Topic 3: Nervous System 1 - Neurons + Electrical Properties of Cells Flashcards
1
Q
What does it mean by “neurons are excitable?”
A
responsive to stimuli
2
Q
What occurs when neurons are stimulated? (3)
A
- stimulated usually on cell body or dendrites
- an electrical impulse may be generated and propagated along the axon
- called a nerve impulse
3
Q
What causes electrical properties of cells? (2)
A
- ionic concentration differences across membranes (gradients)
- Permeability of cell membrane to ions
4
Q
What are the four important ions?
A
- K+
- Na+
- Cl-
- Ca++
5
Q
what are large negatively charged organic ions? (2)
A
org-
- non-diffusable proteins
6
Q
Diagram of cell with important ions
A
7
Q
What is the concentration of sodium and potassium due to?
A
- due to and maintained by the activity of Na+/K+ - ATPase pump in cell membrane
8
Q
What is the concentration of calcium due to?
A
- due to various transporters in cell and ER membranes
9
Q
What is Chlorine repelled by, and what does it cause?
A
- repelled by org- (large, - organic ions)
- therefore its [] is higher outside of cell than inside
10
Q
Where do org- stay?
A
inside the cell
11
Q
What does permeability of cell membrane to ions determined by?
A
- determined by ion channels
- bc ions diffuse through them down CG
12
Q
what are non-gated channels? (2)
A
- always open
- more K+ than Na+, so cell membrane is more permeable to K+ at rest (no stimulus)
13
Q
Why are non-gated channels important?
A
- these channels (esp. K+ is more numerous) establish the resting membrane potential (RMP)
14
Q
What are gated ion channels?
A
- not involved at rest
- open in response to stimuli
15
Q
What are voltage gates?
A
- Membrane voltage changes
