BECOM Exam #5 (Week 2) Flashcards
volume and frequency are measured in
volume: decibels (amplitude of wave)
frequency: hertz (frequency of wave)
Tensor tympani vs stapedius
Tensor tympani: muscle that is attached to the malleus that can contract to lessen transduction of sound to the inner ear
-CN VII (fascial)
Stapedius:
-CN V (trigeminal - mandibular division)
low frequency vs high frequency sound transduction
low: detected in wider region near the apex
higher: detected in narrower region near the base
Endolymphatic hydrops (Meniere’s Disease)
when you have too much endolymph
inner hair cells vs. outer hair cells
Inner hair cells: perceive sounds ( >90% of afferent fibers)
outer hair cells: amplify sound wave propagation
41/42 vs. 22 (Brodmann’s areas)
41 and 42: basic properties of sound, like rainfall vs thunderclap
22 (wernickes): pitch, intensity, melody, prosody – important for interpreting emotional state of a speaker
Descending hearing pathways
Superior olivary nucleus receives afferent input, send efferent outputs:
- Lateral olivocochlear efferents go to IHCs (through spiral ganglion)
- Medial olivocochlear efferents go to OHCs (bypassing spiral ganglion)
Loud noise reflex
Loud noise reflex: hair cells and vestibulocochlear cranial nerve are (primarily) afferents (CN VIII), facial (CN VII) and trigeminal nerves (CN V) are efferents to the stapedius and tensor tympani (respectively)
-L and R sup olivary nucleus -> CN VII nuclei –CN VII–> L and R stapedius
Contraction of these muscles dampens/mitigates conduction and amplification of the stapes and malleus – your built-in ‘volume limiter’
Conductive hearing loss
Sensorineural hearing loss
Conductive hearing loss: dysfunction of a structure in the outer or middle ear
Sensorineural hearing loss: dysfunction of hair cells
-Conductive loss will be able to hear a tuning fork when placed on the skull but sensorineural will not
modiolus
Central axis of the cochlea containing spiral ganglion and cochlear nerve
Ascending hearing pathway
hair cell stimulation -> CN VIII -> synapse at cochlear nuclei (some fibers decussate at sup oliv nuc, some don’t) -> synapse at inferior colliculus -> auditory cortex
-END RESULT: both L & R auditory cortices are ALWAYS receiving input from BOTH EARS
Low vs high frequency processed where
Low frequency sounds are processed superficially/laterally
High frequency sounds are processed deep/medially
Fungiform vs. foliate vs. circumvallate
innervation
location
Fungiform (have taste buds)
Innervation: facial
Location: ant. 2/3 on sides and tip
Foliate (don’t have taste buds)
Innervation: mainly glossopharyngeal and some fascial
Location: on side of tongue
Circumvallate (have taste buds)
Innervation: glossopharyngeal
Location: post. tongue
Taste Receptor Communication (2 separate ways)
- Tastant interacts with microvilli
- Depolarization of receptor potentials
- Na+ channels -> ATP released through Ca2+ independent mechanisms, into extracellular space via gap junction channels (released to extracellular space) -> firing of nerve
- Ca2+ channel -> ATP release onto peripheral nerve ending (directly to neuron) -> firing of nerve
Salt taste
No receptors involved.
