Anatomy and Physiology Flashcards
Part of the neuron that is visible with Nissl staining
Cell bodies and dendrites
Structure in dendrite stained by Nissl staining
RER
Structure of neuron not stained by Nissl staining
Axons - lack RER
Degeneration of axon distal to site of injury and axonal retraction proximally
Wallerian degeneration
Astrocyte marker
GFAP
Tissue astrocytes derived from
Neuroectoderm
Virus that infects astrocytes
JC virus
GFAP positive cerebellar mass in children
Astrocytoma
Cell involved in reactive gliosis in response to neural injury
Astrocyte
Astrocytes are a component of what physical structure
BBB
Buffering provided by astrocytes
Extracellular potassium buffer and glycogen fuel reserve buffer
Cells of the nervous system that remove excess neurotransmitter
Astrocytes
Macrophages of the CNS
Microglia
Composition of multinucleated giant cells in the CNS
HIV-infected microglia
Cells not seen on Nissl stain and are activated by tissue damage in CNS
Microglia
What is found in high concentrations in nodes of Ranvier
Sodium channels
Function of myelin
Increase conduction velocity of signals transmitted down axons
What signal functions are increased by myelin
Signal velocity and length constant
Nodes of Ranvier allow what type of conduction
Saltatory conduction
What is myelin composed of
Lipids and proteins
Disease that injures Schwann cells
Guillain-Barre syndrome
Function of Schwann cells
Myelinate PNS axons
Tissue Schwan cells derived from
Neural crest cells
Function of oligodendrocytes
Myelinate CNS axons
Predominant type of glial cell in white matter
Oligodendrocytes
Tissue oligodendrocytes derived from
Neuroectoderm
Diseases that injure oligodendrocytes
Multiple sclerosis, PML and leukodystrophies
Slow unmyelinated fibers that sense pain and temperature located in skin, epidermis and some viscera
C fibers
Fast unmyelinated fibers that sense pain and temperature located in skin, epidermis and some viscera
A-delta fibers
Fibers that make up free nerve endings
C fibers an A-delta fibers
Sensory receptor located in hairless skin, senses fine/light touch and position sense
Meissner corpuscles
Fibers associated with Meissner corpuscles
Large, fast-adapting myelinated fibers
Fibers associated with Pacinian corpuscles
Large, fast-adapting myelinated fibers
Sensory receptors found in deep skin layers, ligaments and joints that sense vibration and pressure
Pacinian corpuscles
Fibers associated with Merkel discs
Large, slow-adapting myelinated fibers
Sensory fibers found on finger tips and superficial skin that sense pressure, position sense and deep static touch
Merkel discs
Fibers associated with Ruffini corpuscles
Slow-adapting dendritic endings with capsule
Sensory fibers found on finger tips and joints that sense pressure, joint angle changes and slippage of objects along surface of skin
Ruffini corpuscles
Fibers that are 0.5 to 2 microns in diameter blocked more by local anesthetics
C fibers
Fibers that are 3 to 5 microns in diameter and less affected by local anesthetics
A-delta fibers
Surround fascicle of nerve fibers and provides the blood-nerve permeability barrier
Perineurium
Dense connective tissue that surrounds entire nerve
Epineurium
Surrounds single nerve fiber and is location of myelin layer
Endoneurium
Nerve layer that must be rejoined in microsurgery for limb reattachment
Perineurium
Nerve layer attacked in Guillain-Barre syndrome
Endoneurium
Response of cell body to axonal injury with increased protein synthesis in effort to repair damaged axon seen in Wallerian degeneration
Chromatolysis
Location of serotonin synthesis
Raphe nucleus
Location of ACh synthesis
Basal nucleus of Meynert
Location of dopamine synthesis
Ventral tegmentum, SNc
Location of GABA synthesis
Nucleus accumbens
Location of NE synthesis
Locus ceruleus
NT changes seen in Alzheimer’s
Decreased ACh
NT changes seen in anxiety
Decreased GABA, serotonin
Increased NE
NT changes seen in depression
Decreased dopamine, NE, serotonin
NT changes seen in schizophrenia
Increased dopamine
