Chapter 2: Neurophysiology Flashcards
What three things does the ANS innervate
Smooth Muscle, Glands and Cardiac Muscle
What three things does the ANS innervate
Smooth Muscle, Glands and Cardiac Muscle
What does the somatic NS innervate ?
Skeletal muscle
What are the three division of the ANS ?
Sym., Parasympathetic and Enteric
Where are the autonomic ganglia for Parasympathetic nerves ?
Near the effector organ (very long presynaptic axons)
Where are the autonomic ganglia for sympathetic nerves ?
They are in the Paravertebral Ganglia
Where do cell bodies of sympathetic nerves originate ?
T1-L3 (thoracolumbar region)
Where do the cell bodies of the Parasympathetic Nerves come from ?
Cranial Nerves and Cell of S2-4
What cells do preganglionics synapse on in the adrenal medulla ?
Chromaffin Cells
What are the two major substances secreted by the chromaffin cells ?
Epi (80%), NE (20%)
Pheochromocytoma is a tumor of the Adrenal Medulla and can be diagnosed by increased ______ in the blood and urine.
Vanillamandelic Acid (VMA)
Adrenergic neurons release
NE
Cholinergic neurons release
ACh
Certain post-ganglionic parasympathetic neurons release Substance P, VIP and NO. Where are these neurons located ?
In the GI Tract
What NT is release by both Sympathetic and Parasymphathetic pre-synaptic neurons ?
ACh
What receptor type is present in the ganglion of both post-synaptic parasympathetic and sympathetic ganglia ?
Nicotinic
Nicotinic Receptors are : GPCR’s or Gated Ion Channels ?
Gated Ion Channels (Na+)
The NT released by Post-synaptic sympathetic neurons to their target organ is…
NE
The NT released by Post-synaptic Parasympathetic neurons to their target organ is…
ACh
What are the 4 main receptors seen on target organs associated with the Sympathetic NS ?
Alpha 1,2
Beta 1,2
What is the main kind of receptor type seen on effector cells responsive to Parasympathetic neurons ?
Muscarinic (1,2,3)
Which adrenergic receptor is associated with Gq ?
Alpha 1 ( Phospholipase C Leads to an Increase in IP3/DAG)
“Alpha Males are shown in GQ magazine”
Which adrenergic receptor is associated with Gi ?
Alpha II (Decreases cAMP)
“Second Alphas are ‘I’nferior to Alpha 1’s”
Beta 1 and 2 adrenergic receptors are associated with which GPCR ?
Gs (Increased cAMP)
Where in the body do you have a high proportion of Alpha1 receptors ?
Smooth muscle of the skin/splanchnic regions, GI and bladder sphincters and the radial muscle of the iris.
Where in the body do you have many Alpha2 receptors ?
GI tract (Note: Sympathetics typically slow down gastric motility, could be because they work through Gi associated Alpha2’s )
Autoreceptors on autoniomic post-ganglionics
Platelets.
Adrenergic receptor of the heart
Beta1 ((Sinoatrial, AV and ventricular muscle)
Adrenergic Receptor of the lungs
Beta2 (
Where will you find Nm(N1) receptors ? (Nicotinic)
Skeletal muscles
Where will you find Nn (N2) receptors ? (nicotinic)
In the Autonomic Ganglia (post synaptic cells)
What GPCR is the M1 receptor associated with ?
Gq
What GPCR is the M2 receptor associated with ?
Gi (So both the Alpha 2 and M2 are Gi)
What GPCR is M3 associated with ?
Gq
Where in the body will you find the M1 receptor ?
CNS
Where in the body do you find the M2 receptor ?
Heart (AV node)
makes sense. ACh slows the heart rate, M2 is associated with the inhibitory Gi GPCR
Where in the body will you find the M3 receptor ?
Smooth Muscle and Glands
Unlike B1 ones which are equally sensitive to Epi and NE, B2 receptors are more partial to _____.
Epinephrine
Receptor responsible for Increased HR, Contractility and AV node conduction ..
B1
Receptor responsible for Decreased HR, Contractility and AV node conduction ..
M2
Constricts Blood Vessels in skin and splanchnics
A1
Dilates blood vessels in skeletal muscle
B2
T or F: Parasympathetics have no role in vascular smooth muscle control
TRUE !! (a1 and B2)
Decrease motility in GI tract
Alpha2 and Beta2
Constricts sphincters in GI
Alpha1
What receptor constricts bronchiolar smooth muscles ?
M3
What receptor dilates bronchiolar smooth muscles ?
Beta 2
which receptor mediates erection ?
Muscarinics (M3 I’m assuming)
What receptors mediate ejaculation ?
Alpha
Relaxes Bladder wall
Beta2
Constricts Urinary Sphincters ?
