Neuroscience Part 2 Flashcards
(447 cards)
1
Q
where are olfactory receptor cells located?
A
olfactory epithelium in the roof of the nasal cavity (ethomoid)
2
Q
what is the olfactory epithelium composed of?
A
- olfactory sensory/receptor cells (hair cells)
- supporting cells
- basal stem cell
- olfactory glands
3
Q
describe the structure of an olfactory sensory cell
A
bipolar neurons w/cilia (olfactory hairs) on the end of dendrite
4
Q
T/F: the olfactory sensory/receptor cells are referred to as hair cells but are not neuron
A
FALSE
these ARE neurons
5
Q
describe the supporting cells in the olfactory epithelium. What are they and what is their function?
A
mucous membrane lining of nasal cavity, neuroglia cells
function is to support, nourish, insulate, and detoxify olfactory receptor cells
6
Q
what is unique about basal stem cells in the olfactory epithelium?
A
these are neuronal stem cells
olfactory receptor cells have a lifespan of 1 month and are then replaced
7
Q
what is the function of the olfactory glands?
A
provide mucous to cover surface of olfactory epithelium to dissolve odor molecules so that they can interact with receptor cells
8
Q
Describe the olfactory pathway up to the point that an AP is generated on CN 1
A
- odor molecule dissovles in mucous of nasal surface
- odor molecule binds to olfactory receptor protein (ligand binding)
- chemical interaction w/olfactory receptor opens chemical gated channels (Ca and Cl)
- graded potential on dendrite/soma in olfactory epithelium
- graded potenials sum at axon hillock to generate and AP on axon of olfactory receptor cell
9
Q
describe the olfactory pathway from when an AP on CN 1 is generated to integration
A
- CN 1 axon goes through the cribiform plate to olfactory bulb
- signlas from olfactory receptor cell activate multiple cells in olfactory bulb for processing signals and discriminating signals
- olfactory bulb changes the pattern of signaling in response to a new odor
- olfactory tract carries new pattern to:
- ipsi and contralateral limbic structures
- temporal cortex
10
Q
T/F: the olfactory bulb is always sending signals
A
TRUE
11
Q
List the various ipsi and contralateral limbic structures
A
- Amygdale
- Entorhinal cortex
- hippocampus
- prefrontal cortex
- Insula
12
Q
where is odor discrimination occuring?
A
temporal cortex
13
Q
List the accessory structures of the eye
A
- eye lid
- eye brow
- eye lashes
- muscles
- lacrimal apparatus
14
Q
what is the function of the eye lid?
A
protect the eye
15
Q
what muscles and nerves are responsible for closing the eye lid?
A
obicularis occuli orbital and palpebral regions
CN VII
16
Q
what muscles and nerves are responsible for opening the upper eyelid?
A
levator palpebrae superioris
CN 3
17
Q
what is the inner lining of the eyelid called?
A
palpebral conjuctiva
it is continuous with the sclera
18
Q
what is the function of the lacrimal apparatus?
what controls it?
A
produce lacrimal fluid (tears)
secreted superior/lateral and will flow diagonally to inferior/medial lacrimal canals which empty into nasal cavity
CN 7
19
Q
List the extrinsic eye muscles
A
- Superior rectus
- inferior rectus
- lateral rectus
- medial rectus
- superior oblique
- inferior oblique
20
Q
the eyeball can be divided into what 3 layers?
A
- fibrous outer layer
- Vascular middle layer
- retina-inner layer
21
Q
what makes up the fibrous outer layer of the eyeball?
A
sclera (white CT covering the eye)
cornea
22
Q
what is attached to the sclera?
A
- palpebral conjuctiva of eyelid
- dural sheath (epineurium) of CN 2
- tendons of extraoccular muscles
23
Q
what is the cornea?
A
avascular area covering the anterior surface of the eyeball
24
Q
what is another name for the vascular middle layer of the eyeball?
A
uveal tract
25
the uveal tract can be divided into what 2 layers?
1. choroid
2. ciliary body
26
what is the choroid layer of the uveal tract?
middle layer containing blood vessels for the eyeball
27
what is the ciliary body?
anterior modification of choroid containing 3 structures
28
what 3 structures are in the ciliary body?
1. ciliary processes
2. ciliary muscles
3. Iris
29
what are ciliary processes?
a circular ridge attached to supspensory ligaments which connect to the lens
contain capillaries and produce aqueous humor
30
what are ciliary muscles?
circular smooth muscle at the base of ciliar process that changes the shape of the lens by pulling on suspensory ligaments
31
what happens to the lens to allow us to have near vision?
decreased tension on the lens resulting in a convex surface
made possible by contraction of ciliary muscles
32
what happens to the lens to allow us to have far vision?
increased tension on the lens resulting in a flat surface
made possible by relaxation of ciliary muscles
33
which is less tiring on the eyes? Near or Far vision?
Far vision, it is a passive process (ciliary muscles relax)
34
what is the Iris?
area of eye color
smooth muscle fibers that change size of pupil
35
what is the function of the pupil?
opening through which light enters eyeball
36
what constricts the pupil?
circular muscles
parasympathetic (CN 3)
37
what dilates the pupil?
radial muscles
sympathetic (carotid plexus)
38
what is located at the retina inner layer of the eyeball?
neuron sensory receptor cells
\*the beginning of the visual pathway
39
list the structure/layers of the retina-inner layer
1. pigment epithelium
2. photoreceptor layer
1. rods
2. cones
3. outer nuclear layer
4. outer synaptic layer
5. inner nuclear layer
6. inner synpatic layer
7. ganglion cell layer
40
which portion of the retina has the sensory receptors in it?
photoreceptor layer:
rods = dim light, gray images
cones = bright light, color images
41
where are the soma for the rods and cones located?
outer nuclear layer
42
where does initial image processing occur?
inner nuclear layer of the retina
43
there are several specialized areas of the retina, list them
1. optic disc
2. macula lutea
3. ora serrata
44
what is the optic disc?
blind spot
where optic nerve and blood vessels enter/exit the eyeball
\*\*no sensory receptors here!
45
what is the macula lutea?
visual axis/focal point
contains the central fovea
46
why is the central fovea significant?
contains only cones
serves as area of highest visual resolution
47
where is the lens and what is it's function?
connected by suspensory ligaments to ciliary process/muscles
function = bend light to focus image on retina
48
what is the virtreous body (humor) and what is it's function?
located between lens and retina
holds retina in place
contains phagocytes that remove floating debris
49
what is the anterior cavity of the eyeball?
area between cornea and lens
contains aqueous humor which nourishes the lens and cornea
50
how is light directed to the retina?
through a refraction of light rays that can be altered via the processes of accomodation and convergence
51
where is refraction of light rays occuring?
cornea and lens
52
T/F: images are invereted upside down and reversed right to left during refraction?
TRUE
53
what is accomodation?
the process by which the curvature of the lens is changed to focus light rays on the retina
54
List and briefly describe several vision deficits that impact the refraction process
1. myopia (nearsightedness) = distant object is unclear because image is focused **in front** of retina
2. hypermetropia (farsightedness) = near object is unclear because image is focused **behind** retina
3. presbyopia = lens becomes less elastic w/age and thus less convex, moving focal point further away from eyes
55
what is the process of convergence?
process of moving eyes medially for near vision so that images of objects hit the equivalent spot in both retinas
necessary for maintaining proper overlap in visual fields of both eyes for binocular vision
56
what does binocular vision allow for?
depth perception
3D perception
57
Briefly describe the light pathway
1. Light
2. Object
3. reflected light
4. corena
5. aqueous humor
6. lens
7. vitrous body
8. retina
1. pigment cells = absorb light
2. photoreceptor cells = transduce light to nerve impulse
58
Describe the inital route of the visual pathway leading up to the optic chiasm
1. photoreceptor cells generate either excitatory or inhibitory impulse (graded potential)
2. signal is processed and modified (via convergence and divergence) as it moves through neurons of other retinal cell layers
3. AP is generated in ganglion cells
4. AP exits eye by optic nerve
5. optic nerve goes to optic chiasm
59
impulses from which half of the retina cross to the opposite side of the brain at the optic chiasm?
from the Nasal half of retina
(temporal half stay ipislateral)
60
after the optic chiasm, where does the AP travel next in the visual pathway?
optic tracts that head to:
1. pretecal area → pupillary reflex
2. superior colliculus → horizontal tracing eye movements and head turning
3. lateral geniculate nucleus of thalamus
61
the left optic tract is carrying visual info from which visual field?