NT changes seen in Huntington disease
Decreased ACh, GABA
Increased dopamine
NT changes seen in Parkinson’s
Decreased dopamine, serotonin
Increased ACh
Three membranes the surround and protect the brain and spinal cord
Meninges
Thick outer layer closest to skull
Dura mater
Tissue dura mater derived from
Mesoderm
Thin, fibrous layer that firmly adheres to brain and spinal cord
Pia mater
Tissue pia mater derived from
Neural crest
Middle layer of meninges with web-like connections
Arachnoid mater
Tissue arachnoid mater derived from
Neural crest
What is contained in epidural space
Fat and blood vessels
Potential space between dura mater and skull
Epidural space
Space located between arachnoid and pia mater
Subarachnoid space
What is contained in subarachnoid space
CSF
NTs with only CNS effects
Serotonin, GABA, and glutamate
NTs with both PNS and CNS effects
NE, ACh, dopamine
Function of BBB
Prevents blood substances from reaching the CSF/CNS
Structures that make up BBB
- Tight junctions by non-fenestrated capillary endothelial cells
- Basement membrane
- Astrocyte foot processes
How do glucose and amino acids cross BBB
Slowly by carrier-mediated transport mechanism
How do nonpolar, lipid-soluble substances cross BBB
Rapid diffusion
Areas of brain with fenestrated capillaries and no BBB
Area postrema, OVLT, neurohypophysis
BBB complication of infarction or neoplasm
Destruction of endothelial tight junctions causing vasogenic edema
Area of brain that senses changes in osmolarity and not protected by BBB
OVLT
Area of brain that is found in medulla, responds to emetics, and not protected by BBB
Area postrema
Area of hypothalamus that controls hunger
Lateral area
inhibiting hormone to lateral area hypothalamus
Leptin
What does leptin do
Decrease hunger
Stimulating hormone to lateral area of hypothalamus
Ghrelin
What does ghrelin do
Increase hunger
Destruction of lateral are of hypothalamus causes what
Anorexia
Area of hypothalamus that controls satiety
Ventromedial
Stimulating hormone to ventromedial are of hypothalamus
Leptin
What does leptin do in ventromedial area of hypothalamus
Signals fullness
What does destruction of the ventromedial area of hypothalamus cause
Hyperphagia
Mass that can damage ventromedial area of hypothalamus
Craniopharyngioma
Part of the ANS that controls anterior hypothalamus
Parasympathetic
Area of hypothalamus that controls circadian rhythm
Suprachiasmatic nucleus
Area of hypothalamus that controls cooling
Anterior hypothalamus
Part of ANS that controls posterior hypothalamus
Sympathetic
Function of supraoptic and paraventricular nuclei of hypothalamus
Make ADH and oxytocin, respectively
Area of hypothalamus that control heating
Posterior hypothalamus
Locus ceruleus is located near what structure
Posterior pons near 4th ventricle
What regulates the sleep cycle
Circadian rhythm
What controls the circadian rhythm
Suprachiasmatic nucleus
What regulates the suprachiasmatic nucleus
Light (environment)
Process of melatonin release
Suprachiasmatic nucleus stimulates NE release which activates pineal gland to release melatonin
Circadian rhythm controls nocturnal release of which substances
NE, ACTH, prolactin, melatonin
How do alcohol, benzos and barbs affect sleep
Decrease REM and delta wave sleep
How does NE affect sleep
Decreases REM sleep
ECG waveform when awake, eyes open
Beta wave
ECG waveform when awake, eyes closed
Alpha wave
ECG waveform with highest frequency and lowest amplitude
Beta wave
ECG waveform during non-REM sleep stage N1
Theta
ECG waveform during non-REM sleep stage N2
Sleep spindles and K complexes
ECG waveform during non-REM sleep stage N3
Delta
Sleep stage when sleepwalking, night terrors and bedwetting occur
Stage N3 of non-REM sleep
ECG waveform with lowest frequency and highest amplitude
Delta
How does depression affect the sleep cycle
Increases total REM sleep but decreases REM latency
What causes extra-ocular movements during REM sleep
Activity of PPRF
ECG waveform during REM sleep
Beta
Sleep cycle characterized by loss of motor tone, increased brain O2 use, variable HR and BP, and increased ACh
