Unit 2 Sensory and Integrative Nervous System Flashcards
(250 cards)
1
Q
Transduction
A
the conversion of stimulus energy into an electrical signal
2
Q
Adaptation
A
decreased sensitivity to continuous stimuli
3
Q
tonic receptors
A
adapt slowly if at all; pain is sensed with tonic receptors; when the stimulus is applied, the receptor potential is on; when the stimulus is removed, the recereceptor potential is off
4
Q
phasic receptors
A
adapt quickly; touch is sensed with phasic receptors; when the stimulus is applied, the receptor potential signals at the beginning; when the stimulus is removed, the receptor potential signals at the
5
Q
Modality-
A
correctly interpreting electrical signals in the brain; what is perceived has to do with the part of the brain that is stimulated; the brain knows what is sensed based on the location of the signal
6
Q
Intensity-
A
stronger stimuli elicit stronger responses
7
Q
frequency coding-
A
more frequent action potentials on a given sensory neuron
8
Q
population coding-
A
more receptors activated/more sensory neurons recruited
9
Q
exteroreceptors-
A
sense the external environment
10
Q
enteroreceptors-
A
sense the internal environment
11
Q
proprioreceptors-
A
sense the relationship between self and the environment
12
Q
photoreceptors-
A
detect light
13
Q
chemoreceptors-
A
detect chemicals
14
Q
mechanoreceptors-
A
detect pressure, movement, sound to name a few
15
Q
thermoreceptors-
A
detect temperature
16
Q
cutaneous senses-
A
detect touch/pressure, cold, warmth, pain
17
Q
visceral senses-
A
sense the internal environment; chemicals, pain, temperature, pressure
18
Q
special senses-
A
vision, smell, taste, hearing, rotational/linear acceleration (balance)
19
Q
Cutaneous Senses
A
Touch, pain, cold, and warmth are sensed with naked nerve endings. All are histologically identical but physiologically distinct.
20
Q
naked nerve ending-
A
can be positioned between skin cells or wrapped around the base of hairs
21
Q
expanded tips on nerve endings-
A
Ruffini endings, Merkel’s disks; slowly adapting (tonic)
22
Q
encapsulated endings
A
- cells ore extracellular material surrounding the receptor; Meissner’s corpuscles, Pacinian corpuscles, Krause’s corpuscles; rapidly adapting (phasic)
23
Q
In Pacinian corpuscles
A
mechanical distortion causes the opening of Na+ channels. Stronger stimuli open more channels and recruit more receptors.
24
Q
In Pacinian corpuscles
A
mechanical distortion causes the opening of Na+ channels. Stronger stimuli open more channels and recruit more receptors.
25
Touch receptors are most abundant on the fingers and lips but are scarce on
the trunk
26
Two major types of pain
Fast Pain and Slow Pain
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Fast Pain
felt within 0.1 sec of stimulus
sharp, localized sensation immediately after stimulus
mostly cutaneous; cut, burn, electric shock
felt as sharp, prickling, acute, electric pain
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Slow Pain
felt after 1 sec or more or stimulus
dull, intense, diffuse, unpleasant feeling (after initial wave of pain)
"can lead to prolonged, unbearable suffering" (from text)
can be cutaneous or visceral; tissue destruction
felt as slow burning, aching, throbbing, nauseous, chronic pain
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There are three types of stimuli
mechanical, thermal, and chemical
30
Fast pain results from
mechanical and thermal pain, while all three types of stimuli cause slow pain.
31
Chemical pain is the result of
substances often released by damaged cells exciting receptors. Examples of these substances are bradykinin, serotonin, histamine, K+, H+, acetylcholine, and proteolytic enzymes.
32
Pain receptors do no adapt but instead
exhibit progressive increased sensitivity called hyperalgesia, especially with slow pain.
33
Prostaglandins and substance P function
nhance pain receptor sensitivity.
34
Aspirin inhibits
prostaglandins, which is part of its analgesic effect.