Right visual field
(Left temporal and Right nasal retina)
62
the right optic tract is carrying visual info from what visual field?
Left visual field
(Right temporal and Left nasal retina)
63
where does the visual pathway head next after the lateral geniculate nucleus?
to visual cortex in the medial occipital lobes
via the optic radiations
64
All external eyes muscles originate and insert where?
originate = orbital bone
insert = sclera
65
what is the action and innervation of the
Levator palperae superioris?
action = elevate eye lid (open)
innervation = CN 3
66
what is the action and innervation of the
Orbicularis occuli?
action = depress eye lid (close)
innervation = CN 7
67
what is the action and innervation of the
Superior oblique?
actions:
* when eyes are adducted (in near focus) = futher adduct
* when eyes are abducted (far focus) = further abduct
* depress and medially rotate eye
innervation = CN 4
68
what is the action and innervation of the
Inferior Oblique?
action:
* eyes adducted (from near focus) = further adduct
* eyes abducted (from far focus) = further abducted
* elevate and laterally rorate
innervation = CN 3
69
what is the action and innervation of the
Superior rectus?
action: elevate (slight adduct and med rotate)
innervation = CN 3
70
what is the action and innervation of the
Inferior rectus?
action = depress (slight adduct and lateral rotate)
innervation = CN 3
71
what is the action and innervation of the
Medial rectus?
action = adduct
innervation = CN 3
72
what is the action and innervation of the
Lateral rectus?
action = abduction
innervation = CN 6
73
CN 3 innervates what eye muscles?
1. Levator palpebrae superioris
2. Inferior oblique
3. Superior rectus
4. Inferior rectus
5. Medial rectus
74
CN 3 is made up of what types of neurons?
1. somatomotor → to skeletal muscle
2. visceromotor (sympathetic) → to smooth muscle and glands
75
where are the nuclei for CN 3 located?
Brain stem at the level of the midbrain
somatomotor = oculomotor nucleus
parasympathetic nucleus = Edinger-Westphal nucleus
76
Briefly describe the pathway of the oculomotor nerve (CN 3)
1. Nuclei in brainstem
2. exits cranial cavity via superior oribital fissure
3. divides into 2 branches
1. superior division (uncrossed/ipsilateral)
2. inferior division (uncrossed/ipsilateral)
77
what does the superior division of the occulomotor nerve supply?
superior rectus
levator palpebrae
78
what does the inverior division of the oculomotor nerve supply?
inferior rectus
medial rectus
inferior oblique
ciliary ganglion
79
what is the ciliary ganglion?
parasympathetic gangia sending fibers to:
1. ciliary body/ciliary muscles → accomodation
2. circular muscles or iris → pupil constriction
80
What types of neurons make up CN 4?
somatomotor → to eye muscles
somatosensory → proprioception
81
Describe the pathway of CN 4
1. Nucleus = brainstem at level of midbrain
2. Crosses pre-tectum
3. exits via cranial foramen (superior orbtal fissure)
4. supplies contralateral superior oblique
82
what types of neurons make up CN 6?
somatomotor to lateral rectus muscle
83
Describe the pathway of CN 6
1. brain stem nuclei at level of open medulla/pons
2. exits via superior orbital fissure
3. remains ipsilateral and innervates the lateral rectus muscle (abducts eye)
84
Describe the pathway for the pupillary light reflex
1. Light
2. ganglion cells
3. optic nerve/optic tract
4. pre-tectal area
5. Edinger-Westphal nucleus on both sides
6. parasympathetic preganglionic
7. ciliary ganglia
8. parasympathetic postganglionic
9. contracts circular muscle of iris
10. Pupil constricts
85
T/F: if you shine a light on the L pupil both pupils will constrict?
TRUE
via concensual pupillary light reflex (for R pupil)
(direct pupillary light reflex for the L pupil)
86
What 3 pathways make up the accomodation reflex?
1. Motor pathway resulting in convergence of visual field
2. papillary constriction reflex
3. Edinger-Westphal is activates resulting in an increased curved lens for near vision
87
What types of neurons make up CN 5?
1. somatosensory → from skin, muscle, and joint conscious sensory receptors of anterior 2/3 head
2. somatomotor → muscles of mastication nad tensor tympani
88
What are the 3 branches of the trigeminal nerve (CN 5)?
opthalmic
maxillary
mandibular
89
what region of the head/face is the opthalmic nerve the primary sensory neuron for?
1. upper face-forehead
2. cornea
3. upper eyelid
4. dorsum of nose
\*cutaneous sensation (touch, pressure, pain and temp) and proprioception
90
what region of the head/face is the maxillary nerve the primary sensory neuron for?
1. middle face-lower lip
2. lateral nose
3. cheek
4. upper jaw/teeth
5. palate
6. upper lip
91
what region of the head/face is the mandibular nerve the primamry sensory neuron for?
1. lower face-lower lip
2. lower jaw/teeth
3. tongue
4. chin
92
what is the soma for the 3 somatosensory peripheral axons (opthalamic, maxillary, mandibular) of the trigeminal nerve?
trigeminal (semilunar) ganglion
93
where is the trigeminal (semilunar) ganglion located?
base of sella turcica
close proximity to the internal carotid
94
Describe the motor pathway for the Trigeminal Nerve
1. R/L precentral gyrus (lateral homonculus) = UMN
2. corticobulbar tract
3. crossed and uncrossed bilateral input to motor nucleus trigeminal nerve = LMN
4. trigeminal nerve
5. 3 peripheral branches of trigeminal nerve
95
what muscles are innervated by the trigeminal nerve?
1. muscles of mastication
2. mylohyoid
3. anterior belly digastric
4. tensor tympani
96
how does the sensation of taste occur?
it is a result of a chemical interaction between molecules in mouth and membrane chemoreceptors on receptor cells in taste buds
97
Where are taste buds located in the mouth?
in papillae of the:
1. tongue
2. soft palate (roof of mouth)
3. pharynx (throat)
4. larynx
98
T/F: taste buds are the neuronal receptor cells for the sense of taste
FALSE
they are receptor cells but NOT neurons.
dendrites of cranial nerves synapse onto them
99
receptors in the tip of the tongue are more sensitive to \_\_\_\_\_\_
sweet
100
receptors in the posterior tongue are more sensitive to \_\_\_\_\_\_\_
bitter
101
receptors in lateral tongue are most sensitive to \_\_\_\_\_\_\_\_\_
sour and salty
102
T/F: we can decrease our sensitivity to particular tast stimuli?
TRUE
if we are continuously exposed
complete adaptation in 1-5 min of continuous stimulation
103
Describe the initial steps in the gustatory pathway (from molecule to generation of AP)
1. bite of food is chewed and dissolved into food molecules
2. foot molecules dissolve in saliva
3. food molecule binds receptor on **gustatory receptor hair cell**
4. gustatory hair cell releases **chemical messenger**
5. chemical messenger binds chemical gated channel on dendrite of pseudo unipolar taste neuron
6. AP generated on peripheral process of pseudounipolar neuron of CN 7, 9, or 10
104
Describe the general steps in the gustatory pathway from generation of AP to integration of sensation
1. AP is generated on peripheral process of pseudounipolar neuron of CN 7, 9, or 10
2. travels to sensory ganglia for taste (3 different ganglia)
3. then travels into brain stem in the solitary tract
4. synapses on secondary neurons in gustatory portion of solitary tract
5. Tertiary neuron in VPM of thalamus
6. tertiary neuron head to Cerebral cortex an dlimbic system for integration
105
where in the cerebral cortex does taste differentiation occur?
insula
inferior postcentral gyrus
106
what is the limbic system's role within the taste pathway?
emotional response to taste
107
what are the different sensory ganglia for taste?
1. CN 7 → geniculate ganglia
2. CN 9 → inferior petrosal ganglia of CN 9
3. CN 10 → inferior (no dose) ganglia of CN 10
108
CN 7 is responsible for carrying sensory info from taste receptors in what areas?
anterior 2/3 of tongue
109
CN 9 is responsible for carrying sensory info from taste receptors in what areas?
posterior 1/3 of tongue
110
CN 10 is responsible for carrying sensory info from taste receptors located in what areas?
base of tongue/pharynx
111
what types of neurons make up CN 7?
