21 - Nervous Tissue Flashcards
Where is neural grey matter found?
- Peripheral in the brain
- Central in the spinal cord (butterfly shape)
Where is neural white matter found?
- Centrally in the brain
- Peripheral in the spinal cord
What forms grey matter?
Nerve cell bodies, dendrites, axon terminals, non-myelinated axons and neuroglia
What forms white matter?
Myelinated material
What is the ventral fissure of the spinal cord?
A groove in the anterior medial side of the spinal cord that runs down its length. Divides activity into left and right.
What is the basic structure of a neurone?
- Normal cell organelles
- Cytoplasmic projections - many dendrites and a single axon (does differ)
- Main cell body and dendrites are in the CNS
- Distal axon is in the PNS
- Often coated with myelin
How does the source of the myelin sheath differ in the CNS and PNS?
CNS - part of an oligodendrocyte
PNS - part of a Schwann cell
What are the 4 different types of neurone?
- Motor - CNS to effector
- Sensory - signal to CNS
- Integrative - collate information
- Anaxonic - relays
The majority of the nerves in the CNS are …………… (a type of integrative neurone).
Interneurones
What is a multipolar neurone?
- Most common neurone type
- One axon and multiple dendrites
- E.g. brain and spinal cord
What is a bipolar neurone?
- One axon and one dendrite
- E.g. olfactory cells, retina, inner ear
What is a unipolar neurone?
- Single process leaves the soma and splits into two axons
- E.g. sensory neurones from the skin
What is an anaxonic neurone?
- Many dendrites but no axon
- E.g. visual processing
What are nissl bodies?
- Large granular body in neurones containing rough endoplasmic reticulum and free ribosomes
- Sites of protein synthesis
Describe the microtubule shuttle system used to transport vesicles within a neurone.
- Filled vesicles and mitochondria are transported in the anterograde direction away from the soma
- Empty vesicles are transported retrograde back to the cell body (mitochondria cannot return)