Alpha1
Contracts bladder wall and relaxes sphincters
M3
What kind or receptors are associated with sweat glands
Sympathetic cholinergics (Technically they are sympathetic agonists but have Cholinergic Receptors)
Mydriasis (receptor)
Alpha1 (dilation)
Miosis
Muscarinics
Lipolysis
Beta1
Three Autonomic Centers of the Medulla
Vasomotor (regulates BP stimulated by chemoreceptors, CN IX,X. C02 levels are gauged, increased levels lead to vasoconstriction)
Respiratory (Ventral = Expiratory, Dorsal=inspiratory)
Swallowing Coughing and vomitting.
Autonomic Centre of the Pons
Pneumotaxic Center ( Regulates respiratory RATE, senses stretch in the lung and relays information to Respiratory Group in the Medulla)
Autonomic Center of the Midbrain
Micturation Center (Urination)
Autonomic Centers of the Hypothalamus
Temperature Regulation
Thirst and Food intake
Function of Pacinian Corpuscles
Sense vibration
What sensory fiber neurons are found in Muscle Spindles
1A (Large and fast back to the CNS)
1A afferents
What sensory fiber neurons are found in Golgi Tendon Organ
1B (also large and fast)
What will sensory stimuli cause in the receptors ?
Opening of ion channels
Depolarization = Excitatory (Current is usually inward) Hyperpolarization = Inhibitory (current is usually going out)
What kind of stimulus do slowly adapting (Tonic) receptors sense ?
Steady Stimulus (respond repetitively to prolonged stimulus)
Examples (muscle spindle, pressure and slow pain
What kind of stimulus do rapidly adapting (Phasic) receptors respond to ?
Detect onset and offset of stimulus
Decline in AP frequency with time in response to a constant stimulus
Ex. Pacinian, light touch)
First order afferent neurons have their cell bodies in…
Dorsal Root Ganglia (spinal cord ganglia)
Receive signal and send it to CNS
Second order neurons are located in …
Spinal Cord Or Brainstem
Receive info from primary afferents and then transmit to the thalamus
Third order afferents are located in…
The thalamus (relay nuclei)
Receive info from secondary afferents and send into to the cerebral cortex
Fourth Order afferents are located in ….
Appropriate region of sensory cortex –> conscious perception of the stimuli
What 4 sensations does the somatosensory system encode ?
Touch, Movement, Temperature and Pain
What two pathways make up the somatosensory system ?
Dorsal Column
Anterolateral
What sensation does Dorasl Column relay /
Fine touch (not light touch), pressure , Two point discrimination, vibration, proprioception
What sensations does the Anterolateral system relay ?1
Temperature, Pain, Light touch
Describe the Course of the Dorsal Column system
Ascend inpsilaterally to the Nucleus Gracillis and Cuneatus of the Medulla where they cross the midline.
From the Gracilis and Cuneatus the 2nd order neurons go to the contralateral Thalmus.
From the thalamus, 3rd oder neurons go to Cerebral Cortex where they synapse on 4th order neurons
What kind of sensory fibers make up the Dorsal Column
Group II fibers (Medium sized)
Discuss the course of the Anterolateral System
Primary fibers ascend to the spinal cord where they synapse on secondary .
Secondary neurons cross immediately and ascend to the contralateral thalamus where they synapse on 3rd order neurons.
3rd order neurons synapse on fourth order neurons in the cerebral cortex
What kind of fibers make up the anterolateral system ?
Type III and IV
Destruction of the thalamus would lead to loss of sensation on the ________ side.
Contralateral
Pacinian corpuscles encode
Vibration
Meissners corpuscles encode
velocity
Ruffinis corpuscles encode
Pressure
Merkels disks encode
Location
What is the NT for most pain receptors ?
Substance P (Pain = Anterolateral)
What kind of fibers carry Fast Pain
Group III (A-delta).. Localized pain
What kind of Fibers carry Slow Pain
C-fibers (Type IV).. Aching and throbbing that is poorly localized
Reractive power of lens is measured in …
diopters
Emmetropia
Normal
Hypertropia
Farsighted (light focuses behind the retina)
Myopia
Nearsighted (Light focuses in front of the retina)
Atigmatism
Curvature of the lens is not uniform
Presbyopia
Loss of accommodation of the lens seen in aging.
Treatement for Hyperopia
Convex lens
Treament for myopia
Biconcave lens
Treament for astigmatism
cylindric lens
Pigmented epithelial cells are found farthest from the source of light in the eye. What is their role /
absorb stray light
Convert 11-cis retinal to All-Trans Retinal
What are the receptor cells of the eye ?