Na+ ions increase outside and move into the cell through cation channels, causing depolarization
-ATP released to extracellular space
Sour taste
Weak organic acids diffuse across membrane, dissociate and increase intracellular acidity and cause cation channels to open
Stronger acids act as a ligand that will open pH-sensitive cation channels
Sweet, Umami, and bitter taste
-atp release
Bind to GPCR, cause a second messenger cascade that results in cation channels being opened
-ATP released directly onto peripheral nerve ending
Gustatory Information Pathway
Nerves from taste buds travel through respective ganglia and synapse in the nuclei of the solitary tract
- Reflex: CN X will synapse will synapse with reticular fibers allowing reflex activities of salivation, swallowing, coughing
Connections with reticular formation (RF) - Interpretation of taste: Ipsilateral travel to the thalamus to synapse in the most medial portion of the ventral posteromedial nucleus
Then to the gustatory cortex
Olfactory Receptors transduction mechanism
1 – cation channels that are closed when there is no odorant
2 – odorant binds, the G-protein dissociates from the GPCR and activates adenylate cyclase. That triggers the activation of the cAMP
3 – cAMP causes Na+ and Ca2+ in and K+ out
4 – increase in Ca2+ binds Cl- channel causes it to open and depolarize the cell
Depolarization triggers action potential
mitral cells
mitral cells make up the olfactory bulb and receive stimulation from incoming olfactory receptor cells preceding to pass down the olfactory tract
-Different odorants activate different glomeruli (mitral cell dendrites)
Prostacyclin (PGI2) NO Heparan sulfate Thrombomodulin Tissue factor pathway inhibitor Ectonucleotidase Adenosine
Prostacyclin (PGI2): inhibits platelet activation, aggregation, and vasodilates
NO: inhibits platelet activation, aggregation, and vasodilates
Heparan sulfate: activates antithrombin
Thrombomodulin: modifies thrombin activation
Tissue factor pathway inhibitor: inhibits tissue factor not allowing blood coagulation
Ectonucleotidase: destroys nucleotides resulting in the breakdown of ADP which is needed for coagulation
Adenosine: binds to the ADP receptors in the coagulation pathway blocking it
-all released by endothelial cells
GP Ib-V-IX
binds to von wilibrand factor (vWF) that is attached to collagen
-vWF must be bound to collagen for 159 to recognize it
GP IIb/IIIa (integrin alpha IIb beta3)
binds to loose fibrinogen and loose vWF
GP Ia/IIa and GP VI
bind directly to collagen
Platelet secretions upon activation
- Thromboxane A2 (AA derivative using COX), diffuses through the platelet membrane: activates platelet and also secreted by platelets
- Alpha granules exocytosis -> fibrinogen, vWF, coagulation factor V
- Dense granules exocytosis -> ADP, Ca2+
ADAMTS13
breaks down vWF multimers
P2Y1 and P2Y12 receptors
receptors that bind ADP resulting in autocrine and paracrine activation of platelets
shortage of vWF will cause what intrinsic factor def.?
VIIIa
-increases VIIIa half-life
thrombomodulin causes
binds to thrombin making a inhibitory complex that activates Protein C -> inactivation of Va and VIIIa
- secreted by normal endothelium
- Protein S (cofactor) is needed by thrombin/thrombomodulin to activate protein C
Antithrombin
Serine protease inhibitor (serpin) when it binds to heparan it inactivates thrombin, IXa, Xa and XIa
Tissue factor pathway inhibitor
Circulating or attached to vascular endothelium, inhibits Xa and VIIa-TF complex
Role of calcium (IV) in coagulation cascade
- platelet morphological changes
- activation of several coagulation factors
plasmin
active enzyme that breaks up clot by cleaving fibrin threads resulting in the degradation products D-DIMERs
-associated with fibrinolysis
Hemophilia
Excessive bleeding caused by deficiency of one of the factors in the clotting cascade
MOTION DETECTION
semicircular ducts
utricle’s macula
saccule’s macula
semicircular ducts: rotational movement of the head
utricle’s macula: side to side movement (ant. to post. movement)
saccule’s macula: vertical movement
otoconia
Enables continued sensation of head’s position in absence of acceleration
-head is put sideway but you know you head is still sideways although the movement is no longer occurring
loss of one vs loss of two vestibule system sources (eyes, inner ears, body’s proprioceptors)
Loss of one of these systems usually does not produce problems (especially if temporary)
Loss of two of these systems usually results in dizziness/vertigo/system failure
Vestibuloocular reflex
allows eyes to stay fixed with movement of the head
dorsal column medial lemniscal tract issue vs. cerebellar dysfunction (Romberg test)
Medial lemniscal tract/dorsal column: can stand normally with eye open but will fall when eyes are closed