REM sleep
How often does REM sleep occur
Every 90 minutes, duration increases throughout the night
What fibers terminate in the VPL nucleus of the thalamus
Spinothalamic tract and posterior column/medial lemniscus
Where do fibers from the VPL terminate
Primary somatosensory cortex
What does the VPL nucleus sense
Vibration, Pain, Pressure, Proprioception, Light touch, temperature
What fibers terminate in the VPM nucleus
Trigeminal and gustatory pathway
What does the VPM nucleus sense
Face sensation and taste
Where do fibers from the VPM terminate
Primary sensory cortex
What fibers terminate in the lateral geniculate nucleus
CN II
What does the LGN sense
Vision
Where do LGN fibers terminate
Calcarine sulcus
What fibers terminate in the medial geniculate nucleus
Superior olive and inferior colliculus of tectum
What does the MGN sense
Hearing
Where do MGN fibers terminate
Auditory cortex of temporal lobe
What fibers terminate in the Ventral lateral nucleus
Basal ganglia and cerebellum
What is the function of the Ventral lateral nucleus
Motor
Where doe ventral lateral nucleus fibers terminate
Motor cortex
What are the key components of the limbic system
Mamillary bodies, Amygdala, Cingulate gyrus, Hippocampus, Entorhinal cortex Fornix (MACH EF)
What is the function of the limbic system
Behavior modulation, Smell, ANS function, Long-term memory, Emotion (B SALE)
Pathway affected with increased activity leading to positive symptoms and target of antipsychotic drugs
Mesolimbic pathway
Pathway affected with decreased activity increasing prolactin leading to decreased libido, sexual dysfunction, galactorrhea, and gynecomastia
Tuberoinfundibular pathway
Pathway affected with decreased activity causing extrapyramidal symptoms, movement disorders and major dopaminergic pathway
Nigrostriatal pathway
Pathway affected with decreased activity causing negative symptoms and having minimal effects by antipsychotics
Mesocortical pathway
Symptoms of flocculonodular lobe lesions
Truncal ataxia, nystagmus, head tilting (vertigo)
Symptoms caused by medial cerebellar lesions involving the vermal cortex, fastigial nuclei or flocculonodular
Truncal ataxia, nystagmus, head tilting (vertigo)
Symptoms of lateral cerebellar lesions
Propensity to fall toward injured side (ipsilateral)
Bilateral motor deficits affecting axial and proximal limb musculature are caused by what type of cerebellar lesions
Midline cerebellar lesions
Deep nuclei of cerebellum from lateral to medial
Dentate, Emboliform, Globose, Fastigial
Purkinje cells exit the cerebellum via what structure
Deep nuclei of cerebellum to contralateral cortex via superior cerebellar peduncle
What is the only output of the cerebellar cortex
Purkinje cells
Ipsilateral proprioceptive information is received via which cerebellar peduncle
Inferior cerebellar peduncle
The middle cerebellar peduncle sends input to what cerebellar structure
Contralateral cortex
Which cerebellar peduncle is the output for Purkinje cells
Superior cerebellar peduncle
Structures that make up the lentiform nucleus
Putamen and globus pallidus
Structures that make up the striatum
Putamen and caudate nucleus
Which pathway in basal ganglia inhibits movement
Indirect pathway
Dopamine binds to which receptors in the indirect pathway
D2 receptors
What does binding of dopamine to D2 receptors cause
Inhibition of the inhibitory pathway
Inhibitory pathway of basal ganglia
SNc to striatum to GPe to STN to GPi to thalamus
What does binding of dopamine to D1 receptors cause
Stimulation of the excitatory pathway
Which basal ganglia pathway promotes movement
Direct pathway
Direct pathway of basal ganglia
SNc to striatum to GPi to thalamus
What is cerebral perfusion primarily regulated by
PCO2
What modulates cerebral perfusion in severe hypoxia
PO2
What BP and ICP changes decrease cerebral perfusion
Decreased BP or increased ICP
What therapy may be used to treat acute cerebral edema secondary to stroke
Therapeutic hyperventilation
Mechanism of therapeutic hyperventilation
