NEUR1203 Midterm 1 Full Review

List the 4 main types of neurons discussed in the class

Sensory neurons (Afferent), motor neurons (Efferent), Interneurons (In the brain), Pyramidal neurons (excitatory)

List the 5 basic neuronal structures

Axon, Axon Hillock, Axon terminal, Dendrites, Dendritic Spine

List the 4 Basic Types of Glial Cells

Astrocytes, Schwann Cells, Oligodendrocytes, Microglia

Describe the function of Astrocytes

maintain ion and neurotransmitter homeostasis and support the BBB

Describe the main function of Oligodendrocytes

Myelinate axons in the CNS

Describe the main function of Schwann Cells

Myelinate axons in the PNS

Describe the main function of Microglia

Resident immune cell, phagocytosis

List the Five different types of Ion Channels

Passive Diffusion, Leakage Channel, Voltage Gated, Ligand Gated, Signal Gated

Describe a Leakage Channel

Always Open

Describe a Voltage Gated Ion Channel

Opens in response to change in the membrane signal

Describe a Ligand gated Ion Channel

Opens/ closes in response to a specific extracellular neurotransmitter, trigger comes from outside the cell

Describe a Signal Gated Ion Channel

Opens/ Closes In response to a specific intracellular stimuli, trigger comes from inside the cell

Describe the Ion Distributions of a Resting Membrane (Na+, K+, Cl-)

Na high outside, K high inside, Cl- high outside

Describe the reasons why a resting membrane is so negative

K+ leaks channels allow K+ to leave

Na+ permeability is low at rest

Na+/K+ pump, Uses ATP and pimps 3 Na+ out and 2 K+ in, more cations are leaving than coming in

Describe the process of an Action Potential

Dendrites receive signal from presynaptic neuron,

Cell body integrates incoming signals and generates outgoing signal to axon,

Axon passes electrical signals to dendrites of another cell or to an effector cell

Define A Local Graded Potential

A small and short-lived localized change in a neuron’s membrane potential, directly proportional to the initiating stimulus

How does hyperpolarization occur in a Local Graded Potential

Efflux of K+, or an influx of Cl-, both make the extracellular side of the membrane more positive

How does depolarization occur in a Local graded Potential

Influx of Na+ through Na+ channels

Define the Refractory Period

The time interval required to recover from an action potential in order to generate another one

Define the Absolutely Refractory Period

From the depolarization phase to the initial repolarization phase, essentially the entire action potential

Define the Relatively Refractory Period

From the late repolarization phase to the initial repolarization phase of the action potential

Define Depolarization

The initial phase of the action potential, when the membrane reaches -55Mv

Define Repolarization

The second phase, membrane returns to resting state. Restoration of the membrane potential to -70 mV through movement of ions accross the membrane

Define Hyperpolarization Ion Channels

Previously open Ion Channels required a period to revert to their initial confirmation, cations continue to exist the neuron which accumulates a negative charge within the cell

True or False: The Size and Shape of an action potential remain the same along the axon

True

Describe Saltatory Conduction

Axon signals jump over myelinated (insulated) portions of the axon into unmyelinated Nodes of Ranvier

Describe the synthesis site, release and action duration of a Small Molecule Transmitter

The Axon Terminal, Single action Potential, Short

Describe the vesicle of a Small Molecule Transmitter

Small and clear

Is there Recycling of Small Molecule Transmitters

Yes

How does degradation occur in Small Molecule Transmitters

Reuptake transporters and enzymes

Describe the Synthesis Site, Release and Action Duration of a Peptide Transmitter

Cell Body, High Frequency Activity, Long

Describe the Vesicle of a Peptide Transmitter

Large Dense Core

Is there recycling of peptide transmitters?

No

How does degradation occur in Peptide Transmitters

Proteolytic Enzymes