Unit 1 Section 3, Neuroanatomy and Neurophysology

Action Potential: Threshold

The strength of a signal measured in +mV. Necessary to trigger an all-or-none action potential response in a neuron

What does the Na-K ion pump do in a cell?

Uses active transport (Energy expanded in the form of ATP) To move Na ions out and K ions in

Passive transport

Ions diffuse through the cell membrane along the concentrated gradient (higher to lower) and no energy is expanded

Spatial summation

Multiple sub-threshold stimuli, in CLOSE PHYSICAL PROXIMITY to a neuron, add up to produce an action potential

Temporal Summation

When multiple sub-threshold stimuli that are close together IN TIME ADD UP to produce an action potential.

What does overshoot mean

Depolarization

What does Undershoot mean

Repolarization

What is the correct distribution/concentration of ions during resting membrane?

More sodium in the extracellular space, more potassium in the intracellular space.

Absolute refractory period

A new action potential cannot be indicated, no matter how strong the stimulus signals.

Efferent pathway

Carries motor information from the brain to the body

Relative Refractory Period

Occurs when the neurons membrane status returns to (at least) 51% restored to resting membrane potential.

What type of cell is this?

Neuron

What type of cell is this?

Microglial Cell

What cell is this?

Astrocyte

What do Astrocytes do?

Anchors neurons to blood supply, barriers around synapses

What does a neuron do?

Processes and transmits cellular signals inside the brain

What cell is this?

Myelin Cell

What does a Myelin Cell do?

Wraps around nerves, protects them

What cell is this?

Ependymal cell

What do ependymal cells do?

Produces cerebrospinal fluid

What point is #1 on the graph?

Resting

What point is #2 on the graph?

Depolarization

What point is #3 on the graph?

Repolarization

What happens at the top point of the graph, in the middle

Overshoot, too much Na

What happens at the lowest point before #4

Undershoot, too much K

What happens in the space before #4

Absolute refractory

What happens at #4

Relative refractory

Which ions are more present outside the cell

Na

What ions are more present inside the cell

K

Which way does Sodium move during Depolarization

Into the cell

Which way does Potassium move during repolarization?

Outside of the cell