1. special sensory for taste (pseudo unipolar neuron)
2. somatosensory
3. somatic motor
4. autonomic motor
112
what is type of info is carried within the somatosensory neurons of CN 7?
proprioception of muscles of facial expression
skin sensation of posterior ear, external auditory meatus
113
what type of info is carried within somatic motor neurons of CN 7?
motor efferent to muscles of facial expression, stapedius
114
what type of info is carried within autonomic motor neurons of CN 7?
preganglionic parasympathetic input headed to lacrimal and salivary glands
115
where is the primary sensory neuron soma located for the CN 7 sensory pathway?
geniculate ganglia within the petrous portion of temporal bone
116
where is the secondary sensory neuron within the CN 7 sensory pathway?
spinal (trigeminal) nucleus of CN 5
117
where is the tertiary sensory neuron within the CN 7 sensory pathway?
VPM of thalamus
118
after synapsing with the tertiary neuron, where does the sensory pathway of CN 7 head?
contralateral postcentral gyrus
119
Describe the motor pathway for CN 7
1. precentral gyrus (UMN)
2. corticobulbar tracts
3. facial nucleus (LMN at lvl of open medulla/pons)
4. CN 7 exits brainstem at junctin of pons and medulla
5. CN 7 exits skull at stylomastoid foramen and divides in cutaneous nerves of partoid plexus
120
what are the branches of the partoid plexus?
1. auricular nerve
2. temporal branch
3. zygomatic branch
4. buccal branch
5. marginal (mandibular) branch
6. cervical branch
121
How does CN 7 innervate the stapedes muscle?
branch of CN 7 enters petrous portion of temporal bone through internal acoustic meatus and heads to the middle ear
somatomotor to stapedes muscle
122
what types of neurons is CN 9 comprised of?
1. somatosensory from posterior ear
2. special sensory for taste
3. visceral sensory from carotid sinus and carotid body
4. somatomotor to stylopharngeus muscle
5. autonomic motor to salivary glands
123
what types of neurons is CN 10 comprised of?
1. somatosensory from posterior ear and external auditory canal
2. viscerosensory from thoracic and abdomen organs
1. aortic arch baro- and chemoreceptors
3. special sensory for taste
4. somatomotor to pharyngeal and laryngeal muscles, and palatoglossus of tongue
5. autonomic motor to organs of thorax and abdomen
124
what types of neurons in CN 11?
somatomotor to SCM and trapezius muscle
125
what types of neurons are in CN 12?
somatomotor to intrinsic and extrinsic muscles of tongue
126
What does GSA stand for?
general somatic afferent
(neurons carrying touch and proprioceptive info)
127
What CN have GSA neurons?
5, 7, 9 and 10
128
Cranial nerve GSA neurons are headed to what structure in the brainstem?
spinal trigeminal nuclei and tract
129
What does SSA stand for?
Special Somatic Afferent
(special senses)
130
what CN have SSA neurons?
2 and 8
131
what does GVA stand for?
general visceral afferent
(sensory info from visceral like carotid baroreceptors and chemoreceptors)
132
What CN havae GVA neurons?
9 and 10
133
What does SVA stand for?
Special Visceral Afferent
(carrying sensory info for taste)
134
What CN have SVA neurons?
7, 9, and 10
135
where are all SVA neurons heading?
Solitary nucleus in the medulla
136
what does GSE stand for?
General Somatic Efferent
137
What CN have GSE neurons?
3, 4, 6, and 12
(the cranial nerves that are soley have motor function)
138
what does SVE stand for?
Special Visceral Efferent
(these are special because they arise from the brachial/pharangeal arches during development)
139
What CN have SVE neurons?
5, 7, 9, 10 and 11
140
Where are the SVE neurons of CN 9 and 10 coming from?
nucleus ambiguus
(swallowing reflex)
141
what does GVE stand for?
general visceral efferent
(parasympathetic fibers)
142
what CN have GVE neurons?
3, 7, 9 and 10
143
Match the GVE neurons with their parasympathetic destination/function
CN 3 - papillary reflex
CN 7 - salivary and lacrimal glands
CN 9 - parotid gland
CN 10 - viscera
144
Where do somatomotor signals originate?
somatomotor cortex (precentral gyrus)
145
what CNS structures modify somatomotor signals?
1. basal nucleus/thalamus
2. cerebellum
3. reticular formation
4. limbic system
5. red nucleus/substantia nigra
146
where are somatomotor neurons located?
1. spinal cord ventral horn gray matter
2. brainstem CN nuclei
* 3, 4, 5, 6, 7, 9, 10, 11, 12
147
where are LMN located?
somatomotor neurons in CN nuclei of brainstem
OR
spinal cord/ventral horn
148
where are the efferent axons of LMN?
they are carried in peripheral nerves
149
efferent neurons from LMN release what NT?
acetylcholine
always depolarizing (excitatory) the muscle never hyperpolarize
150
what types of neuron innervates slow twitch (red) muscle fibers?
small diameter (slow conducting) alpha motor neurons
151
what types of neurons innervate fast twitch (white) muscle fibers?
large diameter (fast conducting) alpha motor neurons
152
What is the Henneman's Size principle?
slow twich muscle fibers are recruited and activated before fast twitch fibers
this allows 2 fiber types to contract together
153
what are the 2 ways muscle contractions can be initiated?
1. order comes from somatomotor cortex (voluntary)
2. order comes from the spinal cord (reflex)
154
T/F: a reflex does not require an UMN for integration
TRUE
the LMN acts as the integrator
However, an UMN can be invovled in modulating the respones to the reflex
155
T/F: all cardiac and smooth muscle activity are reflexive?
TRUE
156
what is the role of collateral connections between tracts?
helps to coordinate movement and provide context
157
Collateral connections can include what type of coordinating activity?
1. reciprocal inhibition
2. muscle synergism
3. proprioception
4. stepping pattern generators
158
What are the 2 types of descending tracts?
1. specific somatotopic tracts
2. nonspecific upper motor neuron tracts
159
Specific somatotopic tracts can include what types of tracts?
1. postural gross movement tracts
2. tracts that carry info for fine movement
3. tracts for limb flexion
160
T/F: motor unit and motor neuron pools are the same thing
FALSE
motor unit = single somatomotor neuron and all muscle fibers it activates
motor neuron pool = group of motor neuron cell bodies in a ventral horn that innervate a single muscle
161
how are motor neuron pools organized within the ventral horn?
1. flexors are dorsal
2. extensors are ventral
3. axial muscles are medial
4. appendicular muscles are lateral
162
Define reflex
a predictable response to a given stimulus
occur w/o brain input (similar to a neural loop)
163
reflexes are _______ dependent
content
164
what does the phrase "reflexes are content dependent" mean?
the state of the nervous system will affect the properties of the reflex
(if you are relaxed the response may be less intense than if you were anxious)
165
what are the 2 broad categories for reflexes?
1. Stretch reflexes
2. Cutaneous reflexes
166
A stretch reflex that is a result of an UMN lesion will be \_\_\_\_\_\_
tonic
it will respond to the stimulus for the duration of the stimulus
167
What is a phasic stretch reflex?
a reflex that responses briefly to the stimulus
168
what is a monosynaptic reflex?
a reflex when the sensory neuron synapses directly with the motor neuron
\*there is no interneuron
169
Briefly describe the pathway of a stretch reflex
quick stretch stimulus → muscle spindle → Ia sensory neuron (annulospiral/bag and chain) → DRG → spinal cord dorsal horn → synapses w/alpha somatomotor neuron → skeletal muscle
170
what is an uncrossed reflex?
a reflex that involves a single spinal cord level
171
what normally prevents tonic stretch reflexes?
UMN inhibition
172
what is a tonic reflex contraction?
UMN lesion removal of the inhibition of a tonic reflex
it will allow the constant afferent signals to produce a constant efferent signal
173
what are 3 characteristics of a cutaneous reflex?
1. involves interneurons (minimum 3 neuron pathway)
2. involved multiple spinal cord segments
3. crossover in the spinal cord = crossed flexor withdrawl reflex
174
a golgi tendon reflex is what type of reflex?
cutaneous reflex
175
Descending tracts can be divided into what 4 categories?
1. Medial Motor Tracts
2. Lateral Motor Tracts
3. Corticobulbar Tracts
4. Nonspecific Upper Motor Tracts
176
What tracts are included in the Medial Motor Tracts?
1. Tectospinal tract
2. Medial Reticulospinal Tract
3. Medial Vestibulospinal Tract
4. Lateral Vestibulospinal Tract
5. Medial (Anterior) Corticospinal tract
177
What is the sensory input to the tectospinal tract?
visual, auditory, or somatosensory (pain and touch)
178
where does the Tectospinal tract start?
