Download الشريحة 1

‫إعداد الطالب ‪:‬‬
‫‪ -1‬عبدالمجيد العنزي‬
‫‪ -2‬سامر الحربي‬
‫‪ -3‬طالل بن عريعر‬
‫‪ -4‬فهد الزهراني‬
‫‪ -5‬محمد الحماد‬
‫إشراف ‪:‬‬
‫د‪ .‬عبدالعزيز الشيبان‬
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Parasympathetic Nervous System
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Autonomic nervous system
* Chain of two motor neurons
- Preganglionic neuron
- Postganglionic neuron
*Conduction is slower due to thinly myelinated or –
unmyelinated axons
Pre-ganglionic
Post-ganglionic
Ganglion
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Neurotransmitters and Receptors
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Differences between somatic and autonomic nervous Systems :
Somatic nervous system
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Autonomic nervous system
Innervate skeletal (voluntary)
muscles
Innervate smooth (involuntary)
muscles, cardiac muscles, and
glands.
Stimulation of somatic motor
fibers always leads to excitation
(contraction) of skeletal muscles
Stimulation of autonomic
motor fibers may lead to either
excitation or inhibition of
effector organs
Only one neuron
Two neurons :
preganglionic & postganglionic
Thick myelinated fibers
Preganglionic thin myelinated
post ganglionic unmyelinated
acetylcholine
preganglionic ( acetylcholine ),
postganglionic (acetylcholine(
or (noradrelaline(
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Parasympathetic Division Outflow
Nerve
Ganglion
Effector Organ(s)
Occulomotor (III)
Ciliary
Facial (VII)
Pterygopalatine
Submandibular
Glossopharyngeal
(IX)
Otic
Eye (constriction of
pupils & bulging of
lens for close vision)
Submadibular &
sublingual salivary
glands, nasal, and
lacrimal glands
Parotid salivary glands
Vagus (X)
Located within the
walls of target organs
(Intramural)
S2-S4 lateral horns
Located within the
walls of the target
organs (Intramural)
Cranial Outflow
Sacral Outflow
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Heart, lungs, bronchi,
aorta, liver, gall
bladder, stomach, small
intestine., proximal ½
of large intestine
Large intestine, urinary
bladder, ureters, and
reproductive organs
Functions of the parasympathetic nervous system:
A) Cranial parasympathetic outflow
III: Oculomotor nerve:
- Contraction of pupillae ( miosis).
- Contraction of the ciliary muscle leading to an increase in
convexity of the lens which helps accommodation of the eye to
near vision
VII: Facial nerve:
- Stimulation the lacrimal glands causing secretion of tears and
vasodilatation
- Stimulation the mucous membranes of nose causing secretion
of mucous and vasodilatation.
- Stimulation the submandibular and sublingual salivary
glands causing salivary secretion
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IX: Glossopharyngeal nerve:
- Stimulation the parotid salivary gland causing secretion and
vasodilatation.
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X: Vagus nerve:
1) In the thorax:
i) In the heart:
- decrease in the heart rate.
- decrease blood pressure.
ii) In the lungs:
- bronchiole Contraction.
- Vasodilatation to the pulmonary blood vessels.
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2) In the abdomen:
i) In the gastrointestinal tract:
- Motor to the smooth muscles of the esophagus, stomach, small intestine
and proximal part of the large intestine but inhibitory to their sphincters.
In other words, it helps deglutition, gastric motility and evacuation, and
stimulates peristaltic movements in the intestine.
- producing gastric juice .
ii) In the liver:
- Stimulates secretion of hepatic bile.
iii) In the pancreas:
- Secretion of the pancreatic juice which is rich in enzymes.
- Stimulation of insulin secretion from the beta cells of the islets of
Langerhans
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B) Sacral parasympathetic outflow:
i) In the urinary bladder:
- Motor to the wall of the urinary bladder and inhibitory to internal
uretheral sphincter leading to micturition.
ii) In the distal part of the large intestine and rectum:
- Motor to the wall and inhibitory to the internal anal sphincter
leading to defecation.
iii) In the sex organs:
- Vasodilatation of the blood vessels of the pelvic viscera including that
of the sex organs leading to erection of penis.
- Secretory to the seminal vesicles and prostate.
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