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Biology > Chapter 7 - Nervous System > Flashcards

Chapter 7 - Nervous System Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

the nervous sytem enables organisms to

A

receive and respond to stimuli from their external and internal environments

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2
Q

neurons

A

functional units of nervous system

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3
Q

neuron converts stimuli into

A

electrochemical signals

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4
Q

electrochemical signals are

A

conducted through nervous system

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5
Q

the nervous system responds ____ to stimuli than the endocrine system

A

more rapidly

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6
Q

the neuron consists of

A

elongated cell consisting of several dendirtes, a body, a single axon

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7
Q

dendrites

form & fxn

A

cytoplasmic extensions that receive information and transmit it towards the cell body

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8
Q

cell body (soma)

A

contains nucleus and controls metabolic activity of the neuron

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9
Q

axon

A

long cellular process that transmits impulses away from teh cell body

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10
Q

most mammalian neuron body and axon are

A

sheathed by insulating substance - myelin

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11
Q

myelin

A

sheates body and axon of neuron

allows axons to conduct impulses faster

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12
Q

myelin produced by

A

glial cells

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13
Q

oligodendrocytes

A

produce myelin in central nervous system

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14
Q

schwann cells

A

produce myelin in peripheral nervous system

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15
Q

nodes or Ranvier

A

gaps between segments of myelin

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16
Q

axons end as swellings known as

A

synaptic terminals

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17
Q

neurotransmitters released from ____ into _____

A

synaptic terminals;

synapse (synaptic cleft)

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18
Q

synapse (synaptic cleft)

A

gap between axon terminals of one cell and dendrites of next cell

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19
Q

axons travelling from spine to tip of foot may be

A

very long

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20
Q

neurons are specialized to

A

receive signals from sensory receptors or other neurons in body and transfer information along length of axon

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21
Q

action potentials are

A

impulses that travel the length of the axon and invade the nerve terminal

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22
Q

action potentails cause

A

release of neurotransmitters into the synapse

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23
Q

resting potential

A

potential difference between extracellular space and intracellular space when neuron is at rest

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24
Q

even at rest, a neuron is

A

polarized

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25
Q

potential difference is the result of

A

unequal distribution of ions between inside and outside of the cell

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26
Q

typical resting membrane potential is

A

-70 millivolts

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27
Q

typical resting membrane potential of -70 mv means that the inside of the neuron is

A

more negative than the outside

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28
Q

the potential difference is due to

A

selective ionic permeability of neuronal cell membrane

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29
Q

the potential difference is maintained by

A

active transport by Na+/K+ pump

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30
Q

concentration of K+ is higher _____

the concentration of Na+ is higher ____

A

inside; outside

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31
Q

in addition to K+/Na+ difference; negatively charged proteins are

A

trapped inside cell

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32
Q

the resting potential is created because the neuron is selectively permeable to

A

K+

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33
Q

selective permeability of neuron to K+ means that

A

K+ diffuses down its concentration gradient, leaving net negative charge inside

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34
Q

neurons are impermeable to

A

Na+

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35
Q

because neurons are impermeable to Na+

A

cell remains polarized

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36
Q

ionic gradients are restored by

A

Na+/K+ pumps

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37
Q

the Na+/K+ pump operates using ____ for energy

A

ATP

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38
Q

the Na+/K+ pump transports _____ out for every ____ transported into the cell

A

3 Na+

2 K+

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39
Q

nerve cell body receives both ____ and _____ impulses from other cells

A

excitatory and inhibitory impulses

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40
Q

action potential generated when

A

cell becomes sufficiently excited

or

depolarized (less negative)

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41
Q

the minimum threshold membrane potential is

A

-50 mV

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42
Q

the minimum threshold membrane potential is the level at which

A

action potential is initiated

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43
Q

Na+ wants to go ____ the cell because _____

A

into;

it is more negative inside hte cell (electrical gradient) and there is less Na+ inside (chemical gradient)

