6.1 - Tissues of the peripheral nervous system Flashcards
What are the main structural components of a neuron?
cell body
dendrites
axon
terminal arbors
What is the structure and function of the neuron cell body?
structure
- large nucleus with finely dispersed chromatin
- cytoplasm / perikaryon contains RER /golgi body / mitochondria etc
function
- signal integration - receives + processes signals from dendrites
- neurotransmitter synthesis
What is the structure and function of dendrites?
Structure:
- Short, branched extensions of the neuron.
- Branch out from the cell body, increasing the surface area for synaptic input.
- Contain dendritic spines
Function:
receive electrical impulses from other neurons via synapses and transmit INTO cell body
Dendritic spines undergo structural changes in response to synaptic activity, playing a role in learning and memory.
what are dendritic spines
plastic structures = membrane-bound protrusions found on the dendrites of neurons
consists of a neck and an enlarged head that hosts the synaptic junction with the axon
receives input from a single synapse of an axon
Serve as a storage site for synaptic strength and help transmit electrical
signals to the cell body
What is the structure and function of the axon?
Structure:
- Long, singular process that extends from the axon hillock of the cell body.
- Can be myelinated
Function:
Transmits action potentials away from the cell body to target cells
branches into terminals (axon terminal arbors) that make synaptic connections with other cells, allowing communication.
What is the role of axon terminal arbors in neurons?
Terminal branches of the axon that form synapses with target cells
Contain synaptic boutons (endings), where neurotransmitters are released into the synaptic cleft.
Neurotransmitters are released from synaptic vesicles at the terminals, transmitting signals to the next cell.
branching of axon terminals allows a single neuron to communicate with multiple target cells.
importance of axon terminal arbors
branching of axon terminals allows a single neuron to communicate with multiple target cells.
How is structural polarity seen in neurons?
Neurons are asymmetrical
Dendrites and the cell body form the input region (specialized to receive signals).
The axon = output region, transmitting information away from the cell body.
What is functional polarity in neurons
exhibit unidirectional impulse propagation = travel from the dendrites, through the soma, and down the axon to the axon terminals.
Dendrites receive signals, the cell body integrates them, and the axon transmits the signals to target cells.
what are nissl bodies
when cell body stained with dyes = RER appears as clumps of basophilic material called Nissl
bodies
what is the cytoskeleton made up of in neurones
- microfilaments
- neurofilaments
- microtubules /MT
how does transport occur on MT
via motor proteins
kinesin directs
anterograde transport = towards plus end
dynein conducts retrograde transport of produces in the
opposite direction = towards minus end
What is the structure and function of kinesins?
toward PLUS end - anterograde
2 motor domains (heads) for movement on microtubules - STEPWISE MOVEMENT
- Tail binds cargo (vesicles, organelles)
Function:
- Chromosome movement (mitosis)
- Cargo movement like mitochondria, vesicles
What is the structure and function of dyneins?
toward MINUS end - retrograde
Large, multi-subunit complexes
Function:
Retrograde transport - ROTATIONAL movement
Move endosomes, lysosomes, vesicles
Cilia/flagella movement (axonemal dynein)
how do they ‘walk’
idk
why is transport studied in neurones
extremely well polarised
anterograde movement
towards the plus end / synaptic bouton
retrograde
towards minus end // cell nucleus