Soma = corpa quadrigemina
179
where does the Tectospinal tract crossover?
at the level of the mesencephalon
180
after crossing over, where does the tectospinal tract descend/travel?
tectospinal tract in anterior column of spinal cord white matter
181
Where does the tectospinal tract terminate/end/connect?
medial motor neurons of the ventral horn in the cervical region
these control axial muscles
182
what supplies sensory input to the Medial Reticulospinal Tract?
reticular system
183
where does the Medial Reticulospinal tract begin?
soma = pontine reticular formation of metencephalon
184
where is the medial reticulospinal tract located?
anterior column of spinal cord descending from metencephalon
185
where does the medial reticulospinal tract cross?
it doesn't
it remains uncrossed
186
what is the destination/end point of the medial reticulospinal tract?
medial somatomotor neurons along the entire spinal cord
187
what is the role of the medial reticulospinal tract?
prepare postural (axial) and girdle muscles for limb activity (reaching)
188
what supplies sensory input to the medial vestibulospinal tract?
vestibular apparatus/static and dynamic equilibrium
189
where does the medial vestibulospinal tract begin?
soma = medial vestibular nuclei
(elongate nucleus in pons and medulla)
190
where does the medial vestibulospinal tract travel?
anterior column of spinal cord
191
where does the medial vestibulospinal tract cross?
at the medulla
192
what is the destination/end point of the medial vestibulospinal tract?
medial somatomotor neurons along the cervical and thoracic spinal cord (brachial plexus)
193
what is the role of the medial vestibulospinal tract?
effect = balance in response to head movement (coordinate with tectospinal tract to maintain balance with head turning)
194
what provides sensory input to the lateral vestibulospinal tract?
vestibular apparatus/center of gravity
195
where does the lateral vestibulospinal tract begin?
soma located in lateral vestibular nuclei located in pons
196
where does the lateral vestibulospinal tract travel?
anterior column of spinal cord
197
where does the lateral vestibulospinal tract cross?
it doesn't
it remains uncrossed
198
what is the destination/end point of the lateral vestibulospinal tract?
medial somatomotor neurons along entire spinal cord
199
what is the role of the lateral vestibulospinal tract?
effect = upright posture/balance: stimulates axial extensors, and inhibits axial flexors when a person is standing upright
200
what provides input to the medial (anterior) corticospinal tract?
diverse associative input from pre-motor and parietal cortex of frontal lobe
201
where does the medial (anterior) corticospinal tract begin?
soma = somatomotor cortex (pre-central gyrus of frontal lobe)
202
describe the pathway of the medial (anterior) corticospinal tract
leaves the precentral gyrus and descends to the medulla through the internal capsule then the crus cerebrii and then the pons until it reaches the pyramids
203
where does the medial (anterior) corticospinal tract cross?
it doesn't
it is the 10% that remains uncrossed at the pyramids
204
what is the destination/end point of the medial (anterior) corticospinal tract?
medial somatomotor neurons in the cervical and thoracic spinal cord
205
what is the role/effect of the medial (anterior) corticospinal tract?
balance to prepare postural muscles for voluntary movements
206
where are all medial motor tracts located in the spine?
medial spinal cord white matter
207
what is the general function of all medial motor tracts?
function in axial muscle/posture
girdle muscles/stabilizers
contextual info
208
which medial motor tracts do **_not_** cross?
medial reticulospinal tract
lateral vestibulospinal tract
medial (anterior) corticospinal tract
209
which medial motor tracts cross (2)?
tectospinal tract
medial vestibulospinal tract
210
What tracts are included in the Lateral Motor Tracts?
1. lateral corticospinal tract
2. Rubrospinal tract
3. Lateral (medullary) reticulospinal tract
211
where are all the lateral motor tracts located in the spinal cord?
lateral spinal cord white matter
212
what is the general function of all the lateral motor tracts?
function in fine movements of face, and extremities
213
what supplies input to the lateral corticospinal tract?
pre-frontal cortex and motor associative cortex
214
where does the lateral corticospinal tract begin?
soma located in somatomotor cortex (pre-central gyrus) of the frontal lobe = UMN
215
how does the lateral corticospinal tract descend from the frontal lobe?
descends to medulla → corticospinal tracts through internal capsule → crus cerebri → pons → pyramids
216
where does the lateral corticospinal tract cross?
decussation of the pyramids in caudal closed medulla
217
what is the lateral corticospinal tract's destination/end point and how does it get there?
lateral somatomotor neurons in ventral horn (LMN) in brachial plexus and lumbosacral plexus regions of spinal cord
gets there via the lateral spinal column (lateral corticospinal tract)
218
what is the effect of the lateral corticospinal tract?
fine movements of extremities
fractionation of movement
219
what does fractionation of movement mean?
the activation of individual muscles independent of other hand muscles innervated by lateral somatomotor neurons at the same level
220
what supplies input to the rubrospinal tract?
motor cortex
221
where does the rubrospinal tract begin?
soma = red nucleus of mesencephalon
222
where does the rubrospinal tract cross and descend?
crosses at mesencephalon
descends in pons → medulla → spinal cord lateral column
223
what is the destination of the rubrospinal tract?
lateral somatomotor neurons in brachial plexus region of spinal cord
224
what is the effect of the rubrospinal tract?
activates wrist hand extensor muscles
225
what supplies input to the lateral (medullary) reticulospinal tracts?
motor cortex
226
where does the lateral (medullary) reticulospinal tract begin?
reticular nuclei of the medulla
227
where does the lateral (medullary) reticulospinal tract cross and how does it descend?
it doesn't cross
descends in the lateral spinal column
228
what is the destination of the lateral (medullary) reticulospinal tract?
lateral somatomotor neurons in the brachial and lumbosacral plexus of spinal cord
229
what is the effect of the lateral (medullary) reticulospinal tract?
prepare postural (axial) and girdle muscles for limb activity; reaching
230
the corticobulbar tracts is also known as what?
Corticobrainstem Tract
231
what supplies input to the corticobrainstem tract?
associative cortex = premotor cortex
232
where does the corticobrainstem tract begin?
pre-central gyrus of frontal lobe (somatomotor cortex)
233
Describe how the corticobrainstem descends and where it heads
descends to cranial nerve nuclei in pons, medulla, and cervical spinal cord via internal capsule and cerebral peduncles
234
where are the LMN for the corticobrainstem tract?
somatomotor neurons in cranial nerve nuclei
235
where does the corticobrainstem tract cross?
in brainstem pons and medulla
(muscles of upper face = controlled by bilateral cerebral hemispheres CN 7)
(muscles of lower face = controlled by contralateral hemisphere of CN 7)
236
what are the effects of the corticobrainstem tract?
1. CN 5 controls muscles of mastication
2. CN 7 controls muscles of facial expression
3. CN 9, 10 control pharynx and larynx muscles
4. CN 11 controls traps and SCM
5. CN 12 controls tongue muscles
237
what tracts make up the nonspecific upper motor tracts?
1. cerulospinal tract
2. raphespinal tract
238
what activates the nonspecific upper motor tracts and what is their role?
both are activated by the limbic system (emotions) and provide context to affect other descending tracts
239
how does the cerulospinal tract work?
mediates it effects by release of NE from locus ceruleus
240
how does the raphespinal tract work?
mediates its effects by release of serotonin form raphe nucleus
241
The anatomy of the ear can be broken down into 3 sections, what are they?
1. External ear
2. Middle ear
3. Internal ear
242
what are the 3 structures of the external ear?
1. auricle (pinna)
2. external auditory canal
3. ear drum (tympanic membrane)
243
what is the auricle (pinna)?
outer ear structure
244
what is the external auditory canal?
a tube connecting the auricle to the ear drum
245
what is the ear drum?
also called tympanic membrane
sheet across external auditory canal composed of:
epidermis, epithelium, and CT fibers (elastic)
246
what is the middle ear?
the small air-filled cavity within the ear
composed of 5 structures
247
what structures are inside of the middle ear?
1. auditory ossicles
2. oval window
3. round window
4. tensor tympani and stapedius muscles
5. opening to the auditory tube (eustuchian tube)
248
what are the auditory ossicles?
the 3 smallest bones in the body:
malleus
incus
stapes
249
what is the malleus?
"the hammer"
connects ear drum to anvil (incus)
250
what is the incus?
