PNB 2274 Exam 4 TANNER/CHEN Flashcards
rectus muscles
left, right, up, down
oblique muscles
angular directions
abducens
lateral rectus
trochlear
superior oblique
cornea
shields eye from germs and dust, focuses light onto retina
iris
colored disc; separates cornea from lens
creates anterior and posterior chamber
aperture for light
anterior chamber
between cornea and iris
posterior chamber
between iris and lens
eye color pigments
melanin, lipochrome
melanin
brown color
lipochrome
gold tone
no pigment in iris
pink from blood vessels
some pigment in iris
blue from radiscattering
sphincter pupillae
contracts to make pupil small
parasympathetic
dilator pupillae
relaxes to dilate eye
sympathetic
relaxed ciliary muscle
ligaments taut, lens stretched, refracts less light
distance
contracted ciliary msucle
ligaments loose, lens relaxed, more refraction of light
close focus
lens
adjust focus to near and far
provides mode of transduction for muscle contraction
aqueous humor
water fluid, refracts light
vitreous humor
gelatinous collagen fibers, maintains pressure of eye
hyaluronic acid gives structure; peripheral cells, inorganic salts, ascorbic acid
fovea
many cones
macula
with fovea; area of highest visual acuity due to cone density
macula degeneration
lack of blood flow that causes blindness
optic disc
nerve entry point; blind spot due to no sensory cells
pigments
absorb light; melanin keeps photons from bouncing around
cones
detect light and color; day vision
cone pigment
opsin
3 visual pigments named by peak absorption
red, green, blue
red/green colorblindness
loss of red gene, perception of yellow and orange as green
rods
light intensity, sensitive to scattered light; night vision
rod pigment
rhodopsin = opsin and retinal
inactive (in dark) rhodopsin
11-cis
active (in light) rhodopsin
11-trans
rod cells in the dark
rhodopsin inactive cGMP levels high CNG channels open membrane depolarizing NT released
depth perception
when light hits 2D surface, there are 2 cues for 3D:
monocular, binocular
monocular cue for depth perception
determines distance
binocular cue for depth perception
stereopsis; relative positions
based on retinal disparity
horizontal cells
large receptive fields
allows eyes to adjust to light from lateral inhibition
amacrine cells
producing type M cells and integrates rods and cones with bipolar cells
bipolar cells
brightness and color contrast; graded response; two types
why do bipolar cells use graded responses?
graded potentials are important because light intensity varies whereas regular AP is all or none
Varying light allows varying depolarization with varying vesicular release of NT
on bipolar cells
depolarization/ responsive in light
glutamate hyperpolarizes
light hits rods; rods release less NT; stops hyperpolarization; bipolar cell is now active
off bipolar cells
hyperpolarization in light
glutamate depolarizes
darkness hits rods; rods release a lot of NT; bipolar cell depolarizes and is active
lateral geniculate nucleus
4 parvi layers, a copule magni layers
point to point projection from retina to LGN
3 parallel pathways
3 parallel pathways in LGN
m-blob pathway
p-blob pathway
p-interblob pathway
m-blob pathway
rod pathway
p-blob pathway
color perception (cone) pathway
p-interblob pathway
depth, form (cone) pathway
primary visual cortex (striate; V1)
2D primal sketch; no color, depth, or form
simple cortical cells, complex cortical cells
two streams:
dorsal and ventral
simple cortical cells
perceives bars
complex cortical cells
perceives other stimuli with wider fields; more preference for orientation
dorsal stream
where pathway
motion
towards upper portion of head
motion and eye movement to inferior parietal lobe
ventral stream
what pathway
form and color
towards side of head
inferior temporal lobe (V4)
form and color
medial temporal lobe
motion processing
association visual cortex (extrastriate)
25 higher visual processing areas
inferior temporal cortex
facial recognition
achromatopia
color can be sensed but there is no comprehension of it
sound wave
pressure waves impinging on the air which creates a compression wave which is perceived as sound
characterized by frequency and intensity
frequency
how often the waves strike the air
directly related to pitch
measured in hertz
frequencies humans can hear
20-20kHz
intensity
loudness; amplitude of sound waves
measured in decibles
external ear (pinna)
funnels sound into ear canal
middle ear
auditory ossicles
incus, stapes, malleus
auditory ossicles
force multiplier; deal with impedance mismatch and transduce air waves into water waves
process of sound transmission
air vibrates tympanic membrane which are amplified and transduced by auditory ossicles into water waves; this fluid vibrates the oval window of the cochlea; first travels through the vestibular canal, then tympanic, towards round window
impedence
difference in how medias conduct waves
impedance mismatch
difference in how readily the different media conduct waves
cochlea
uses hair cells to transduce waves into electrochemical signal and connects to auditory nerve
semicircular canals
balance and sense of accelleration
vestibular apparatus
