85. types of neurones 86. dendrites and axon Flashcards
What is a neuron
an electrically excitable cell that responds to stimuli and processes and transmits info through ELECTRICAL AND CHEMICAL signals
What are the three main parts of a neuron
cell body (soma/perikaryon)- contains nucleus and organelles
dentrites- elongated processes from the cell body receives stimuli from synapses
axon- single long process ending at synapses specialized to generate and conduct nerve impulses to other cells
NEURONES ONLY HV 1NUCLEUS
What are the three main type of neurons
Sensory- afferent meaning they receive stimuli
Motor- efferent meaning sends impulses to effector organs
interneurons- connect different neurons together
neirones can be classfied by the number of processes coming from their body. What are the types
Multipolar- one axon, 2 or more dendrites
bipolar- one axon, one dendrite
pseudounipolar/unipolar-single process that bifurcates, one branch peripheral, one CNS
axaxonic- no true axon, many dentrites. doesn’t produce action potential
what are the granulations you can view with microscope in the cytoplasm of perikaryon
Nissl granulations
because of highly developed RER
What are dendrites
short processes that carry info back towards the soma
action potential propagates down dendrite
they occur on dendritic spines- depends on actin filaments (key in neural plasticity
what is axon
fine cable like projection
carries signals to and from soma
plasma membrane= axolemma contents-axoplasm
where does the neuron have the greatest density of voltage dependent sodium channels
where the axon emerges from soma : axon hilock
making it the most excitable part of neuron
axons are surrounded by myelin sheath. How does this help the neuron
increases speed of info transmission because of the gaps this sheath makes called nodes of ranvier
