Lab 9 Nervous System

Question 1

What is Chronaxie?

Answer 1

It’s the minimal duration that’s necessary to elicit an AP, if the stimulus strength is twice the Rheobase.

Question 2

What factor determines if we have a monophasic or biphasic CAP?

Answer 2

The distance btw the electrodes

Question 3

Define local response

Answer 3

The decreasing magnitude of potential change due to physical process

Question 4

What is resting membrane potential?

Answer 4

The difference btw intra and extracellular space potential

Question 5

What’s the name of the fibers leading impulses from organ to spinal cord?

Answer 5

Neuron fibers type Ia and type II

Question 6

Explain exteroceptive reflex

Answer 6

Receptors outside of the effector organ

E.g in the skin and the effector is the muscle, pick up a signal and through an arch, reaches the muscle

Question 7

Explain the all- or none-law concerning the AP?

Answer 7

Must have a certain polarization to get a reaction, either or not.

Question 8

Explain depolarization

Answer 8

Positive charges decreases inside the cell

Question 9

Define threshold

Answer 9

When depolarization reaches a certain level

Question 10

Main component of reflex arch?

Answer 10

Receptor
Afferent nerve
Synapse
Efferent nerve
Target organ

Question 11

How to check a normal reaction of Achilles reflex?

Answer 11

Hit just above the insertion of Achilles’ tendon on a free hanging leg

Question 12

In which phase do you have absolute refractory period?

Answer 12

In the period before repolarization where the CAP will disappear.

Question 13

What is proprioceptive(reflexes)?

Answer 13

Receptors in the organ

Spinal reflexes where the receptors are in the organ(muscle)

This reflex doesn’t fatigue!!

Question 14

4 stages of an AP?

Answer 14

Depolarization
Overshoot
Repolarization
Post-hyperpolarization

Question 15

What’s frequency coding?

Answer 15

Stronger stimulus, more frequent AP

Question 16

Describe CAP

Answer 16

“Compound Action Potentials”

A summation of different fibers that make up a nerve

Question 17

Receptors in an intrafusal muscle

Answer 17

Nuclear chain receptors and bag receptors

Question 18

Describe the normal reaction of an ankle jerk reflex

Answer 18

Stretching the ankle, plantar flexion

Question 19

Where do you tap to get the knee jerk reflex?

Answer 19

Patellar ligament

Question 20

Which channel opens during repolarization?

Answer 20

Potassium channels

Question 21

What is a rheobase?

Answer 21

Minimal stimulus intensity that generates an AP after long time application

Question 22

Give the most characteristic features of non-myelinated impulse transmission

Answer 22

AP propagates step by step, a channel activates immediately the adjacent one.
The conduction velocity is slow.

Question 23

The most characteristics of impulse transmission of myelinated fibers

Answer 23

AP develops only in the Nodes of Ranvier (Where Na+ channels occur).
AP propagates by leaping from one node to the other

Question 24

What’s saltatory conduction?

Answer 24

When the AP of myelinated fibers is leaping from one node to the other

Question 25

What does the conduction velocity of the AP of myelinated fibers depend on?

Answer 25

The diameter of the fiber

The distance btw the Nodes of Ranvier