35
There are two types of temperature receptors
cold and warm
36
Cold receptors response range
8 to 43C
37
warm receptors response range
30 to 50C
38
adaptation temperature range
20 to 40 C
39
Normal Body Temperature
37 C
40
Tissue damage occurs and cold/warmth becomes pain at what temperatures
below 8C and above 50C
41
Temperature center in the body
Hypothalamus
42
Visceral pain is often referred to as a
somatic structure (ex. Heart pain is felt in the Left arm)
43
Common Visceral Receptors
Stretch and chemical receptors
44
baroreceptors-
walls of great elastic arteries, which are responsible for short-term regulation of blood pressure (Stretch Receptor)
45
walls of atria-
responsible for long term regulation of blood pressure (Stretch receptor)
46
alveoli of lungs-
Herring-Breuer Reflex to regulate respirations; this isn't that important in humans (Stretch Receptor)
47
stomach-
gastrocholic reflex; causes contractions in the large intestine and regulates hunger (Stretch receptor)
48
colon-
primary stimulus for defecation (Stretch Receptor)
49
urinary bladder-
primary stimulus for urination (Stretch Receptor)
50
arterial PO2 (Chemoreceptor)-
walls of great elastic arteries; limited importance
51
H+/CO2 in medulla oblongata (Chemoreceptor)
pH of cerebrospinal fluid; important for regulation of respiration
52
osmotic pressure of plasma (Chemoreceptor)-
hypothalamus; water and salt balance
53
arteriovenous blood differences in glucose (Chemoreceptor)-
hypothalamus; regulates appetite
54
protein/lipid/H+ in small intestine (Chemoreceptor)-
enterogastric reflex; regulates stomach activity
55
NUmber of taste buds and location
10,000 taste buds on the upper surface of the tongue in fungiform and vallate papillae.
56
Fungifom Papillae are found
on the tip of the tongue , and there are
57
Vallate Papillae are found
at the back of the tongue, and there are ≤100 taste buds per papillae
58
Taste receptors are modified
Epithelial cells
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In each taste bud, there are ___receptor cells and supporting cells that will become receptors. They are arranged like slices of an orange in the taste bud.
50
60
Microvilli from receptor cells are sticking out of the taste pore and in contact with mucous in which
food particles are dissolved.
61
five taste modalities:
bitter, sweet, sour, salt, and umami
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Umami
Japanese for delicous, the associated chemical is L-Glutamate which is a savory taste (meat, aging cheese, soy)
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Perceived taste depends on
the combination and degree of receptors stimualted similar to perception of color
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Taste Blindness Chemical
phenyl-thiocarbamide
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Frequency of Taste Blindness
15-30% of people can't taste this chemical (phenyl-thiocarbamide)
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Sour Taste Threshold (HCl)
0.0009 M
67
Salt Taste Threshold (NaCl)
0.01 M
68
Sweet Taste Threshold (Sucrose)
0.01 M
69
Bitter Taste Threshold (Quinine)
0.000008 M
70
Bitter may be a warning of
Dangerous chemicals since many toxins are bitter. The lowest threshold is for bitter and most are alkaloids and long-chain organics containing nitrogen
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50% of taste adaptation occurs in the
Central nervous system
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Sensory neurons for the anterior 2/3 of the tongue travel in
Cranial Nerve VII (facial nerve)
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neurons for the posterior 1/3 of the tongue travel in
Cranial Nerve IX (glossopharyngeal nerve
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Cells involved in smell
Olfactory Cells
Sustenacular Cells
Bowman's Glands
75
Bowman's Glands function
Mucous secretion
76
Olfactory cells
receptors; humans have about 100,000,000; neurons are replaced every 1-2 months (the only neurons in the human body that divide)
77
Sustenacular Cells
receptor precursors
78
Process of Smell
odorants bind to cilia of olfactory cells . The olfactory cells depolarize in response to the odorants. Olfactory cells penetrate the ethmoid bone and synapse at the olfactory bulb. The Olfactory Nerve (Cranial Nerve I) carries signals from there to the cerebrum and limbic systems
79
Ear is divided into three parts:
Inner, Middle, Outer
80
Outer and middle ear are
air-filled tunnels that direct and amplify sound waves
81
The inner ear
is fluid-filled and is the location of receptors for hearing and equilibrium
82
The outer ear consists of
Pinna, ear canal, and ear drum (tympanic membrane). The eardrum vibrates when struck with sound waves
83
Middle Ear
Cavity between the eardrum and the inner ear. It opens into the nasopharynx via eustachian tube. The tube is normally closed, but opening allows for pressure equalization
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The main function of the middle ear
Transmit sound waves as vibrations to the inner ear
85
Three bones in the middle ear
Malleus, incus, and stapes
Malleus is next to the eardrum, the stapes is attached to the oval window (Beginning of inner ear), and the incus is between the malleus and the stapes.