balance and accelleration
oval and round window
membranes to prevent leaks
3 canals/ ducts in cochlea
tympanic, vestibular, cochlear
cochlear duct
organ of corti;
fundamental hearing organ
basilar membrane and hair cells
basilar membrane
thick and thin at different ends and can vibrate at different frequencies
inner hair cells
sensory receptors
outer hair cells
increase amplitude and sound clarity
tympanic reflex
very loud sounds (high amplitude) can cause damage
reflex: the tensor tympani and stapedius muscle contract and put a limit on the tympanic membrane vibration to limit sound transmission
kinocilium
peak stereocilium; moved with tectorial membrane
when stereocilium bend towards the kinocilium…
cell depolarizes from mechanical opening of nonselective cation channels
when stereocilium bend away from the kinocilium…
cell hyperpolarizes from the mechanical closing of nonselective cation channels and K+ leak channels dominate
endolymph
hair on the hair cell fluid; 80mV, high K+ concentration (calcium is low because it degrades tip links)
Perilymph
hair CELL fluid; 0mv; low K+ concentration
cochlear duct
scala media
vestibular canal
scala vestibuli
tympanic canal
scala tympani
upward phase of basilar membrane
tip links open; depolarization; excitation of sensory neurons
downward phase of basilar membrane
tip links close; hyperpolarization
frequency coding
physical mechanism for sound transmission
low frequencies: vibrates helicotroma region because it is thinner and less rigid
high frequencies: vibrates close to oval window
labeled line system
neurons that make contact with hair cells at/near oval window are tagged to represent a different frequency than neurons
tonotopic map
alternating current (AC)
up to 1000 Hz; high fidelity
300 Hz = 300x depolarization
direct current (DC)
2000 Hz and up; low fidelity because baseline is more depolarized and depolarization is therefore more favorable
direct current (DC)
2000 Hz and up; low fidelity because baseline is more depolarized and depolarization is therefore more favorable
intensity coding
frequency of AP is proportional to loudness
rate coding: neuron firing is indicative of intensity
phase lock firing
cannot fire at high frequencies, so hair cells will respond but neuron will fire at intervals
PRIMARILY how will neurons rate code at frequencies LESS than 1000Hz?
via the labeled line system and AC with high fidelity
PRIMARILY how will neurons rate code at frequencies HIGHER than 2000Hz?
via the labeled line system and DC with less fidelity (and phase lock firing)
somatic nervous system
conscious control of motor output; voluntary
brainstem pathway
indirect; subcortical
alters motor neuron sensitivity and activates feedback loops
axial and proximal muscle control: posture and equilibrium
brainstem pathway tracts
rubrospinal
tectospinal
vestibulospinal
reticulospinal
rubrospinal tract
stems from red nucleus; excites flexor and inhibits extensor; movement of limbs (arm, leg)
tectospinal tract
stems from superior colliculus; visual reflexes and orienting the eye and head towards visual stimuli
vestibulospinal tract
stems from vestibular nucleus; balance and orientation
reticulospinal tract
stems from reticular formation; posture and balance
corticospinal pathway
direct; pyramidal (decussation in medulla)
rapid and fine movements of distal extremities
corticospinal pathway tracts
lateral corticospinal tract
anterior corticospinal tract
corticobulbar pathway
lateral corticospinal tract
skilled movements in the limbs (fingers)
anterior corticospinal tract
innervates axial skeletal muscle; extra source of control
corticobulbar pathway
voluntary control of head and neck muscle
not in spinal cord
dorsolateral pathway
control of limbs; fine motor control; skilled movements
rubrospinal, lateral corticospinal
ventromedial pathway
axial and proximal muscle, posture, balance, equilibrium
reticulospinal, tectospinal, anterior corticospinal, vestibulospinal
motor regions of cerebral cortex
primary motor cortex (M1)
secondary motor areas
association areas
primary motor cortex (M1)
direction and speed; sends “go” signal
secondary motor areas
planning
SMA and premotor
supplementary motor area (SMA)
bilateral movement
premotor cortex
mirror neurons (allows you to learn how to use a tool before actually touching it)
association areas
prefrontal cortex
parietal cortex
parietal cortex
goal/target location; hand- eye coordination
spinal cord motor disorders: quadriplegia
paralysis of all limbs
spinal cord motor disorders: paraplegia
paralysis of lower limbs
motor cortex disorders: hemiplegia
paralysis of contralateral limbs (M1 damage)
motor cortex disorders: hemiparesis
weakness, impaired control of contralateral limbs (SMA damage)
motor cortex disorders:
secondary / association motor areas
apraxia
apraxia
loss of ability to generate coordinated actions; stroke of premotor or parietal, left hemisphere lesions
praxis: outcome of tapping experiments
dominant hand generates better movement
praxis: outcome of sequential tapping experiments
right hand generates better movement
why did the right hand generate better sequential tapping movements?
