w1

Question 1

What is the key difference between CNS vs PNS

Answer 1

CNS determines signals while PNS delivers those signals to the rest of the body

Question 2

What is the key difference between afferent vs efferent

Answer 2

Efferent is the output (CNS to PNS) and afferent is the input (PNS to CNS)

Question 3

What is the key difference between sympathetic vs parasympathetic

Answer 3

Sympathetic is fight or flight (excitory) and parasympathetic is rest and relax (inhibitory)

Question 4

what is the resting voltage state of a neuron

Answer 4

-70mV due to mostly sodium outside and mostly potassium inside

Question 5

What is the threshold voltage of a neuron

Answer 5

-55mV

Question 6

What ion enters the neuron once the threshold voltage is passed

Answer 6

sodium

Question 7

what is the maximum voltage due to depolarization of a neuron

Answer 7

+30mV

Question 8

what happens after depolarization of a neuron

Answer 8

repolarization and hyperpolarization. voltage dependent sodium channels close and voltage dependent potassium ions open, letting potassium ions out.

Question 9

What’s the difference between lateral inhibition (spatial high pass filtering) and adaptation (temporal high pass filtering)?

Answer 9

Lateral inhibition is when an excited neuron makes “edges” more pronounced by making the edge values more extreme

Adaptation is a change over time in the responsiveness of the sensory system to constant stimulation. This occurs in most sensory systems, peripheral and central, by several methods:

Question 10

What element of the nervous system is the most likely to be stimulated by electrical stimulation

Answer 10

axons

Question 11

Describe the ion transfer that occurs at ion pumps

Answer 11

pumps 3 sodiums out of the cell and 2 potassiums into the cell

Question 12

what mechanisms does the eye use to employ adaptation

Answer 12

change pupil diameter, activation/ deactivation of cones throughout the day (fovea active during daytime), modification of lateral inhibition and rod/cone sensitivity via biochemical effects (e.g. calcium levels)

Question 13

what mechanisms does the ear use to employ adaptation

Answer 13

strapedius reflex: decreases the transmission of vibrational energy to the cochlea by disarticulating the stapes, outer hair cells of basilar membrane tune the other cells (over 3 orders of magnitude), modulation of quiet sounds via spontaneous firing.

Question 14

by how much does myelin insulation increase conduction velocity of action potentials

Answer 14

10 fold

Question 15

roughly how long does it take for a neighboring node to reach threshold voltage when the current node is activated

Answer 15

roughly proportional to the resistance of the nerve between the nodes and the capacitance of the node.

Question 16

what is a refractory period

Answer 16

the time period at which hyperpolarization occurs. This ensures that the sodium channels do not open again i.e. prevents another action potential.

Question 17

How can nerves transmit analogue data?

Answer 17

through using multiple channels, changing the rate of firing, modulation of small sensory inputs through spontaneous firing.