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Vibrations on the eardrum move the bones which result in vibrations on the oval window
with 20x amplification and faithful frequency
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Inner ear modalities
Hearing and equilibrium
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Hearing is detected with the
cochlea, which is innervated by the auditory nerve
89
Equilibrium is detected by the
vestibular apparatus, which is innervated by the vestibular nerve.
90
The auditory and vestibular nerves join to form the
Vestibulocochlear nerve (CN VIII), Sensory only
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CN VIII
Vestibulocochlear nerve is routed through the medulla, then thalamus, and finally the auditory cortex of the cerebrum. Receptors in both modalities are hair cells, which are irreplaceable.
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scala vestibuli
upper chamber filled with perilymph, connected to the oval window, communicates with the scala tympani via helicotrema
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scala tympani-
lower chamber filled with perilymph, connected to the round window
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scala media-
middle chamber filled with endolymph
95
Inner ear
Contains a canal within a canal. Outer canal is bony labrynth , channels within the temporal bone that are filled with fluid called perilymph.
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Outer Canal of the inner ear
Outer canal is bony labrynth , channels within the temporal bone that are filled with fluid called perilymph.
97
Inner canal of the inner ear
is the membraneous labyrinth, channels with more or less the same shape as the bony labyrinth and filled with fluid called endolymph
98
Does communication exist between the endolymph and perilymph?
No. The two labyrinths divide the cochlea into three chambers:
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Three chambers of the Cochlea
Scala Vestibuli
Scala Tympani
Scala Media
100
Organ of Corti
is found along the length of the floor of the scala media, making up the basilar membrane. Hair cells are found here, which are the sound receptors
101
Membrane covering the hair cells
tectorial membrane
102
Reissner's membrane
Roof of the scala media/floor of scala vestibu
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Endolymph is located between
the tectorial and Reissner's membranes
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Steps of sound detection
Sound waves funneled through the outer ear hit the eardrum, which vibrate the middle ear bones. The stapes hits the oval window causing the perilymph to vibrate
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Reisner's Membrane role in sound detection
causes endolymph to vibrate; moves the tectorial membrane causing hair cells to move. The mechanical deformation of hairs opens and closes K+ and Ca++ gates causing alternating depolarizing and hyperpolarizing graded potentials.
106
Round window Role in sound detection
bulging of window dissipates sound waves
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Inner hair cells in sound detection
Sound waves cause a mechanical bend of inner hair cells that results in a graded potential. A sensory neurotransmitter, possible glutamate but still unclear, is released by the hair cell and binds to the next neuron in line
108
Outer Hair cells in sound detection
they receive input from motor neurons. Outer hair cells frantically bound up and down if sounds are loud (high amplitude), possibly to enhance the response to inner hair cells.
109
Sound Pitch
depends on frequency
seven notes
human ears can detect 20-20,000 Hz
120 Hz is the frequency of the average male's voice, 250 Hz is the frequency of the average female's voice
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intensity-
depends on amplitude; loudness
measure in decibels (DB), which is a log scale
jet plane = 160 DB
threshold of human hearing = 0.0002 DB
normal conversation = 60 DB
sounds ≥100 DB are dangerous
threshold of hearing moves the basilar membrane a fraction of a diameter of an H atom
111
Frequency discrimination depends on
where waves hit High frequency hits early, low frequency hits late = place principle
112
Amplitude discrimination depends on
how much of the hair on a hair cell is bent. Loud sounds bend the hair more
113
Two types of deadfness
Conduction deafness and Nerve Deafness
114
Conduction Deafness-
sound waves are poorly conducted to the Organ of Corti. This can be caused by a blocked ear canal, ruptured eardrum, fluid buildup in eustachian tube, problems with middle ear bones, and damage to oval window. Common treatments are hearing aides and tubes to drain the ears.
115
Nerve Deafness-
sound waves in the inner ear are not transduced to action potentials. This can be caused by damage to the Organ of Corti, damage to the auditory nerve, damage to the auditory cortex of the brain, and excessive exposure to loud noises which kills hair cells. A common treatment is cochlear implants.
