Nervous System

Question 1

synapse

Answer 1

Space between two cells (can be between two nerve cells, a cell and a gland cell, etc.)

Question 2

neuromuscular junction

Answer 2

example of a synapse

synapse between motor neuron and skeletal muscle cell

Question 3

process of neuromuscular junction

Answer 3

An action potential in the motor neuron causes voltage-gated Ca2+
channels open and Ca2+ enters the axon terminal.
Ø Calcium causes vesicles to fuse with the presynaptic membrane and
release acetylcholine (Ach) into the synaptic cleft, the space
between the presynaptic and postsynaptic membranes.
Ø The postsynaptic membrane of the muscle cell is the motor end
plate. Ach binding to receptors causes depolarization of the muscle.

Question 4

neuromuscular junction is an

Answer 4

excitatory

synapse.

Question 5

when are other synapses inhibitory?

Answer 5

if postsynaptic response is hyperpolarization

Make the cell even more negative (move K+ out of cell)

Question 6

summation is

Answer 6

both spatial and temporal

spatial: input at different synaptic sites
temporal: input at the same site, over time

Question 7

what occurs at the axon hillock

Answer 7

Neurons have many synapses that must sum excitatory and inhibitory input

Axon hillock decides whether or not to fire action potential
§ Depends on the potential at the axon hillock as a result of all synapses.

Question 8

excitatory synapse

Answer 8

Depends on both spatial and temporal
• Must reach a certain threshold for an action potential to be fired to
postsynaptic membrane.

Question 9

Main neurotransmitters in the CNS

Answer 9

ACh, Glutamate, Gly, adenosine, and GABA, monoamines, peptides

Question 10

Glutamate

Answer 10

an excitatory amino acid mostly in CNS

receptors are:
• NMDA (inotropic: Na+)
• AMPA (inotropic: Ca2+)- repeated stimulation can cause longterm
potentiation (memory)

Question 11

Glycine, adenosine, and GABA

Answer 11

inhibitory (amino acids and nucleosides)

Question 12

Drugs that affect Action potentials

Answer 12

Drugs treat the nervous system by modulating
synaptic interactions.

agonists

antagonists

Question 13

agonists

Answer 13

mimic or potentiate the effect of a
neurotransmitter.

morphine is an agonist at the endorphin receptor, therefore blocks pain

Question 14

antagonists

Answer 14

block the actions of a
neurotransmitter.

caffeine is an antagonist and binds at the adenosine receptor on nerve cells
initiates brain activity

caffeine ties up the receptor and hyperpolarizes the membrane

both are purines

Question 15

sensory cells

Answer 15

s transduce physical and chemical
stimuli into neuronal signals using different
channels and/or receptors:

Question 16

chemically-gated channels

Answer 16

depend on
molecules that bind or alter channel protein
(chemoreceptors, photoreceptors)

Question 17

mechanically gated channels

Answer 17

respond to
force applied to membrane (mechanoreceptors,
thermoreceptors, electrosensors)

Question 18

difference between iontropic and metabotropic sensory receptors

Answer 18

no secondary messengers involved with iontropic sensory receptors

Question 19

Autonomic Nervous System

Answer 19

— the
output (efferent) of the CNS that controls
involuntary functions.

has two divisions that work in opposition: sympathetic and parasympathetic that are distinguished by anatomy, neurotransmitters, and action potentials

Question 20

Sympathetic

Answer 20

increase a function

cholinergic (preganglionic) and noradrenergic neurons (postglanglionic) go to the glands

Ganglia that are part of central nervous system that are attached to the
spine–>sympathetic nervous system responses

Question 21

parasympathetic

Answer 21

decrease a function
cholinergic neurons (preganglionic) and
cholinergic neurons (postganglionic)

Postganglionic neurons very close to the gland that it innervates

Question 22

autonomic commands

Answer 22

heart rate, sweating, salivation

Question 23

neural afferents

Answer 23

sends info to CNS

Question 24

human eye

Answer 24

sensory stem for light

Question 25

pupil

Answer 25

decides how much light to let in

Question 26

retina

Answer 26

shoots action potential down optic nerve

Question 27

human retina

Answer 27

different types of cells that innervate together

ganglion cells, amacrine cells, horizontal cells, photoreceptor cells

Question 28

photoreceptor cells

Answer 28

metabotropic sensory receptors that transform light

energy into action potentials

Question 29

rod cells

Answer 29

highly light-sensitive and perceive shades of gray in dim

light

Question 30

cone cells

Answer 30

function at high light levels and responsible for highacuity
color vision

Question 31

rhodopsin

Answer 31

visual pigment
absorb photons of light and change conformation

consists of opsin ( a protein) and a light absorbing group, 11-cis-rental

rhodopsin sits in plasma membrane of a photoreceptor cell

Question 32

double negative

Answer 32

inhibits something that inhibits

Question 33

light to action potential

Answer 33

Change in shape of Opsin–>activation of G protein (Transducin)–>
Activation of Phosphodiesterase (Breaks down cGMP to GMP)–> Loss of
inhibition in bipolar cells–> fire into ganglia
Light changes shape of 11-cis-retinal to all-trans-retinal that allows you to
see light

Question 34

Light from both eyeballs cross at the optic chiasm

Answer 34

Info from both eyes are processed at the visual cortex