the nervous system Flashcards
(129 cards)
1
Q
Neuron’s job
A
conduct electrochemiical impulses
2
Q
Glial cells
A
support neurons, hold them together without touching
3
Q
types of glial cells
A
astrocytes: clean up brain debris, transport nutrients
4
Q
schwann cells
A
form myelin
5
Q
Axon terminal
or synaptic terminals
A
have little bumps
contain synapric vesicles
have little sacs containing neurotransmitters
6
Q
Node de Ranvier
A
where the axon is unprotected
7
Q
axon
A
the long part of the neuron
can be covered in myelin sheath
8
Q
myelin sheath
A
- Schwann cells
-increase speed of the neural impulse
-provides axon with nutrients and protexts it
-outer membrane is called neurilemma ; regenerate damaged neurons
9
Q
cell body
A
aka soma, contains nucleus and neuroplasm
10
Q
dendrites
A
extensions from soma
contain receptors
pick up electrical impulses
11
Q
Saltatory conduction
A
impulses jump from one node to another
12
Q
white matter
A
neurons contain myelin
13
Q
grey matter
A
neurons that do not contain myelin
cannot be fixed once damaged (cognitive part of the brain)
14
Q
types of neurons
A
- interneuron
- motor neuron
- sensory neuron
15
Q
interneuron
A
carry impulses in the CNS
short axon without myelin
interprets sensory info and sends motor info
16
Q
motor neuron
A
from CNS to the effectors
have long myelinated axons
17
Q
sensory neurons
A
relay info from the environment to CNS
dendrites have sensory receptors disgned to receive external stimuli
long myelinated neurons
18
Q
steps of neurotransmission
A
-resting neuron
-stimulated neuron
-depolarization
-repolarization
-refractry period
-the synapse
19
Q
resting neuron
A
ICF is (-) with respect to ECF that is (+)
the membrrane is fairly impermeable to Na+ and mostly impermeable to K+
Na+ in ECF is 10x greater ICF
K+ in ICF is 30x greater than in ECF
20
Q
Sodium-potassium pump
A
some ions leak through, the cell fix that with Sodium-Potassium pump (need ATP)
21
Q
the way Sodium-potassium pump works
A
Na+ gets into the pump (with ATP) then it flips, Na+ gets out, K+ gets into the pump that flips again, releases K+ and ATP
22
Q
what is a voltage?
A
the seperation in charge between ECF and ICF
the inside is negatively charged or POLARIZED
23
Q
axon’s voltage equals to…
A
-70 mV
24
Q
Stimulating a neuron
A
when neuron is stimulated, action potential begins (neurotransmission)
25
stimuli that can trigger a neuron to fire
chemicals, negatively charged electrodes, change in pH, mechanical deformation, heat/cold
26
treshhold level
around -55 mV
it is a minimum level of stimulus required
27
all or none response
either reaches the treshhold and fires or it doesn't
28
Summation
two neurons can release neurotransmitters at the same time
29
Depolarization
(action potential 1)
Na+ channels opens
rush of Na+ into ECF due to diffusion
the inside becomes (+) (almost +40mV)
Na+ channels are found in the nodes of Ranvier
30
Repolarization
action potential 2
normal polarity must be restored
K+ channels open
K+ rushes out
31
action potential 2
normal polarity must be restored
K+ channels open
K+ rushes out
Na+/K+ pumps moves Na+ out and K+ in
32
refracotry period
time it takes to repolarize a membrane
if a second stimulus is applied, the neuron will not fire
33
the synapse
region between two nerve cells
neurotransmission passes through presynaptic neuron to postsynaptic neuron
34
cynaptic cleft
actual gap between presynaptic and postsynaptic neuron
35
what does the end of the axon contain?
synaptic vesicles that contain neurotransmitters
36
Acetylcholine (Ach)
is the neurotransmitter found most in the body
37
when the nerve impulse reaches the axon terminal...
a calcium channel opens up and Ca2+ rushes in
neurotransmitters get released into the synaptic cleft
neurotransmitters bind to the receptors in the postsynaptic membrane ina lock and key style
38
excitation- depolarization
positive ion channels (Na+ or Ca2+) opens up
positive ions rush in
reaches the treshhold
39
inhibition- hyperpolarization
K+ channels open up
K+ rushes out
Cl- channels open up
Cl- rushes in
neuron becomes more (-)
40
GABA
is the most common inhibitory neurotransmitter
41
why does the body need inhibitory neurotransmitters
-prioritize sensory info
-coordinate muscle mvt
-pain killers inhibit transmission
42
getting rid of neurotransmitters in the synapse
1.enzymes; break down transmitters
(cholinesterase; breaks down Ach)
2.re-uptake systems; allow neurotransmitters to be carried back inside the axon terminal.