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44
Q

in response to changes in voltage,

A

ion channels located in nerve cell membrane open

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45
Q

voltage-gated ion channels

A

ion channels located in nerve cell membrane that open in response to changes in voltage are called

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46
Q

action potential begins when

A

voltage-gated Na+ channel open in response to depolarization

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47
Q

voltage-gated Na+ channels open in response to

A

depolarization

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48
Q

the opening of the voltage-gated Na+ channels allows Na+ to

A

rush down electrochemical gradient into the cell

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49
Q

depolarization leads to opening the voltage-gated Na+ channels, allowing Na+ to rush down its electrochemical gradient into the cell

this causes

A

rapid further depolarization of that segment of the cell

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50
Q

after the cascade of depolarization, the voltage-gated Na_ channels close and then

A

the voltage-gated K+ channels open and K+ rushes out down electrochemical gradient

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51
Q

voltage-gated K+ channels opening and allowing K+ ions to rush down the electrochemical gradient allows for

A

the cell to return to a mor enegative potential

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52
Q

repolarization

A

the cell returning to a more negative potential after the voltage-gated K+ channels open to allow K+ ions to rush down the electrochemical gradient to balance the depolarization of the Na+ ions

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53
Q

hyperpolarization

A

neuron may shoot past resting potential and become even more negative inside than normal

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54
Q

refractory period

A

immediately following action potential, may be very difficult or impossible to initiate another action potential

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55
Q

all-or-none response

A

action potential all-or none response

when threshold membrane potential is reached, action potential with consistent size and duration is produced

nerve fires maximally or not at all

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56
Q

stimulus intensity is coded by

A

frequency of action potentials

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57
Q

axons can theoretically propagate action potentials bidirectionally, however, information transfer occurs only

A

in one direction:

dendrite —> synaptic terminal

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58
Q

backward information transfer through the axon is impossible because

A

synapses operate only in one direction

and

refractory periods make backward travel of action potentials impossible

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59
Q

speeds of action potentials

A

different axons can propagate action potentials at different speeds

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60
Q

speed of action potential depends on

A

the greater the diameter

and

the more heavily it is myelinated

the faster the impulses

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61
Q

myelin increases conduction of velocity down the axon by

A

insulating segments of hte axon

membrane permeable to ions only at nodes of Ranvier

action potential “jumps” from node to node

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62
Q

synapse

A

gap between axon terminal of one neuron and dendrites of another neuron

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63
Q

presynaptic neuron

A

neuron before synapse

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64
Q

postsynaptic neuron

A

neuron after synapse

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65
Q

neurons may communicate with

A

neurons

muscles or glands

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66
Q

effector cell

A

The muscle, gland or organ cell capable of responding to a stimulus at the terminal end of an efferent neuron or motor neuron.

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67
Q

neurotransmitters

A

chemical messengers stored in membrane-bound vesicles at the nerve terminal

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68
Q

nerve terminal contains thousands of membrane-bound vesciles full of

A

neurotransmitters

(chemical messengers)

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69
Q

when the action potential arrives at the nerve terminal and depolarizes it

A

the synaptic vesicles fuse with the presynaptic membrane and release neurotransmitters into the synapse

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70
Q

once the synaptic vesicles fuse with presynaptic membrane and release neurotransmitters into the synapse,

the neurotransmitter…

A

diffuses across the synapse and acts on receptor proteins embedded in the postsynaptic membrane

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71
Q

neurotransmitters diffuse across the synapse and act on

A

receptor proteins on the post-synaptic membrane

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72
Q

the neurotransmitter can lead to ____ on the post-synaptic cell and consequent _____

A

depolarization;

firing an action potential

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73
Q

how is neurotransmitter removed from synapse?