Decreases PCO2 causing vasoconstriction leading to decreased cerebral blood flow and decreased ICP
What does Cerebral perfusion pressure (CPP) rely on
Gradient between MAP and ICP
What happens when CPP = 0
No cerebral perfusion which can lead to brain death
When does hypoxemia increase cerebral perfusion pressure
When PO2 < 50 mmHg
Artery that supplies the lateral surface of brain
Middle cerebral artery (MCA)
Artery that supplies the anteromedial surface of brain
Anterior cerebral artery (ACA)
Artery that supplies the posterior and inferior surface of brain
Posterior cerebral artery (PCA)
Watershed zones in the brain are located between what arteries
ACA/MCA and PCA/MCA
Severe hypotension can affect watershed zones and cause what symptoms
Upper leg/upper arm weakness and deficits in higher-order visual processing
What arteries make up the anterior circulation
ACA, internal carotid, MCA
Posterior inferior cerebellar arteries branch of what artery
Vertebral artery
Pontine arteries branch off what artery
Basilar artery
Anterior spinal artery branches off what artery
Vertebral artery
Artery that connects anterior circulation to posterior circulation
Posterior communicating artery
Lenticulostriate arteries branch of what artery
MCA
The last arteries that branch off the basilar artery
Superior cerebellar arteries
The ACA branches off what artery
Internal carotid artery
The common carotid artery branches into what arteries
Internal carotid and external carotid arteries
MCA is a branch of what artery
Internal carotid artery
The anterior choroidal artery branches off what artery
MCA
Unpaired artery that is formed from paired vertebral arteries
Basilar artery
Unpaired artery that is part of the anterior circulation
Anterior communicating artery
Main location of CSF return via arachnoid granulations
Superior sagittal sinus
Superior sagittal sinus drains into what vessel
Confluence of sinuses
What two veins drain into the straight sinus
Great cerebral vein and inferior sagittal sinus
The confluence of sinuses drains into what vein
Transverse sinus
The transverse sinus drains into what vein
Sigmoid sinus
The sigmoid sinus passes through what and becomes what
Jugular foramen to become internal jugular vein
Presents with headache, swollen eyes, impairment of ocular nerves, Horner’s syndrome, CN V1 and V2 sensory loss
Cavernous sinus syndrome
Connects lateral ventricle to 3rd ventricle
Interventricular foramina of Monro
Connects 3rd ventricle to 4th ventricle
Cerebral aqueduct of Sylvius
Paired lateral canals connecting 4th ventricle to subarachnoid space
Foramina of Luschka
Unpaired medial canal connecting 4th ventricle to subarachnoid space
Foramen of Magendie
What makes CSF
Ependymal cells of choroid plexus
What reabsorbs CSF
Arachnoid granulations
Decreased CSF absorption by arachnoid granulations leading to increased ICP with dilation of all ventricles in CT
Communicating hydrocephalus
Structural blockage of CSF flow within ventricles with dilation above blockage
Non-communicating hydrocephalus
CNs located above pons
CNs I, II, III, IV
CNs located in the pons
CNs V, VI, VII, VIII
CNs located in the medulla
CNs IX, X, XI, XII
CNs located medially
CNs III, IV, VI, XII (factors of 12)
Pineal gland function
Melatonin secretion, circadian rhythms
Superior colliculi function
Conjugate vertical gaze center
Inferior colliculi function
Auditory
Location of pineal gland
Midline above superior colliculi
Location of colliculi
Midline above superior cerebellar peduncles
CN nuclei located in midbrain
CN nuclei III, IV
CN nuclei located in pons
CN nuclei V, Vi, VII, VIII
CN nuclei located in medulla
CN nuclei IX, X, XII
CN nuclei located in spinal cord
CN nucleus X
Anterior cranial fossa
Cribriform plate
Middle cranial fossa
Optic canal, Superior orbital fissure, Foramen Rotundum, Ovale, Spinosum
Posterior cranial fossa
Internal auditory meatus, jugular foramen, hypoglossal canal, foramen magnum
Structures exit cribriform plate
CN I
Structures exit optic canal
CN II, ophthalmic artery
Structures exit superior orbital fissure