116
Embryonically and morphologically the structures of the eye are derived from
The central nervous system
117
The most complex sense organ
The eye
118
Sclera
tough outer layer that makes up the white of the eye
| Made from connective tissue
119
cornea-
transparent portion of sclera that covers the iris and pupi
120
choroid-
next layer of the eye inside the sclera
Highly vascularized
Feeds the retina
121
retina-
found on the back of the eye
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Retina is made of
nervous tissue; photoreceptors and sensory neurons
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fovea centralis-
center of field of vision; loaded with conestext annotation indicator
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optic disk-
no photoreceptors because all sensory neurons converge to form the root of the optic nerve (Cranial Nerve II); also called the blind spot
125
Lens-
proteinaceous, transparent structure behind the iris
Focuses light on the retina
associated with suspensory ligaments and ciliary muscles to change the shape of the lens for focusing on images
126
cataracts
cloudiness in the lens, occur when proteins in the lens are denatured
127
iris-
pigmented cells above the lens
layers of circular and longitudinal muscles that constrict or dilate to control the amount of light entering the eye
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pupil-
opening in the middle of the iris that allows light to enter the eye
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Humors of the eye
aqueous humor and Vitreous humor
130
aqueous Humor
fluid between the lens and the cornea; produced by the ciliary body (modified choroid); drained through the canal of Schlemm; blocking the canal causes glaucoma, which is an increase in intraocular pressure due to buildup of aqueous humor
131
vitreous humor-
clear gelatinous material between lens and retina
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Focusing on light types
Far objects and near objects
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Focusing on far objects
pupil is dilated to let in light; longitudinal muscles contracted
lens is thin; ciliary muscles relaxed and suspensory ligaments taut
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Focusing on Near objects
pupil constricted to minimize light entry; circular muscles contracted
lens is thick; ciliary muscles contracted and suspensory ligaments relaxed
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Properties of light
Light resembles sound except frequencies are much higher. Light waves are measured in nm (1 m = 109 nm). Human eyes are sensitive to wavelengths between 400-700 nm. 400 nm = 7.52 X 1014 cycles/sec. Refer to Figure 50-8 to see the various wavelengths of light.
136
Retina
the pigmented layer of the eye. It is black and absorbs light not directly striking photoreceptors. This is why pupils are black.
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Two types of photoreceptors in the eye
Rods and Cones
138
Rods
detect light intensity or black and white vision
extremely sensitive to light but are unable to discriminate frequency
most numerous on the periphery of the retina
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Cones
detect color in the form of wavelengths
not very sensitive to light but discriminate frequency
1 cone:1 sensory neuron in the fovea centralis results in little convergence, high acuity or good detail resolution; no summation possible
concentrated in the center of the retina, especially in the fovea centralis
140
Three types of cones
red, green, and blue
141
Bipolar Cells
synapse with rods and cones
142
ganglion cells-
synapse with bipolar cells; leave the eye in the optic nerve
143
horizontal cells-
lateral connections between photoreceptors and bipolar cells
144
amacrine cells-
lateral connections between bipolar and ganglion cells
145
Opsin in Rods
rhodopsin, and it absorbs all wavelengths in the visible spectrum.
146
Opsin in Cone Pigments
Absorbs at different wavelengths than rhodopsin
147
Photopigments have 2 parts
Opsin and Retinal. Retinal is the same in all photoreceptors, but opsins vary
148
Electrical Activity in the Dark
1. In the outer segment, there is a high concentration of CGMP.
2. Na+ channels open.
3. Depolarization spreads across the receptor.
4. Once at the synaptic end of the photoreceptor, Ca++ channels open.
5. There is an increase in the release of the neurotransmitter glutamate.
6. This inhibits bipolar cells.
7. As a result, there is no action potential on ganglion cells.
149
Electrical Activity in Light
1. In the outer segment, a photopigment absorbs light causing a conformational change in the retina that activates opsin.
2. This decreases the concentration of CGMP.
3. Na+ channels close.
4. The photoreceptor is hyperpolarized.
5. Ca++ channels close.
6. There is a decrease in the release of neurotransmitter.
7. The bipolar cells are disinhibited (excited), and the potential is graded. Stronger light causes greater excitation.
8. This causes an action potential on ganglion cells.
150
Red-Green Colorblindness
Individuals with red-green color blindness are unable to distinguish between red and green because they have two types of cones instead of three (blue and red/green cones). Red-green color blindness is much more common in males because it is a sex-linked recessive trait.
