Quiz 2

Question 1

what are the two general classes of cells in the nervous system?

Answer 1

neurons and glia

Question 2

neurons

Answer 2

• most structurally diverse

Question 3

glia

Answer 3

helps neurons carry out basic functions

Question 4

action potentials

Answer 4

• able to propagate quickly down an axon
• velocity is determined by temperature, axon diameter, and myelin

Question 5

what do chemical synapses use to jump from cell to cell?

Answer 5

• neurotransmitters

Question 6

what makes nervous responses faster than endocrine responses?

Answer 6

Action potentials transmit really fast

Question 7

what is the purpose of graded potentials?

Answer 7

-To act as short distance signals within a neuron

cell receives stimulus but doesn’t get to the threshold that needs to fire an action potential

Question 8

what causes ion leakage? how do myelin and thicker axons reduce this?

Answer 8

ion leakage occurs when ions move out of the cell due to stress (maybe too much positive charge inside the cell forcing them out). myelinated axons move fast and a ticker axon makes more space for movement down the axon.

Question 9

Axon

Answer 9

• conducting fiber transmits information out

Question 10

Axon hillock

Answer 10

where the axon connects to the soma

Question 11

dendrites

Answer 11

grow from the cell body and reach into the tissue to find other cells to receive signals from

Question 12

soma

Answer 12

body of the neuron

Question 13

motor neurons

Answer 13

sends out of the brain and spinal cord

Question 14

inter-neurons

Answer 14

all the ones in the middle that process (brain and spinal cord)

Question 15

sensory neurons

Answer 15

• goes into the brain and spinal cord
• brings info fro body to the Central Nervous System (CNS)

Question 16

unipolar neuron

Answer 16

• one pole
• signal received and goes straight to axon

Question 17

bipolar neuron

Answer 17

• a nerve cell with one dendrite and one axon, extending from opposite sides of the cell body.

Question 18

multipolar neuron

Answer 18

• type of neuron that has a single axon and MANY dendrites

Question 19

pseudounipolar neuron

Answer 19

sensory neuron that has one extension from its cell body that splits into two branches.

Question 20

the life cycle of neuron

Answer 20

• when first born it comes off a neuroblast cell
• a little ball will be located where it’s needed
• grows branches called dendrites
• grows one pole to transmit information out (axon)
• action potentials begins at the hillock

Question 21

effector

Answer 21

• any cell that a motor synapse is onto
• cells that carry out the responses or orders of the central nervous system

Question 22

neural circuits

Answer 22

• the movement of signals from one type of neuron to another

Question 23

neural responses are mediated by ____.

Answer 23

circuits

Question 24

what is the simplest neural circuit?

Answer 24

sensory
- it synapses onto another motor neuron

Question 25

opposite charges ____ & the same charges ____

Answer 25

- attract - repel

Question 26

what do you need to separate opposite charges?

Answer 26

- requires energy

Question 27

conductor

Answer 27

transmit energy

Question 28

insulator

Answer 28

- prevent from moving - ex/ phospholipid bilayer

Question 29

law of conservation of electrical charges

Answer 29

- charges can be separated from one another but cannot be brand-new

Question 30

membrane potentials

Answer 30

most cells have a negative charge at rest

Question 31

why is the phospholipid bilayer impermeable to ions?

Answer 31

to make sure ions do not move on their own

Question 32

how can ions move

Answer 32

- only through channels - only can move at specific times

Question 33

leak channel

Answer 33

channel that is always open

Question 34

gated channel

Answer 34

channeled that either are opened or closed

Question 35

ligand-gated channel

Answer 35

- hormone receptor has to bind to the channel to open - ligand is a neurotransmitter - something will enter and cause something to occur

Question 36

voltage-gated channel

Answer 36

- has to reach a certain voltage - opens between (-55 to -40mV) - Na+ channel - if drops below that voltage, it will close

Question 37

what does an unequal distribution of charges cause?

Answer 37

membrane potential - bc there is an unequal amount of charges

Question 38

polarized

Answer 38

- carries a negative charge while at rest

Question 39

what are the three changes in polarization?

Answer 39

- depolarization - repolarization - hyperpolarization

Question 40

depolarization

Answer 40

cells lose negative charge - excitatory= can push closer to the threshold (action potential) - influx of + charges

Question 41

repolarization

Answer 41

cells gain back the original charge

Question 42

hyperpolarization

Answer 42

has more negative charge than it was at the start - inhibitory= may allow chloride in (pushed further from the threshold) - influx of - charges

Question 43

membrane potentials are influenced by what?

Answer 43

- concentration gradient of ions - membrane permeability to those ions

Question 44

the concentration gradient of ions

Answer 44

- the stronger the gradient, the more important it is

Question 45

what does the Goldman equation do?

Answer 45

- predicts membrane potential that results from the contribution of all ions that can cross the membrane

Question 46

propagation

Answer 46

- action potential is going back up to its original action potential

Question 47

refractory period

Answer 47

- time until you can reset

Question 48

How fast an action potential propagates down an axon is influenced by what?

Answer 48

- diameter of the axon (larger axons are faster) - resistance of the axon membrane to ion leakage out of the cell - temperature

Question 49

myelin sheath

Answer 49

goes around the axon - when removed, you end up with a thin axon again and more ion leakage

Question 50

synapses

Answer 50

- connection between cells that transmit signals - comes in three forms

Question 51

three forms of synapses

Answer 51

- metabotropic - ionotropic - electrical synapse

Question 52

ionotropic synapse

Answer 52

- fast - signal transmission - excitation, inhibition

Question 53

metabotropic synapse

Answer 53

- slow - signal transmission, neuronal modulation - excitation, inhibition, other

Question 54

electrical synapse

Answer 54

- instantaneous current flow - electrical transmission - electrical coupling

Question 55

neurotransmitter

Answer 55

- chemical released by a neuron to transmit a signal to another cell

Question 56

electrical synapses

Answer 56

- ions flow directly between cells through GAP junctions - nearly instantaneous - important for cardiac muscle contraction

Question 57

chemical synapses

Answer 57

- action potential triggers neurotransmitter release - neurotransmitters act as ligands for receptors on the post-synaptic cell

Question 58

nicotine

Answer 58

- acetylcholine agonist - toxin that acts as acetylcholine

Question 59

muscarinic

Answer 59

- receptors that are part of the parasympathetic nervous system and are activated by acetylcholine

Question 60

what are the different PSPs ionotropic responses can cause?

Answer 60

- depolarization - hyperpolarization

Question 61

why is the diversity of glia so much higher in the CNS than in the PNS?

Answer 61

- CNS has a much more complex structure and functional demands - it requires a wider variety of glial cell types to support different neural circuits and maintain homeostasis

Question 62

why are neurotransmitters short-lived in the synapse?

Answer 62

they need to be quickly removed from the synaptic cleft to allow for rapid signal transmission and prevent continuous stimulation of the postsynaptic neuron.

Question 63

how and why do neural circuits use summation?

Answer 63

to integrate multiple signals from various neurons