(3)

A
  1. taken back up into nerve terminal via uptake carrier (protein)
  2. degraded by enzymes located in the synapse
  3. diffuse out of synapse
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74
Q

neurotransmitmter may be taken back into the nerve terminal from synapse via

A

a protein: uptake carrier

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75
Q

enzymes that may degrade neurotransmitters in the synapse

A

acetylcholinesterase inactivates neurotransmitter acetylcholine

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76
Q

curare

(drug)

A

blocks post-synaptic acetylcholine receptors so that acetylcholine is unable to interact with receptor

leads to paralysis by blocking nerve impluses to muscles

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77
Q

botulism toxin

A

prevents realease of acetylcholine from pre-synaptic membrane

results in paralysis

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78
Q

anti-cholinesterases

A

used as nerve gases and in insecticide parathion

inhibit activity in acetylcholinesterase enzyme

acetylcholine is not degraded in the synapse and continues to affect post-synaptic membrane

no coordinated muscular contractions can take place

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79
Q

afferent neurons

A

sensory neurons

80
Q

efferent neurons

A

motor neurons

81
Q

afferent neurons carry sensory information about

A

external or internal environment to the brain or spinal cord

82
Q

efferent neurons carry motor commands

A

from brain or spinal cord **to **various parts of the body (e.g. muscles, glands)

83
Q

interneurons

A

only in local circuits

linking sensory and motor neurons in the brain and spinal cord

cell bodies and nerve terminals in same location

84
Q

nerves are

A

bundles of axons covered with connective tissue

85
Q

plexus

A

network of nerve fibers

86
Q

ganglia

A

neuronal cell bodies clustered together in the periphery

87
Q

nuclei

A

neuronal cell bodies clustered together in the central nervous system

88
Q

nervous system divided into two major systems

A

central nervous system

peripheral nervous system

89
Q

central nervous system

A

brain

spinal cord

90
Q

peripheral nervous system

A

somatic

autonomic

91
Q

autonomic nervous system

A

sympathetic

parasympathetic

92
Q

central nervous system (CNS) consists of

A

brain and spinal cord

93
Q

brain

composition

A

mass of neurons in the skull

94
Q

brain

function

A

interpreting sensory information

forming motor plans

cognitive functions (thinking)

95
Q

brain

structure

A

outer portion - gray matter (cell bodies)

inner portion - white matter (myelinated axons)

96
Q

brain divided into three parts

A

forebrain

midbrain

hindbrain

97
Q

forebrain

composition

A

telencephalon

diencephalon

98
Q

telencephalon

A

cerebral cortex

olfactory bulb

99
Q

cerebral cortex

A

highly convoluted gray matter that can be seen on teh surface of the brain

processes and integrates sensory input and motor responses

important for memory and creative thought

100
Q

diencephalon

A

thalamus

hypothalamus

101
Q

thalamus

A

relay and integration center for spinal cord and cerebral cortex

102
Q

hypothalamus

A

controls visceral functions

e.g. hunger, thirst, sex drive, water balance, blood pressure, temperature regulation

control endocrine system

103
Q

midbrain

composition

A

mesencephalon

104
Q

midbrain

(mesencephalon)

function

A

relay center for visual and auditory impulses

motor control

105
Q

hindbrain

location

A

posterior part of brain

106
Q

hindbrain

composition

A

cerebellum

pons

medulla

107
Q

cerebellum

A

modulate motor impulses initiated by cerebral cortex

maintenance of balance, hand-eye coordination, timing of rapid movements

108
Q

pons

A

relay center

allows cortex to communicate with cerebellum

109
Q

medulla oblongata

A

controls vital fxns

breathing, heart rate, gi activity

110
Q

brainstem

composition

A

midbrain, pons, medulla

111
Q

spinal cord

A

elongated extension of brain

conduit for sensory information to the brain

motor information from the brain

112
Q

reflexes

A

spinal cord can integrate simple motor responses by itself

113
Q

spinal cord

structure

A

outer white matter - motor and sensory axons

inner gray matter area - nerve cell bodies

114
Q

dorsal horn

A

sensory information enters spinal cord through the dorsal horn

115
Q

dorsal root ganglia

A

contain cell bodies of sensory neurons

116
Q

ventral horn

A

all motor information exits spinal cord through ventral horn

117
Q

for simple reflexes

e.g. knee-jerk reflex

A

sensory fibers (entering through dorsal root ganglion) synapse directly on ventral horn moter fibers