151
Our perception of color depends on
the relative excitement of three types of cones.
152
Blue light color percentages
97% Blue cones stimulated
153
Yellow light color percentages
83% Green cones stimulated
| 83% Red cones stimulated
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Green Light Color Percentages
36% Blue Cones stimulated
67% Green Cones Stimulated
31% Red Cones Stimulated
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Orange Light Color Percentages
42% Green Cones stimulated
| 99% Red Cones Stimulated
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3 Parts of the Brain
Hindbrain
Midbrain
Forebrain
157
Parts of the Hindbrain
medulla oblongata, pons, and cerebellum
158
medulla oblongata-
```
This is the most posterior part of the brain just anterior to the spinal cord. It is the major control center for several vital functions
Respirations
CV function
Vomiting
Swallowing
Coughing
```
159
respiration-
location of medullary chemoreceptors that sample H+/CO2; location of neurons that control ventilation
160
cardiovascular function-
input from baroreceptors; location of neurons that control heart activity
161
vomiting-
sample the blood looking for toxins
162
Pons
This is next up from the medulla. The pons is mostly involved in conduction of impulses to and from the cerebrum.
163
cerebellum-
This is off the main stem. The cerebellum can be divided into three lobes or hemispheres. The function of the cerebellum is to control motor function
164
vestibulocerebellum-
responsible for balance and control of eye movements
165
spinocerebellum-
regulates muscle tone and coordination of skilled voluntary movement; compares intentions of cerebrum with performance of muscles and corrects any errors or deviations from the intended movement
166
cerebrocerebellum-
planning and initiation of voluntary motor activity
167
Roof of the midbrain
corpora quadrigemina and has four bumps
168
superior colliculli that
have roles in visual reflexes and moving the head in response to visual stimuli
169
inferior colliculli
have roles in auditory reflexes and moving the head in response to auditory stimuli.
170
The base of the midbrain is called
the cerebral peduncles, which are massive nerve tracts carrying information to and from the cerebrum.
171
Parts of the Forebrain
thalamus, hypothalamus, and cerebrum
172
thalamus-
The thalamus is on top of the midbrain and found deep in the brain. It is an important relay station for preliminary processing of virtually all sensory input going to the cerebrum
173
hypothalamus-
The hypothalamus is below the thalamus and has several vital functions.
174
temperature center-
thermostats that control body temperature; origin of sweating and shivering
175
Food intake
Glucostats
Feeding Center
Station Center
176
feeding center-
when stimulated, it causes feeding; if destroyed, the individual will not eat
177
satiation center-
when stimulated, it stops feeding; if destroyed, the individual will not stop eating
178
water intake-
osmoreceptors; when there is high osmolarity (salt) in the blood, the individual becomes thirsty and urine volume decreases
179
sleep/wake cycles-
daily clock; affected by jet lag, daylight savings time, and photoperiod
180
hormones-
produces hormones that regulate urine production, uterus contractions during labor, ejection of milk during lactaction, and the pituitary gland
181
cerebrum-
largest, most conspicuous part of the brain; made up of two hemispheres (left and right); connected by the corpus callosum, which is a thick band of approximately 300,000,000 axons
182
Function of the Cerebrum
intelligence, reason, consciousness, discretion, etc.; not much known about the cerebrum, and there is no suitable animal model
183
Two regions of the cerebrum
White and grey matter
184
Outer Layer of the cerebrum
called the cerebral cortex, is made of grey matter and is made up of cell bodies.
185
White matter contains
myelinated fibers and is found inside the cerebrum
186
In the spinal cord, the position of the grey and white matter
is reversed with the grey matter in the inner layer of the cord and white matter in the outer layer of the cord.
