Lecture 19: Nervous Tissue (Structure and Function) Flashcards
(48 cards)
What are the 2 parts of the nervous system?
Central and peripheral
What are the 2 components of the central nervous system?
Brain and spinal cord
What are the 2 components of the peripheral nervous system?
Cranial nerves, spinal nerves and peripheral nerves
Where are 2 places that grey matter located?
- Peripheral in brain and in areas called nuclei
- Central in spinal cord (H shaped / butterfly shaped)
What are the 5 components of grey matter?
Nerve cell bodies Dendrites Axon terminals Non-myelinated axons Neuroglia
Where are the 2 locations that white matter is located?
Central in brain
Peripheral in spinal cord
What does white matter consist of?
Myelinated material
What are the 3 parts of the axon in the CNS?
Cell body, dendrites and proximal part of the axon
What part of the neuron is part of the PNS?
Distal axon
In the CNS, what produces myelin for the axon?
Oligodendrocyte
In the PNS, what produces the myelin?
Schwann cell
What are the 4 types of neurons?
Motor
Sensory
Integrative
Anaxonic
Where is motor neurons located?
CNS to PNS
Where is sensory neurons located?
PNS towards CNS
Where is integrative neurons located?
CNS
Where are anaxonic neurons located?
Retina (some parts of CNS)
What is the function of motor neurons?
Send signals to effector tissues
What is the function of sensory neurons?
Send environmental signals to integrative centre
What is the function of integrative neurons?
Collate all information
What is the function of anaxonic neurons?
Acts as relays
What are the 8 steps of neurotransmitter synthesis?
- Synthesis of neurotransmitter and formation of vesicles
- Transport neurotransmitter down the axon
- Action potential travels down the axon
- Action potential causes calcium to enter, evoking release of neurotransmitter
- Neurotransmitter attaches to receptor, exciting or inhibiting postsynaptic neuron
- Separation of neurotransmitter molecules from receptors
- Reuptake of neurotransmitter to be recycled
- Vesicles without neurotransmitter transported back to cell body
What are the organizations of peripheral nerves?
Endometrium (loose) surrounds single nerve cells
Perineurium (loose) surrounds a fascicle (clusters of axons)
Epineurium (dense irregular) separates different types of nerves and fills spaces between fascicles
Paraneurium (fascia) separates nerves from surrounding structure
What are the 4 steps of myelination?
- Axon sitting in a groove is surrounded by a Schwann cell
- Mesaxon membrane initiates myelination by surrounding the embedded axon
- Sheet like extension of the mesaxon membrane wraps successively around the axon, forming multiple membrane layers
- Cytoplasm is extruded from between the membranes - becomes compacted to form myelin
What is the relationship between intermodal distance and axon size?
Larger internodal distance = larger axon diameter = fastest saltatory conduction