118
Q

example of other reflexes:

interneurons between sensory and motor fibers

A

allow for some preocessing in spinal cord

119
Q

peripheral nervous system (PNS)

consists of

A

nerves

ganglia

120
Q

sensory nerves which enter CNS and motor nerves which leave CNS are part of the

A

PNS

121
Q

PNS two primary divisions

A

somatic nervous system

autonomic nervous system

122
Q

both somatic and autonomic nervous systems have both

A

sensory and motor components

123
Q

somatic nervous system

A

innervates skeletal muscles and is resopnsible for VOLUNTARY movement

124
Q

autonomic nervous system

aka

A

involuntary nervous system

125
Q

ANS regulates

A

body’s intenral environment without aid of conscious control

126
Q

autonomic innervation of body includes both

A

sensory and motor fibers

127
Q

ANS innervates these two types of muscle

A

cardiac

smooth muscle

128
Q

smooth muscle

A

located in blood vessels, digestive tract, bladder, bronchi

129
Q

ANS innervates smooth muscle, which is located in the bladder, digestive tract, bronchi, blood vessels

so it is not surprising that the ANS is important in

A

excretory processes, respiration, gastrointestinal motility and reproductive processes

130
Q

ANS composed of two subdivisions

A

sympathetic nervous system

parasympathetic nervous system

131
Q

parasympathetic nervous system and sympathetic nervous system act ______ to each other

A

in opposition

132
Q

sympathetic nervous system

A

“fight or flight”

increases blood pressure and heart rate

increases blood flow to skeletal muscles

decreases gut motility

dilates bronchioles to increase gas exchange

133
Q

sympathetic nervous system uses _____ as it’s primary neurotransmitter

A

norepinephrine

134
Q

parasympathetic nervous system

A

acts to conserve energy and restore activity levels following exertion

“rest and digest”

lowers heart rate

increase gut motility

135
Q

vagus nerve

A

parasympathetic nerve

innervates thoracic and abdominal vicsera

136
Q

parasympathetic nervous system uses ____ as it’s primary neurotransmitter

A

acetylcholine

137
Q

the eye and ear are examples of

A

specialized receptors designed to detect stimuli

138
Q

the eye detects

A

light energy

139
Q

after detecting light energy, the eye transmits information about ____ to the _____

A

intensity, color, shape to the brain

140
Q

sclera

A

thick, opaque layer covering the eyeball

“white” of the eye

141
Q

choroid layer

A

beneath the sclera

helps supply retina with blood

dark, pigmented area

reduces reflection in the eye

142
Q

retina

A

innermost layer of the eye

contains phtoreceptors that sense light

143
Q

cornea

A

transparent layer at the front of the eye

bends and focuses light rays

144
Q

pupil

A

rays travel through this opening

145
Q

diameter of pupil is controlled by

A

pigmented, muscular iris

146
Q

iris

A

responds to intensity of light and surroundings (makes pupil constrict)

147
Q

lens

A

light continues through lens after going through pupil

suspended behind pupil

focuses the image onto the retina

148
Q

the shape and focal length of the lens is controlled by

A

ciliary muscles

149
Q

photoreceptors

A

in the retina

transduce light into action potentials

150
Q

two main types of photoreceptors

A

cones

rods

151
Q

cones

A

type of photoreceptor in retina

respond to high-intensity illumination

sensitive to color

152
Q

rods

A

type of photoreceptor in retina

detect low-intensity illumination

important in night vision

153
Q

cones and rods contain various pigments that

A

absorb specific wavelengths of light

154
Q

cones and pigments (absorb wavelengths of light)