Rods and Cones
Where are rods and cones not present ?
optic disk
The cells that synapse of bipolar cells that lead to high acuity but low sensitivity…
Cones (very few cones synapse on these)
Better for day vision
The cells that synapse of bipolar cells that lead to low acuity but high sensitivity
Rods (many rods synapse on one bipolar cell)
High sensitivity –> Good night blindness
What are the output cells of the retina ?
Ganglion cells (bipolar cells synapse onto ganglion cells)
Axons of ganglion cells form the Optic Nerve.
Axons from which hemiretina cross at the optic chiasm ?
The Nasal hemiretina (whereas the temporal hemiretina cells remain ipsilateral
Cells from which two hemiretinas form the right optic tract ? (not optic nerve, tract forms post chiasm)
Right Temporal hemiretina and Left Nasal hemiretina (these two see your left world)
What results from cutting of the left optic Nerve /
Blindness of ipsilateral Eye
What results from cutting of the left optic Chiasm ?
Loss of the nasal hemiretina (cannot see your temporal fields )
Heteromynous bitemporal Hemianopia
What results from cutting of the left optic tract ?
Lose left temporal hemiretina (loses left nasal field) and right nasal hemiretina (Loses right temporal field)
Homonymous Contralaterl Hemianopia
What occurs with the cutting of the left Geniculocalacrine tracts ?
Homonymous hemianopia with Macular sparing
Light converts 11-cis rhodopsin to…
All-trans rhodopsi
What mediates opening and closure of Na+ channels in receptors of the eye ?
cGMP levels (high –> open, Low –> closed0)
Phosphodiesterase degrades cGMP , leading to closure of Na+ channels
Like most cells, low Na+ influx leads to …
hyperpolarization !
sound frequency is measured in
Hertz
Sound intensity is measured in
decibells
db = 20 log (P/Po)
P= measured pressure
Po: reference pressure at the threshold frequency.
Purpose of the outer ear
direct sound in to the auditory canal
Middle ear consists of
Typmpanic membrane , ossicles (Malleus, Incus and Stapes) and oval window (stapes connects to the oval window
Perilymph
Fluid that fills the outside of the duct (Scala Vestibuli and Scala Typmani)
High Na+ concentration
Endolymph
Fluid that fills the indside of the ducts (Scala Media)
High K+ concentration
Endolymph
Fluid that fills the indside of the ducts (Scala Vestibuli and Scala Typmani)
What does the somatic NS innervate ?
Skeletal muscle
What are the three division of the ANS ?
Sym., Parasympathetic and Enteric
Where are the autonomic ganglia for Parasympathetic nerves ?
Near the effector organ (very long presynaptic axons)
Where are the autonomic ganglia for sympathetic nerves ?
They are in the Paravertebral Ganglia
Where do cell bodies of sympathetic nerves originate ?
T1-L3 (thoracolumbar region)
Where do the cell bodies of the Parasympathetic Nerves come from ?
Cranial Nerves and Cell of S2-4
What cells do preganglionics synapse on in the adrenal medulla ?
Chromaffin Cells
What are the two major substances secreted by the chromaffin cells ?
Epi (80%), NE (20%)
Pheochromocytoma is a tumor of the Adrenal Medulla and can be diagnosed by increased ______ in the blood and urine.
Vanillamandelic Acid (VMA)
What is nystagmus ?
Whene the head rotates on direction the eyes will rotate the other way to maintain fixation on the object it was looking at. when they can no longer rotate they will snap back then move again
The direction of nystagmus is the direction of rapid eye movement (the snap back phase), usually in the same direction as the head rotation.
Cholinergic neurons release
ACh
Certain post-ganglionic parasympathetic neurons release Substance P, VIP and NO. Where are these neurons located ?
In the GI Tract
What NT is release by both Sympathetic and Parasymphathetic pre-synaptic neurons ?
ACh
What receptor type is present in the ganglion of both post-synaptic parasympathetic and sympathetic ganglia ?
Nicotinic
Nicotinic Receptors are : GPCR’s or Gated Ion Channels ?
Gated Ion Channels (Na+)
The NT released by Post-synaptic sympathetic neurons to their target organ is…
NE
The NT released by Post-synaptic Parasympathetic neurons to their target organ is…
ACh
What are the 4 main receptors seen on target organs associated with the Sympathetic NS ?
Alpha 1,2
Beta 1,2
What is the main kind of receptor type seen on effector cells responsive to Parasympathetic neurons ?
Muscarinic (1,2,3)
Which adrenergic receptor is associated with Gq ?
Alpha 1 ( Phospholipase C Leads to an Increase in IP3/DAG)
“Alpha Males are shown in GQ magazine”
Which adrenergic receptor is associated with Gi ?
