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
Importance of equatorial region Action potential are generated from this equatorial region by stretching. Muscle spindle receptors lie parallel to the extra fusal fibers. Functionally these receptors are connected to the origin and insertion of the tendon i.e. lengthening of the whole muscle will stretch the equatorial region. Contraction of polar ends also generate action
Myotatic reflex or Knee jerk reflex Myotatic reflex is a sudden stretch of a muscle causes its reflex contraction. Commonly known as “KNEE-JERK” reflex. It forms the basis of the maintanence of “Muscletone” Receptor organ concerned with this reflex is Muscle –spindle organ. These receptors are encapsulated in the belly of skeletal muscle. CNS receives sensation from these
Nystagmus Nystagmus is the movement of the eye in relation to the movement in the head of the animal. It consists of rhythmic movements of the eyes in a dorsoventral, lateromedial, or oblique directions. It is characterized by the slow movement of the eye in one direction and then quick return to its original starting
Physiology of Vestibular apparatus The vestibular apparatus located in internal ear that detects sensation related to equilibrium (linear acceleration of head). Popularly known as OTOLITHIC organ. It consist of bony labyrinth (semicircular canal with utricule and saccule) and membranous labryinth. This is the functional part of the vestibular apparatus and is composed of cochlear duct,
Postural Reflexes Postural Reflexes is also known as postural reactions. It is defined as the position or arrangement of the body and its limbs. It is controlled by the activity of the skeletal muscles of the neck and limbs. Control of posture involves mechanisms that alter the excitable activity of α-motor neurons of the spinal