A

contain 3 different pigments

absorb red, green, blue wavelengths

155
Q

rod and pigments (absorb wavelengths of light)

A

rod pigment: rhodopsin

absorbs a single wavelength

156
Q

photoreceptor cells synapse into

A

bipolar cells

157
Q

bipolar cells synapse into

A

ganglion cells

158
Q

axons of the ganglion cells bundle to form

A

optic nerves

159
Q

optic nerves

A

conduct visual information to the brain

160
Q

blind spot

A

point at which the optic nerve exits the eye

photoreceptors not present here

161
Q

fovea

A

small area of retina

densely packed with cones

high acuity vision

162
Q

vitreous humor

A

jellylike material composing most space between lens and retina

maintains shape and optical properties of eye

163
Q

aqueous humor

A

formed by eye

exits through ducts to join venous blood

164
Q

disorders of the eye

5

A

myopia

hyperopia

astigmatism

cataracts

glaucoma

165
Q

myopia

(nearsightedness)

A

image is focused in front of retina

166
Q

hyperopia

(farsightedness)

A

image is focused behind retina

167
Q

astigmatism

caused by

A

irregularly shaped cornea

168
Q

cataracts develop when

A

lens becomes opaque

light cannot enter the eye and blindness results

169
Q

glaucoma

A

increase of pressure in the eye

due to blocking of outflow of aqueous humor

170
Q

ear

function

A

transduces pressure waves (sound energy) into impulses perceived by brain as sound

171
Q

sound waves pass through ___ regions as they enter the ear

A
172
Q

regions sound waves pass through when entering ear

A
  1. outer ear
  2. middle ear
  3. inner era
173
Q

outer ear

consists of

A

auricle (external ear)

auditory canal

174
Q

at the end of the auditory canal is the

A

tympanic membrane (eardrum)

of the middle ear

175
Q

tympanic membrane (eardrum)

A

vibrates at same frequency as incoming sound

176
Q

middle ear

A
  1. tympanic membrane (eardrum)
  2. ossicles (bones) (3- malleus, incus, stapes)
  3. oval window
177
Q

three ossicles (bones) of the ear

A

malleus

incus

stapes

178
Q

fxn of ossicles

A

amplify the stimulus

transmit stimulus through oval window

179
Q

oval window (last part of middle ear) leads to

A

inner era

180
Q

inner ear is filled with

A

fluid

181
Q

inner ear consists of

A

cochlea

vestibular apparatus

182
Q

vestibular apparatus

A

maintains equilibrium

183
Q

vibration of the ossicles exerts pressure on _____

A

fluid of the cochlea

184
Q

pressure on the fluid of the cochlea stimulates ____

A

hair cells in the basilar membrane to transduce pressure into action potentials

pressure —-> action potentials via hair cells in basilar membrane

185
Q

action potentials transduced by hair cells in the basilar membrane travel via the _____ to the ____ for processing

A

auditory (cochlear) nerve

brain

186
Q

basilar membrane

A

within the cochlea of the inner ear

stiff structural element

separates two liquid-filled tubes that run along the coil of the cochlea, the scala media and the scala tympani

187
Q

protozoa nervous system

A

unicellular organisms - no organized nervous system

188
Q

single celled organisms may respond to stimuli such as

A

touch

heat

light

chemicals

189
Q

cindaria nervous system

A

simple nervous system - nerve net

network of nerve cells

may have limited centralization

190
Q

jellyfish nervous system

A

clusters of cells and pathways

coordinate movements required for swimming

191
Q

annelida nervous system

A

central nervous system

192
Q

the central nervous system of annelida (earthworm) consists of

A

ventral nerve cord

anterior “brain” of fused ganglia

nerve pathways between receptors to effectors

193
Q

arthropoda nervous system

A

brains similiar to annelids

more specialized organs

194
Q

examples of complex organs in arthropoda

(related to nervous system)

A

compound or simple eyes

tympanum for detecting sound

195
Q
A

Biology (19 decks)

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