Unit 4 Flash Cards

Question 1

Central Nervous System (CNS)

Answer 1

think brain and spinal cord; integrate and process sensory info and coordinate motor response

Question 2

Peripheral Nervous System (PNS)

Answer 2

sensory receptors of sense organs, nerves connect nervous system w/other systems, deliver sensory info to the CNS and carry motor commands to peripheral tissues and system

Question 3

functions of Central Nervous System

Answer 3

integrates, processes, and coordinates sensory data + motor commands; motor commands control or adjust peripheral organs like skeletal muscles

Question 4

functions of Peripheral Nervous System

Answer 4

sensory receptors again, but you have different branches within the PNS which are Afferent Division, and Efferent Division. Efferent Division has the Autonomic and Somatic Nervous System within it

Question 5

Afferent Division

Answer 5

Carries info from PNS to CNS

Question 6

Efferent Division

Answer 6

carries motor commands from CNS to PNS muscle glands and effectors

Question 7

Autonomic Nervous System (within Efferent and PNS)

Answer 7

controls subconscious actions, contraction of smooth muscle + cardiac muscle, and glandular secretions

sympathetic- “fight or flight”
parasympathetic- “resting and digesting”

Question 8

Somatic Nervous System (within Efferent and PNS)

Answer 8

controls VOLUNTARY and sometimes involuntary reflexes such as skeletal contractions

Question 9

Presynaptic Cell

Answer 9

neuron that sends a message via neurtransmitter

Question 10

Postsynaptic cell

Answer 10

cell that receives the message

Question 11

Schwann Cells

Answer 11

surrounds axons in the PNS, responsible for their myelination

Question 12

Satellite cells

Answer 12

(PNS) surround neuron cell bodies, regulate O2 + CO2, nutrient and neurotransmitters levels around ganglia

Question 13

Ependymal Cells

Answer 13

makes cerebral fluid in CNS

Question 14

Astrocytes

Answer 14

helps w/Brain blood barrier

Question 15

Microglia

Answer 15

removes cell debris, wastes, and other pathogens by phagocytosis

Question 16

Ogliodendrocytes

Answer 16

myelinate CNS axons; provide structural framework

Question 17

White Matter

Answer 17

regions dominated by myelinated axons of the CNS

Question 18

Grey Matter

Answer 18

areas containing neuron cell bodies, dendrites, and unmyelinated axons

Question 19

Three important concepts regarding Membrane Potential

Answer 19

1) extracellular fluid and intracellular fluid differ greatly in ionic composition
2) Cells have selectively permeable membranes
3) Membrane permeability varies by ion

Question 20

Graded Potentials

Answer 20

1) any stimulus that opens a chemically or mechanically gated channel that allows ions to move across the membrane

2) IF stimulus is strong enough, it can lead to an action potential at the axon hillock, for example neuromuscular junction and postsynaptic potentials are GP

Question 21

Action Potential

Answer 21

propagated changes in transmembrane potential

Question 22

Generation of Action Potential

Answer 22

you need an initial stimulus that is caused by a graded depolarization of axion hillock that is big enough (10-15 mV) to change resting membrane potential (-70 mV) to threshold level of voltage gated sodium channels

Question 23

Each Step of Action Potential

Answer 23

1) Depolarization to Threshold (via graded potential): basically stimulus initiates AP and that opens up the sodium channels

2) Activation of Na+ channels: basically the sodium channels open and the membrane depolarizes/becomes more positive because sodium ions are going INTO the membrane

3) Inactivation of Na+ channels and ACTIVATION of K+ channels: the membrane gets positive enough to the point that the voltage gated sodium channels close and the potassium one opens, releasing K+ out of the membrane and repolarizing it, making it more negative relatively.

4) Return to normal Permeability: potassium channels are slow to close which can lead to hyperpolarization, but basically they start to close at -70mV

Question 24

Sodium-Potassium Pump role in Action Potential

Answer 24

after sodium has entered the cell and potassium has left the cell, the sodium-potassium pump restores sodium and potassium to their original concentration

more sodium OUTside the cell
more potassium INside the cell

Question 25

Refractory Period

Answer 25

the time period from the beginning of action potential to the return to resting state where the membrane will not respond to additional stimuli

Question 26

Absolute Refractory period

Answer 26

sodium channels cannot reopen no matter how strong the stimuli is, no action potential possible

Question 27

Relative Refractory Period

Answer 27

membrane potential almost normal, very large stimulus can initiate action potential

Question 28

Conduction Velocity of an AP is based on 2 factors

Answer 28

1) axon diameter: the larger the diameter, the faster it will be

2) degree of mylenation: the more myelin you have, the faster the AP will be

Question 29

Continuous Propagation

Answer 29

done through UNmyelinated axons

Question 30

Saltatory Propagation

Answer 30

done through Mylenated axons, much faster than continuous propagation, and it’s where the current jumps from node to node between Schwann cells so PNS

Question 31

Removal of Neurotransmitters from the Synapse

Answer 31

1) NT is degraded (ACh into acetate and choline)
2) NT diffuses away from synapse
3) NT may be taken back up by the presynaptic neuron

Question 32

Neurotransmitter

Answer 32

chemical messengers that bind to a receptor either on the presynaptic cell or postsynaptic cell; there are two types either Excitatory or Inhibitory

Question 33

Excitatory NT

Answer 33

causes depolarization of postsynaptic membranes, promotes action potentials, and stimulates EPSP (excitatory postsynaptic potentials)

Question 34

Inhibitory NT

Answer 34

causes hyperpolarization or postsynaptic membranes, suppresses AP, stimulates (IPSP) inhibitory postsyaptic potentials

Question 35

Temporal Summation

Answer 35

multiple times, rapid, repeated stimuli at once

Question 36

Spatial Summation

Answer 36

multiple locations, many stimuli, arrives at MULTIPLE synapses

Question 37

Presynaptic Inhibition

Answer 37

decreases the NT released by presynaptic membrane

Question 38

Presynaptic Factilitation

Answer 38

Increases the NT released by presynaptic membrane