13.2 Neurones Flashcards
what is the role of a neurone?
to transmit electrical impulses around the body
what are the 3 types of neurone?
sensory
relay
motor
what are sensory neurones?
transmit impulses from sensory receptors to a relay neurone
what are relay neurones?
transmit impulses between neurones
what are motor neurones?
transmit impulses from a relay neurone to an effector
what are the key features in a neurone?
cell body
dendrons
axons
myelin sheath
nodes of Ranvier
what is the cell body?
contains a nucleus and cytoplasm and lots of ER and mitochondria needed to produce neurotransmitters
what is the dendron?
transmit electrical impulses TOWARDS the cell body
what is the axon?
transmit electrical impulses AWAY from the cell body
what is the myelin sheath?
consists of a layer of Schwann cells which increase the rate of electrical transmission in the neurone
what is the node of Ranvier?
gaps between adjacent Schwann cells which speeds up the propagation of action potentials
what effect does myelination have on impulses?
a myelinated neurone can transmit impulses further as well as at a faster rate due to the nodes of Ranvier
how are impulses transmitted with a myelinated neurone?
the electrical impulse jumps from one node to another
called saltatory conduction
much faster
are the nodes of ranvier conductors or insulators?
electrical conductors
what is the function of Schwann Cells?
produces myelin
insulates
prevents depolarisation
speeds up transmission of action potentials
depolarisation only occur at the nodes of ranvier
allows for saltatory conduction