"the anvil"
connects hammer to stirrup (stapes)
251
what is the stapes
"the stirrup"
connects anvil to oval window
252
what is the oval window?
a membrane covered opening into perilymph of cochlea
253
what is the round window?
a membrane covering opening in to the perilymph at the other end of the cochlea
254
what innervates the tensor tempani and stapedius muscles?
tensor tympani (V3)
stapedius (CN 7)
these contract to prevent damage to middle ear structures by loud noise
255
why is there an opening to auditory tube(eustachian tube) in the middle ear?
the opening connects the middle ear chamber to nasopharynx (upper throat) to equilibrate pressure in the ears
(the pop you hear during swallowing)
256
what is inside of the inner ear?
1. bony labyrinth
2. membranous labyrinth
3. Vestibulocochlear nerve
257
what is the bony labyrinth in the inner ear?
a series of 3 structures lined by periosteum and containing perilymph
258
what are the 3 structures within the bony labyrinth?
1. semicircular canals
2. vestibule
3. cochlea
259
what are the semicircular canals?
contain the sensory receptors (crista ampullaris) for equilibrium (angular)
lie at right angles in 3 geomtric planes within the inner ear
260
what is the vestibule within the bony labyrinth?
contains sensory receptors (macula) for equilibrium (linear)
261
what is the cochlea?
a part of the bony labyrinth that contains sensory receptors (spiral organ of corti) for hearing
262
what is the membranous labyrinth?
sacs and tubes inside the bony labyrinth that have the same shape as the inside of the bony labryinth.
it is filled with endolymph
made up of 4 structures
263
what are the 4 structures found within the membranous labyrinth?
1. utricle - membranous sac → connected to semicircular canals
2. saccule- membranous sac → connected to utricle
3. membranous semicircular canal
4. cochlear duct for hearing
264
List the ganglia for the 1st order neurons of the Vestibulocochlear nerve
1. vestibular branch → S/I vestibular ganglia
2. cochlear branch → spiral ganglia
265
what makes up the hearing apparatus within the spiral organ of corti?
a hair cell layer on the basilar membrane arranged around the spiral core of the cochlear bony labyrinth (modiolus);
hair cell stereo cilia are embedded in a matrix = tectoral membrane which does not move
266
Define pitch and amplitude pertaining to sound waves
1. pitch = frequency of sound waves
2. amplitude = size of sound wave
pitch + amplitude = tone
267
Describe the hearing pathway
(from outside the ear all the way to the spiral organ of corti)
1. sound wave directed to eardrum by auricle and external auditory canal
2. sound waves cause ear drum to vibrate
3. vibration is amplified and transmitted to oval window by auditory ossicles
4. pressure waves in peri- and endolymph
5. pressure waves bend stereo-cilia of hair cells (in spiral organ of corti) embedded in tectoral membrane
6. this produces a change in the pattern of signaling from the spiral organ of Corti
7. this stimulates the peripheral process of the auditory sensory neuron
268
is the direction of bend in the stereo-cilia of hair cells in the tectoral membrane important? How?
Yes
bend lateral direction → depolarization
bend medial direction → hyperpolarization
269
T/F: different areas of the spiral organ of Corti are sensitive to different pitches?
TRUE
base = high pitch
apex = low pitch
270
Describe the start of the auditory nerve pathway
(from recieving the signal to entering the brainstem)
1. signal on bipolar neuron in spiral ganglia
2. signals cochlear nerve
3. cochlear nerve travels through petrous portion of temporal bone exiting the internal auditory meatus
4. enters brainstem at junction of pons and medulla and synapses with dorsal and ventral cochlear nuclei in tonotopic manner
271
what are the 3 destinations for the auditory nerve after it synapses with the 2nd order neurons in the cochlear nuclei?
1. tectum → tectospinal head turning reflex
1. inferior and superior colliculus
2. medial geniculate body of thalamus → heads to auditory cortex next
3. reticular formation → activates the CNS
272
do fibers from the cochlear nucleus cross to the contralateral side?
most fibers do (at the trapezoid body)
some stay ipsilateral
but bilateral projections to the cortex allow discrimination of sound differences in each ear
273
In order for us to have equilibrium we need what type of information?
linear acceleration → change in velocity when traveling in one direction
angular acceleration → change in velocity when rotating
274
what is our organ of equilibrium?
Vestibular apparatus within the inner ear
275
what are the 2 sensory receptors within the Vestibular Apparatus and what are they sensitive to?
1. macula → linear acceleartion
2. crista ampullaris → angular acceleration
276
what/where are the macula?
2 thickened regions in the walls of the utricle and saccule
277
what/where are the crista ampullaris?
elevations in the lumen of each semicircular canal
sensory receptors for angular acceleration
278
describe the makeup of the macula
1. support cells
2. hair cells (containing stero cilia/microvilla)
3. otolithic membrane
279
how do the macula respond to stimuli?
body movement causes the otolithic membrane to move and bend the sterocilia of the hair cell resulting in either
depolarization/hyperpolarization of the membrane
this changes the pattern of excitation/inhibition from the utricle and saccula macula to the Vestibular nerve
280
describe the makeup of the crista ampullaris
1. support cells
2. hair cells (contain sterocilia and kinocilia)
3. cupula (gelatinous ECM in which the stereocilia are embedded)
281
how does the crista ampularris respond to stimuli?
rotational movement of the head bends the sterocilia of the hair resulting in membrane depolarization/hyperpolarization
to change the pattern of excitation/inhibition from the crista ampullaris to the vestibular nerve
282
When the crista ampullaris on the L side is depolarized, the one on the R side is \_\_\_\_\_\_\_
hyperpolarizaed
283
Describe the Vestibular pathway
(from sensory receptors to brainstem nuclei)
1. bending sterocilia of hair cell
2. depolarize/hyperpolarize the hair cell
3. change in pattern of excitation/inhibition of peripheral axon of bipolar neuron in vestibular ganglia
4. central axon forms vestibular branch of vestibulocochlear nerve
5. exit petrous portion of temporal bone at internal acoustic meatus
6. enter brainstem at junction of pons and medulla
7. Fibers head to S/I and M/L vestibular nuclei
284
Fibers from the semicircular canals, utricle, and saccule all go to specific vestibular nuclei. List them
1. semicircular canal (crista ampullaris) → superior and medial vestibular nuclei
2. utricle maculae → lateral vestibular nuclei
3. saccule maculae → lateral and inferior vestibular nuclei
285
Where do the vestibular nuclei project to after receiving input from the crista ampullaris and maculae?
1. cerebellum flocculonodular lobe
2. cervical spinal cord head turning muscles
* medial vestibulospinal tract
3. both cervical and lumbar spinal cord extensor muscles
* lateral vestibulospinal tract
4. CN III, IV, VI nuclei (via MLF)
5. MLF
286
Where do vestibular nuclei that project to the MLF head next?
bilateral ventro-basal complex of the thalamus
then
premotor and other regions of cerebral cortex (post central and adjacent associative cortex dealing with head proprioception)
287
what are the components of the basal ganglia?
1. caudate
2. putamen
3. globus pallidus
1. internus = medial GP
2. externus = lateral GP
4. subthalamic nucleus
5. substantia nigra
1. compacta (dopamine)
2. reticularis
288
there are 3 structures within the basal ganglia that are made by combining 2 other structures. List those 3 structures
1. striatum (neostriatum)
2. ventral striatrum
3. lentiform
289
what is the striatum (neostriatum)?
caudate + putamen
290
what is the ventral striatrum?
an area of striatum where caudate joints putamen it contains nucleus accumbens (primarily a limbic structure)
291
what is the lentiform?
putamen + globus pallidus
292
what is the overall function of the basal ganglia?
psychomotor (both behavior and motor)
293
what types of behavior does the basal ganglia help regulate?
goal directed behavior
social behavior
emotions
294
what type of motor tasks does the basal ganglia help regulate?
1. decision making (initiation)
2. judgement (how much force is needed)
3. prioritizing (multi-joint movements and sequencing)
4. emotional response
5. learning
6. eye movements
7. spatial attention
295
The basal ganglia acts by ________ to the motor cortex (ie. it is \_\_\_\_\_\_\_\_\_\_)
reducing excitatory input
(ie. it is inhibitory)
296
Most afferent input to the basal ganglia is \_\_\_\_\_\_\_\_\_
excitatory
297
what supplies input to the basal ganglia?
1. cerebral cortex
* (glutamate = excitatory)
2. pedunculopontine nucleus (PPN)
* (glutamate and AcH = excitatory)
3. raphe nucleus
* (serotonin = inhibitory)
298
efferent output from the basal ganglia utilizes what NT?
GABA
inhibitory
299
efferent output from the basal ganglia is headed to what structures?
