Exam 1 Flashcards Preview

Neurophysiology > Exam 1 > Flashcards

Flashcards in Exam 1 Deck (95)
Loading flashcards...
1

What is the function of neurons?

reception, integration, transmission, and transfer of information

2

Intracellular vs. Extracellular Ion Concentrations

Sodium: high extracellular concentration
Potassium: high intracellular concentration
Chloride: high extracellular concentration
Calcium: very low intracellular concentration

3

Three Properties of Ion Channels

1) conduct ions
2) selective for specific ions
3) open and close in response to specific electrical, mechanical, or chemical signal

4

Non-Gated Ion Channels

always open (leak channels)

5

Modality-Gated Ion Channels

open and close to a specific stimulus (touch, chemical, photons, etc.)

6

Ligand-Gated Ion Channels

open following binding of a chemical (ligand) to a receptor on the membrane surface

7

Voltage-Gated Ion Channels

open in response to changes in the cell membrane potential

8

Gradients are maintained by...

1) presence of large intracellular anions
2) passive diffusion of ions
3) active transport of sodium and potassium via the Na/K pump

9

Modulation

the membrane potential can be altered to become either more positive or more negative (gradual and long-lasting change)

10

Axoplasmic Resistance

smaller axon diameter provides more resistance

11

Membrane Resistance

leakage of ions results in decreased strength of charge

12

Lidocaine

blocks voltage-gated sodium channels

13

Tetrodotoxin (TTX)

blocks voltage-gated sodium channels

14

Lethal Injection (KCl)

eliminated the concentration gradient by flooding the extracellular space with potassium

15

Dehydration/Overhydration

alters resting membrane potential and affects action potential generation

16

Guillain-Barre Syndrome

autoimmune response against myelin. Slowing of nerve conduction and response.

17

Charcot-Marie-Tooth Disease

progressive neural muscular atrophy with weakness in arms and feet; loss of reflexes, loss of sensation, and muscular atrophy

18

Multiple Sclerosis

disease attacks the myelin sheaths in the brain, spinal cord, and optic n.

19

ALS

destruction of alpha motor neurons that give rise to the corticospinal tract and motor neurons in the spinal cord and brainstem

20

Myasthenia Gravis

autoimmune disease that affects the NMJ. Pts display fatigue and exhaustion. Antibodies develop against the ACh receptor.

21

Where are synapses located?

- neurons in the brain
- brain and spinal cord neurons (via spinal cord tracts)
- neurons in the spinal cord
- spinal cord neurons and anterior horn cells (motor)
- peripheral nerves and muscles
- autonomic fibers and target organs

22

Types of Synapses

- axo-somatic: often inhibitory
- axo-dendritic: often excitatory
- axo-axonic: often modulatory

23

Neuromotransmitters

a chemical induces a response in post-synaptic membrane via ligand-gated receptors, then the chemical is acting as a neurotransmitter: can be excitatory or inhibitory

24

Neuromodulators

act to alter neuronal functions by acting at a distance away from the synaptic cleft. They are released into the extracellular fluid and can modulate many neurons simultaneously (ex: Substance P).

25

Presynaptic Facilitation

slightly depolarizes axon, fires longer when action potential arrives; more neurotransmitter is released

26

Presynaptic Inhibition

slightly hyperpolarizes neuron, action potential duration decreased; less neurotransmitter is released

27

Acetylcholine

neurotransmitter at NMJ (excitatory) and in ANS; in CNS it is primarily a neuromodulator

28

Neurotransmitters: Amino Acids

- glutamate
- aspartate
- gamma aminobutyric acid (GABA)
- glycine

29

Neurotransmitters: Amines

- dopamine
- histamine
- serotonin
- norepinephrine

30

Neurotransmitters: Peptides

- substance P
- endorphines
- enkephalins
- calcitonin gene-related peptide (CGRP)
- galanin