187
Deep within the white matter is
more grey matter called basal nuclei
188
Cerebrum 4 lobes
Occipital Lobes
Temporal Lobes
Parietal Lobes
Frontal Lobes
189
occipital lobes-
back of the cerebrum; processes visual input
190
temporal lobes-
sides of the cerebrum; processes auditory input
191
parietal lobes-
top of the cerebrum; two main functions
192
Parietal Lobe functions
processing sensory input from the surface of the body such as temperature, pressure, pain, proprioreception; left side of body sends input to the right parietal lobe; somatosensory cortex is just behind the central sulcus which is a deep notch separating the parietal and frontal lobes; homunculus and modality apply here (partnership with thalamus)
understanding speech- Wernicke's Area (discussed more later)
193
frontal lobes-
front of the cerebrum; three main functions
voluntary motor activity- primary motor cortex; located just in front of the central sulcus; has partnership with cerebellum; left side muscles controlled by right frontal lobe; homonculus applies and modality in reverse
speaking ability- Broca's Area (discussed more later)
elaboration of thought
194
Simple and initial motor/sensory integration occurs in
the primary motor cortex or somatosensory cortex
195
More complex integration occurs
more inward in the parietal and frontal lobes
196
Association areas are "silent areas", meaning
that electrical stimulation in these regions causes no observable motor or sensory response.
197
Prefrontal Association Cortex-
in the frontal lobe; controls planning, decision making, and personality traits; this part is removed in a lobotomy
198
Parietal-temporal-occipital Association Cortex-
pools and interprets somatic/auditory/visual sensations; comlex perceptual processing; also part of connection between Wernicke's Area and visual and auditory cortexes
199
Limbic Association Cortex-
inner surface and bottom of temporal lobe; motivation, emotion, and memory
200
Wernicke's Area-
posterior parietal lobe (left side of right-handed people); somatic, visual, auditory association areas all come together here; general interpretative area; gnostic area; knowing area; tertiary association area; electrical stimulation in Wernicke's Area occassionally causes a complex thought
201
Angular Gyrus-
just behind Wernicke's Area and fusing with occipital lobe in behind; interpretation of visual information; if angular gyrus is destroyed, one can still interpret auditory data normally because the person can see the words but can't interpret the meaning (dyslexia or word blindness)
202
When a person learns a second language, where is it stored?
In a separate place from the first language
203
When two languages are learned at the same time, where is it stored?
in the same place
204
Broca's Area is found
in the left frontal lobe
205
Broca's Area function
responsible for language expression. It is wired to facial muscles causing contractions that make appropriate sounds. Broca's Area is also wired to hand muscles causing contractions responsible for writing.
206
Wernicke's Area is found
The left parietal Lobe
207
Wernicke's Area Function
responsible for language comprehension and formulation of coherent speech for expression by Broca's Area. It receives input from the occipital lobe for reading comprehension and describing an object. Input from the temporal lobe is used for speech comprehension.
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Basal nuclei are made of
grey matter deep within the white matter
209
The basal nuclei have three main functions
Inhibitory aspects of maintaining muscle tone
Help monitor and coordinate slow, contractions
selecting and maintaining useful motor activity
210
inhibitory aspects of maintaining muscle tone-
Tone is the balance between excitation and inhibition of neurons associated with skeletal muscles.
211
Parkinson's Disease is caused by
degeneration of dopamine-secreting neurons of basal nuclei
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The symptoms of Parkinson's
are useless or unwanted movements (trembling), increased muscle tone (rigidity), difficulty (slowness) initiating and carrying out different motor behaviors, and impeded speech.
213
Parkinson's can be treated with
administration of L-dopa, an isomer of dopamine. Dopamine itself cannot cross the blood brain barrier, but L-dopa can cross.
214
The limbic system is
a ring of forebrain tissue (cerebrum, thalamus, hypothalamus components) surrounding the midbrain.
215
If you stimulate parts of the limbic system, you can produce
joy, satisfaction, fear, anxiety, anger, etc. If you stimulate other parts, copulatory movements are produced.
216
An EEG
is a record of the electrical activity in the brain. Electrodes on the scalp record electrons, mostly EPSPs and IPSPs in the brain. EEGs are used to diagnose cerebral dysfunction, distinguish between different types of sleep, and determine legal brain death (no EEG activity).
217
On average, about 20% of time sleeping is
REM (Rapid Eye Movement)
218
Short-term memory is
used for rapid retrieval and is usually permanently lost or forgotten.
219
information that is consolidated or practiced can become part of
one's long-term memory. Long-term memory is used for slower retrieval but is usually only transiently forgotten.
