Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCAT BIO > Nervous System/Hearing > Flashcards

Nervous System/Hearing Flashcards

You may prefer our related Brainscape-certified flashcards:
MCAT flashcards Biology 101 flashcards
1
Q

Neuron

A

single cell w/dendrite, soma, axon hillock, axon (myelin, nods of Ranvier)
*cannot change size of action potentials it transmits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Nerve

A

bundle of many different axons from different neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Soma

A

central body of the neuron

contains the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Axons

A

carry info away from soma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Myelin Sheath

A

allow for saltatory conduction
no ions can enter or exit neural axon that’s myelinated
dramatically speeds the movement of action potentials by forcing AP to jump from node to node

CNS - Oligodendrocytes
PNS - Schwaan Cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Dendrite

A

carry info into the soma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Axon Hillock

A

initiates action potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Synaptic Cleft

A

small gap between the presynpatic and the postsynaptic neuron
chemicals released into the space to excite the next neuron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Synaptic Knob

A

axons terminate in synaptic knobs

form connections with target cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Axon Velocity Increases with

A

increasing myelin

increasing diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Na+/K+ ATPase

A

3 Na+ out
2 K+ in
w/hydrolysis of 1 ATP molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

potassium leak channels

A

open all the time

allow some of the K+ from the cell to go out into the extracellular space (down the gradient)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Resting Membrane Potential

A

-70 mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Sodium leak channels

A

very few

100 K+ leak channels: 1 Na+ leak channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Are neurons the only cells with a resting membrane potential?

A

No. All cells have a resting membrane potential (rmp)

Neurons and muscle tissue use rmp to generate action potentials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Depolarization

A

sodium voltage-gated channels open (in response to membrane potential) to allow Na+ into the cell (down the gradient)
Once membrane potential reaches -50mV (threshold), all Na+ channels are opened fully
Channels are closed before threshold potential
Reaches +35 mV before inactivating Na+ channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Threshold potential

A

-50 mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Can an action potential run out of energy and not reach the other end?

A

Action potentials are continually renewed at each point in the axon as they travel
Assuming enough voltage-gated channels, once an action potential starts, it will propagate without a change in amplitude until it reaches a synapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

All or none response

A

if membrane potential doesn’t reach the threshold, the voltage-gated sodium channels won’t open up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Repolarization

A
  1. voltage-gated K+ channels open more slowly than the Na+ ones -> respond to the depolarization of the membrane
  2. membrane potential returns to negative because K+ ions are leaving the cells
  3. overshoots the resting potential, -90 mV
  4. K+ voltage-gated channels close
  5. K+ leak channels and Na+/K+ ATPase bring the membrane back to resting potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Saltatory Conduction

A

rapid jumping conduction in myelinated axons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Glial cells

A

specialized, non-neural cells that typically provide structural and metabolic support to neurons
ex. Schwaan cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Schwaan cells

A

PNS

form myelin - increase speed of conduction of APs along axon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Oligodendrocytes

A

CNS

form myelin - increase speed of conduction of APs along axon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Astrocytes

A

CNS
Guide neuronal development
Regulate synaptic communication via regulation of neurotransmitter levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Microglia

A

CNS

Remove dead cells and debris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Ependymal cells

A

CNS

produce and circulate cerebrospinal fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Nernst Equation

A

Eion = RT/zF = ln [X]outside/[X]inside

z= valence of ion
F= Faraday's constant
Eion = equilibrium potential
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Equilibrium potential

A

membrane potential at which this driving force (gradient) does not exist
no net movement of ions across membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

chemical gradient across membranes

A

created by relative concentrations of ions on each side of the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Electrical gradient across membranes

A

determined by valence (charge of ion)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Absolute refractory period

A

neuron will not fire another action potential no matter how strong a membrane depolarization is induced
Na+ volt-gate channels inactivated
on the way back down (at the threshold), Na+ channels are closed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Relative refractory period

A

neuron can be induced to transmit an action potential
requires greater depolarization (b/c its hyperpolarized)
from the point where Na+ channels closed to the point where resting membrane potential is established

