drive - neurons and glial cells Flashcards
What are the 4 basic components that all neurons have?
Dendrites
Cell body/soma
Axon
Presynaptic terminal
Describe the path of a signal after initial stimulation.
information received via the dendrites which transmit to the cell body. The information is then transmitted via the axon to the presynaptic terminal (where it can then pass to another neurone)
What are the 3 functional classes of neurones?
Afferent
interneurons
Efferent
What type of information do afferent neurones carry?
Sensory
What type of information do efferent neurones carry?
Motor
What is referred to by the term nerve fibre?
A single axon
What is referred to by the term nerve?
A bundle of axons bound together by connective fibres
In what direction do afferent signals pass?
From the tissues and organs towards the CNS
In what direction do efferent signals pass?
From the CNS to effector cells
Where are the cell bodies of afferent neurons located?
Outside the CNS
Where are the cell bodies of efferent neurones located?
Within the CNS
Where are interneurons located
Entirely within the CNS
What are the myelinating cells in the brain and spinal cord?
Oligodendrocytes
What are the myelinating cells in the peripheral nervous system?
Schwann cells
How many axons can an oligodendrocyte myelinate?
Lots (as many as 40)
How many axons can a Schwann cells myelinate?
1
What are the nodes of Ranvier?
Spaces between adjacent sections of myelin where the axons plasma membrane is exposed to extracellular fluid
What does myelination increase?
The speed of conduction along axons
Which are thicker myelinated or unmyelinated axons?
Myelinated
Where are glial cells found?
Surrounding the cell body of neurones, axons and dendrites.
What is the function of glial cells?
To provide physical and metabolic support
What is the function astrocytes?
To help regulate the composition of the extracellular fluid in the CNS.
Stimulate the formation of tight junctions between the cells
What forms the blood brain barrier? (3)
The foot processes of astrocytes that closely applied around capillaries
Endothelial cells
Pericytes
Where are protoplasmic glial cells found?
In the grey matter