Lecture 6 Flashcards
(29 cards)
Where are action potentials generated?
The axon hillock
What is the cytoplasm in axons called?
Axoplasm
What is the plasmalemma in the axon called?
Axolemma
What are Nissl bodies?
rER and free ribosomes in the neurons
What is a neurofilament?
An intermediate filament present in the neuron that provides structural support
What is the myelin sheath?
A sheet made from Schwann cells that insulates the axon
What are Schwann cells?
A type of glial cell that wraps around the axon in neurons in the PNS to form the myelin sheath
What is saltatory conduction?
Since the axon is myelinated, the action potential is able to jump from one node of ranvier to the next which is quicker than it going the whole way along
What is multiple sclerosis?
A disorder that disintegrates the myelin sheath
What is a nerve fibre?
A nerve cell and its myelinating Schwann cell
What is the endoneurium?
The connective tissue that surrounds a nerve fibre
What is a fascicle?
When many nerve cell come together, they form a fascicle
What is the perineurium?
Connective tissue that surrounds a single fascicle
What is the epineurium?
Connective tissue that wraps around many fascicles
What is chromatolysis?
Degenerating neurones having their Nissl substance start to disappear
What are the neuron classifications?
Sensory/afferent
Motor/efferent
Interneurons
Multipolar
Bipolar
(Pseudo)unipolar
What do afferent neurons do?
Send signals to the CNS
What do efferent neurons do?
Send signals from the CNS to the periphery
What are interneurons?
They act locally within the CNS and connect neurons with each other
What are bipolar neurons?
They are usually found in the retina
They connect ganglion cells to photoreceptors
What are the types of synapses?
Axo-dendritic (connect axon to dendrites)
Axo-axonic (connect axon to axons)
Axo-somatic (connect axons to cell body)
What are the glia cells in the CNS?
Ependymal cells
Oligodendrocytes
Astrocytes
Microglia
What are the glia cells in the PNS?
Schwann cells
Satellite cells
What are astrocytes?
The most abundant type of glia cell
They can be fibrous or protoplasmic (long but less protrusions of short but more protrusions)
They provide structural support, energy storage, form the blood brain barrier, etc
