion???????

11
Three fates of preganglionic fibers
15 pairs white communicating branch
Preganglionic fibers
Sympathetic trunk
(only spinal levels T1L3 have white
communicating branch)
12
Three fates of preganglionic fibers

• Relay in corresponding ganglion
• Ascend or descend in sympathetic trunk and relay
  in higher or lower ganglia
• Pass without synapse to a prevertebral ganglion
  for relay

13

• Greater splanchnic nerve ????? formed by
  preganglionic fibers from T5T9 ganglia, and
  relay in celiac ganglion.
• Lesser splanchnic nerve ????? formed by
  preganglionic fibers from T10T12 ganglia, and
  relay in aorticorenal ganglion.
• The postganglionic fibers supply the liver,
  spleen, kidney and alimentary tract as far as the
  left colic flexure.

14

• Lumbar splanchnic nerve ?????
• Formed by preganglionic fibers from L1L4
  ganglia, and relay in prevertebral ganglia.
• The postganglionic fibers supplydescending and
  sigmoid colon, rectum, pelvic viscera and lower
  limbs.

15
Three fates of postganglionic fibers

• Back to a spinal nerve along gray communicating
  branches ( 31 pairs ) to terminate in blood
  vessels, arrectores pilorum and sweat glands of
  head, neck, trunk and limbs
• The fibers from their networks around blood
  vessels passing to visceral end organs
• Terminate directly in certain organs

16
Distribution of sympathetic nerve
Preganglionic fibers Postganglionic fibers
T1T5 Head, neck, upper limb and thoracic viscera
T5T12 Abdominal viscera
L1L3 Pelvic viscera and lower limb
17
Parasympathetic part ????

• Lower center located in four pairs
  parasympathetic nuclei in brain stem and in
  sacral parasympathetic nucleus of spinal cord
  segments S2S4
• Parasympathetic ganglia terminal ganglia are
  near or within the wall of a visceral organ
• Para-organ ganglia ????
• Ciliary ganglion ?????
• Pterygopalatine ganglion ?????
• Submandibular ganglion ??????
• Otic ganglion ????
• Intramural ganglia ???

18
Cranial portion??
?
sphincter pupillae and ciliary muscles
ciliary ganglion

• lacrimal gland

?
pterygopalatine ganglion

• sublingual gland
• submandibular gland

?
submandibular ganglion

• parotid gland

?

• otic ganglion

• heart, lungs, liver, spleen
• kidneys,alimentary tract
• as far as left colic flexure

terminal ganglia
19
Cranial portion??

• 
  ?
• accessory oculomotor nucleus lt?
  sphincter pupillae and ciliary muscles
  
• 
  ciliary ganglion
• 
  pterygopalatine ganglion
• 
  ? lt?
  lacrimal gland
• superior salivatory nucleus
• 
  lt?
  sublingual gland
• 
  submandibular ganglion
  submandibular gland
• 
  
• 
  ?
• inferior salivator nucleus lt?
  parotid gland
• 
  otic ganglion
• 
  ? heart, lungs,
  liver, spleen,
• dorsal nucleus of vagus n. lt?
  kidneys,alimentary tract
• 
  terminal ganglia as far as left colic
  flexure

20
Sacral portion ??

• Preganglionic fibers from sacral parasympathetic
  nucleus leave spinal cord with anterior roots of
  the spinal nerves S2S4,
• Then leave sacral nerves and form pelvic
  splanchnic nerve and travel by way of pelvic
  plexus to terminal ganglia in pelvic cavity
• Postganglionic fibers terminate in descending and
  sigmoid colon, rectum and pelvic viscera

21
(No Transcript)
22
Main differences between sympathetic and
parasympathetic
23
Main differences between sympathetic and
parasympathetic
Sympathetic Parasympathetic
Lower center Lateral gray horn of spinal cord segments T1L3 Four pairs parasympathetic nuclei and sacral parasympathetic nucleus
Ganglia Paravertebral, prevertebral Terminal
Preganglionic f. Shorter Longer
Postganglionic f. Longer Shorter
Pre Postganglionic 1 many more 1 a few
Distributions Throughout the body Limited primarily to head and viscera of thorax, abdomen, and pelvis
Different action Prepares for emergency situation (fight or flight) Conserve and restore body energy (rest and relaxation)
24
Visceral plexuses

• Cardiac plexuses
• Superficial , below aortic arch
• Deep, anterior to bifurcation on trachea
• Pulmonary plexus
• Celiac plexus
• Abdominal aortic plexus
• Hypogastric plexus
• Superior hypogastric plexus
• Inferior hypogastric plexus (pelvic plexus)

25
Visceral sensory nerves
Nucleus of solitary tract
?,?, ?
Thalamus
Cerebral cortex
Enteroceptors
Hypothalamus
Posterior horn
Effectors
Sympathetic nerve Pelvic
splanchnic nerve
Somatic motor neurons visceral motor neuclei
26
Referred pain ???

27
The Endocrine System

• ??????? ?????
• ???

28
The Endocrine System

• Composition
• Endocrine glands have no ducts, their
  secretions (hormone) release directly into
  bloodstream to its target organ
  
  
• Endocrine tissue

29
Thyroid gland ???

• Shape and position
• H-shape
• Left and right lobes lie on either side of
  inferior part of larynx and superior part of
  trachea, extend from middle of thyroid cartilage
  to level of sixth trachea cartilage
• Isthmus overlies 2nd to 4th tracheal cartilage
• Pyramidal lobe some times arises from isthmus
• Fibrous capsule a sheath of pretracheal fascia
  which is attached to arch of cricoid and thyroid
  cartilages, hence, the thyroid gland moves with
  larynx during swallowing and oscillates during
  speaking
• Function to produce thyroxin, regulating the
  rate of metabolism and growth of bony and nervous
  system

30
Parathyroid gland ????

• Yellowish-brown, ovoid bodies
• Position
• Two superior parathyroid glands lie at junction
  of superior and middle third of posterior border
  of thyroid gland
• Two inferior parathyroid glands lie near the
  inferior thyroid artery, close to the inferior
  poles of thyroid gland
• Function regulate calcium and phosphate balance
  and is therefore essential for life

31
Suprarenal gland

• Shape and position
• Right is pyramidal in shape, left one semilunar
  in shape, consisting of out cortex and inner
  medulla
• Located retroperitoneally, superomedial to
  superior poles of each kidney, enclose with the
  kidney by the renal fascia
• Function secretes adrenaline, noradrenaline and
  several steroid hormones

32
Hypophysis

• Shape and position
• Pea-sized organ, attached by infundibulum to
  hypothalamus, lies in hypophysial fossa
• Consists of two parts
• Adenohypophysis
• Neurohypophysis
• Relationship
• Above-diaphragm sellae
• Anterosuperior-optic chiasma and optic nerve
• Laterally-cavernous sinus
• Below-sphenoid sinus

33
Pineal body ???

• locates in posterosuperior to thalamus, attached
  by stalk to posterior part of roof of third
  ventricle

34
Thymus ??

• Position
• Located in superior mediastinum
• Posterior to sternum and between the lungs
• Function
• Secrets thymosin to aid in maturation of T-cell
• Secrets thymopoietin

35
Endocrine tissue

• Pancreatic islet
• Gonad
• Ovary
• Testis