Alpha II (Decreases cAMP)
“Second Alphas are ‘I’nferior to Alpha 1’s”
Beta 1 and 2 adrenergic receptors are associated with which GPCR ?
Gs (Increased cAMP)
Where in the body do you have a high proportion of Alpha1 receptors ?
Smooth muscle of the skin/splanchnic regions, GI and bladder sphincters and the radial muscle of the iris.
Where in the body do you have many Alpha2 receptors ?
GI tract (Note: Sympathetics typically slow down gastric motility, could be because they work through Gi associated Alpha2’s )
Autoreceptors on autoniomic post-ganglionics
Platelets.
Adrenergic receptor of the heart
Beta1 ((Sinoatrial, AV and ventricular muscle)
Adrenergic Receptor of the lungs
Beta2 (
Where will you find Nm(N1) receptors ? (Nicotinic)
Skeletal muscles
Where will you find Nn (N2) receptors ? (nicotinic)
In the Autonomic Ganglia (post synaptic cells)
What GPCR is the M1 receptor associated with ?
Gq
What GPCR is the M2 receptor associated with ?
Gi (So both the Alpha 2 and M2 are Gi)
What GPCR is M3 associated with ?
Gq
Where in the body will you find the M1 receptor ?
CNS
Where in the body do you find the M2 receptor ?
Heart (AV node)
makes sense. ACh slows the heart rate, M2 is associated with the inhibitory Gi GPCR
Where in the body will you find the M3 receptor ?
Smooth Muscle and Glands
Unlike B1 ones which are equally sensitive to Epi and NE, B2 receptors are more partial to _____.
Epinephrine
Receptor responsible for Increased HR, Contractility and AV node conduction ..
B1
Receptor responsible for Decreased HR, Contractility and AV node conduction ..
M2
Constricts Blood Vessels in skin and splanchnics
A1
Dilates blood vessels in skeletal muscle
B2
T or F: Parasympathetics have no role in vascular smooth muscle control
TRUE !! (a1 and B2)
Decrease motility in GI tract
Alpha2 and Beta2
Constricts sphincters in GI
Alpha1
What receptor constricts bronchiolar smooth muscles ?
M3
What receptor dilates bronchiolar smooth muscles ?
Beta 2
which receptor mediates erection ?
Muscarinics (M3 I’m assuming)
What receptors mediate ejaculation ?
Alpha
Relaxes Bladder wall
Beta2
Constricts Urinary Sphincters ?
Alpha1
Contracts bladder wall and relaxes sphincters
M3
What kind or receptors are associated with sweat glands
Sympathetic cholinergics (Technically they are sympathetic agonists but have Cholinergic Receptors)
Mydriasis (receptor)
Alpha1 (dilation)
Miosis
Muscarinics
Lipolysis
Beta1
Three Autonomic Centers of the Medulla
Vasomotor (regulates BP stimulated by chemoreceptors, CN IX,X. C02 levels are gauged, increased levels lead to vasoconstriction)
Respiratory (Ventral = Expiratory, Dorsal=inspiratory)
Swallowing Coughing and vomitting.
Autonomic Centre of the Pons
Pneumotaxic Center ( Regulates respiratory RATE, senses stretch in the lung and relays information to Respiratory Group in the Medulla)
Autonomic Center of the Midbrain
Micturation Center (Urination)
Autonomic Centers of the Hypothalamus
Temperature Regulation
Thirst and Food intake
Function of Pacinian Corpuscles
Sense vibration
What sensory fiber neurons are found in Muscle Spindles
1A (Large and fast back to the CNS)
1A afferents
What sensory fiber neurons are found in Golgi Tendon Organ
1B (also large and fast)
What will sensory stimuli cause in the receptors ?
Opening of ion channels
Depolarization = Excitatory (Current is usually inward) Hyperpolarization = Inhibitory (current is usually going out)
What kind of stimulus do slowly adapting (Tonic) receptors sense ?
Steady Stimulus (respond repetitively to prolonged stimulus)
Examples (muscle spindle, pressure and slow pain
What kind of stimulus do rapidly adapting (Phasic) receptors respond to ?
Detect onset and offset of stimulus
Decline in AP frequency with time in response to a constant stimulus
Ex. Pacinian, light touch)
First order afferent neurons have their cell bodies in…
Dorsal Root Ganglia (spinal cord ganglia)
Receive signal and send it to CNS
Second order neurons are located in …
Spinal Cord Or Brainstem
Receive info from primary afferents and then transmit to the thalamus
Third order afferents are located in…
The thalamus (relay nuclei)
Receive info from secondary afferents and send into to the cerebral cortex
Fourth Order afferents are located in ….
Appropriate region of sensory cortex –> conscious perception of the stimuli
What 4 sensations does the somatosensory system encode ?
