Nerve Tissue Structure and Function Flashcards
What are the two nervous systems and what are their components?
Central Nervous System - brain and spinal cord
Peripheral Nervous System - cranial and spinal nerves
Is grey matter central or peripheral in the brain?
Peripheral
Name 3 components of grey matter
- Nerve cell bodies
- Dendrites
- Axon terminals
- Non-myelinated axons
- Neuroglia
What shape does the grey matter form and what are the anterior and posterior horns called?
- Butterfly shaped
Anterior - ventral horns
Posterior - dorsal horns
What constitutes white matter?
Myelinated material
What two tracts are formed by nerve fibres in white matter?
Ascending and descending tracts
What name is given to the gap between the ventral horns?
Ventral fissure
What is the name of the main body and extensions of a neuron?
Soma - main cell body
Dendrites - cytoplasmic projections
Which parts of a neuron lie in the CNS?
- Soma
- Dendrites
- Proximal part of axon
Which parts of the neuron lie in the PNS?
- Distal axons
- Arborisations
What are the two types of myelin cell and where is each found?
Oligodendrocyte - Found in CNS
Schwann Cell - Found in PNS
What 3 types of neuron make up the reflex arc?
- Sensory
- Interneuron
- Motor
What are the 3 types of neuron found outside of the CNS?
- Unipolar
- Bipolar
- Anaxonic
Name two specialised neurons found in the CNS
- Purkinje cells
- Pyramidal cells
What is the most common neuron in the CNS and what is its structure?
Multipolar - one axon and multiple dendrites
Which organelles are abundant in neurons?
- Rough endoplasmic reticulum
- Golgi apparatus
- Free ribosomes
- Vesicles
Which organelle aids vesicles to move along the neuron and which directions can they travel?
- Microtubulues
Anterograde - soma to synapse
Retrograde - synapse to soma
What does neurotransmitter synthesis require?
- Vesicle
- Enzyme
- Neurotransmitter
When are neurotransmitters synthesised?
When vesicles travel down the axon
Name 2 types of synapse
- Axodendritic
- Axoaxonic
- Dendo-dendritic
- Axo-axonal
What are the 3 types of nerve fibre found in the peripheral nerve?
- Sensory
- Integrative
- Motor
What are the four layers of a peripheral nerve from outer to inner?
- Paraneurium
- Epineurium
- Perineurium
- Endoneurium
What is a fascicle?
A cluster of axons
What is the Endoneurium?
Inner loose connection layer of a nerve that surrounds single nerve cells
What is the difference between myelinated and non-myelinated?
Myelinated - Schwann cells surround the axon
Non-Myelinated - Axons are on the edge of the Schwann cell
What variants influence the speed of nerve conduction?
- Internodal distance
- Axon diameter
- Myelinatiom
Describe 2 differences between A, B and C fibres
A Fibres - thick, fast, in CNS, motor function, myelinated, large internodal distance
B Fibres - medium, average speed, in viscera, sensory function, myelinated, small internodal distance
C Fibres - thin, slow, in peripheries, sensory function, unmyelinated, no nodes
Which membrane initiates myelination?
Mesaxon Membrane
Which part of the cell forms multiple layers around an axon?
Sheet extension of the mesaxon membrane
What happens to the cytoplasm in myelination?
It is compressed to form myelin
What is the name of the cell similar to a Schwann cell but found in the CNS?
Oligodendrocyte
How is an Oligodendrocyte different from a Schwann cell?
- It can wrap around more than one axon simultaneously
- Smaller than Schwann cells
What 4 cell types support the function of the CNS?
- Oligodendrocytes
- Astrocytes
- Microglial cells
- Ependymal cells
Name 2 functions of Astrocyte cells in CNS
- Nutrient transport from blood to nerve cells
- Biochemical support
- Regulate nerve impulses using glutamate
- Contribute to blood-brain barrier
Which cell acts as a macrophage in the CNS?
Microglial cell
Which type of cell lines the spinal canal?
Ependymal cell
What does an Ependymal cell look similar to?
Columnar epithelium but has no basement membrane
Name 2 functions of Ependymal cells
- Synthesise and secrete CSF in the ventricles
- Cilia move CSF through ventricles to spinal cord
- Microvilli absorb CSF for pathogen removal
- Modified tight junctions control fluid release into the brain
Name 3 symptoms of Multiple Sclerosis
- Fatigue
- Decreased mobility
- Vision problems
- Slurred speech
- Numbness and tingling
What causes Multiple Sclerosis?
- Autoimmune myelin degradation
- Loss of conduction velocity
