Exam 2- Neurons

Question 0

Glial cells

Answer 0

Support
10:1 (glial:neuron)
Ogliodendrocytes (many)

Question 1

Neurons

Answer 1

Excitable cells

Pre-natal

Question 2

(Glial cells)

Schwann cells

Answer 2

Dedicated entirely to 1 neuron
Myelin
PNS

Question 3

(Glial cells)

Astrocytes

Answer 3

Most abundant
CNS
Forms blood-brain barrier (things which diffuse out of capillary must pass through)

Question 4

(Glial cells)

Microglial

Answer 4

Immune cell of CNS

Phagocytic

Question 5

Neuron anatomy

Answer 5

Dendrite (receive signal)
Cell body
Axon (conduct signal)
Presynaptic terminal (contact with target; release neurotransmitters)

Question 6

Afferent neuron

Answer 6

Receiving sensory info (internal/external); conduction of action potentials to CNS

Question 7

Efferent neurons

Answer 7

Motor (muscle movement, glands);
Conduction of action potential from CNS;
Getting a response

Question 8

Interneurons

Answer 8

Transmit info btwn two neurons; contained in CNS

Question 9

Current

Answer 9

Flow of electrical charge

Current carried by ions

Question 10

Capacitance

Answer 10

Ability to separate charges

Lipid membrane maintains ion concentration gradient

Question 11

Conductance

Answer 11

Ability to allow current to cross a membrane

Current is allowed by open channels

Question 12

Resistance

Answer 12

Measurement of membranes impermeability to ions

Resistance is enabled by closed ion channels

Question 13

Ion channels

Answer 13

With gradient, no energy required, dynamic, facilitated diffusion

Question 14

Ion transporters

Answer 14

Set up concentration gradient (capacitance) which is exploited by ion channels
Use energy; against conc. gradient; bind to ions

Question 15

Sodium-potassium pump

Answer 15

Putting more positive our than negative

Question 16

Potential

Answer 16

Measurement of the charge difference (voltage) across lipid membrane
Determined by: ion conc (capacitance) and ion current (conductance vs. resistance)

Question 17

Resting potential

Answer 17

Charge difference in a resting cell

Outside cell= 0mV

Question 18

Equilibrium potential

Electrochemical

Answer 18

For a particular ion, the potential at which there would be no net ion movement.
Depends on ion conc (capacitance)
Independent of ion current
Theoretical

Question 19

Nernst equation

Answer 19

For equilibrium potential

Question 20

Goldman equation

Answer 20

For membrane potential

Question 21

Depolarization

Answer 21

Size of membrane potential decreases; sides of the membrane become more similar
Resting potential becomes less negative

Question 22

Hyperpolarization

Answer 22

Size of the membrane potential increases; sides of the membrane become less similar
Resting potential more negative

Question 23

Repolarization

Answer 23

Return to the original resting potential following a change in membrane potential

Question 24

Overshoot

Answer 24

Reversal of charge

Membrane potential becomes positively charged

Question 25

Action potential

Answer 25

An electrical signal that can travel (propagate) down an axon; involves overshoot

Question 26

Action potential characteristics

Answer 26

All or none response, non decremental, no summation, refractory period

Question 27

K voltage gated channel

Answer 27

Single gate closed at resting potential
Depolarization stimulus, slowly opens
Negative k current repolarizes

Question 28

Na voltage gated channel

Answer 28

2 gates (activation and inactivation)
Activation (depol and opens fast, generates positive current)
Inactivation (slow, closes once activation gate is closed)
Refractory period

Question 29

K leaky channel

Answer 29

Always open

Question 30

Speed of action potential

Answer 30

Depends on ratio of transverse (across membrane) to longitudinal (down length of axon) resistance
Increased axon radius decreases both resistance (longitudinal at greater rate)
Myelin increases velocity (decrease longitudinal and increase transverse)