Touch, Movement, Temperature and Pain
What two pathways make up the somatosensory system ?
Dorsal Column
Anterolateral
What sensation does Dorasl Column relay /
Fine touch (not light touch), pressure , Two point discrimination, vibration, proprioception
What sensations does the Anterolateral system relay ?1
Temperature, Pain, Light touch
Describe the Course of the Dorsal Column system
Ascend inpsilaterally to the Nucleus Gracillis and Cuneatus of the Medulla where they cross the midline.
From the Gracilis and Cuneatus the 2nd order neurons go to the contralateral Thalmus.
From the thalamus, 3rd oder neurons go to Cerebral Cortex where they synapse on 4th order neurons
What kind of sensory fibers make up the Dorsal Column
Group II fibers (Medium sized)
Discuss the course of the Anterolateral System
Primary fibers ascend to the spinal cord where they synapse on secondary .
Secondary neurons cross immediately and ascend to the contralateral thalamus where they synapse on 3rd order neurons.
3rd order neurons synapse on fourth order neurons in the cerebral cortex
What kind of fibers make up the anterolateral system ?
Type III and IV
Destruction of the thalamus would lead to loss of sensation on the ________ side.
Contralateral
Pacinian corpuscles encode
Vibration
Meissners corpuscles encode
velocity
Ruffinis corpuscles encode
Pressure
Merkels disks encode
Location
What is the NT for most pain receptors ?
Substance P (Pain = Anterolateral)
What kind of fibers carry Fast Pain
Group III (A-delta).. Localized pain
What kind of Fibers carry Slow Pain
C-fibers (Type IV).. Aching and throbbing that is poorly localized
Reractive power of lens is measured in …
diopters
Emmetropia
Normal
Hypertropia
Farsighted (light focuses behind the retina)
Myopia
Nearsighted (Light focuses in front of the retina)
Atigmatism
Curvature of the lens is not uniform
Presbyopia
Loss of accommodation of the lens seen in aging.
Treatement for Hyperopia
Convex lens
Treament for myopia
Biconcave lens
Treament for astigmatism
cylindric lens
Pigmented epithelial cells are found farthest from the source of light in the eye. What is their role /
absorb stray light
Convert 11-cis retinal to All-Trans Retinal
What are the receptor cells of the eye ?
Rods and Cones
Where are rods and cones not present ?
optic disk
The cells that synapse of bipolar cells that lead to high acuity but low sensitivity…
Cones (very few cones synapse on these)
Better for day vision
The cells that synapse of bipolar cells that lead to low acuity but high sensitivity
Rods (many rods synapse on one bipolar cell)
High sensitivity –> Good night blindness
What are the output cells of the retina ?
Ganglion cells (bipolar cells synapse onto ganglion cells)
Axons of ganglion cells form the Optic Nerve.
Axons from which hemiretina cross at the optic chiasm ?
The Nasal hemiretina (whereas the temporal hemiretina cells remain ipsilateral
Cells from which two hemiretinas form the right optic tract ? (not optic nerve, tract forms post chiasm)
Right Temporal hemiretina and Left Nasal hemiretina (these two see your left world)
What results from cutting of the left optic Nerve /
Blindness of ipsilateral Eye
What results from cutting of the left optic Chiasm ?
Loss of the nasal hemiretina (cannot see your temporal fields )
Heteromynous bitemporal Hemianopia
What results from cutting of the left optic tract ?
Lose left temporal hemiretina (loses left nasal field) and right nasal hemiretina (Loses right temporal field)
Homonymous Contralaterl Hemianopia
What occurs with the cutting of the left Geniculocalacrine tracts ?
Homonymous hemianopia with Macular sparing
Light converts 11-cis rhodopsin to…
All-trans rhodopsi
What mediates opening and closure of Na+ channels in receptors of the eye ?
cGMP levels (high –> open, Low –> closed0)
Phosphodiesterase degrades cGMP , leading to closure of Na+ channels
Like most cells, low Na+ influx leads to …
hyperpolarization !
sound frequency is measured in
Hertz
Sound intensity is measured in
decibells
db = 20 log (P/Po)
P= measured pressure
Po: reference pressure at the threshold frequency.
Purpose of the outer ear
direct sound in to the auditory canal
Middle ear consists of
Typmpanic membrane , ossicles (Malleus, Incus and Stapes) and oval window (stapes connects to the oval window
Inner ear
Fluid filled
Bony labyrinth
Perilymph
Fluid that fills the outside of the duct
Endolymph
Fluid that fills the indside of the ducts (Scala Vestibuli and Scala Typmani)
What boders the Scala Media and is the site of the Organ of Corti ?
Basilar membrane (hair cells are attached to this)
Where are the cilia of hair cells imbedded ?