1. thalamus
2. Pedunculopontine nucleus (PPN)
3. Tectum
300
what areas of the thalamus does the basal ganglia interact with?
1. VA and VL = motor
2. MD = limbic to decrease activity precentral gyrus
301
what is the role of efferent output from the basal ganglia to the peduncopontine nucleus (PPN)?
to increase activity of axial, postural muscles
(this nucleus controls the reticulospinal tracts)
302
what is the role of effernet output from the basal ganglia to the tectum?
decrease activity of stepping pattern generators (walking)
affect reflex eye movements
303
the basal ganglia can be broken down into how many pathways? List them.
5
1. goal-directed behavior loop
2. social behavior loop
3. emotion loop
4. oculomotor loop
5. motor loop
304
what are the 3 non-motor loops in the basal ganglia?
1. goal-directed behavior loop
2. social behavior loop
3. emotion loop
305
describe the goal-directed behavior loop and what it's function is
loop: prefrontal cortex → cuadate →GPi → decrease VA thalamus
function: decision making, goal-directed behavior, planning, choosing action, learning
306
describe the social behavior loop and it's function
loop: prefrontal cortex → head/caudate nucleus + SN reticularis → MD Thalamus
Function: recognize social cues, regulate self-control, evaluates what info is relevant and irrelevant
307
describe the emotion loop and it's function
loop: prefrontal cortex → striatum → MD thalamus
Function: link emotions to cognitive and motor systems, reward seeking, outcome prediction
308
describe the oculomotor loop and it's function
Loop: frontal and supplemental eye fields → caudate nucleus → SN reticularis → decrease activity VA thalamus allow for reflexive prosaccades
Function: spatial attention, initiate fast eye movements toward an object (prosaccades)
309
the motor loops of the basal ganglia can be further subdivided into 3 more pathways. What are they?
1. hyper direct no go
2. go pathway
3. no go pathway
310
describe the **hyper direct no go** pathway
cortex → subthalamic nuclei → GPi:
results in:
* inhibit motor thalamus
* inhibit PPN → increase activity of reticulospinal tract/postural and girdle muscles by inhibiting an inhibitor (disinhibition)
* inhibit midbrain locomotor/step pattern generator
311
what is the **go pathway**?
direct pathway that decreases activity of GPi
results in disinhibition of:
1. motor thalamus and cortex = increase precentral gyrus activity
2. PPN = inhibition of reticulospinal/postural and girdle muscle activity
3. midbrain locomotor/step pattern generator
312
what is the **no go pathway**?
indirect pathway, works by inhibiting GPe which normally inhibits GPi = disinhibition to increase activity of GPi
313
what is the result of the no go pathway?
inhibition of:
motor thalamus/cortex
PPN reticulospinal/postural and girdle muscle activity
midbrain locomotor/step pattern generator
314
what is the role of the substantia nigra in the basal ganglia
modulates the neostriatum to modulate GPi
315
what is the input and output of the substantia nigra reticularis?
1. Input = GABA inhibitory from neostriatum
2. Output = GABA inhibitory to:
* substantia nigra compacta
* midbrain tectum
* motor thalamus
316
what is the input and output of the substantia nigra compacta?
1. Input = GABA inhibitory from substantia nigra reticularis
2. Output = dopamine stimulation and inhibition of neostriatum
3. effect = modulate neostriatum to modulate GP
317
what occurs if the substantia nigra is inhibited?
disinhibition of:
1. Thalamus → increased motor cortex activity
2. Tectum → increased eye movement, step generator
3. substantia nigra compacta
318
how is the substantia nigra reticularis inhibited? Describe the pathway
Cortex → stimulates putamen → inhibits SN reticularis
319
what causes Parkinson's Disease?
1. loss of DA from substantia nigra pars compacta
2. go pathway is no longer stimulated → decreased thalamic motor activity
3. no go pathway is no longer inhibited → decreased thalamic motor activity
320
what causes Huntington's Disease?
1. due to loss of GABA from neostriatum
2. no go pathway no longer inhibits thalamus → increased thalamic motor activity
321
What is the difference between a hypokinetic and hyperkinetic disease?
hypokinetic = decreased bodily movements (PD)
hyperkinetic = increased bodily movements (Huntington's)
322
what is the function of the cerebellum?
modulation of:
1. somatomotor signaling
2. balance
3. tone
323
What structures make up the general gross anatomy of the cerebellum?
1. 2 hemispheres joined by vermis
2. anterior lobe (paleocerebellum)
3. posterior lobe (neocerebellum)
4. flocculonodular lobe
5. lateral anterior and posterior lobe
6. vermal/paravermal (medial anterior and posterior lobe)
7. nuclei
8. peduncles
324
describe the general makeup of the 2 hemispheres of the cerebellum
1. cortex = gray matter
2. white matter below cortex = afferent and efferent axons
3. nuclei = gray matter located in white matter below cortex
325
what is the anterior lobe (paleocerebellum) also called? why? What is it's function?
1. also called spinocerebellum
2. becuase it receives spinal cord afferents
3. functions = controlling axial muscle tone; and a degree of flexion and extension
326
what is the posterior (neocerebellar) lobe also called and why? what is it's function?
1. cerebrocerebellum = it is linked to cerebrum and has input and output to the cerebral cortex
2. function = planning, organization, and coordination of motor activity
327
What is the flocculonodular lobe also called? What is it's function?
1. vestibulocerebellum (called this because it receives input from vestibular system)
2. function = control of eyes and head position
328
what is the role of the lateral anterior and posterior lobes?
efferent fine motor to limbs
329
what is the role of the vermal/paravermal (also called medial anterior and posterior) lobes?
efferent axial muscles for head turning, posture, and tone
330
list the nuclei found in the cerebellum
1. fastigial nucleus
2. dentate nucleus
3. globose nucleus
4. emboliform nucleus
331
what is the role of the fastigial nucleus?
relay efferent signals to vestibular nuclei and reticular formation
332
what is the role of the dentate nucleus?
relay efferent signals to cortex via superior cerebellar peduncle
333
what is the role of the globose nucleus?
efferent to red nucleus
334
what is the role of the emboliform nucleus?
efferent to red nucleus
335
what does the inferior peduncle carry?
afferent from spinal cord/medulla
(cuneocerebellar, rostrocerebellar, postrerior spinocerebellar)
336
what does the middle peduncle carry?
afferent from cerebal cortex to cerebellum via pontine nuclei
337
what does the superior peduncle carry?
1. efferent from cerebellar nuclei to brainstem and cortex
* (dentate nucleus → cortex
* interposed nuclei → brain stem)
2. afferent from anterior spinocerebellar
338
What structures supply afferent input to the cerebellum?
1. spinal cord = body
2. inferior olivary nucleus
3. vestibular apparatus
4. reticular formation
5. cerebral cortex
6. tectum
7. mesencephalic trigeminal nucleus
339
how does the spinal cord supply afferent input to the cerebellum?
body to vermis and perivermal cortex of anterior and adjacent lobes
via:
1. dorsal spinocerebellar → proprioceptors of legs
2. ventral spinocerebellar → monitor ventral horn activity of leg spinal cord segments
3. cuneocerebellar → proprioceptors of arms
4. rostrocerebellar → monitor ventral horn acitivity of arm spinal cord segments
340
the inferior olivary nucleus is a relay and receives input from where?
1. spinal cord → proprioceptors
2. sensory motor cerebral cortex → red nucleus → inferior olivary nucleus
sends output to anterior and posterior lobes of cerebellar hemispheres
341
the reticular formation provides afferent input to what part of the cerebellum?
vermis and paravermis of anterior and posterior lobes
342
how does the cerebral cortex provide afferent input to the cerebellum?
3 ways:
1. via red nucleus → inferior olivary nucleus which sends input to A/P lobes of cerebellar hemispheres
2. via deep pontine nucleus → sends input to A/P lobes of cerebellar hemispheres
3. via reticular formation → to vermis and paravermis of A/P lobes
343
how does the tectum supply afferent input to the cerebellum?
S/I colliculi to A/P lobes of cerebellar hemispheres
344
what does the mesencephalic trigeminal nucleus supply afferent input to?
vermal and paravermal regions of cerebellum
345
afferent inputs to the cerebellum have 2 types of fibers, what are they?
1. mossy fibers
2. climbing fibers
346
what are mossy fibers?
glutamate excitatory fibers from all areas of afferent input except inferior olivary nucleus
347
what do mossy fibers synapse with?