-Cerebellar dysfunction: can’t stand when eyes are open or closed
Nystagmus
-ABNORMAL nystagmus issue
“snapping back”
- jumping from one object to another while driving
- ABNORMAL nystagmus: tracking finger and left eye follows but right eye stops but then snaps back to following (CN VIII)
Benign paroxysmal positional vertigo
Forceful, abrupt head movement (trauma ) cause the otoconia to dislodge -> loose otoconia can cause vertigo when the head is in certain, specific positions
alc effect on hearing
Relaxation of stapedius and tympani -> inc sound transduction
alc effect on vestibulocochlear system
alc infiltrates the endolymph causing a drop in density of cupulae relative to endolymph -> body is more sensitive to movement
as alc exfiltrates the cupulae density increases leading to slower movement of hair cells -> slow/exaggerated movements
scala vestibule
scala media
scala tympani
Scala vestibule (starts with oval window) -perilymph (Na+) Scala media -endolymph (K+) Scala tympani (ends with round window) -perilymph (Na+)
stria vascularis
pushes K+ and Ca2+ out of the cells into endolymph
- K+ has a strong gradient into cell
- it produces endolymph gradient for the scala media
prestin
once OHC is stimulated causes contraction and elongation of leading to amplification of sound
depolarization route in IHC
Tip link: connects stereocilia
- also connected to a cation gate that can be physically opened when stereocilia are displaced
- allows K+ in depolarizing cell -> activate Ca2+ channles -> neurotransmitter released
olfactory pathway
cilia on olfactory receptor cell -> glomeruli -> mitral cells -> olfactory tract
olfactory receptor activation pathway
Ligand binds -> cAMP -> activation of CNG channel -> influx of Na+ and Ca2+ -> depolarization
olfactory adaptation via
- internalization of receptor on olfactory receptor cell
- Ca2+ inhibits AC and CNG channel
- GABA released from inhibitory neurons inhibits synapse
-mechanism so not one odor can control system
Ageusia
Disguise
Hypogeusia
Ageusia: Absence of taste sensation
Dysgeusia: Disturbed taste sensation
Hypogeusia: Diminished taste sensation
Injection of an anesthetic in celiac plexus nerve fibers can relieve intractable pain arising from
foregut
Lumbar epidural space (L3 IV space) will block pain signals from both
uterus and the vagina
Obstetric anesthetics via a caudal epidural block (sacral hiatus) will anesthetize
uterine cervix and the vagina (inferior to the pelvic pain line) but will have little effect on pain signals from the uterine body -> allowing the mother to be aware of her uterine contractions during participatory childbirth
Horner syndrome
Interruption (central or peripheral) of the sympathetic pathway through the superior cervical ganglion results in
- Constriction of the pupil (miosis)
- Drooping of the upper eyelid (ptosis)
- Flushing of the face
- Diminished or absent sweating (anhidrosis) on the face
Contraction of the detrusor and inhibition of the internal sphincter are mediated by
parasympathetic outflow
medial preoptic nucleus
controls temp and body water
- detect changes in temp and will initiate heat retention/production
- will cause supraoptic nuclei secrete ADH
Ventromedial nucleus control and lesion
controls satiety/rage
-lesions leads to chronic hunger
Lateral hypothalamic area control and lesion
controls desire to eat
-wont eat leading to death
Arcuate nucleus control and lesion
secretes ghrelin (hunger hormone) and leptin (inhibit hunger) -drive hunger via glucose levels and stomach distention
Suprachiasmatic nuclei
involved in regulation of circadian rhythms
Therapeutic window equals
TD50 (toxic dose) / ED50 (effective dose)
Efficacy
the effect of a drug
-if two drugs have the same efficacy then they have the same effect
Potency
the amount of drug needed to get an effect
Volume of distribution def and equation
Volume of distribution: the measure of the apparent space in the body available to contain the drug
Vd = amount of drug in body / concentration of drug in plasma
-low Vd = drug got absorbed into tissue somewhere
Compression of the optic chiasm
bitemporal hemianopia: blindness in the temporal field of vision of both eyes
Vascular and neoplastic lesions of the optic tract, optic radiation or occipital cortex
homonymous hemianopia
blindness in the corresponding (right or left) field of vision of each eye
-left and right eye loose same side of vision
Lateral corticospinal tract controls
Lateral corticospinal tract: limbs and digits
-Decussates at the pyramids
Anterior corticospinal tract controls
Anterior corticospinal tract: trunk/axial muscles
-Does NOT decussate at pyramids but rather spinal segment
Muscle unit and control range
lower motor neuron + muscle fibers being innervated
Low muscles fibers per motor unit = finer movement
More muscle fibers per motor unit = gross movement
lower motor neuron cell body location (lateral vs medial) given muscle location
more medial cell body control a muscle of limb that are more proximal
Vestibulospinal tracts controls
- medial
- lateral
postural adjustments to body in response to tilting and movement and postural adjustments to head in response to movement, including walking
- Medial: antigravity muscles (extensors)
- Lateral: stabilizes head
- disfunction: cant walk and read at the same time
Reticulospinal tracts controls
- medial
- lateral
is another alternate motor control pathway
- medial: pons (ipsilateral only)
- lateral: medulla (ipsilateral and contralateral)
Corticobulbar tract
motor to cranial nerve innervated muscles
upper vs lower motor neuron damage
Upper damage: increase muscle tone and strength reflexes, moderate atrophy
- clonus (babinski sign) CUM
- hyperreflexia
Lower damage: decrease muscle tone and strength reflexes, severe atrophy
- fasciculations
- hypotonia/paralysis
Motor cortex/corticospinal tract lesions
contralateral motor deficits to limbs, hands, and feet
Hereditary spastic paraplegia
disfunction in the long axons/UMNs of the spinal cord causing Weakness and spasticity of the lower limb, bilaterally (gate problems)
Primary lateral sclerosis
Gradual degeneration of motor cortex neuronal cell bodies (Betz cells) causing gradual loss of lower limb first, then body, then arms, then laryngopharyngeal muscles
The study of genomic influence on drug response, often using high-throughput data
Pharmacogenomics
The study of individual gene-drug interactions, usually one or two genes that have dominant effect on a drug response
Pharmacogenetics
An alteration of DNA sequence that is present commonly in the population (affects > 1% of the population
Polymorphism
Single nucleotide polymorphism (SNP)
a polymorphism due to a change in a single nucleotide
- Coding nonsynonymous SNPs
- Coding synonymous SNPs
- Noncoding SNPs
Indels
Short repeats in the promoter (which can affect transcript amount) or indels that add or subtract amino acids
refer to a combination of alleles or to a set of SNPs found on the same chromosome and tend to inherit together
haploid
CYP 2D6
codeine metabolizer that depending on variant can lead to increased activity, decreased activity, or normal activity
CYP 2C19
The CYP 2C19 is responsible for metabolizing or activating approximately 10% of commonly prescribed drugs
CYP 2C9
assists in metabolizing numerous drugs, such as Phenytoin, Tamoxifen, Warfarin, NSAIDs such as Aspirin, Ibuprofen and Naproxen
- can decrease metabolism of warfarin so won’t need to give as much medication
- all individuals with atrial fibrillation will be given anticoagulants
Role of lateral/medial superior olives in hearing
locate sound sources in space
pain sensation in the nose
trigeminal nerve is stimulated by irritating substances in the nose
-responsible for initiating sneezing, lacrimation and other reflex responses
bowman’s gland
produce mucous in the nose that allow odorants smelt
hippocampus
orbitofrontal cortex
Hypothalamus/Amygdala
-smell
hippocampus: odor memory
orbitofrontal cortex: conscious perception of smell
Hypothalamus/Amygdala: motivational and emotional aspect of smell
Proust effect
memories produced by smell
Amiloride
blocks ENAC (salt taste)
Gustatory Pathway
CN VII, IX, and X -> solitary nucleus -> VPM of thalamus ->
- gustatory cortex (taste)
- hypothalamic/limbic system (emotion/memory)
coratid body and aortic body sensory pathway
Carotid body: glossopharyngeal
Aortic body: vagus
jugular foramen ->solitary nucleus ->
- Dorsal Vagal Nucleus: parasympathetic
- to heart via vagus - Nucleus Ambiguus: parasympathetic
- to heart via vagus - Anterolateral Medulla: sympathetic
- -> Intermediolateral cell column
cortical areas responsible for viscerosensory information
spinal cord -> VPL -> inferolateral part of the post central gyrus or insular cortex
-inferolateral part of the post central gyrus or insular cortex
Ascending Reticular Activation System
-lesion
afferent visceral information from the gut (sympathetic) and pelvic viscera (sympathetic)
spinorecticular fibers -> reticulothalamic -> intralaminar nuclei of the thalamus
(stomach/SI pain or full bladder)
- Wake a person from deep sleep
- Alert person to internal stimulus
Damage can result in persistent coma
referred pain
- heart
- diaphragm
Heart: left arm
Lungs: left shoulder
Hirschsprung disease
A congenital disease caused by a disruption of neural blast cell migration in the colon. The lack of nerve innervation in the colon results in no peristalsis of that segment resulting in a bowel obstruction and megacolon.
sympathetic preganglionic neuron location
intermeidolateral nucleus ->
- up and down sympathetic trunk
- splanchnic nerve
Sup cervical gang
innervate blood vessels and cutaneous targets of the face, scalp, and neck via branches of the internal and external carotid nerves
-also innervates the salivary glands, nasal glands, lacrimal glands, and structures of the eye such as the pupillary dilator muscle and the superior and inferior tarsal muscles
Horizontal gaze center
paramedian pontine reticular formation (PPRF)
Vertical Gaze Center
Rostral Interstitial Nucleus of the Medial Longitudinal Fasciculus (riNMLF)
-main control rostrally
Akinetic Mutism
- symptoms
- lesion
patients that neither move nor speak; however, their eyes may follow their observer or be diverted by sound. Patients lack most motor functions such as speech, facial expression, and gestures, but demonstrate apparent alertness
-lesion: frontal lobe damage, thalamic stroke, damage to cingulate gyrus
Kluver-Bucy Syndrome
- symptoms
- lesion
behavioral changes
placidity (fear and anger non longer shown), hyperorality (examine things with mouth), hypersexuality, hyperphagia (eating excessive amounts), and visual agnosia (inability to recognize objects by sight)
-lesion: bilateral temporal lobe lesions that abolish both amygdalas
Alzheimer Disease
- symptoms
- lesion
loss of recent memories
-lesion: loss of neuron in the hippocampus
Lewis-Sommer Syndrome
-symptoms
demyelinating polyneuropathy characterized by asymmetrical distal weakness of the upper or lower extremities and motor dysfunction with adult onset
Korsakoff
- symptoms
- lesion
loss of recent memory and tendency to FABRICATE recent events
-medial dorsal thalamic nuclei and mammillary bodies
Papez circuit
Mammillary Bodies
Anterior Thalamic Nucleus
Cingulate Gyrus
Hippocampus
Ant thalamic n -> cingulate gyrus -> parahippocampal gyrus & entorhinal cortex -> hippocampus (subiculum) -> mammillary body bodies
Orbitofrontal Cortex function
associated with social behavior
-if effected complete personality change can take place
Anterior Part of Cingulate Gyrus
controls second thoughts or caution before performing an action
-problem may be present in drug addicts that cannot control their addiction
Subcallosal Part of the Cingulate Gyrus
associated with sadness
-stimulation of this area can relieve depression
Medial forebrain bundle connects what to the hypothalamus
brainstem structure
septal nuclei
insula/orbitofrontal cortex
Drug development stages Stage 1 Stage 2 Stage 3 Stage 4
Stage 1: safety
Stage 2: efficacy and dosage range
Stage 3: safety and efficacy in different populations
Stage 4: adverse events, drug-drug interaction
what drug precipitate together (chemical antagonist)
penicillin and aminoglycoside
what binds to digoxin preventing absorption
cholestyramine
-digoxin is broken down by bacterial flora
what increases cyclosporine absorption
Antiemetic (metochopramide)
what displaces warfarin from albumin
bucolome
CYP inducers
Carbamazepine
rifampin
-inc warfarin metabolism
CYP inhibitor to warfarin theophylline phenytoin
cimetidine
- grape fruit juice
- ethanol
inhibits CYP3A4 which breaks down cylocsprine
ketoconazole
Synergistic effects -> increase beyond double
nitroglycerin and phosphodiesterase inhibitors (sildenafil)
