Neuron Neural Tissue Flashcards
Smallest cell of the body
Microglial cell
Considered as macrophage if neural tissue
Excitability
Nerve fibres are highly excitable structures that respond to several stimuli and also generate electrical impulses
Irritability
The ability of neurons to detect and respond to external stimuli
Conductibility
The electical impulses generated in the nerve fibre are propogated along its entire lenght and to diff neurons muscles and glands by synaptic connections
Nissl’s granules
Rough endoplasmic reticulum
protein synthesis
Are found in cyton and dendrites
Not found in axion and neuroglial cells
The conduction of impulse occurs through
Axolemma and not axoplasm
Because axolemma has voltage gated ion channels
Myelin sheath is
Lipid rich hence white
↓↓
Hence acts as an insulator (doesnt carry impulse) or electricity
Function of schwann cell in non myelinated neuron of PNS
Formation of neurilemma
Myelin sheath helps in fast/ rapid conduction of impulse
Most on the neurons of CNS are myelinated
Saltatory or jumping conduction
Rate of conduction of impulse depends on
① presence or absence of myelin sheath
② directly proportional to the diameter of neuron
Brain white mater, grey mater
Cortex grey mater
Due to the presence of cell
bodies
Medula White mater
Due to the presence of
myelinated axons
IN SPINAL CORD
OPPOSITE TO BRAIN
Apolar neurons
No dendrites
No axons
Eg. Coelentarata / cnidaria
Hydra
Unipolar neuron
No dendrite
one axon
Eg. Early embryonic phase
Bipolar
One dendrite
one axon
Retina of eye
olfactory epithelium
Multipolar neurons
Many dendrites
one axon
Most commonly found in neurons of human body