1. deep cerebellar nuclei
2. excitatory granule cells of cortex
3. inhibitory golgi cells of cortex
348
what are climbing fibers?
glutamate excitatory fibers from inferior olivary nucleus
349
what do climbing fibers synpase on?
1. deep cerebellar nuclei
2. Purkinje cells of cortex making the refractile to granule cell stimulation
350
What cells make up the 3 layers of the cerebellar cortex?
1. granule and golgi cells = innermost layer
2. Purkinje cell = middle layer
3. basket cell = molecular layer = surface layer
351
List the basic functions of the thalamus
1. filter and process afferent input from:
* basal ganglia (VA, VL)
* cerebellum (VL)
* all conscious sensory except olfaction
2. send efferent output to cerebral cortex
352
List the type of sensory info that is processed by the thalamus and where it is processed/filtered.
1. body somatosensation (VPL)
2. head somatosensation (VPM)
3. vision (lateral geniculate)
4. auditory (medial geniculate)
5. taste (VPM)
6. balance (VPL)
353
the thalamus is functionally divided into 3 nuclei types. List them
1. relay
2. association
3. nonspecific
354
what is the role of relay thalamic nuclei?
connect BG, cerebellum, and conscious sensory (except olfaction) to the cerebral cortex
355
relay thalamic nuclei can be subdivided by whether it is motor or sensory relays. List the portion of the thalamus that is responsible for each
1. motor = VA, VL
2. sensory = VPM, VPL, medial/lateral geniculate
356
what is the role of associative thalamic nuclei?
sensory, memory, emotion (limbic function) integration
357
what portions/parts of the thalamus are associative nuclei? Pair the location with it's associative role
1. declarative memory
* anterior nuclei
* lateral dorsal nuclei
* midline nuclei
2. sensory integration
* lateral posterior
* pulvinar
3. emotion
* medial group
358
what is the role of nonspecific thalamic nuclei?
regulate consciousness, arousal, attention
359
what portions of the thalamus are nonspecific nuclei?
interlaminar nuclei
reticular nuclei
\*\*these modulate the signals of the other thalamic nuclei
360
what is the hypothalamus?
about a dozen nuclei located in the diencephalon
connected to the pituitary by infundibulum
\*\*king of homeostasis
361
what are the functions of the hypothalamus
regulate homeostasis → subdivided into 2 categories:
1. visceral regulation
2. behavior regulation
362
What does the hypothalamus visceral (unconscious autonomic reflex) control include?
1. reflex control for viscerosensory afferent and autonomic motor efferent
2. endocrine control
3. thermoregulation
363
what hypothalamic nuclei is responsible for reflex control of viscersensory afferent and autonomic motor efferent?
paraventricular nuclei
364
what brainstem nuclei coordinate with the paraventricular nuclei of the hypothalamus to control BP?
1. viscerosensory afferent for BP = solitary nuclei
2. autonomic motor efferent for BP:
1. PNS = dorsal motor nuclei (decrease BP)
2. SNS = ventrolateral medulla (increase BP)
365
the hypothalamus coordinates and controls what endocrine organ to influence endocrine function?
pituitary gland
366
what hypothalamic nuclei communicate with the posterior pituitary? What hormones do these nuclei release?
supraoptic and paraventricular nuclei
ADH = increase BP, fluid retention
Oxytocin = "feel good hormone"
367
what hypothalamic nuclei influence and control the release of hormones from the anterior pituitary?
arcuate nuclei
ventromedial nuclei
dorsomedial nuclei
tuberal nuclei
368
how do hypothalamic nuclei influence the release of hormones from the anterior pituitary?
the hypothalamic nuclei release tropins (+/- factors) that will either inhibit/stimulate the release of hormones from the anterior pituitary
369
what hypothalamic nuclei control/influence rhythmic endocrine control?
suprachiasmatic nucleus = circadian (time of year)
preoptic nucleus = diurnal (time of day)
370
what hypothalamic nuclei is responsible for thermoregulation?
preoptic nuclei
371
what does the process of thermoregulation involve?
1. heat loss center
2. heat conservation center
372
how does the heat loss center perform thermoregulation?
↑blood temp →hypothalamus thermosensory cells →cardiovascular & respiratory centers →vasodilation/perspiration & panting
373
how does the heat conservation center perform thermoregulation?
↓blood temp →hypothalamus thermosensory cells →brainstem control centers →vasoconstriction, ↑CO, ↑metabolism, piloerection, shivering
374
what behaviors are influenced by hypothalamic nuclei?
1. drinking
2. feeding
3. sexual
4. emotional
5. sleep
6. memory
375
what hypothalamic nucleus is the thirst center?
paraventricular nucleus
376
what hypothalamic nuclei influence feeding behaviors?
dorsomedial nucleus
ventromedial nucleus
377
T/F: feeding behaviors are tied to the limbic system and have an emotional aspect to them?
TRUE
feeding center = governed by olfaction, taste and **amgydala**
378
what is the satiety center?
set point relative to metabolic rate, previous caloric intake, and current calorie intake
379
what hypothalamic nucleus is responsible for sexual behaviors?
preoptic
(female hypothalamus has estrogen and progesteron receptors)
(male hypothalamus has testosterone receptors)
380
what hypothalamic nuclei are responsible for emotional behaviors?
aggression/fight or flight behavior
dorsomedial nucleus
ventromedial nucleus
mamillary bodies
381
what hypothalamic nucleus is responsible for sleep behavior?
suprachiasmatic nucleus
382
what hypothalamic nuclei are responsible for memory?
dorsomedial nucleus
ventromedial nucleus
mamillary bodies
383
other than the hypothalamus and thalamus, what other structures are in the diencephalon?
subthalamus
epithalamus
384
what is the function of the subthalamus?
relay for basal ganglion mediated motor modulation
385
what is the epithalamus made up of?
1. habenular complex
2. pineal gland
386
what is the role of the habenular complex?
it is a relay linking the limbic system/hypothalamus to the midbrain
387
what is the role of the pineal gland?
it is an endocrine gland whose function is not well characterized but may include:
1. day length modulated hormone release
2. secretion of:
1. neurosecretory hormones (NE, serotonin, and melatonin)
2. hypothalamic releasing/inhibitory factors
388
what is the limbic system?
a collection of structures in the telencephalon and diencephalon whose overall function is to modulate the hypothalamus and PAG to affect emotional behavior, motivation, and short term memory
389
what structures are included in the limbic system?
1. hippocampal formation
1. hippocampus
2. dentate gyrus
3. subicular gyrus (parahippocampal gyrus)
2. septal area
1. M/L septal nuclei
2. diagonal band of Broca
3. amygdale
4. prefrontal cortex
5. cingulated gyrus
6. substantia innominate
7. insula
390
what is a defining property of a limbic structure?
it communicates with the hypothalamus and PAG to modulate the activity of these structures
391
what are the specific functions of the hippocampal formation?
1. modulation of aggression and rage
2. autonomic and endocrine = visceral
3. learning and memory
* via long term potentiation
392
what are the specific functions of the septal area?
1. modulation of aggression and rage
2. autonomic visceral
3. drinking behavior
393
what are the specific functions of the amgydale?
1. aggression and rage
2. feeding behavior
3. cardiovascular, endocrine visceral
4. learning and memory
394
what are the specific limbic functions of the prefrontal cortex?
1. emotional and intellectual processes
2. suppresses aggression and rage
3. affects feeding behaviors
4. visceral functions:
1. BP, respiration, gastric motility, thermoregulation
395
what are the specific limbic functions of the cingulated gyrus?
function is similar to that of prefrontal cortex
396
what are the specific limbic functions of the substantia innominata?
1. relay between amygdale and hypothalamus
2. contains basal nucleus of Meynert = a cholinergic efferent to cortex and other limbic structures
397
what supplies afferent input to the limbic system?
1. special senses
2. reticular formation monoamine neuronal projections
3. hypothalamus feedback connections
4. thalamus
398
T/F: the limbic system has an associative aspect to it?
TRUE
different parts of the limbic system are interconnected
399
List the efferent outputs from the limbic system
1. thalamus
2. hypothalamus
3. cerebral cortex
4. periaqueductal gray
400
briefly describe the reticular system
a diffuse set of nuclei located in the core of the brainstem running from the diencephalon to the spinal cord. It has synaptic connections with ascending and descending tracts as well as CN nuclei
401
what is the function of the reticular system?
1. modulate sensory, motor and autonomic activity
2. behavioral
1. sleep/wake (RAS)
2. consciousness
3. emotion
4. refine motor signals
5. pain modulation
402
List the afferent inputs to the reticular system
1. conscious sensation (somatosensation and special sensory)
2. motor
3. autonomic
403
what provides conscious sensation afferent input to the reticular system?
