Neuro transmitters of Autonomic Nervous System Acetyl choline (Ach) This is the neuro transmitter produced by preganglionic fibers of both sympathetic & parasympathetic systems. Post ganglionic fiber of parasympathetic system produce Ach at their neuro effector site in visceral organ Adrenaline/Nor-adrenaline Post ganglionic fibers of sympathetic system produce noradrenaline or adrenaline at their neuro effector site on the effector organs. Exception– […]

Segment of Autonomic Nervous System The ANS is divided into small segments after its origin from CNS. Three segments are Cranial segment, Thoraco lumbar segment and Sacral segment. Cranial segment From brain stem with nerve fibers of oculomotor, facial, Glossopharyngeal & Vagus Thoraco lumbar segment From spinal cord with ventral root of spinal nerves from T1 or L5or6 segments. Sacral

Nerve fibers of ANS Ganglia possess two types of nerve fibers- Pre ganglionic nerve fiber and Post ganglionic nerve fiber. Pre ganglionic nerve fiber Nerve fiber from CNS to cells of ganglia for synapse. Pre ganglionic nerve fiber are small, myelinated with conduction velocity of 3-15 m/sec, representing class B fiber. Post ganglionic nerve fiber

Classification of ganglia Vertebral ganglia Vertebral ganglia located along vertebral column and are associated with sympathetic trunk. Collateral ganglia Collateral ganglia located in between CNS and viscera, associated with visceral blood vessels. eg. celiac ,pelvic and cranial & caudal mesentric Terminal ganglia Terminal ganglia located in the wall of the visceral organ eg. Cardiac, pulmonary & enteric ganglia.

Autonomic Nervous System or ANS Autonomic Nervous System or ANS described as visceral efferent system by Langley in 1898. All efferent axons leaving the CNS other than those of skeletal muscle belong to ANS. ANS supplies efferent information to smooth muscle, glands & cardiac muscle. ANS modifies motor activities that have been initiated with in

Peripheral nervous system or PNS Peripheral nervous system or PNS includes all nervous structures, the peripheral ganglia, spinal nerves, cranial nerves and the autonomic nerves, located out of the brain and the spinal cord. It functions to provide communication between the receptor organ and the CNS (sensory), from the CNS and the effector organs (motor). 

Conditioned reflexes (Conditioned responses) Conditioned reflexes (Conditioned responses) reflexes are acquired or reflexes that are gained naturally or artificially by the individual during the course of their lifetime. Salivary and the gastric secretions produced in response to food is a natural and inborn reflex.  The sight or the smell of the food forms the natural

Scratch reflex or Multisynaptic reflex Initiated by combination of tactile and pain receptor organ. Afferent enters the spinal cord and end in internuncial neurons. Preventive reflex helps to remove the irritating stimuli from skin (dorsal lateral surface of the thorax and neck ) with one rear limb and out affecting the posture of the animal. 

Withdrawal reflex Withdrawal reflex is achieved by contraction of flexors (the muscle should be excited) and inhibition of extensors (occurs simultaneously). Protective reflex, helps to avoid noxious stimuli by flexion, hence known as flexion reflex. Ex. Withdrawal of limb if noxious stimuli is applied to the limb. This reflex is poly synaptic Crossed extensor reflex To

Golgi tendon reflex Golgi tendon reflex or inverse myotatic reflex or clasp-knife reflex is a protective reflex to prevent over stretching and tear of muscle fibres and coordinate skeletal muscle acti. Sensory receptor organ : golgi tendon organ Present in tendons of somatic skeletal muscle Present in pheripheral terminal and large of mylinated, class Ib nerve