Tectorial membrane
Which is more elastic the basilar or the tectorial membrane
Basilar (vibrations cause it to move –> transductons)
Which portion of the basilar membrane is narrow stiff and responds to high frequency ?
Base
Which portion of the basilar membrane is wide, compliant and responds to low frequency /
Apex
Describe the path of fibers carrying auditory information ?
Lateral lemniscus –> Inferior Colliculus –> Medial Geniculate –> Auditory cortex
What is the purpose of the vestibular organ ?
Detecting the angular and linear acceleration of the head.
What makes up the vestibular organ ?
Three perpendicular semi circles
Urtricle
Sacule
What fills the canals of the vestibular organ ?
Endolymph (high in K+)
If the hair cells cilia are bent towards the kinocilia the cell willl…
Depolarize
if they are bent away, they will hyper polarize
What is nystagmus ?
Whene the head rotates on direction the eyes will rotate the other way to maintain fixation on the object it was looking at. when they can no longer rotate they will snap back then move again
The direction of nystagmus is the direction of rapid eye movement (the snap back phase)
What is unique about the productions of olfactory receptor neuron cells ?
They are constantly replaced by basal cells. Only nerves in the body to do so !
CN1 (olfactory) are what kind of fibers ?
C-Fibers (Typr IV) .. .Small and slow
What other CN is used in olfaction to detect noxious stimuli like ammonia ?
CN V
Fractures of what structure can damage the olfactory nerve as it courses to the olfactory bulb ?
Cribiform plate (the olfactory nerve goes through the cribiform plate)
–> Anosmia !
What are the cells that are second order neurons of olfaction ?
Mitral cells
Project directly to the pre-piriform plexus
What kind of receptors are found on olfactory cells ?
GCPR (Golf)
G-olf function in the same way as….
Gs … Increas cAMP –> Opening of Na+ channels –> Action potentials
Where are taste receptors usually found ?
on papillae
What are found on receptor cells that help increase the surface are of the cells ?
Microvilli
Are taste cells, neurons ?
NO ! (unlike olfactory cells)
What kind of papillae are seen on the anterior 2/3s of the tongue ?
Fungiform papillae
What tastes are sensed by the anterior 2/3s ?
Salty, Sweet and Umami
What two types of papillae are seen on the posterior 1/3 of the tongue /
Cicrumvellate and Foliate
What tastes are sensed on the posterior 1/3 of tongue ?
Sour and bitter
What nerve innervates the anterior 2/3 of the tongue ?
CNVII
Chorda Tympani
What nerve innervates the posterior 1/3 of the tongue ?
CN IX (glossopharyngeal)
CN VII, IX and X will ascend into which nucleus to relay tastes ?
Solitary nucleus
Do taste fibers cross ?
No, typically stay ipsilateral to the thalamus and to the taste cortex
What makes up a motor unit ?
Single motor neuron and the muscle fiber it innervates.
Generally , fine control of muscle movement requires that a neuron innervate how many muscle fibers ?
Just a few
Oppositely, nerves used for gross motion innervate many muscles fibers.
motor neuron pool
The neurons which innervate all of the fibers within a muscle.
Recruitment
Increasing the force of contraction means that you must increase the number of motor units active in a muscle.
Small Motor neurons
Fire first
Smallest force generated
Innervate few muscle fibers
Large motor neurons
Innervate many muscle fibers
Have higher threshold thus fire last
Largest force generated.
How are muscle spindles arranged in muscle fibers ?
Parallel to the extrafusel muscle fibers
What do Muscle Spindles detect ?
Static and dynamic changes in muscle LENGTH
What kind of afferent neurons are seen in Muscle Spindles ?
Ia and II
How are golgi tendon organs arranged ?
Arranged in series.
What do golgi tendon organs detect ?
Tension in the muscle
What kind of neuron fibers are seen in golgi tendon organs ?
1b
what kind of afferent fibers come from Pacinian corpuscles ?
Group II (Sense Vibration, Dorsal Column)
Free nerve ending show which kind of afferent fibers ?
Group III and IV (Noxious stimuli such as pain temperature, Anterolateral System)
What neurons innervate the extrafusal muscles fibers of a muscle ?
Alpha motor neurons –> Muscle Contraction
What are the motor neurons that go to the Intrafusal fibers (muscle spindles) ?
Gamma motor neurons (do not generate a significant force since muscle spindle fibers are short)
(Remember the afferents of muscle spindles are group Ia
In general the more fine the movement required the ________ muscle spindle fibers there needs to be.
MORE
What are the two kinds of intrafusal fibers seen in Muscle Spindles >
Nuclear Bag
Nuclear Chain
Which of the intrafusal fibers detects rate of change in muscle length ?
Nuclear Bag Fibers
What doe the Nuclear Chain fibers detect ?