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Electrical synapses

A 
occur when cytoplasm of 2 cells are joined by gap junctions 
not common in nervous system 
prominent in smooth and cardiac muscle
excitatory only - depolarizes
bidirectional
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Chemical synapses

A

found at the end of axons where they meet their target cell
action potential converted into a chemical signal
synaptic cleft present
excitatory (depolarizes) or inhibitory (hyperpolarizes)
unidirectional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Steps in chemical synapses

A
  1. action potential reaches end of an axon (synaptic knob)
  2. depolarization of presynaptic membrane opens Ca++ voltage-gated channels
  3. Ca++ influx causes exocytosis of neurotransmitters stored in secretory vesicles
  4. Neurotransmitter molecules diffuse across the narrow synaptic cleft
  5. Neurotransmitters bind to receptor proteins (ligand-gated ion channels) in postsynaptic membrane
  6. Opening the ion channels alters membrane polarization
  7. if threshold is reached, Na+ voltage-gated channels are opened => action potential is initiated
  8. Neurotransmitter in the synaptic cleft is degraded/removed to terminate the signal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Neurotransmitter Breakdown

A

reuptake
enzyme (ex. acetylcholinesterase)
glial cells (astrocytes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Each presynaptic neuron can only___

postsynaptic neuron can respond to ____

A

release one type of neurotransmitter

respond to many different neurotransmitters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

If an inhibitor of acetylcholinesterase is added, what happens to the postsynaptic membrane?

A

it will be depolarized longer w/each potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Temporal summation

A

summing up synapses over time

*increased frequency of action potentials will add up to increase the number of action potentials transmitted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Spatial summation

A

summation over space

multiple inputs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Excitatory postsynaptic potentials (EPSPs)

A

excitatory neurotransmitters cause postsynaptic depolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Inhibitory postsynaptic potential (IPSPs)

A

inhibitory neurotransmitters cause postsynaptic hyperpolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Peripheral Nervous System (PNS)

A

receiving info = sensory function
acting on the info = motor function
all nerves and sensory structures outside of the brain and spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Central Nervous System (CNS)

A

processing info = integrative function

brain and spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Motor neurons (PNS)

A

carry info from nervous system to the organs

efferent neurons = exit CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Sensory neurons (PNS)

A

carry info towards the CNS

afferent neurons = approach CNS

48
Q

Integration (CNS)

A

interneurons (association neurons)

49
Q

Reflexes

A

direct motor response -> sensory input (w/o conscious thought)

50
Q

Somatic (PNS)

A 
subdivision of PNS
voluntary control of skeletal muscle
stimulation only
ACH only
one neuron from spinal cord to effector organ
51
Q

Autonomic (PNS)

A

subdivision of PNS
involuntary control of glands and smooth muscle
stimulatory or inhibitory
2 neurons from spinal cord to effector organ
ACH, NE

52
Q

Sympathetic system

A

Subdivision of autonomic, PNS
“flight or fight” “4 Fs = Flight, Fight, Fright, Freak (sex)”
ACH at ganglion, NE at organ
increase blood flow to skeletal muscle
increase body activity :
-increase HR, blood pressure, breathing rate, sweating
-pupils and bronchioles dilate

53
Q

Parasympathetic system

A 
subdivision of autonomic, PNS
"rest and digest"
ACH at ganglion and organ
increase blood flow to the GI tract
increase GI motility 
decrease body activity:
-decrease HR, blood pressure, breathing rate, sweating
-pupils and bronchioles constrict
54
Q

Catecholamines (epinephrine, norepinephrine)

A

housed in the adrenal medulla

releases EPI and NOREPI

55
Q

Cerebrospinal Fluid (CSF)

A

clear liquid
CNS floats in it
shock absorption
exchange of nutrients/waste

56
Q

spinal cord

A

protected by CSF and vertebral column
pathway for info to and from the brain
site for information integration and processing
basic reflexes (simple spinal reflexes)
involved in primitive processes (walking, urination, sex organ function)

