Signalling in the body L12 Flashcards
direct signalling=
substances pass freely between adjacent cells through channels
intracrine signalling=
substances act within the cell
autocrine signalling=
substances act upon the cell that secreted it
juxtacrine signalling=
substances act upon adjacent cells
paracrine signalling=
substances act upon cells nearby (neurotransmitters)
endocrine signalling=
substances act upon cells throughout the body
neuron=
a nerve cell
nerve=
an enclosed cable-like bundle of axons
afferent neurons=
sensory
efferent neurons=
motor neurons
3 main parts of a neuron
dendrites
soma (cell body)
axons
3 neuron types
multipolar
bipolar
unipolar
what is neuroglia
supports the cells of the nervous system
motor unit=
muscle fibers innervated by the same motor neuron
myasthenia gravis=
antibodies against acetylcholine receptors
what does the soma do
integrates inputs and generates action potential
what do dendrites do
receive input from other neurons
what does the axon do
conveys output to other neurons
structure of a nerve (layers) inner-outer (4)
endoneurium
fasciculus
perineurium
epineurium
what does the endoneurium surround
individual nerve fibres
what is a fasciculus
a bundle of nerve fibres surrounded by connective tissue
what is the perineurium
the layer of connective tissue surrounding a fasciculus
what is the epineurium
connective tissue sheath which surrounds each nerve
botulinum toxin =
prevents neurosecretory vesicles from docking/ fusing with the nerve synapse at presynaptic terminal
curare =
blocks nicotinic acetylcholine receptors at the postsynaptic terminal
