Semester 1 Final: Nervous System

Question 1

dendrites

Answer 1

receive signals from sensor cells & other neurons

Question 2

cell body

Answer 2

contains main organelles and nucleus

Question 3

axon hillock

Answer 3

the region where the action potential is generated

Question 4

axon

Answer 4

transmits the signal (action potential) to other cells

Question 5

myelin sheath

Answer 5

insulating cells surrounding the axon that increase conduction speed of action potential

Question 6

synaptic (axon) terminal

Answer 6

the site where neurotransmitters are released into the synapse to communicate with other cells

Question 7

synapse/synaptic cleft

Answer 7

gap between two neurons where communication through neurotransmitters occurs

Question 8

types of supporting cells

Answer 8

glial cells (astrocytes, radial glial cells, oligodendrocytes/Schwann cells)

Question 9

astrocytes

Answer 9

regulate the concentration of ions and neurotransmitters and forms the blood-brain barrier in the CNS

Question 10

glial cells

Answer 10

responsible for structural support & functioning of neurons

Question 11

Oligodendrocytes

Answer 11

form the myelin sheath in the CNS

Question 12

Schwann Cells

Answer 12

form the myelin sheath in the PNS

Question 13

neurotransmitters

Answer 13

chemical messengers

Question 14

radial glia

Answer 14

CNS, lay the foundation for the development neural tube in fetuses

Question 15

resting potential

Answer 15

-70mV
-results from differences in ionic concentration between the inside and outside of the cell
-higher concentration of Na+ on the outside
-higher concentration of K+ on the inside
Na+/K+ pumps are used to maintain resting potential once it has been achieved

Question 16

steps of action potential

Answer 16

1. resting potential
2. depolarization
3. rising phase
   action potential
4. falling phase (repolarization)
5. undershoot

Question 17

Depolarization

Answer 17

stimulus depolarizes membrane opening some gated Na+ channels & allowing a small increase in Na+

Question 18

Rising phase

Answer 18

threshold (-55mV) is crossed opening most gated Na+ channels & inside of membrane becomes positive as Na+ rushes in

Question 19

Falling phase/Repolarization

Answer 19

Na+ gated channels close & K+ gated channels open allowing K+ ions to exit which restores the negative charge

Question 20

Undershoot/Hyperpolarization

Answer 20

K+ gated channels cause temporary extra negative charge until the membrane returns to resting potential as Na+ pass through open channels
- after -80mV, K+ gated channels close and the Na+/K+ pump restores resting potential

Question 21

Chemical Communication

Answer 21

• Action potential reaches synaptic terminal & opens voltage-gated calcium channels
• Vesicles fuse and release neurotransmitters into synaptic cleft via exocytosis
• Neurotransmitters bind to ligand-gated ion channels on postsynaptic cell & opens channels
• Excitatory postsynaptic potentials
• Inhibitory postsynaptic potentials
• Neurotransmitters degraded (by enzymes) or are recycled to presynaptic cell (reuptake)

Question 22

Central Nervous System (CNS)

Answer 22

• Consists of the brain & spinal cord

* Integration center for complex behaviors

Question 23

Peripheral Nervous System (PNS)

Answer 23

• Consists of cranial & spinal nerves along with associated ganglia
• Transmits information to and from the CNS

Question 24

PNS: somatic nervous system

Answer 24

the voluntary system because it is under conscious control to move skeletal muscles in response to external stimuli

Question 25

PNS: autonomic nervous system

Answer 25

the involuntary system because it regulates internal conditions by contracting smooth & cardiac muscles

parasympathetic: rest and digest
sympathetic: fight or flight response

Question 26

ion channels

Answer 26

Either *Always open
or

• Gated until opened by stimuli
  
  • Ligand-gated ion channels
  • Voltage-gated ion channels
• Selective for specific ions