Parasympathetic Nervous System Regulation

1. REGULATION
Bilal Sami Al-Mosheqah
Parasympathetic Nervous
System

3. Parasympathetic
NS
(Rest and digest)
 Work in relaxed state
 Involuntary control
 Two neurons
 Discrete and localized effect

4. Parasympathetic NS
Receptors Neurotransmitter
Nicotinic
Muscarinic
 Ach
{acetylcholine]
M1,M2,M3
M4,M5

6. The Eyes (M3)
 Stimulate lacrimal gland → ↑ lacrimal secretion
 Contraction of constrictor pupillae (circular muscle of
the iris)→ miosis
 Contraction of ciliary muscle → accommodation for
near vision
 ↓ intraocular pressure (IOP)
Miosis

7. Heart (M2) and Arteries (M3)
↓heart rate
 ↓ force of contraction (atria)
 ↓ conduction
 Arteries (M3) → Vasodilatation
NB: Vessels have no parasympathetic supply
Decrease BP

8. Lung (M3)
Bronchial secretion
↑
Bronchial muscles Contraction
Bronchial
gland

9. Gastrointestinal tract
Motility
Sphincters
gastric secretion
Smooth muscles
Contraction
Relaxation
Increase
Acceleration
Digestion
(M1)
(M3)
(M3)
(M3)

10. Liver and Pancreas
 Stimulates bile release
 Contraction of the gall bladder
 Increase pancreatic secretions

11. Urinary Bladder (M3)
 Contraction of the bladder muscle (Detrusor muscle)
 Relaxation of the external sphincter
Urination

12. What happens if the
parasympathetic NS is blocked
Eye
Salivary
gland
Bronchi Intestine
Urinary
Tract
Heart
Tachycardia Urine retention
Constipation
Broncho-
dilatation
Dry mouth
mydriasis,
cycloplegia
, ↑
IOP

13. The Absence of Parasympathetic Supply
Adrenal
medulla
Piloerector
Muscle
Sweat gland Kidney
Ventricles of the
heart

14. Here is the summary . . .

16. Thanks for listening

17. Lippincott Illustrated Reviews, Pharmacology -Whalen, Karen
Medical Physiology for Undergraduate Students - book44-1
Guyton and HallTextbook of Medical Physiology, 13th edition
Lippincott’s Illustrated Reviews Physiology 1st Edition