Summary of sympathetic nervous system

Sympathetic nervous system is the part of autonomic nervous system .

Functionally Nervous system can be divided into two part
somatic nervous system and autonomic nervous system .
Sympathetic system is the part of autonomic nervous system

•Like somatic nervous system autonomic nervous system has two parts •Motor part of autonomic system innervate smooth muscle, cardiac muscles  and most of the glands of the body
•Sensory part of autonomic system carry sensory impulse from viscera to the brain . Sensory parts of autonomic system usually ran along the sensory system of somatic system so we often perceive visceral pain in the body wall .

short description of sympathetic nervous system

Topics	Sympathetic nervous system
Out flow	it is also known as thoraco lumbar outflow T1 to L 2
Pre ganglionic fibres	Short
Post ganglionic fibres	Longer
Ganglia	Para vertebral sympathetic ganglia  is away from the target organ
Location of pre-ganglionic neuron	•       Lateral horn cells of all thoracic segments and upper two or three lumbar segments of spinal cord
Location of post-ganglionic neuron	•       Lateral: sympathetic trunk •       Collateral : coeliac, superior mesenteric ganglia •       Terminal ganglia: supra-renal medulla
	This system activate during emergency and works during stress and strain for fight or flight
	Liberates non adrenaline at postganglionic ending except eccrine type of sweat glands and most of the blood vessels of skeletal muscle
	This system is not essential for to life
Urinary bladder	It is the nerve of filling It contract (close) urethral sphincter and relax detrusor muscles
Heart	Cardiac muscles cells : increase force of contraction Coronary vessels :  vasodilator ( so supply of nutrition and oxygen increase in cardiac muscle cells  )
Lung:	Bronchodilator / Trachealis muscles relax so diameter of trachea increase Decrease secretion of tracheal glands
Stomach	Gastric musculature (smooth muscle cells ) is relax  but smooth muscle cells at the pyloric sphincter is contract (closer of pyloric sphincter )
Small gut	Inhibit peristalsis Vasoconstriction (vaso motor)
Summary : effect	•       Produce mass reaction •       Cutaneous blood vessels undergo vasoconstriction but, skeletal and coronary vessels are dilated thus supplying more blood to the muscles, heart, brain. Heart rate is increased, blood pressure and blood sugar are elevated , pupil and bronchi are dilated. Intestinal peristalsis is suppressed and the sphincters of gut are closed.
Eye	Pupil dilates
*Uterus	Uterine contraction Vasoconstriction
Salivary glands	_
Pancreas	_
Gastric glands	_
Adrenal glands	secretomotor
Vessels of Skeletal muscle	Vasodilatation
Sweat gland	secretomotor
Afferents	Convey most of the visceral pain except pelvic organ
Cells of origin of afferents fibres	Dorsal root ganglia of T 1 to L1/L2
Central control	Posterior part of hypothalamus