43
organization of the nervous system
Nervous system: -central nervous system:-spinal cord + brain
-peripheral nervous system: *autonomic: involuntary: sympathetic and parasympathetic
*sensory-somatic nerves: voluntary: sensory neurons and motor neurons
44
spinal cord
runs from the sacrum into the brain through foramen magnum
large bundle of neurons
45
spinal cord is protected by...
vertebrae and 3 protected membranes called meninges
46
layers of spinal cord
outer layer is white matter
inner layer shaped H grey matter
47
the small hole running through the middle of the spinal cord is called
cerebrospinal canal contains cerebrospinal fluid that protects and carry nutrients and wastes to and from the spinal cord
48
how many roots each side has?
31 mixed spinal nerves
one half carries the sensory neurons, the other carries motor neurons
49
the 2 functions of the spinal cord?
1. relaying info via interneurons from and to the brain
2. the reflex arc
50
the reflex arc
automatic and involuntary response
1. sensory receptor
2.sensory neuron
3. interneuron
4.motor neuron
5.effector
51
protecting the brain
skull
3 membranes called meninges ( inflammation of these membranes is called meningitis)
and cerebrospinal fluid
52
hypothalamus
release hormone
control many autonomic fct
closely related to the pituitary gland
53
the pituitary gland
controls many hormones
is under the control of the hypothalamus
mostly made of gland tissue
54
cerebrum
largest part of the brain
consists of 2 hemospheres connected by corpus callosum
emotion, intellect, memory, reasoning
have an outer convulted layer, grey matter called cerebral cortex
55
each hemosphere of the brain is devided into 4 lobes
frontal lobe: intellect reasoning, planning, speech, mvt
contains motor cortex; controls voluntary mvt
56
parietal lobe
sensory areas, tpuch, temperature
has a sensory cortex; interpreting touch
57
occipital lobe
vision, has visual cortex
58
temporal lobe
hearing, has auditory cortex
59
left vs right hemospheres
left= math, logic and languages
right= spatial awareness, facial recognition, visual imagery
60
cerebellum
coordiantion of muscle activity
maintenance of balance
core white matter, convulted outer grey matter layer
61
pons
relay station for info
passes between cerebellum and medulla
62
medulla oblangata
swelling on top of the spinal cord
connect PNS and CNS controls autonomic fct
63
PNS
Peripheral nervous system
64
sensory somatic nervous system
carries sensory info to the CNS and motor messages to effectors
65
it has 2 nervess
cranial nerves and spinal nerves
66
cranial nerves
supply the sense organs and muscles of the head, neck and viscera
67
Vagus nerve
10th cranial nerve
supplies branches to many internal organs
carries motor nerve fibre to the heart and lungs
68
Autonomic nervous system
involuntary
part of the peripheral nervous system
autonomic motor nervous to the smooth and cardiac muscles and glabnds
69
sympathetic
fight or fly response
in stress
uses Ach and adrenaline as neurotransmitters
neurons arise from the middle of the spinal cord
70
parasympathetic
rest and digest
relaxed
uses only Ach as neurotransmitters
neurons arise from top and bottom of CNS vagus and palvic nerve
71
sensory receptors
convert various energy into electrochemical energy
72
baroreceptor ->
chemoreceptors ->
proprioreceptors ->
blood pressure
CO2, O2
mvt of limbs
73
taste
sweet, sour, bitter, salt and savoury(aka umami)
74
smell
stimulat eolfactory receptors
75
sensory adaptation
adjust to a change in the envrmnt
sensory receptors become less sensitive
the thalamus( above hypothalamus blocks those messages)
76
the eye has.... muscles
6 extrinsic muscles
77
the sclera
the flexible and thick outermost layer of the eye
at the front become CORNEA
nutrients are supplied by aqueous humor
78
the chroid layer
black/dark blue pigmented middle layer
prevents light reflexion
becomes iris at the front
79
iris
a band of thin circular muscles whch controls the amount of light that enters the pupil
80
the pupil
hole in which the light enters
81
retina
thin, brown layer
converts light into electrical impluses
contain rods and cons
82
fovea centralis
area at the back of the retina
it has the most cones for color reception
83
Fluids in the eye
aqueous humor
vitreous humor
84
aqueous humor
chamber of transparent fluid between cornea and the lens
85
vitreous humor
colorless jelly between the lens and retina
86
the lens