hemisphere lateralization: left brain controls the right hand
hierarchy of motor control
- Parietal (uses spatial info to develop action goal)
- Premotor / SMA (translates goal into movement trajectory)
- Primary motor cortex (translates plan into motor command)
- Spine (activates muscles and maintains reflexes)
basal nuclei
modulates motor output to prevent unwanted movement
parkinson’s disease
loss of dopaminergic neurons which excites both pathways
fixed by L-dopa (dopamine)
characteristics of parkinson’s disease
rigidity, slow movement, parkinsonian mask, hands do stuff
huntington’s disease
destruction of indirect pathway in basal ganglia
characteristics of huntington’s disease
abnormal involuntary movement because more excitatory; huntington’s chorea
afferent neurons
neurons going towards the CNS
efferent neurons
neurons going away from CNS
what was the activity in monkeys about?
electrical activity was recorded in the M1 in monkeys during reaching movements
finding: when moving hand to the right, neurons don’t fire; when moving hand to the left, they do fire
significance: cells have a preferred direction; tells you which neurons fire during specific directions and you can stimulate these neurons to command movements
autonomic nervous system
efferent innervation of tissues other than skeletal; involuntary
sympathetic autonomic nervous system division
fight or flight
lumbar and thoracic spine nuclei
overall excitatory
short pre ganglionic axons, long post ganglionic axons
preganglionic neurons in sympathetic
all release Ach
postganglionic neurons in sympathetic
epinephrine and norepinephrine
termination of norepinephrine and epinephrine
active transport, diffusion, enzymatic degradation (MAO)
sympathetic division post-ganglionic neuron
sympathetic chain
collateral ganglia
adrenal medulla
sympathetic chain
paravertebral ganglia directly adjacent to spine on both sides
collateral ganglia
excretory and alimentary;
celiac
superior mesenteric
inferior mesenteric
celiac collateral ganglia
stomach and duodenum
superior mesenteric collateral ganglia
pancreas, liver, kidney, colon
inferior mesenteric collateral ganglia
colon
adrenal medulla post ganglionic neuron
endocrine gland; medulla has modified (not quite neuronal) sympathetic ganglion
chromaffin cells in medulla secrete norepi and epi
parasympathetic autonomic nervous system division
rest and digest
preganglionic nuclei emerge from cranial nerves and sacral region of spinal cord
CN III (parasympathetic division)
ciliary ganglion; intrinsic eye muscles
CN VII (parasympathetic division)
pteryopalatine and submandibular ganglion (wtf); nasal, tear, salivary glands
CN IX (parasympathetic division)
otic ganglion; parotid salivary
CN X (parasympathetic division)
intramural ganglia; visceral organs of neck, thoracic, abdominal
broad effects
** vagus ** most important
nuclei in S2-S4 pelvic nerves (parasympathetic division)
intramural ganglia; visceral organs in inferior portion of abdominopelvic cavity
target organs of autonomic nervous system
cardiac muscle, smooth muscle, adipocyte, glands
cholinergic receptor subtypes
nicotinic and muscarinic
nicotinic cholinergic receptor
ionotropic
always excitatory
autonomic ganglia in both divisions
nicotinic receptor agonist
Ach, Nicotine
nicotinic receptor antagonist
TEA, currare
muscarinic cholinergic receptor subtypes
metabotropic
target organs of parasympathetic
agonist muscarinic
Ach, muscarine
antagonist muscarinic
atropine
adrenergic receptor subtypes
alpha 1 alpha 2 beta 1 beta 2 beta 3
Alpha 1
Gq coupled
smooth muscle constriction
vasoconstriction, increase in BP
Alpha 2
Gi coupled
inhibitory release of NE and Ach
Beta 1
Gs coupled
increase in contractility; tachycardia
Beta 2
Gs coupled
relax, vasodilation
Beta 3
Gs coupled,
enhance lipolysis
horizontal plane sound localization
loudness difference (above 3000Hz) time difference (below 3000Hz)
loudness difference horizontal sound localization
lateral superior olive encodes location through interaural intensity differences
excitation neuron perceives sound from one hemisphere which excites a neuron in LSO; at the same time, an axon from that hemisphere splits and sends axon to contralateral side and excites inhibition on the contralateral side; one side is all excitatory and perceived as closer to that ear
time difference horizontal sound localization
medial superior olive computes sound by interaural time differences
series of neurons in MS are connected to neurons from cochlea
vertical plane sound localization
the phase and change in sound wave; ears reflect and filter sound difference from top and bottom
unilateral lesion of auditory cortex
little effect