220
Engraved memories are
long-term memories that are rapidly retrieved
221
Declarative memories are
things stated and are stored in the temporal lobes.
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Procedural memories
such as the steps of a certain dance, are stored in the cerebellum.
223
Memory is located in
temporal lobes, limbic system, cerebellum, and diffuse other regions of the cerebrum.
224
Short-term memory causes transient changes in
pre-existing synapses
225
Long-term memory causes permanent physical changes
in the brain
226
The steps in storing long-term memories are:
new synaptic connections between neurons form
changes in presynaptic or postsynaptic neurons
increase or decrease neurotransmitter release and synthesis
227
Anterograde amnesia occurs when
the hippocampus is surgically removed
228
A person with anterograde amnesia can recall
previously learned memoried fine but is unable to learn anything new based on verbal symbolism. They can remember for moments then forget, even names they see every day.
229
Tumors in the CNS are
inappropriate divisions of glial cells since neurons don't divide by mitosis.
230
Four types of Glial Cells
Astrocytes
Oligodentrocytes
Ependymal Cells
Microglia
231
Astrocytes-
most abundant glial cell; several functions
act as glue holding neurons together in correct spatial arrangements
help repair injuries and with scar formation
help with metabolic needs of neurons
232
Astrocytes
remove excess K+ from the extracellular fluid when brain activity outstrips the Na+/K+ pump; if excess K+ wasn't removed, the membranes would be hyperpolarized; hyperpolarization is related to epileptic seizures
help form the blood-brain-barrier;
233
Oligodendrocytes-
form myelin sheaths around CNS axons; increase conduction speed; found in white matter; not capable of regeneration the way Schwann cells help with peripheral neurons
234
Ependymal Cells-
line internal cavities of CNS; contribute to the formation of cerebrospinal fluid
235
Microglia-
macrophages; cousins of monocytes; scavenge and phagocytize cell debris or foreign invaders
236
Astrocytes in the blood brain barrier
astrocytes form tight junctions that prevent material from leaving the brain through capillary pores; no capillary pores in brain capillaries; material must move through protein channels and can move more easily into the plasma from the interstitial fluid and cerebrospinal fluid
237
Meninges
Three protective and nourishing membranes
| lie between bone and nervous tissue; meningitis is swelling associated with meninges
238
Meninges (Layers)
Dura Mater
Arachnoid Mater
Subarachnoid Space
Pia Mater
239
dura mater-
"tough mother"; tough, inelastic membrane overlying bone
240
arachnoid mater-
"spiderlike mother"; delicate, highly vascularized layer; communication between the cerebrospinal fluid and blood; overlying bone
241
subarachnoid space-
space between arachnoid and pia mater (see next); filled with cerebrospinal fluid
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pia mater-
"gentle mother"; fragile, highly vascularized; closely adheres to brain tissue; supplies brain tissue with blood; overlying brain tissue
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Brain and CNS surrounded by special shock-absorbing fluid called
Cerebrospinal Fluid (CSF)
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Blood-Brain Barrier
The blood–brain barrier (BBB) is a highly selective semipermeable border of endothelial cells that prevents solutes in the circulating blood from non-selectively crossing into the extracellular fluid of the central nervous system where neurons reside.
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Serotonin is
a "feel good" neurotransmitter. It is associated with clinical depression, post-traumatic stress disorder, and anxiety disorders. Paxil is a drug administered to treat all these disorders, and it works by blocking serotonin reuptake pumps so serotonin remains in the synapses longer. Serotonin is primarily an inhibitory neurotransmitter.
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Dopamine is
also a feel good neurotransmitter and is associated with Parkinson's Disease. People with Parkinson's Disease have low dopamine levels. Dopamine may also be associated with schizophrenia. Dopamine is primarily an inhibitory neurotransmitter.
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Nitric Oxide is associated with
memory
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Enkephalins and endorphins are opiates associated with
suppression of pain. Morphine is an analgesic that stimulates the same receptors as enkephalins and endorphins
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GABA
a major inhibitory neurotransmitter. GABA inhibits skeletal muscle pathways. Tetanus toxin prevents the release of GABA, which explains the symptoms of lockjaw. Death from lockjaw is due to respiratory failure because the diaphragm wouldn't relax
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Glycine
an inhibitory neurotransmitter. Strychnine, a component of rat poison, blocks receptors for glycine.