held in place by suspensory ligaments the surround the lens
87
suspensory ligaments
are held in place by ciliary muscles
they atter the shape of the lens
88
refraction
bent upside down onto the retina by the cornea, aqueous humor and the vitreous humor
89
accommodation
the bending of the lens to focus on objects
90
changes in the eye to see objects in the distance
lens become concave (flat)
ciliary muscles relax and the suspensory ligaments become taut
pupils dialate to capture as much light as possibel
91
changes to see object up close
lens become convex (rounded)
ciliary muscles contract
suspensory ligaments become slick
92
near point
the closest an object can get to the eye and remain focused
93
eye strain
close objects for long period of time
muscles become tired of contracting
94
interpreting the size of the image
the brain determines the siwze by the image projected on the retina
smaller image, means smaller imprint
95
eye problems
myopia
hyperopia
96
myopia
nearsightness
eyeball is too long
see near not far
97
hyperopia
farsightness
eyeball is too short
see far not near
98
other vision defects
astigmatism
a cataract
claucoma
99
astigmatism
abnormal curvature on the surface of the cornea
100
catarct
when the lens or the cornea becomes opaque
101
Rods
detect shades of white and grey
there's no rods in the fovea
function when light levels are low
they are found in the periphery of the retina
102
cones
color vision
detect blue, red, green
most cones are located in the fovea centralis
103
colour blindness
one or more types of cones does not work properly
104
rhodospsin
light absorbing pigments found in rods
105
how do brain get messages?
impulses travel into the optic nerve, and then to the occipital nerve
106
blind spot
where the optic nerve connects to the retina
has no rods nor cons
107
the outer ear
aka pinna, visible part of the ear
108
auditory canal
carries waves to the eardrum
has sweat glans that produce ear wax
109
middle ear
tympanum & ossicles
110
tympanum
aka eardrum or tympanic membrane
flexible membrane that responds to compressions
vibrates at the same frequency and amplitude as the vibrations
111
ossicles
bones that carry the soumd waves to the inner ear
the first strikes 20x harder that it was struck by.
112
the eustachian tube
connects throat/nose and middle ear
equalizes pressure between the middle and outer ear
113
the inner ear
the cochlea (3 coiled chambers)
114
the cochlea
is snail-shaped structure converts mechanical vibrations into electrical messages
it contains 3 coiled chambers
115
organ of corti
located in the middle chamber
consists of layer of hair cells which have many cilia
116
cilia
hair cells standing in a layer of gelatinous fluid
117
how's sound waves are transferred?
sound waves come down the cochlea and cause cilia to bend
the neurons connected to cilia fire, then those impulses go through the auditory nerve to the temporal lobe
118
how's sound waves travel?
it compress and rarefy at different rates
119
what is high frequency wave?
the shorter the wavelength is, the higher pitch sound is
120
what is lower frequency wave?
the longer the wavelength is, the lower pitch the sound is
121
Amplitude
loudness of the sound is controlled by the amplitude
122
How does the organ of corti respond to the sound wave?
the first part responds to shorter wavelength
shorter wavelength touches sooner
lower frequency sound seem to travel further
123
the two types of deafness
1. conduction deafness
2.nerve deafness
124
conduction deafness
the sound wave is not conducted to cochlear nerve
either is cognitial condition or scarring in the middle ear from an ear infection which causes the fossicles to fuse together.
125
nerve deafness
cochlea cannot transmit impulse to the brain
damaged cilia either by loud sounds or aging
126
treatment for deafness
hearing aids can be worn.
surgery to repair or replace damaged ossicles
cochear implants
127
how does the inner ear contributes to the balance?
there's two parts of the inner ear that contribute to the balance; vestibule and semisercular canals
128
vestibule
gives info to the brain about the position of the head with respect to gravity
129
semisercular canals
three chambers that provide balance moving
these canals contain tiny ciliated hair cells attached to the neuron
when a person moves the fluid "sloshes" over hair cells
impulse is then transmitted to the auditory nerve to the brain
