Nerves Flashcards
What are the types of cell in the nervous system?
Neurone
Astrocyte
Microglial
Ependymal
Myelin-producing cells - two types, name them
What are the types of neurone? How do they vary?
Unipolar
Pseudo-unipolar
Bipolar
Multipolar
- Pyramidal - pyramid shaped
- Purkinje - GABA neurone
- Golgi - GABA neurone
Describe the function and structure of a neurone
Excitable cell of the nervous system
Non dividing
Soma - cell body - has nucleus + ribosome
Axon - Long process, originates at AXON HILLOCK - myelinated
Dendrite - not myelinated, gets signals from neurons
Describe the function and structure of astrocytes
Most abundant
Used for REPAIR HOMEOSTASIS IMMUNITY
- Cell repair
- As structural cells
- Facultative macrophages
- Neurotransmitter release
What are the two types of myelin producing cells and what are the differences?>
Oligodendrocyte
- myelination in the CNS
- many axons get myelinated by one cell
Schwann cell
- myelin prodn in PNS
- one cell, one axon
WHat are the functions of microglial cells?
Specialised cells similar to macrophages
What are the functions of ependymal cells
Epithelial cells for lining
Regulate prodn of CSF and movement
Provide an overview of the anatomy of the CNS
Cerebral hemsipheres consisting of:
- Frontal
- Parietal
- Temporal
- Occipital lobes
Brainstem - target/source of all cranial nerves
- Midbrain
- Pons
- Medulla
Cerebellum
- Hindbrain - ATTACHED to brainstem
- Important for motor, balance and posture
Spinal cord
- From medull
- For neural transmission
HOw is the resting membrane potential maintained and what is it caused by?
Varying concentrations of 4 physiological ions are pumped in and out as membrane i simpermeable
- Na+
- K+
- Ca2+
- Cl-
Difference in concentration is:
- EC, Na and Cl are high, K is low
- Ca2+ has a high [gradient]
Leads to a negative resting potential
Describe the steps of an AP
At rest, VGSC and VGKC are closed
1 - Depolarisation
VGSC open, influx of Na+
2 - Repolarisation
VGKC opens, efflux of K+ to repolarise membrane
3 - NaK ATPase pump reduces hyperpolarisation
What are the two configurations of the NaK ATPase pump?
Resting - Na+ enters upon phosphorylation and enters cell
Active - Na removed from cell, K+ enters
How are APs propagated?
Saltatory condution due to myelination by Schwann, oligodendrocytes
AP jumps to NODES OF RANVIER
How is AP moved across synapse?
Same as propagation, when repolarisation occurs at adjacent cell, VGCC are opened, causing Ca INFLUX
This leads to vesicle exocytosis
Nt travels across cleft and binds to post-synaptic membrane
NT disasocc from receptor and taken by enzymes