1. discriminative pain sensation from body/head
2. nondiscriminative pain sensation from body
3. special senses
404
describe the discriminative pain from body/head pathway (with respect to the reticular system)
spinothalamic/trigeminothalamic tract → reticular formation → thalamus (VPM/VPL) → cortex/post central gyrus → localized pain response
405
describe the nondiscriminative pain pathway (with respect to the reticular system(
spinoreticular tract → reticular formation → thalamus (non discriminative) → hypothalamus/cortex → emotional non localizable pain response
406
what supplies motor afferent input to the reticular system?
1. sensory/motor cortex → reticular formation (PPN) → reticulospinal tracts → affect extensor motor neurons → affect posture
2. cerebellum
* cortex → reticular formation → fastigial nucleus and vermal/paravermal
407
what automonic structures provide afferent input to the reticular system?
1. chemo and baroreceptors
* CN 9 and 10 → inferior ganglia → solitary nucleus → reticular formation → dorsal motor nucleus/ventrolateral → PNS/SNS control of BP
2. limbic structures
3. hypothalamus
408
List the efferent outputs of the reticular system
1. nonspecific thalamic nuclei
2. PAG
3. from monoamine and cholinergic nuclei of reticular formation to the cortex, hypothalamus and limbic system
4. cerebral cortex
5. spinal cord
6. horizontal gaze center
7. autonomic function
409
how does the reticular formation increase/decrease activity of the thalamus and cortex to regualte wakefulness?
1. ACh (PPN) and serotonin (raphe nucleus) → sleep
2. NE (locus cerulus) → wakefulness
410
what are alpha and beta rhythms with respect to sleep?
1. alpha rhythm = awake
2. beta rhythm = REM sleep = dreaming sleep
411
the autonomic nervous system is made up of many \_\_\_\_\_\_\_\_\_
neural loops
it is all reflexive
412
list the neurons that make up a neural loop within the autonomic nervous system.
1. interoreceptors
2. viscerosensory neurons
3. association neurons
4. autonomic motor neurons
5. effectors
413
what are interoreceptors?
receptors in the ANS that monitor body internal conditions
414
what are viscerosensory neurons?
ANS neurons that send/carry unconscious input to the CNS
415
what is the role of association neurons in the ANS?
control center
function to formulate a response to viscerosensory input
located in a variey of integrating centers within the CNS
416
list locations where association neurons in the ANS can be found
1. upper level emotional center (limbic)
2. hypothalamus
* paraventricular nucleus
* dorsomedial, posterior and mammillary nuclei
3. brain stem/reticular
* CN 3, 7, 9, 10
* ventrolateral medulla
4. spinal cord dorsal/lateral horns
* T1-L2 and S1-S3
417
autonomic motor neurons can be subdivded into what 2 categories?
sympathetic
parasympathetic
418
list some categories for effector tissues in the ANS
1. smooth muscle (gut wall, blood vessels, etc.)
2. cardiac muscle
3. glands (secretory cells)
419
how are sensory neurons different between the somatic and autonomic nervous system?
1. somatic → conscious, percieved sensation (special senses and somatic sense)
2. autonomic → primarily monitor conditions in the interior of the body
* sensory receptors are chemoreceptors, mechanoreceptors
* NOT consciously percieved
420
how are motor neurons different between the somatic and autonomic nervous system?
1. somatic → always excite skeletal muscle to cause contraction
* the effector they are stimulating has no intrinisc activity
2. autonomic → control effector function by either increasing or decreasing the intrinisc activity
* the effector they are stimulating has intrinsic activity (like HR)
421
how are motor (efferent) pathways different between the somatic and autonomic nervous system?
1. somatic → motor neuron pathway consists of 1 neuron going from ventral horn of spinal cord gray matter directly to effector muscle
2. autonomic → consists of 2 neurons
* preganglionic
* postganglionic
422
what is a preganglionic neuron in a motor neuron pathway in the ANS?
neuron is located in the lateral horn of the spinal cord gray matter
or
in the cranical nerve nuclei of the brain stem.
they send myelinated axons to the 2nd (postganglionic) neuron
423
what is a postganglionic neuron in the ANS?
located in a nerve cell ganglion which sends an unmyelinated axon to the effector (smooth/cardiac muscle or gland)
424
T/F: most targets of ANS motor neurons have nerve endings from both the sympathetic and parasympatheic parts of the ANS?
TRUE
called dual innervation
one will increase activity while the other decreses it
the NT released by either determines if it will be increasing/decreasing activity
425
differentiate between the location of sympathetic and parasympathetic preganglionic neurons
1. sympathetic → cell bodies located in lateral horn T1-L2
2. parasympathetic → cell bodies located in CN nuclei of brain stem (3,7,9,10) and lateral horn of S2-S4
426
differentiate between the location of sympathetic and parasympathetic postganglionic neurons
1. sympathetic
* sympathetic trunk (paravertebral) ganglia
* prevertebral ganglia
* adrenal gland cells of adrenal medulla
2. parasympathetic
* ciliary ganglia
* pterygopalatine ganglia
* otic ganglia
* submandibular ganglia
427
what/where are the sympathetic trunk (paravertebral) ganglia?
two chains of ganglia that run the length of the vertebral column
located along the sides of the vertebral column
428
what/where are the prevertebral ganglia?
lie anterior to the vertebral column and close to large abdominal arteries
include:
1. celiac
2. aorticorenal
3. superior mesenteric
4. inferior mesenteric ganglion
429
where are parasympathetic ganglia located?
close to/within the organ of innervation
result is a long preganglionc fiber and a short postganglionic fiber
430
what connects pre to postganglionic neurons?
1. white rami
2. gray rami
3. splanchnic nerves
4. vagus nerves
5. carotid periarterial plexus
431
what do white rami connect?
these carry preganglionic sympathetic axons to paravertebral ganglia
432
what do gray rami connect?
these carry postganglionic sympathetic axons back to spinal nerve for distribution with peripheral nerves
433
what do splanchnic nerves connect?
carry preganglionic sympathetic axons from paravertebral chain to prevertebral ganglia
434
describe how an autonomic motor pathway generally functions within the sympathetic system
mass activate targets due to divergence of neurons resulting in stimulation of many effector targerts, and release of the hormone epinephrine
435
describe how an autonomic motor pathway in the parasympathetic system generally functions
do not mass activate target organs
instead at the target organ the fiber synapses with a few postganglionic neurons which act on only one target organ at that location
436
what are the broad categories of neuron type according to NT/receptor?
1. Cholinergic → release ACh
2. Adrenergic → release NE
437
T/F: all sympathetic and parasympathetic preganglionic neurons are cholingeric?
TRUE
438
what type of postganglionic fibers are cholinergic?
all parasympathetic postganglionic neurons
sympathetic postganglionic neurons to sweat glands
439
cholinergic neurons will interact with what type of receptors?
cholingeric receptos:
1. nicotinic → always lead to depolarization/stimulation of target
2. muscarinic → found in all effectors innervated by PNS postganglionic neurons, can lead to either depolarization/hyperpolarization of the target
440
adrenergic neurons will interact with what types of receptors?
adrenergic (alpha and beta)
* 1's → depolarize and excite
* 2's → hyperpolarize and inhibt
441
what terminates the effects of NTs?
1. enzymatic inactivation
* acetylcholinesterase
* COMT
* MAO
2. removed from synapse by endocytosis
3. NT diffuses out of synapse
442
what regulates the activity of both PNS and SNS nerves to achieve a balance of inhibition and stimulation?
hypothalamus
443
list the structures that are not dual innervated and recieve only sympathetic innervation
1. sweat glands (ACh sympathetic)
2. erector pili muscles
3. most blood vessels
4. adrenal medulla
444
why are sympathetic responses longer lasting than PNS responses?
1. divergence of postganglionic fibers to activate effector targets in several tissues at once
2. slower inactivation of NE in synapse
3. presence of NE and Epi from adrenal medulla in blood
445
list body functions that are increased by parasympathetic nerves
SLUDD
1. salivation
2. lacrimation
3. urination
4. digestion
5. defecation
446
list the body functions decreased by the parasympathetic nerves
1. HR
2. airway diameter
3. pupil diameter
447
T/F: the cortex controls autonomic reflexes just like it does motor reflexes?
FALSE
the hypothalamus controls autonomic reflexes
there is a lack of awareness or consciousness with autonomic functions
