Cells of the Nervous system Flashcards
What is a neuron?
- basic structural and functional unit of NS
- info processing unit
- responsible for generation and conduction of electrical signals
What are neurones supported by?
Neuroglia
Describe the soma.
- metabolic centre of cell
- large nucleus, prominent nucleolus
- abundant rough ER and free ribosomes
- well developed golgi
- large number of mitochondria
- numerous lysosomes
- highly organised cytoskeleton
Describe dendrites
- input for incoming info
- diameter dec further away from cell body
- greatly inc. SA of neurone
- covered in dendritic spines
Describe dendritic spines
- receive majority of synapses
- dynamic (can inc or dec number of spines present)
What is Schizophrenia caused by?
Loss of dendritic spines present
describe the axon
- output
- emerge at axon hillock
- prominent microtubules + neurofilaments
What is the molecular composition of the axon?
Organised into domains:
- Node: consists of all Na+ channels
- Paranode: next to node
- Juxtaparanode: next to paranode, consists of all K+ channels
Bouton (synaptic terminal)
Large, bulb-like structure which forms at end of terminal branches
Varicosities (synaptic terminal)
swelling like structures that form along axon
What is the function of the neuronal cytoskeleton?
Axon maintains tensile strength, allow transport of proteins
Neurofilaments play critical role in determining axon calibre
What is fast axonal transport?
- transport of membrane
- vesicles w/ associated motors moved down axon
What is anterograde transport?
Transport of materials needed for neurotransmission and survival away from cell body
uses specific molecular motors
Give some examples of fast retrograde transport.
- return of organelles
- transport of substances from EC space
Pseudounipolar
single axon acts as continuous cable carrying AP from peripheral receptor organ to central terminal in spinal cord
Bipolar
2 axonal processes with central soma e.g. in cerebral cortex, retina
Golgi type I multipolar
- highly branched dendritic trees
- axons extend long distances
Pyrimidal cells of cerebral cortex
- responsible for all of cortical output
- major excitatory neurones
- triangular shaped soma
- single axon
- as distance from soma inc, basal dendrites branch profusely
Golgi type II multipolar
- short axons terminating quite close to cell body of origin
- small multipolar cells
- use glutamate/ aspartate as neurotransmitter
Sensory neurones
- pseudounipolar ( 1 major process, divides into 2 branches)
- conducts impulses from sensory receptors to CNS
e. g. dorsal root ganglia
Motor neurones
- conduct impulses from CNS to effectors
- multipolar w/ large soma
e. g. spinal motor neurones
Interneurones
- cell bodies and processes remain within CNS
- responsible for modification, coordination, integration facilitation and inhibition that must occur b/ sensory input + motor output
Laminae
layers of neurones of similar type and function
e.g. cerebral cortex grey matter
Ganglion
group of encapsulated neuronal cell bodies in PNS
e.g. dorsal root ganglia
