Sympathetic Nervous System

Horners syndrome

results from an interruption of the sympathetic nerve supply to the eye (cervical sympathectomy) and is characterized by the classical triad of miosis (i.e. constricted pupil), partial ptosis and loss of hemifacial sweating (i.e. anhidrosis)

Male

________: ejaculation, inhibition of erection.Female: vary according to hormones and menstrual cycle.

Decrease mobility

________, contraction of pyloric sphincter, decrease defecation, increase glycogenolysis in liver, release epinephrine and norepinephrine from adrenal medulla, contraction of spleen and release of red blood cells.

Α2

________ (inhibitory): relaxation of GIT wall.

Β2

________ (inhibitory): relaxation of bronchial smooth muscle (bronchial dilation)

Α1

________ (stimulatory): stimulation of sphincters.

Increase all cardiac properties

________: contractility, rate, conductivity, excitability, increase blood pressure.

Sympathetic nervous system

subdivision of the autonomic nervous system

• ‘fight or flight’ system

• diffuse activation

Cervical Division arises from

lateral horn cells of T1, T2

Cervical Division ends at

1st superior cervical ganglion

Cervical Division affects

• Eye

• Salivary glands:

• Skin:

• Cerebral blood vessels

Cardio-Pulmonary Division arises from

lateral horn cells of T1, T2, T3, T4

Cardio-Pulmonary Division ends at

3rd superior cervical ganglion and upper 4 thoracic ganglia

Cardio-Pulmonary Division affects

• Heart

• Lungs

Splanchnic Division arises from

lateral horn cells of T5-L3

Splanchnic Division ends at

collateral ganglia

Greater splanchnic nerve arises from

T5 - T9

Greater splanchnic nerve relays

celiac ganglia

Greater splanchnic nerve affects

• wall of GIT

• sphincters

• liver

• spleen

• adipose tissue

• adrenal medulla

Increase all cardiac properties

contractility, rate, conductivity, excitability, increase blood pressure

α1 (stimulatory)

stimulation of sphincters

α2 (inhibitory)

relaxation of GIT wall

β1 (stimulatory)

increase heart rate

β2 (inhibitory)

relaxation of bronchial smooth muscle (bronchial dilation)

Distribution of Sympathetic Nervous System

1. Cervical division

2. Cardio-pulmonary division

3. Splanchnic division

4. Somatic division

Somatic Division arises from:

lateral horn cells of T4 - L8 (upper limbs), T10- L12 (lower limbs)

Somatic Division relays in

the sympathetic chain

Somatic Division affects

• Skin

  • blood vessels

  • sweat

  • hair

• Skeletal muscles

  • blood vessels

  • chemical reactions

Horner’s Syndrome can be caused by:

• lesion of primary neuron

• brainstem stroke or tumor or syrinx of the pre-ganglionic neuron

• trauma to the brachial plexus

• tumors or infection of the lung apex

Organs supplied by Sympathetic fibers only

• Ventricles

• Skin structures

• Skeletal blood vessels

• Dilator pupillary muscles

• Adrenal medulla