Static Changes in muscle lengths.
Unlike Nuclear bag fibers which are associated with Type Ia afferents, Nuclear Chain Fibers are associated with …
Type II fibers (like others associated with Dorsal Column)
which are more numerous nuclear bag fibers or nuclear chain fibers ?
Nuclear chain fibers
What does the muscle spindle reflex correct for ?
Increases in length
When a muscle in stretched, the 1a and II afferents are activated leading to activation of the Alpha motor neurons which innervate the extrafusal fibers –> contraction and shortening of the muscle.
Since it is not intricately linked to extrafusal contraction like the alpha motor units, what is the purpose of the Gamma motor units ?
To sensitize the muscle spindle so that it acts accordingly during the contraction of muscle. Makes it so that they remain sensitive to rate of change of length etc.
The knee jerk reflex is associated with Golgi Tendon Organ activation or Muscle Spindle Activation ?
MUSCLE SPINDLE (weird, I know since you are hitting the tendon causing it to lengthen. This is simulating a stretch of the muscle)
In this , Ia (and II) afferents are activated leading to Alpha motor neuron activation in the spinal cord. Alpha motor neurons will lead to the contraction of the muscle thus shortening it and stopping the 1a outputs.
MONOSYNAPTIC
What leads to activation of the Golgi Tendon Reflex ?
Contraction of the muscle –> Tension in the tendon.
Explain the Golgi Tendon Reflex
Active muscle contraction leads to increased tension in the tendon. Ib afferents are activated and send information back to the spine where they stimulate inhibitory interneurons which stop the Alpha Motor neuron output –> relaxation of the muscle
DISYNAPTIC
Explain the Flexor withdrawal reflex (Flexion on ipsilateral side leads to extension on the contralateral side.
Pain fibers elicit withdrawal of the affected limb (ipsilateral flexion). Type III and IV afferents (Anterolateral System) relay pain signal to the Spinal cord and activate interneurons which do exactly what was just said)
POLYSYNAPTIC
What is convergence ?
When a single Alpha motor neuron receives input from many muscle spindle Ia fibers.
What does convergence lead to ?
Spatial Summation (many signals at once) allowing for contraction of said muscle or fiber (single input from 1a fiber will not reach threshold but many will lead to it)
May also see temporal summation (many signals in succession)
DIvergence
When the 1a muscle spindle fibers project to all of the alpha motor neurons in a muscle
Renshaw cells
Inhibitory cells in the ventral horn of the spinal cord that receive input from collateral axons of motor neurons and lead to inhibition of the alpha motor neurons.
What two segments make up the Pyramidal Tracts ?
Corticospinal
Corticobulbar
Where do the Pyramidal tracts pass through ?
The Medullary Pyrmamids
What are the 5 spinal tracts that make up the Extrapyramidal tracts ?
Rubrospinal Pontine Reticulospinal Medullary Reticulospinal Tract Lateral Vestibulospinal Tectospinal
Where does the Rubrospinal Tract originate/project to ?
Red nucleus
Lateral spinal cord Interneurons
What is the overall function of the Rubrospinal tract ?
Stimulation of Flexors and inhibition of Extensors !!!!!
Where does the Pontine Reticulospinal tract project to ?
Pons
Ventromedial spinal cord
What is the overall function of the Pontine Reticulospinal tract ?
Stimulates both flexors and extensors. (MAINLY EXTENSORS)
Where does the Medullary Reticulospinal Tract originate/project to ?
Medullary Reticular formation
goes into the interneurons of the spinal cord grey area.
What is the overall function of the Medullary Reticulospinal tract ?
INHIBITORY effect on both flexors and extensors (MAINLY EXTENSORS)
Where does the Lateral Vestibulospinal Tract originate/project to ?
Deiters Nucleus
Ipsilateral Motorneurons and interneurons.
What is the overall function of the Lateral Vestibulospinal Tract ?
POWERFUL stimulation of extensors and inhibition of flexors
quite the opposite of the rubrospinal tract
Where does the Tectospinal originate/project to ?
Superior Colliculus
Projects to cervical spinal chord
What is the overall function of the Tectospinal tract ?
Control of Neck Muscle
What occurs to reflexes right after transection of the spinal cord ?
Loss of innervation from alpha and gamma neurons leads to loss of reflexes initially
What occurs 1-2 weeks after transection of the spinal cord ?
Reflexes return , often are hyper reflexive
What will occur if lesion occurs in the spinal cord at C7 ?
Loss of sympathetic tone to the heart –> decrease in HR and arterial pressure (T1-4 control sympathetics to the heart)
What occurs if a lesion of the spinal cord occurs at C3 ?
