Neurocytology Flashcards
What are the features of a typical vertebrate neuron?
Cell body, dendrite, axon, terminal branches of axon
What is the cell body?
Region of integration of incoming information and metabolic center of the cell. Large amount of condensed rER. Nissl Substance
What is a Dendrite?
Major area of reception of incoming information. Apical and basal locations on cell body. Tend to taper in diameter. Cell can give rise to many dendrites from soma.
What is a Axon?
Specialized for carrying information away from the cell body to other parts of the circuit. Cell tend to give rise to only one axon but it branch extensively.
What are the axon terminals?
Also known a boutons/varicosities)
Location of synapse
What is a characteristic of dendrites on axons found in the cerebellum?
Form tree like structure. Extensive network of dendrites
Neurons found in the cerebellum are called?
Purkinje cell
Neuron found in the cortex are called?
Pyramidal cell
How can you tell a dendrite from a axon?
Dendrites are thick and axons are small
What are nissl bodies and how do they stain?
They are rER and free ribosomes and they stain dark`
Where are motor neurons located?
Spinal cord
This neuron has one axon and several dendrites. It can be found in most vertebrates
Multipolar neuron
This neuron has one axon and one dendrite. It can be found in the retina (photoreceptors) and the olfactory epithelium.
Bipolar Neuron
This neuron contains central and peripheral axons. No dendrites. Can be found in the dorsal root ganglia.
Pseudo-unipolar Neuron
The peripheral axon of the pseudo-unipolar neuron behaves like what?
Like a dendrite
This neuron has on axon with dendritic branches and is found in the autonomic system and invertebrates
Unipolar Neuron
What is the Neuron doctrine?
Explains that together neurons form a network of interconnected cells, but not through a syncytial arrangement.
What is the structure of a synapse?
It is where the synaptic knob meets the target cells (postsynaptic neuron)
What is the state of synaptic knob when the nerve terminal is at rest?
Voltage Gated calcium channels are closed. Neurotransmitter is within a synaptic vesicle
What is the state of the synaptic knob when the nerve terminal is activated by an action potential?
Voltage Gated Calcium channels are open. Vesicle fuses with membrane releasing Neurotransmitter into synaptic cleft. Neurotransmitter binds to receptors on postsynaptic cell
What is the order of synaptic transmission?
- Vesicle “dock” at active site
- Action potential leads to influx of calcium
- Rise in Calcium triggers vesicle fusion and release of transmitter
- Transmitter diffuses across cleft and binds to receptors
- Membrane retrieved by coated vesicles for reuse
What is a characteristic of the neuromuscular junction?
Deep invagination on the postsynaptic cell (muscle cell)
How are synaptic vesicles (SV) formed?
- Delivery of SV components to PM
- Endocytosis of SV components to form new SV directly or endocytosis of SV components and delivered to endosome
- Budding of synaptic vesicle from endosome
- Loading of neurotransmitter into vesicle
- Excocytosis in response to AP
Where can synaptic vesicles be found?
Only in nerve cells and some endocrine cells.