bilateral damage of auditory cortex
trouble distinguishing frequency and intensity, localization, speech understanding
peripheral or cochlear damage
unilateral deafness
damage to tympanic membrane or ossicles
results in impaired perception of all frequencies
conductive deafness
trouble with sound transmission; modern hearing aid amplifies sound
sensorineural (perception) deafness
too much excitation results in damaged hair cells which can be fixed with a cochlear implant
organs innervated only by sympathetic nervous system
adrenal medulla arrector pili muscles sweat glands most blood vessels nonshivering thermogenesis
autonomic reflex centers
receptors from sensory neurons pick up stimulus
2 pathways: long and short
long autonomic reflex
sensory neuron synapses to interneuron spinal cord; interneuron synapses to preganglionic neuron in spinal cord; then to postganglionic neuron; postganglionic neuron will synapse on target organ
short autonomic reflex
sensory neuron synapses to interneuron; skips preganglionic neuron; then synapses with postganglionic neuron which synapses on target organ
sympathetic reflex
cardioacceleratory
vasomotor reflex
parasympathetic reflex
swallowing reflex
gastric and intestinal reflex
coughing reflex
endocrine system
slow chemical messenger
endocrine glands
have ducts; pancreas, thyroid pituitary, parathyroid, adrenal, gonads, placenta
endocrine tissues
lungs, heart, liver, GI, adipose
tissues that modify hormones
lungs, skin, liver, kidney
peptide hormone synthesis
preprohormone to prohormone to hormone
release of peptides and catecholamines
exocytosis
release of steroids and thyroid hormones
simple diffusion
transport of steroids and thyroid hormones
carrier proteins
half life of peptide and catecholamines
short
half life of steroids and thyroid hormones
long
transport of peptides and catecholamines
dissolution in plasma
response to binding peptide and catecholamines
second messenger system activation
response to binding steroids and thyroid hormones
gene transcription and translation
general response of peptide hormones and catecholamines
modification of existing proteins (new protein synthesis for peptides too)
general response of steroid hormones and thyroid hormones
induction of new protein synthesis
examples of peptide hormones
insulin, PTH
examples of steroid hormones
sex steroids, corticosteroids
examples of catecholamines
epinephrine, norepinephrine
thyroid homonres
T3, T4
tyrosine derivatives
catecholamines, thyroid hormones
tryptophan derivative
melatonin
why does the liver and kidney excrete peptide hormones and catecholamines?
they are quicker and easier to excrete since they are dissolved in the plasma
first messenger
hormone
second messenger
cAMP
types of G proteins
alpha, beta, gamma
types of Galpha proteins
stimulatory, inhibitory, q
describe the sitmulatory cAMP pathway
- Hormone binds to Gprotein coupled receptor and undergoes conformational change
- G alpha s protein detaches from membrane and drops GDP which characterized it as inactive
- G alpha s protein attaches to GTP, becoming active
- adenylate cyclase converts ATP to cAMP
- cAMP is now the second messenger and can be phosphorylated by protein kinase A and can be amplified
hormone secretion is controlled by…
circadian rhythms
ion concentration changes
plasma changes
NT activation
complex control of hormone secretion
hypothalamus secretes releasing hormone –> pituitary gland secretes tropic hormone –> endocrine gland secretes effector hormone onto –> target cell/ organ
hypothalamus
neural control of hormone release
Supraoptic region produces oxytocin and ADH
oxytocin
uterine contraction, milk, romance
ADH
urine, water conservation
supraoptic region
Paraventricular nucleus
Supraoptic nucleus
anterior pituitary gland
secretes tropic hormones, responds to hypothalamus and controls other glands
epithelial tissue
posterior pituitary gland
stores ADH and oxytocin
nervous tissue
endocrine gland (complex control pathway)
produces effector hormone
hypophyseal portal system
carotid artery –> primary capillary plexus –> portal vein –> secondary capillary plexus –> jugular vein
primary capillary plexus
in median eminence; delivers RH from hypothalamus to pituitary
portal vein
connects pri capillary plexus to secondary capillary plexus
secondary capillary plexus
delivers tropic hormones
jugular vein
receives tropic hormones and distributes it
short loop feedback control
tropic hormone controls hypothalamus and inhibits it
long loop feedback control
effector hormone on hypothalamus and pituitary
simple control
calcium levels are high: calcitonin is raised; calcium goes into bones; calcium level is now lower