57
Q

medulla oblongata

A

part of hind brain
connected to the brain stem
relays info between other areas of the brain
controls AUTONOMIC FUNCTIONS (breathing, heart rate)
contains respiratory rhythmicity centers

58
Q

pons

A 
part of the hind brain
balance and equilibrium 
antigravity posture
controls some autonomic functions
receive info from vestibular apparatus in the inner ear -> monitors acceleration and position due to gravity
59
Q

Cerebellum

A

part of the hind brain
balance and coordination
integrating center where complex movements are coordinated
receive info from vestibular apparatus in the inner ear -> monitors acceleration and position due to gravity

60
Q

Midbrain

A

relays visual and auditory info
contains much of the reticular activating system (RAS) -> responsible for arousal/wakefulness
startle reflexes

61
Q

Thalamus

A

part of the diencephalon

contains relay and processing centers for sensory info

62
Q

Hypothalamus

A

part of the diencephalon
maintain homeostasis
contains centers for controlling emotions and autonomic functions
pituitary gland => primary link between nervous and endocrine systems

63
Q

Telencephalon

A

left hemisphere = controls right side of body; responsible for speech
right hemisphere = controls left side of the body; responsible for visual-spatial reasoning, music

64
Q

Corpus collosum

A

thick bundle of axons that connect the cerebral hemispheres

if cut => split brain = 2 independent cortices

65
Q

Cerebrum

A

largest region of human brain
cerebral cortex = 4 mm of gray matter (unmyelineated axons) on the outside; . houses the conscious mind
responsible for thought processes and intellectual functions
process somatic sensory and motor info
contain 4 lobes: frontal, parietal, temporal, occipital

66
Q

Frontal lobe

A

all voluntary movement
reasoning skills
problem solving

67
Q

Parietal lobe

A 
general sensations (touch, temp)
gustation (taste)
68
Q

Temporal lobe

A 
process auditory and olfactory sensations 
-contains olfactory bulbs
short-term memory 
language comprehension
emotion
69
Q

Occipital lobe

A

visual sensation

70
Q

Basal nuclei (basal ganglia)

A

composed of gray matter
voluntary motor control
procedural learning related to habits
works with cerebellum to control coordination of movements
-basal ganglia = inhibitory (prevents excess movement)
-cerebellum = excitatory

71
Q

Limbic system

A

contains structures such as amygdala (fear), hippocampus (memory)
emotion, memory

72
Q

All neurons entering/exiting the CNS are carried by __ pairs of cranial nerves and __ pairs of spinal nerves

A

12 pairs of cranial nerves

31 pairs of spinal nerves

73
Q

Cranial nerves

A

convey sensory and motor info to and from brain stem

74
Q

Spinal nerves

A

convey sensory and motor info to and from spinal cord

75
Q

Vagus nerve

A

very important cranial nerve
important in parasympathetic: decreases HR, increases GI activity
bundle of axons end in ganglia on the surface of the target organ

76
Q

All somatic motor neurons ___

A

innervate skeletal muscle

use Ach

77
Q

All somatic sensory neurons ___

A

have long dendrites extending from sensory receptor toward the soma (just outside the CNS in dorsal root ganglion)

78
Q

dorsal root ganglion

A

bunch of somatic and autonomic sensory neuron cell bodies located just dorsal to the spinal cord

79
Q

All autonomic preganglion neurons release ____

A

Acetylcholine (Ach)

80
Q

All parasympathetic postganglion neurons release ____

A

Ach

81
Q

Nearly all sympathetic postganglion neurons realease ___

A

Norepinephrine (NE)

82
Q

Sympathetic pre/postganglion

lenght, location

A 
preganglion = long; located in thoracolumbar = thoracic and lumbar spinal cord
postganglion = short
83
Q

Parasympathetic pre/postganglion

lenght, location

A 
preganglion = short ; located in craniosacral = brainstem and sacral (towards tail bone) spinal cord
postganglion = long
84
Q

Adrenal medulla

A

part of the sympathetic nervous system

releases epinephrine = stimulation of heart

85
Q

Sensation

A

act of receiving info

86
Q

Perception

A

act of organizing, assimilating, and interpreting sensory info into useful, meaningful info

