Autonomic Nervous System 1

Feature	Sensory nervous system	Motor nervous system	Autonomic nervous system
Function	Carry neural impulses from skin to CNS	Carry neural impulses from CNS to skeletal muscles	Carry neural impulses from CNS to smooth and cardiac muscles
Location of cell body	Outside the spinal cord	Inside the spinal cord	Inside the spinal cord
Site in grey matter	Dorsal horn	Ventral horn	Lateral horn

Feature	Autonomic nervous system	Somatic nervous system
Control	Involuntary	Voluntary
Type	2 types	One
Efferent	2 efferent	One
Muscle	Smooth muscle - cardiac muscle	Skeletal muscle
Chemical transmitter	Acetylcholine & Norepinephrine	Acetylcholine
Autonomic ganglia	Present	Absent
Arise from	LHC (Lateral Horn Cell)	AHC (Anterior Horn Cell)

Definition: collection of neurons outside CNS.
Function: acts as distributing center.
Types:
- Paravertebral ganglia (lateral): present on both sides of vertebral column, relay of sympathetic nervous system.
- Collateral ganglia: present midway between spinal cord and viscera, relay of sympathetic & parasympathetic.
- Terminal ganglia: present near or inside the viscous, relay of parasympathetic.

Divisions of ANS: Sympathetic nervous system & Parasympathetic nervous system.
Sympathetic Origin: Thoracolumbar (LHC of all thoracic and upper 3 lumbar segments).

Eye:
- pupil dilatation (mydriasis) due to contraction of dilator pupillae muscle.
- elevation of upper eyelid (widening of palpebral fissure).
- decrease tear secretion of lacrimal gland.
Salivary glands: Decreases salivary secretions.

Heart:
- increase excitability and rate of conduction.
- +ve inotropic effect (increase in force of contraction).
- +ve chronotropic effect (increase in heart rate).
- vasodilatation of coronary vessels.
Lung:
- bronchodilatation (relaxation of bronchial muscle).
- vasoconstriction of pulmonary vessels.

Liver: glycogenolysis (hyperglycemia), increase metabolic rate, increase fibrinogen synthesis (limit bleeding).
Pancreas: Stimulates glucagon secretion, inhibits insulin secretion.
Adrenal medulla: secretion of 80% adrenaline - 20% noradrenaline.
* Adrenaline: Greater effect on Cardiac contractility (B1)
* Noradrenaline: Greater effect on arterial blood pressure (VC via a1)
Gastrointestinal tract: Inhibition (relaxation) of wall, contraction of sphincters.

Urinary bladder (retention of urine): inhibition of wall, contraction of internal urethral sphincter.
Rectum (retention of feces): inhibition of wall, contraction of internal anal sphincter.
Male genitalia: Ejaculation.