Neurones Flashcards
what is nervous tissue composed of
- Neruones – transits the information
- Glia – sepicalised support cells
what is the same as a PNS ganglion in the CNS
- a brain nucleus
what is brain nucleus or PNS ganglion
it is a collection of neurones with common circuitry and function that are found in the grey matter
in the PNS what is a collection of axons called
it is always called a nerve
in the CNS what is a collection of axons called
might be called various names including fasciculus, column, leminscus, tract or bundle
How do you stain cell bodies and the first part of dendrons
Staiend blue with nissl stain due to the large amouts of RER
describe the staining comparison between neurones and glial cells
Neruones are larger compared to the smaller glial cells
– but glial cells have more predominant nuclear staining are supporting glial stage – darker blue for the nucleus
What passes through the brain stem
- Axonal tracts carrying sensory input to the rest of the brain as well as morot outputs from the brain to the spinal cord pass through it
- Motor and sensory innervation ot the head and neck is carried in cranial nerves arising from the brain stem
What is a neurophil
It is a dense tangle of neuronal axons and dendrites and glial processes
- it is the site of communication between various components for example where synapses are formed between terminal boutons of axons and dendritic processes
dendrites ..
have spikes this is how you distinguish them from axons
- axons also have myelin sheaths making them easy to identify
how does myelin stain
Myelin stains in somium fixed preparations so axons have myelin sheaths that are easy to idetify
Describe the characteristics of the neurone
- Irritable and conductive – recepotrs and ion channelsl and membrane properties
Parts of the neuroen - Dendrities – sensory (afferent) – receive information and relay it to the cell body (electrical signals)
- Cell body – large nucleus, abudnatn in rer, performs synthetic and metabolic functions, integrates information at the axon hillock to produce axon potentails
Describe the parts of the neurone
- Cell body (or soma)
- axon - effector portion and propagates the action potential (efferent role goes away)
- terminal boutons - terminal expansions of the axon specialised for chemical neurotransmission, are at the end where cell to cell communication occurs at the synapses, within terminal boutons there are synaptic vesicles which contain the neurotransmitter used in chemical neurotransmission
- dendrites - these arise from the cell body (afferent role goes to)
- only one axon will leave the cell body
- action potential is initiated at the axon hillock
what increases the speed of the action potential
- myelination
- larger diameter
what does afferent mean
goes to