87
Q

Sensory Repectors

A

detect 1 type of stimulus from either internal/external stimulus
receives only 1 kind of info

88
Q

Mechanoreceptors

A

respond to mechanical disturbances (pressure, stretch, vibrations)

89
Q

Nocioreceptors

A

respond to pain
stimulated by tissue injury
DO NOT ADAPT under any circumstances

90
Q

Thermoreceptors

A

respond to temp

91
Q

Chemoreceptors

A

respond to chemical stimuli

92
Q

Photoreceptors (Electromagnetic receptors)

A

respond to electromagnetic waves

93
Q

4 properties of sensory stimuli communicated to the CNS

A
  1. Modality = type of stimulus
  2. location = communicated by receptive field of receptor sending the signal
  3. intensity = frequency of action potentials
  4. duration = may or may not be coded explicitly
    - tonic/phasic receptors
94
Q

Tonic receptors

A

fire action potentials as long as the stimulus continues

95
Q

Phasic receptors

A

only fire action potentials when stimulus begins

do not explicitly communicate the duration of the stimulus

96
Q

Adaptation

A

decrease in firing frequency when intensity of a stimulus remains constant

97
Q

Proprioception (kinesthetic sense)

A

awareness of self

essential for coordinated motion

98
Q

Taste buds

A

bunch of specialized epithelial cells

have taste pore w/taste hairs = detect food chemicals

99
Q

Bones in the middle ear (malleus, incus, stapes) are arranged in a way to _____ sound vibrations

A

amplify

100
Q

Vibrations of the oval window creates ____ ______

A

pressures waves

101
Q

Organ of Corti

A

primary site at which auditory stimuli are detected
has hair cells that brush the tectorial membrane
in the cochlear duct

102
Q

From Sound to Hearing

A

sound waves-> auricle -> external auditory canal -> tympanic membrane (ear drum) -> malleus -> incus -> stapes -> oval window -> perilymph -> endolymph -> basilar membrane -> auditory hair cells -> tectorial membrane -> neurotransmitters stimulate bipolar auditory neurons -> brain -> perception

103
Q

Pitch

A

frequency
distinguished by which regions of basilar membrane vibrate
low frequency (long wavelength) = stimulate hair cells at apex of cochlear duct (furthest away from the oval window)
high frequency (short wavelength) = stimulate hair cells at base of cochlea (closest to the oval window)

104
Q

Large vibrations cause

A

more frequent action potentials in auditory neurons

105
Q

If auditory nerve is severed ___

A

no hearing of any kind is possible

106
Q

Bone conductance can ____ and result in ____ if the middle ear is nonfunctional

A

still stimulate the cochlea

result in hearing

107
Q

Cones

A

extreme visual acuity
concentrated in the fovea (focal point)
require abundant light
color vision depends on red, blue, green

108
Q

What physical difference allows cones to absorb red/blue/green light?

A

each type of cone make a particular pigment protein (opsin) which is specialized to change conformation when light of the appropriate frequency strikes it

109
Q

Emmetropia (normal vision)

A

incoming light rays are converged to the retina

110
Q

Myopia (nearsightedness)

A

too much refraction at lens (ciliary muscles too strong) or abnormally long eyeball results in a focal length that is too short
Use diverging lens (concave) to correct

111
Q

Hyperopia (farsightedness)

A

too little refraction at the lens (ciliary muscles weak) or abnormally short eyeball => focal length is too long
use converging lens (convex) to correct

112
Q

Absolute Threshold

A

minimum stimulus required to activate a sensory receptor 50% of the time

113
Q

Differential Threshold

Just Noticeable Difference

A

minimum noticeable difference between any 2 sensory stimuli 50% of the time

114
Q

Weber’s law

A

two stimuli must differ by a constant proportion for the difference to be perceptible

115
Q

Why can’t older people hear higher frequencies?

A

Loud sounds can mechanically harm the hair cells causing them to die
Once hair cells die, they NEVER regrow
Hair cell that detect high frequency are the smallest and most easily damaged
Loss of hair cell = loss of hearing

MCAT BIO (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions