Exam 3 (Neuro and EENT) Flashcards
Efferent
Motor.
Send signals from CNS to effector organs
Afferent
Sensory.
Sends signals to CNS
Visceral stimuli
Internal organs and mucosal surfaces
Sensory stimuli
External sources.
Like touching a hot stove
Somatic nervous system
Conscious, voluntary, controlled function.
Direct connection from CNS to skeletal muscle (no ganglia).
Myelinated
Autonomic nervous system
Automatic.
Unconscious, involuntary, regulatory functions.
Broken up into sympathetic and parasympathetic
Cholinergic and adrenergic neurons innervate various target organs.
Preganglionc neurons
Cell body originates in CNS from brainstem or spinal cord.
Form synaptic connection in ganglia.
Myelinated
Postganglionic neurons
Cell body begins in ganglia.
Ends on effector organ.
Nonmyelinated.
Ganglia
Synaptic relay station between neurons.
Sympathetic nervous system
Fight or flight.
Release energy.
Sympathetic nervous system neuron lengths
Short preganglionic and long postganglionic.
Is sympathetic or parasympathetic considered a complete system
Sympathetic
Sympathetic nervous system effects
Pupil dilation through contraction of iris radial.
Bronchiole dilation.
Secretion of epinephrine and norepinephrine.
Relaxation of detrusor, contraction of trigone and sphincter in bladder.
Blood vessels of skeletal muscle dilate.
Increased HR.
Thick secretion from salivary glands.
Decreased GI motility
Parasympathetic nervous system
Rest and digest.
Conserves energy.
Parasympathetic neuron lengths
Long preganglionic and short post ganglionic.
Where do parasympathetic neurons originate
Cranial nerves III, VII, IX, X, and sacral region of spinal chord.
Where do sympathetic neurons originate
Thoracic and lumbar regions (T1-L2)
Parasympathetic effects
Pupil contracts from contraction of iris sphincter.
Bronchioles constrict.
Detrusor contracts, trigone and sphincter relax of bladder.
Increased GI motility.
Decreased HR.
Watery secretion from salivary glands.
Production of tears
Glutamate
Most common excitatory neurotransmitter in the brain.
GABA
Major inhibitory neurotransmitter in the brain.
Uses Cl ligand gated channels to devrease cAMP and increase K channels
Glutamate and GABA relationship
Most and least excitatory neurotransmitters.
Balance each other
Epinephrine and norepinephrine receptors
alpha and beta adrenergic receptors
Dopamine receptors
D receptors
Serotonin receptor
5-HT receptors
GABA receptor
NMDA, AMPA
Acetylecholine receptors
Nicotinic and muscarinic cholinergic receptors
Glutamate receptor
NMDA, AMPA,mGLuR
Endorphin receptors
Opioid receptors
What are good drug targets
enzymes
Cholinergic nerve fibers in preganglionic autonomic neurons
Release ACh taht binds to nicotinic receptors
Cholinergic nerve fibers in somatic motor neurons
Release ACh whcih binds to nicotinic receptors on skeletal muscle cell.
Cholinergic fibers in parasympathetic postgalnglionic neurons
Release ACh that binds to muscarinic R
Adrenergic Nerve fibers
Release NE from sympathetic postganglionic neurons to adrenergic receptors on effector organ cells.
What releases epinephrine (a catecholamine) into blood
Adrenal medulla
Types of cholinergic receptors
Nicotinic and muscarinic
Nicotinic receptor
Ligand gated.
Ion channel
Faster than muscarinic
Ionotropic
Muscarinic receptors
G protein-coupled receptor.
Uses second messsenger system.
Slower than cholinergic
Matabotropic
Adrenergic receptor
On effector organs of sympathetic system.
G-protein coupled receptors
Uses secondary messenger system
Metabotropic.
Botulinum toxin
Block release of ACh.
Actions of acetylcholine
SLUDGE
Salivation
Lacrimation
Urination
Deification/diaphoresis
GI
Emesis
Acetylcholineesterase (AChE)
Breaks down ACh
What does nicotinic receptors bind to
Nicotine, ACh.
Weakly to muscarine
Three functionally characterized muscarinic receptors
M1 - on gastric parietal cells
M2 - cardiac cells and smooth muscle
M3 - on bladder , exocrine glands, and smppthe muscles
What does muscarinic receptors bind to
muscarine and ACh
Weak affinity for nicotine
Direct acting cholinergic agonists
ACh itself.
Little specificity
Quickly broken down
Not much clinical use
Indiract acting cholinergic agonists
AChE inhibitors.
Prevent ACh breakdown thus increasing ACh concentration
Antimuscarinics
Cholinergic antagonist that is selective for muscarinic receptors. (ex. Atropine)
Ganglionic blockers
Cholinergic antagonist that prefers nicotinic receptors, limited clinical use
Neuromuscular blocking agents
Cholinergic antagonist, mostly nicotinic antagonists that interrupt efferent impulses to skeletal muscles.
Used in surgery
Synthesis of epinephrine
Tyrosine –> DOPA –> Dopamine –> Norepinephrine –> Epinephrine
What is the rate limiting step of the creation of epinephrine
Hydoxylation of tyrosine by tyrosine hydroxylase
Reserpine
Stops the carrier system that transports dopamine into the synaptic vesicles to be treansformed into NE
COMT, MAO-
matabolize NE
Soma
Neuron cell body
Neurite
Process extending from cell body of neuron
Dendrite
Receives impulses from other neurons
Axon
carries action potentials away from soma
how many cranial nerves`
12 pairs
How many spinal nerves
31 pairs
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
Cerebrum job
Generate motor function.
Process info.
Higher order thinking
Cerebellum job
equilibrium
coordination
muscle tone
achieve motor learning tasks.
Brainstem jobs
Flow of info between cerebrum and spinal chord.
Breathing,
Consciousness.
BP.
HR.
Sleep.
Cortex of brain
gray matter surface of brain
Gyri
Folds of brain
Sulci
Fissures of brain
Interneurons
In the gray matter of the spinal chord.
Translate between afferent and efferent nerves
White matter
Axons
Gray matter
cell bodies
What column of spinal chord is only sensory
Dorsal column
What column of spinal chord is both sensory and motor
Ventral and lateral
Three extracellular fluid compartments of CNS
Inside vascular system (blood plasma).
Between neural and glial cells (interstitial fluid).
In ventricular system and subarachnoid space (CSF)
Why is regulation of brain fluids important
Increased pressure leads to decreased perfusion.
Increased pressure can cause herniation.
Ionic environments effects neuronal firing.
Where does CSF come from
Derived from blood plasma.
Continuously secreted by choroid plexus.
Exits fourth ventricle into subarachnoid space and drains into venous system through arachnod granulations.
Functions of CSF
Protection
Homeostasis
Waste removal
Choroid Plexus
Network of blood vessels in each ventricle.
Made of pia mater CT and epithelial cells.
Filters blood plasma to make CSF.
Tight junctions to maintain blood-CSF barrier.
Similar to plasma but less protein
Where on the spine is a lumbar puncture done
Between L3 and L4
Blood brain barrier (BBB)
Highly selective semipermeable border of endothelial cells.
Small lipophilic substances can go through.
Glucose enters through facilitated diffusion with GLUT-1 protein
Things that can disrupt BBB
Hypertension
Hyperosmolality
Microwaves
Radiation
Infection
Trauma
Unipolar neuron
one neurite
Bipolar neuron
Two neurites
Multipolar neurons
Three or more neurites
Golgi Type I
Longer axon.
Connect different parts of system.
In pyramidal cells of cerebral cortex, motor cells of spinal chord
Golgi type II
Shorter axon.
In local v
Glial cells
Support cells that provide nutrients and energy to neurons.
10x more glial cells than neurons in brain.
Ependymal cells, astrocytes, microglia, and myelinating glia (oligodendrocytes and schwann cells)
Ependymal cells
Ciliated epithelial glial cells.
Line ventricles/central canal.
Produce CSF
Astrocytes
Glial cell that maintains BBB.
Provides structural scaffold for neurons.
Stores glycogen and provides neurons with lactate for energy.
Maintains stable K in brain.
Removes neurotransmitters from extracellular fluid.
Microglia
Glial cell that functions like macrophage in immune respnse of the brain
Oligodendrocyte
Glial cell that produces myelin sheaths in the CNS.
Myelinate multiple neurons
Schwann cell
Glial cell that produces myelin sheaths in the PNS.
Only myelinate one axon
necrosis
Cell lysis and inflammation usually a rapid process.
Seen in acute trauma or stroke
Apoptosis
Programmed cell death that does not cause inflammation
Gliosis
Proliferation of astrocytes secondary to CNS injury (scarring).
Long term effect of stroke, MS, Alzheimer’s
Gliosis
Scar tissue in brain
Generation of action potential steps
- Threshold met.
- Na channels open and Na goes into cell (depolarization).
- K channels open and K goes out of cell (repolarization).
- Voltage drops below resting potential (Hyperpolarization)
Glycine
Most common inhibitory neurotransmitter in the spinal cord.
Binds to Cl- ligand gated channels
Serotonin
Important in limbic function
Chatecholamines
Function as neurotransmitters and hormones.
Dopamine
Epinephrine
Norepinephrine
What releases norepinephrine
postganglionic neurons of sympathetic nervous system
Mu opiod receptor
Bind to beta endorphins causing inhibition of substance P protein (pain protein). Also inhibiting the release of GABA which results in excess dopamine
What are the attributes of stimulus
MILD
Modality (taste, smell touch, vision, hearing)
Intensity
Location
Duration
Merkel’s disk
Sense steady pressure.
Slowly adapting
Messiner’s corpuscle
Sense light pressure.
Rapidly adapting
Ruggini endings
Sense stretching skin.
Slowly adapting
Pacinian corpuscle
Sense vibrations.
Very rapidly adapting
Spinotharamic tract
Sensory.
3 neuron chain.
Decussation at spinal cord.
Temp, pain, and localizing touch.
Where is the primary somatosensory cortex
Postcentral gyrus
Secondary somatosensory cortex
Posterior parietal cortex.
Integrates touch with other sensations (recognizing objects).
Where is pain felt during myocardial infarction
All over left side above abdomen.
Where is pain from hepatitis felt
Right shoulder
Where is pain from ruptured spleen flet
Left shoulder
Where is. pain from stomach ulcer or cancer felt
Midback between scapula or epigastrium
Where is pain from lower lobe pneumonia felt
Upper quadrant of abdomen on same side as pneumonia
Where is pain from appendicitis from
Periumbilical area
Where is pain from kidney stone felt
Flank radiating to groin
Pain gating
Interneuron in spinal cordreleases enkephalins (opioids) to inhibit pain pathways between first and second order neurons so you can run away when hurt.
Upper motor neurons
Regulate voluntary movements.
Mostly inhibitory making your body not over do movements or overreact
Cell bodies in brain or brainstem.
Lesions cause spastic paralysis, hyperreflexia, positive babinski, increased tone, stroke
Spinal neurons
May be excitatory or inhibitory.
Form extensive circuits.
Type Ia sensory fibers
Muscle spindles
Very fast conduction.
Conveys info about muscle STRETCH and SPEED.
Gama motor neurons
Innervate intrafusal muscle fibers.
Cell bodies in ventral grey matter of spinal chord.
Regulate muscle spindle sensitivity.
Type Ib sensory fibers
In the tendons.
Provide info about muscle FORCE
Myotatic Reflex
Tapping on tendon makes muscle stretch (like patellar reflex)
Flexor-Withdrawal reflex
Rapidly removes limb from pain and sticks out opposite limb for support.
Corticospinal tract (pyramidal)
Lateral descending motor pathway.
Originate in motor cortex and crosses at medullary pyramids.
Lesions above medullary pyramids result in contralteral weakness.
Lesions below medullary pyramids result in ipsilateral weakness.
Rubrospinal tract
Lateral descending motor pathway.
Originates in red nucleus of midbrain and crosses immediately.
Controls muscle tone in flexor groups.
Decorticate posturing indicates damage immediately rostral to red nucleus.
Decerebrate posturing indicates midbrain lesion that involves red nucleus
Decerebrate posture
Lesion includes red nucleus.
Extensors predominate.
Decorticate posture
Lesion rostral to red nucleus.
Flexors predominate
Ventromedial pathways
provide info from vestibular and visual system about body position and balance.
Neurons DO NOT cross.
Vestibulospinal
Ventromedial pathway that does posture and equilibrium.
Tectospinal
Ventromedial pathway that makes head and eyes move in direction of stimulus.
Reticulospinal
Venntromedial pathway that does posture
Lower motor neurons
Cell bodies in anterior horn of spinal chord.
Lesion causes Flaccid paralysis, areflexia, decreased tone, atrophy, fasiculatoins, polio
Basal Ganglia job
inhibit unwanted movement
Direct pathway of motor loop
Inhibitory via GABAergic neurons
Indirect pathway of motor loop
Excitatory.
Cerebellum fuctions
Coordinate
Hypothalamus job
Control homeostatic functions.
Eating.
Circadian rhythms.
Sex drive.
Temp regulation,
Reticular formation job
Level of consciousness and general arousal (how awake they are).
releases neurotransmitters that regulate wakefulness (serotonergic), arousal (noradrenergic), attention and memory (cholinergic), and voluntary movement and rewards (dopaminergic)
Limbic system job
Emotions
What temp is considered a fever
100.4ºF
Peripheral thermoreceptors
In the skin.
Info about body surface temp.
Central thermoreceptors
In the hypothalamus.
Info about core temp.
What causes fever
Cytokines released by immune cells bc of infection.
Capilary endothelial cells in BBB release prostaglandin E2 that stimulates hypothalamus to raise set-point temp
Non REM sleep
HR and RR reduces.
Muscles relax
Three stages.
Stage three is most restful
REM
Dreaming.
Awake brain in paralyzed body
Contigulate cortex
Part of limbic system.
Highest levels of cognition.
Sensations of emotions are perceived.
Hippocampus
Part of limbic system.
Conversion of short-term to long-term memory.
Does negative feedback on fear response in response to increased cortisol levels.
Amygdala
Part of limbic system.
Strong emotions like fear and agression.
Links emotions to memories
Cognitive fear
Learned response that creates sensation of fear.
Reactive fear
Response to direct threat
Declarative memory
Facts and events that can be consciously recalled
Nondeclarative memory
Not consciously recalled.
Like muscle memory.
Learned emotion.
Conditioned reflexes (Pavlov’s dogs)
Broca’s Area
In frontal lobe.
Production and movement of tongue and mouth needed to speak.
Can’t find the words.
Wernicke’s area
In temporal lobe.
Understanding and meaning.
Processing.
Speaking nonsense.
Palpebral conjunctiva
Covers the inner side of the eyelid.
Orbicularis oculi muscle
Closes the eye.
Innervated by CN VII
Levator palpebrae superioris muscle
Elevates upper eyelid.
Innervated by CN III.
Superior Tarsal Muscle
Elevates the eyelid.
Innervated by sympathetic nerves
Sclera
“White of the eye”
Protective ehite fibrous opaque covering the eye.
Continuous with dura mater
Only transparent regions of eye
Lens and cornea
Cornea
Curved transparent region where light enters front of eye.
Bends to refract light onto retina
Sensory inervation from CN V
Lacrimal gland
Releases Aqueous part of tears
Conjunctiva
Releases Mucous part of tears
Meimbomian gland
Releases Oil part of tears
Nasolacrimal duct
Where tears drain into.
Why crying gives you a runny nose.
Vascular choroid
Highly vascular CT between sclera and retina.
WHere everything gets its nutrients
Iris
Colored part of eye.
Controls pupil size
Pupil
Hole in center of eye.
Diamerter controled by muscles of iris
Mydriasis
Pupil dilation to allow light into eye either bc its dark or focusing on something far away.
mediated by alpha1 andrenergic receptor stimulation
Miosis
Pupil constricts in bright light or to focus on something near.
Mediated by M3 cholinergenic receptor stimulation
Ciliary Body
Contains ciliary muscle and ciliary epithelium
Ciliary muscles
Contract to lower tension in suspensory ligaments to cause lens to become more round.
Ciliary epithelium
Secretes aqueous humor
Uvea
Iris
Ciliary Body
Choroid
Lens
Transparent behind the cornes.
Ciliary muscles and suspensory ligaments effect curvature to focus eyesight.
Optic apparatus of the eye
Lens + Cornea
Anterior chamber
Space between the cornea and lens including the iris and ciliary body filled with aqueous humor
Aqueous humor
Fluid continuously being secreted and reabsorbed in the anterior chamber of the eye.
Constantly secreted from ciliary epithelial cells into the posterior compartment of anterior chamber. Flows into the anterior compartment through the pupil.
Drains into venous system via Canal of Schlemm
Posterior chamber
Space behind lens that extends to the posterior side of the interior eyeball where retina is located.
Filled with vitreous humor.
Vitreous humor
Fluid that Fills the posterior chamber
Posterior compartment
Part of the anterior chamber.
Between iris and lens
Anterior compartment
Part of anterior chamber.
Between cornea and iris.
Intraocular pressure
Around 15mm Hg.
balance between secretion and absorption of aqueous humor
Retina fovea (Fovea centralis)
Center of retina where light is focused.
High concentration of photoreceptors.
Highest level of visual acuity
Macula
Area surrounding fovea.
Responsible for central vision
Optic Disc
Blind spot (no photo receptors)
Consists of fibers from optic nerve (CN II)
What’s weird about photoreceptors when it comes to polarization
They are excited by hyperpolarization instead of depolarization.
Depolarize in absence of stimuli (light) activating cGMP cation channels for Na to enter
Scotopic
Low light
Photopic
Well-lit
Rods
Highly sensitive to light.
In periphery of retina.
Let us see in darker conditions.
Contain rhodopsin in outer segment.
Low acuity
Cones
In center of retina-Retina Fovea
Outer segment has photopsin
functions best in lots of light.
High-acuity
Three types of cone
Blue (S-short wavelength)
Green (M-medium wavelength)
Red (L-long wavelength)
Optic Chasm
Where the optic nerves meet
Suspensory ligaments
Keep lens flat and under tension.
3 Cs of the eye mediated by parasympathetic.
Convergence of eyes.
Constriction of pupils
Contraction of ciliary muscles
Myopia
Nearsightedness.
Light from distant object focused in front of retina.
Eyeball too long
Need concave (diverging) lense to fix
Hyperopia
Farsightedness.
Short eyeball.
Need convex (converging) lens to fix.
Presbyopia
Lowering in elasticity and accommodation of lens with age.
need bifocals
Astigmatism
Incorrect curvature of lens.
Two different focal distances.
Blurry vision.
Need glasses with cylindrical lenses.
papilla
bumps on tongue with lots of taste buds.
Taste receptor cells
Have microvilla and taste pores
Is taste transduction depolarization or repolarization
Depolarization that leads to Ca entry into cell,
Salty taste
Senses Na concentration adn depolarization of TRC
Sourness
Responds to acidic H+ concentrations.
Reduced K conductance depolarize TRC
Bitterness
Direct binding to K channels and changes in second messenger pathways
Sweetness
Glucose dissolved in saliva
Umami
Tasted in response to amino acid (mostly glutamate
What Cranial Nerve does anterior 2/3rd of tongue taste
VII - facial
What cranial nerve does posterior 1/3rd taste
IX - glossopharangeal
Primary sensory neurons of gustatory
Synapse of gustatory nucleus of medulla
Second order neurons of gustatory
Ascend to thalamus
Third order neurons of gustatory
Relayed to primary gustatory cortex
Olfactory receptor cells
Bipolar
Peripheral neurite goes to nasal membrane and olfactory epithelium.
Central axon joins olfactory nerve.
Enter brain through hole in cribiform plate of olfactory foramina
Olfactory cilia
On peripheral neurite.
Project into mucus which contains odorant binding proteins over nasal membrane.
Come in contact with odorant trapped in mucus
G protein Golf
stimulated by olfactory receptor proteins.
Stimulates adenylyl cyclase increasing creation of cAMP.
cAMP opens channels causing depolarization..
Voltage gated Ca channels open increasing depolarization.
Limbic System
Where smell becomes part of long term memory
Vestibular aparatus
3 Semicircular canals + otolith organs
Otolith organs
utricle and saccule has two endolymph filled chambers with labyrinth detect tilting of head and linear acceleration
Macula
Where vestibular hair cells are found.
Stereocilia
Vestibular hair cells finger like projections.
Movement of head bends them displacing the otoliths causing hair cells to be depolarized.
Same for audio receptor hairs
Otoliths
Calcium carbonate crystals on top of otolithic channels.
Displaced by movement of head causing hair cells to depolarize
What two signals are transduced by the otolith organs
Static angle (tilting) of head
Linear acceleration
Three semicircular canals
Superior/Anterior - yes
Horizontal - no
Posterior- idk
Cupula
Gelatinous mass that the sterio cilia project into.
Scarpa’s Ganglion
Where primary afferent vestibular neurons are located in the swelling on vestibular nerve
What cranial nerve travels in vestibular part of vestibular nucleus of brainstem
CN VIII
Second order vestibular neurons
Relay to cerebellum to coordinate movements using info about body position
Vestibuloocular reflex
Makes eyes turn opposite rotation of head keeping object in view.
Relies on CN III, IV, VI
Vertigo
dizziness
Ossicles
Malleus (hammer)
Incus (anvil)
Stapes (stirrups)
Eustachian tube jobs
Links middle ear to nasopharynx.
Equalizes air pressure between middle ear and nasopharynx
Protect middle ear from reflux
Clear middle ear secretion
Attenuation reflex
Tensor tympani and muscles contract and stiffen ossicles to lower transmission of vibrations to inner ear during lots of loud noise to protect hair cells from damage from excess vibration.
cochlea
Auditory part of labyrinth.
Three coiled fluid filled tubes (scala vestibuli, scala media, scala tympani)
Scala vestibuli
Top tube of cochlea.
Filled with perilymph
Low K high NA
continuous with scala tympani via helicotrema
Scala media
Cochlear duct (middle tube)
Filled with endolymph.
Has neuro-epithelium called organ of corti
High K low NA
Stria vascularis secretes endolymph
Scala tympani
Bottom tube of cochlea.
Filled with perilymph
Low K High NA.
Continuous with scala vestibuli via helicotrema
Helicotrema
Apex of cochlea where ttympani and vestibuli
Endocochlear potential difference
Caused by difference of K in perilymph and endolymph
Reissner’s (vestibular) membrane
separates scala vestibuli from scala media
Basilar membrane
Separates scala tympani from scala media
Organ of corti
Locatoin for audiotry transduction above basilar membrane
Auditory receptors (sensory hair cells)
Rest on basilar membrane that moves causing the hairs to bend
Tectorial membrane
Gelatinous membrane where tips of stereocilia of auditory receptor hairs are embedded
What direction does the stereocilia bend to be depolarized causing opening of Ca channels
Toward kinocilium
Inner hair cells
Responsible for auditory transduction
Neurites from inner hair cells connect to spiral ganglion
Outer hair cells
Amplify traveling wave that passes along basilar membrane.
If damaged can lead to deafness.
Aminoglycoside antibiotics can damage them
Transmission of soudnd waves
TM vibrations –> ossicles –>liquid vibrations in cohclea –> transformed into nerve impulses in auditory cortex of CNS
Where do high freq sounds make basilar membrane move
Base of cochlea
Where do low freq sounds make basilar membrane move
apex (hericotrema)
Amplitude
How high wave is
Loudness
dB
Loudest human can hear
130 dB
Frequence
Pitch
Waves per unit time
Weber test
Stick tuning fork on head
Rinne test
put tuning fork on mastoid process then put in front of ear
Dorsal Column-Medial Lemniscus
Ascending tract
Three neuron chain
Crosses at medulla
Info about discriminative touch, vibration, proprioception, and pressure