Test 4 Nervous System

Question 1

What neurons are responsible for transmitting conducting Sensory stimuli from Peripheral Nervous System to the Central Nervous System?

Answer 1

Afferent Neurons

Question 2

What are the different Sensory Neurons?

Answer 2

Somatic Senses
Special Senses
Visceral Senses

Question 3

What neurons are responsible for transmitting signals from the Central Nervous System to the muscles and glands?

Answer 3

Efferent

Question 4

What portion of the Neuron contains the nucleus and other cell organelles?

Answer 4

Soma (Cell Body)

Question 5

What portion of the Neuron receives stimuli or messages via chemoreceptors?

Answer 5

Dendrites

Question 6

What portion of the Neuron carries nerve impulses away from the soma to axon terminal?

Answer 6

Axon

Question 7

What portion of the Neuron releases neurotransmitters in synaptic knobs/terminal buttons?

Answer 7

Axon Terminals

Question 8

How do Neurons communicate with one another?

Answer 8

Via Chemical neurotransmitters via synaptic transmission

Question 9

What portion of the Neuron is a phospholipid membrane that surrounds, protects, electrically insulates the axon, and is a signal amplifier?

Answer 9

Myelin Sheath

Question 10

What is the primary phospholipid of the Myelin Sheath of a Neuron?

Answer 10

Galactocerebroside (Sphingolipid, strengthens the sheath)

Question 11

What produces the Myelin Sheath that surrounds Neurons in the PNS and CNS?

Answer 11

PNS: Schwann Cells
CNS: Oligodendrocytes

Question 12

What are the gaps in the myelin sheath, where the action potential occurs during conduction along the axon of a Neuron called?

Answer 12

Nodes of Ranvier (Neurofibrillar Nodes)

Question 13

What is the resting membrane potential a Neuron maintains and how is this accomplished?

Answer 13

-70mV

Via: Adenosine tri-phosphate (ATP) mediated active transport and passive diffusion of ions

Question 14

What creates the resting membrane potential?

Answer 14

Na+-K+ ATPase Pump

Question 15

To create the resting membrane potential of -70mV what is being transferred by the Na+-K+ ATPase pump of the cell membrane?

Answer 15

3 Na+ out of the cell

2 K+ intracellularly

Question 16

What function does the Na+-K+ ATPase pump have after action potential has passed?

Answer 16

Restore resting concentration.
Na+ outside cell
K+ inside cell

Question 17

What is the mmol concentration of Na+ and K+ Extracellular and Intracellular in the steady-state condition of the cell membrane?

Answer 17

Extracellular:
-Na+ = 150mmol/L
-K+ = 3-4mmol/L
Intracellular:
-Na+ = 5-10mmol/L
-K+ = 120-135mmol/L

Question 18

Uncompensated positive charges outside and inside the cell arrange along the inner and outer cell membrane causing what?

Answer 18

only vicinity of cell membrane is charged

Question 19

What does the concentration gradient favor upon depolarization of the cell membrane?

Answer 19

• Extracellular Diffusion of K+

- Intracellular Diffusion of NA+

Question 20

Chemical, Mechanical, or electrical stimuli can activate a neuron leading to the generation of what?

Answer 20

Nerve Impulse

Question 21

At what point will a Neuron generate a Nerve Impulse?

Answer 21

Depolarization exceeds the THRESHOLD level of -55mV

Question 22

What occurs regarding to ion follow when the threshold level -55mV is reached?

Answer 22

• Activated Gated-Na+ Channels open

- Causing: large influx of Na+ into the cell

Question 23

The opened Gated-Na+ Channels will drive the depolarization to what level?

Answer 23

+30-35mV (max membrane potential)

Question 24

The depolarization/electrical signal that propagates down the axon membrane is referred to as?

Answer 24

Action Potential

Question 25

How is the Neuron’s action potential/depolarization carried from one Neuron to another across the Synaptic Cleft (AKA Synaptic Gap)?

Answer 25

• Axon Terminal: Voltage-gated calcium channels open causing an influx of calcium ions
• Ca^2+ triggers fusion of storage vesicles w/terminal bud membrane
• Releasing a neurotransmitter into synaptic cleft