Knowt
Recording-2025-03-04T12:58:56.844Z
Overview of Upcoming Quiz
Bonus quiz scheduled from Thursday to Saturday of this week.
No quiz will be held next week due to spring break.
Neurons and Glial Cells
Finish the basic information about neurons in the upcoming lecture.
Discuss types of neurons and glial cells.
Glial Cells: Supporting cells in the nervous system; crucial for the function of neurons.
Types of Neurons
Different kinds of neurons to be covered.
Neurons are responsible for generating electrical signals.
Electrical Signal Generation
Overview of the generation of electrical signals in neurons.
Dendrites and soma are initial parts of neurons involved in signal integration.
Axon initial segment: Site where signals are integrated based on inputs from multiple synapses.
Integration of Signals
Neurons can receive hundreds of synaptic inputs (depolarizing/hyperpolarizing).
The dominant signal will determine if an action potential is generated.
Integration of inputs is comparable to binary signaling (zeros and ones).
Voltage-Gated Channels
Channels open in response to membrane potential changes.
Threshold potential must be reached for channels to open.
Axon Structure and Functions
Axon Collateral: Branch of the axon that can form synapses.
Telodendria: Branches at the end of axons leading to synaptic knobs.
Release of neurotransmitters occurs here upon action potential arrival.
Synaptic Transmission
Neurotransmitter released in response to action potentials at synaptic knobs.
Neurons vs. Glial Cells
Neurons: Send electrical signals.
Glial Cells: Provide support, not directly involved in signaling.
Types of Glial Cells (CNS)
Microglia:
Function as immune cells in the brain.
Monitor brain tissue for infections and inflammation.
Act as phagocytes to ingest damaged cells.
Astrocytes:
Support neurons and form a structural framework within the brain.
Regulate ion concentrations in the extracellular fluid.
Remove excess neurotransmitters.
Oligodendrocytes:
Myelinate axons in the central nervous system.
Their processes wrap around multiple axons in CNS.
Peripheral Nervous System (PNS) Glial Cells
Schwann Cells:
Form myelin sheath around a single axon.
Support repair and regeneration of peripheral nerves following damage.
Satellite Cells:
Surround neuron cell bodies in ganglia; regulate neurotransmitter levels.
Communication and Neurotransmitters
Discussion on how neurotransmitters become 'used'.
Release and recycling of neurotransmitters occur at synapses.
Axon Initial Segment Function
Acts as integration point for incoming signals; determines if action potential is triggered.
Action Potential and Signal Propagation
Action potential can propagate along the axon once initiated.
Na+ influx leads to depolarization; K+ efflux results in repolarization.
Length Constant and Signal Degradation
Signals lose strength over distance; requiring boosters to maintain intensity.
Length constant: Measure of how far electrical signals can travel without degrading.
Key Concept Review
Importance of maintaining resting membrane potential and ion gradients in neurons.
Memory retention of these concepts is crucial before moving forward into deeper topics, such as neuroplasticity and the mechanics of synapses.
