Lesson 2 - Nervous Tissues and Neurophysiology

Question 1

neurons

Answer 1

nerve cells that function to transmit electrical impulses

Question 2

neuroglia

Answer 2

cells that support the neurons

Question 3

structures in a neuron: soma

Answer 3

the neuron’s cell body

Question 4

ganglion

Answer 4

a cluster of cell bodies in the PNS

Question 5

nucleus

Answer 5

a cluster of cell bodies in the CNS

Question 6

structures in a neuron: axon hillock

Answer 6

tapered structure between the some and axon that is important for producing the action potential

Question 7

structures in a neuron: dendrites

Answer 7

processes that conduct electrical impulses towards the soma, usually receives a signal from another cell

Question 8

structures in a neuron: axon

Answer 8

process that conduct electrical impulses away from the soma

Question 9

tracts

Answer 9

bundles of axons in the CNS

Question 10

nerves

Answer 10

bundles of axons in the PNS

Question 11

structures in a neuron: axon/synaptic terminal

Answer 11

found at the end of an axon

Question 12

structures in a neuron: synaptic cleft

Answer 12

gap found between the axon terminal of one neuron and the target cell

Question 13

oligodendrocytes

Answer 13

neuroglia that produces myelin in the CNS

Question 14

Schwann cells

Answer 14

neuroglia that produces myelin in the PNS

Question 15

neuroglia are important to neuron function, they can: (2)

Answer 15

• produce myelin to insulate a neuron’s axon
• form nodes of Ranvier found between myelinated sections of the axon, and these nodes help propagate and increase action potential velocity

Question 16

nerve cells are able to propagate an electrical impulse because: (2)

Answer 16

• can change their membrane potential
• membrane potential is maintained by Na+/K+ pump

Question 17

the action potential is generated at the _____ _____ and travels down the _____

Answer 17

axon hillock, axon

Question 18

the Na+/K+ pump moves ___ Na+ ions _____ of the cell in exchange for ___ K+ ions _____ of the cell causing a net -1 charge inside

Answer 18

3, outside, 2, inside

Question 19

an action potential is formed at the axon hillock when:

Answer 19

an excitatory stimulus reaches the axon hillock

Question 20

what does an excitatory stimulus at the axon hillock cause? (5)

Answer 20

• an influx of Na+ ions into the neuron which depolarizes the membrane in that area
• when it reaches threshold, more Na+ enters the cell in that area
• further membrane depolarization occurs so the charge inside becomes positive
• Na+ influx stops around ~+30mV, then K+ ions starts leaving the cell to depolarize it
• once the cell is repolarized, the K+ ions stop leaving and the resting potential is restored

Question 21

absolute refractory period

Answer 21

immediately follows an action potential, where further stimulation cannot generate another AP

Question 22

relative refractory period

Answer 22

follows the absolute refractory period, when a strong stimulus can generate another AP

Question 23

Label A-D

Answer 23

A: neurofibril
B: nucleus
C: dendrites
D: chromatophilic substance

Question 24

Label A-C

Answer 24

A: dendrites (receptive regions)
B: cell body (biosynthetic center/receptive region
C: nucleus

Question 25

Label D-F

Answer 25

D: chromatophilic substance (rough ER)
E: axon hillock
F: axon (impulse generating/conduction region)

Question 26

Label G-J

Answer 26

G: Schwann cell
H: node of Ranvier
I: terminal branches
J: axon terminals

Question 27

Label A-C

Answer 27

A: presynaptic neuron
B: direction of action potential
C: mitochondrion

Question 28

Label D-F

Answer 28

D: synaptic cleft
E: synaptic vesicles
F: axon terminal

Question 29

Label A-C

Answer 29

A: axon hillock
B: cell body
C: area of polarity reversal/ node of Ranvier

Question 30

Label D and E

Answer 30

D: myelin sheath
E: distal axon

Question 31

Label A-C

Answer 31

A: absolute refractory period
B: relative refractory period
C: depolarization

Question 32

Label D-F

Answer 32

D: action potential
E: repolarization
F: hyperpolarization

Question 33

Label G and H

Answer 33

G; threshold
H: resting membrane potential