Breathing stops since C3,4,5 all innervate the diaphragm
What occurs if a lesion of the spinal cord occurs at C1?
DEATH
What occurs if there is a lesion ABOVE the Lateral Vestibular Nucleus ?
Decerebate Rigidity
Removes inhibition from higher centers leading to excitation of Alpha and Gamma motor neurons and rigid posture .
What occurs if there is a lesion ABOVE the Potine Reticular formation ?
Decerebate Rigidity
Removal of inhibition from the pontine reticular formation. –> alpha and gamma motor neurons
Lesions above the red nucleus
decorticate postruine and intact tonic neck reflexes
Center in control of balance and eye movement
Vestibulocerebelum
Plannin and initiation of movement
Pontocerebellum
Control of rate, force, range and direction of movement
Spinocerebellum
Innermost layer of the cerebellar cortex, contains granule cells, golgi type II cells and Glomeruli
Granular layer
What occurs in the glomeruli of the Granular Layer of the Cerebellar cortex ?
Axons from the mossy fibers form synaptic connections on dendrites of granular and Golgi Type II Cells.
What is the middle layer of the Cerebellar Cortex ?
Purkinje Cell Layer
What kind of input comes from the Purkinje cells in the cerebellar cortex ?
Inhibitory (ALWAYS)
What is the outermost layer of the cerebellar cortex ?
Molecular Layer
What cells are found tin the Molecular layer ?
Stellate , Basket Cells, dendrite of purkinje and Golgi Type II cells as well as parallel fibers !
Parallel fibers synapse on the dendrites of Purkinje Basket Golgi II and stellate cells
Where do the climbing fibers that enter the cerebellum originate fro, ?
Inferior olive of the medulla ( form many synapses on purkinje cells , leading to COMPLEX SPIKES of activity)
Plays a role in motor learning.
What kind of spikes are seen from Mossy Fibers ?
Simple spikes on Purkinje Cells.
What other cells of the granule layer do mossy fibers synapse with ?
Granule cells of the glomeruli
Where do parallel fibers come from ?
They are the bifurcated axons of of granule cells
What are the ONLY OUTPUT from the cerebellar cortex ?
Purkinje cells (inhibitory)
Release GABA
What is the function of the basal ganglia of the cerebellum ?
Plan and execute smooth movements
What make up the basal ganglia of the cerebellum ?
Striatum, Globus Pallidus, Subthalamic Nuclei, Substantia Nigra.
What are the two pathways in which the striatum communicates with the thalamus and cerebral cortex ?
Indirect (inhibitory)
Direct (excitatory
Dopamine is _______ in/on the indirect pathway via binding to D2 receptor.
Inhibitory
Dopamine is excitatory to the direct pathway by binding______ Receptors
D1.
Lesion of the globus pallid us –>
inability to maintain postural support
Lesions of the sub thalamic nuclei –>
wild flinging movements
Lesions of the striatum –>
Quick continuous, uncontrolled movements such as in Huntingtons (destruction of the striatum –> loss of inhibitory tone (D2 receptors activation by dopamine)
Lesions of the substantial nigra –>
Destruction of dopaminergic neurons –> Parkinson disease ( in this disease the loss of dopamine is Inhibitory since the direct pathway is not activated)
What kind of EEG waves are seen in people who are awake and have eyes open ?
Beta Waves
What kind of EEG waves are seen in people who are awake and have eyes Closed ?
Alpha (also seen in REM sleep)
When do most dreams occur in the sleep cycle ?
REM
What motor activity is seen in REM ?
Eye movement, loss of muscle tone, pupillary constriction and penile erecton
What tasks is the right hemisphere most associated with ?
Facial expression, intonation, body language,
What tasks is the left hemisphere associated with ?
LANGUAGE (damage to the left hemisphere leads to aphasia)
Damage to which area causes sensory aphasia ( difficulty understanding written or spoken language) ?
Wernickes (word salad)
Damage to which area leads to motor aphasia (understanding intact but can’t speak or write)
Brocas
What can freely cross the BBB ?
Lipid Soluble substances
What two substances are excluded from the CSF ?
Protein and Cholesterol (due to large size)
What molecule class increase the set point for temp regulation in the anterior hypothalamus ?
Pyrogens
Pyrogens cause an increase in the release of IL-1 from phagocytic cells. What will IL-1 increase ?
Levels of prostaglandins which will lead to an increase in the set point for temperature regulation.
What type of drugs can you give to stop set point increases due to pyrogens ?
COX inhibitors like Aspirin
Steroids
Heat Exhaustion
Due to excessive Sweating
Low BP
Heat Stroke
Body heat increases to a point that tissues are damaged
Malignant hyperthermia is due to …
Sensitivity to inhaled anesthetics
GIVE DANTROLENE !