CNs III, IV, V(1) and VI
Structures exit foramen rotundum
CN V(2)
Structures exit foramen ovale
CN V(3)
Structures exit foramen spinosum
Middle meningeal artery
Structures exit internal auditory meatus
CNs VII, VIII
Structures exit jugular foramen
CNs IX, X, XI, jugular vein
Structures exit hypoglossal canal
CN XII
Structures exit foramen magnum
Brainstem, spinal roots CN XI, vertebral arteries
Only CN without thalamic relay to cortex
CN I
CN III muscles innervated for eye movement
Superior rectus, Inferior rectus, Medial rectus, Inferior oblique
CN III muscle innervated for eyelid opening
levator palpebrae
CN that controls pupillary constriction
CN III
Muscle that controls pupillary constriction
Sphincter pupillae
Actions controlled by CN III
Eye movement, pupillary constriction, accommodation, eyelid opening
Muscle controlled by CN IV
Superior oblique
CN V motor function
Mastication
CN V sensory function
Ophthalmic, maxillary, and mandibular facial sensation
Sensation anterior 2/3 of tongue
CN VI function
Motor to lateral rectus
CN VI motor function
Facial movement, eyelid closing, stapedius
CN VII sensory function
Taste anterior 2/3 of tongue
CN VII parasympathetic function
Lacrimation, salivation
Salivary glands innervated by CN VII
Submandibular and sublingual glands
Eye muscles innervated by CN VII
Orbicularis oculi
Function of stapedius muscle
Modulate auditory volume
CN VIII function
Hearing, balance
CN IX sensory function
Taste and sensation from posterior 1/3 of tongue
CN IX motor function
Elevate pharynx/larynx, swallowing,
CN IX parasympathetic function
Salivation, monitoring carotid body and sinus chemo and baroreceptors
Salivary gland innervated by CN IX
Parotid gland
Oropharynx muscle innervated by CN IX
Stylopharyngeus
CN XI function
Head turning, shoulder shrugging
Muscles innervated by CN XI
Trapezius, SCM
CN XII function
Tongue movement
Function of nucleus solitarius
Visceral sensory information like taste, baroreceptors, and gut distention
CNs found in nucleus solitarius
CNs VII, IX, X
Function of nucleus ambiguus
Motor innervation to pharynx, larynx, upper esophagus
CNs found in nucleus ambiguus
CNs IX, X, XI
Function of dorsal motor nucleus
Sends autonomic fibers to heart, lungs, upper GI
CNs in dorsal motor nucleus
CN X
Afferent CN for corneal reflex
CN V(1)
Efferent CN for corneal reflex
CN VII temporal branch - orbicularis oculi
Afferent CN for lacrimation
CN V(1)
Efferent CN for lacrimation
CN VII
Sensory receptor for jaw jerk reflex
Muscle spindle from masseter
Afferent CN for jaw jerk reflex
CN V(3)
Motor muscle for jaw jerk reflex
Masseter
Efferent CN for jaw jerk reflex
CN V(3)
Afferent CN for pupillary reflex
CN II
Efferent CN for pupillary reflex
CN III
Afferent CN for gag reflex
CN IX
Efferent CN for gag reflex
CN X
Muscles that close jaw
Masseter, Temporalis, Medial pterygoid
Muscles that open jaw
Lateral pterygoid
CN that innervates muscles of mastication
CN V3 (mandibular division)
Total number of spinal nerves
31
Number of cervical nerves
8
Number of thoracic nerves
12
Number of lumbar nerves
5
Number of sacral nerves
5
Number of coccygeal nerves
1
Spinal nerves C1-C7 exit how
Above corresponding vertebra
How does C8 spinal nerve exit
Below C7 and above T1 vertebrae
How do spinal nerves T1 and below exit
Below its corresponding vertebra
Absent ankle reflex is caused by compression of what spinal nerve
S1
In adults, at what spinal level does spinal cord end
L1-L2
To what spinal level does the subarachnoid space extend to
Lower border of S2
At what level is lumbar puncture usually performed
Between L3-L4 or L4-L5
At what spinal level is the cauda equina
Between L3 to L5
Function of Dorsal column-medial lemniscus tract
Pressure, vibration, fine touch, proprioception
Part of dorsal column for lower body and legs
Fasciculus gracilis
Which spinal tracts are ascending
Dorsal column, lateral spinothalamic, and anterior spinothalamic tract
Part of dorsal column for upper body and arms
Fasciculus cuneatus
Spinal level that corresponds to Fasciculus cuneatus
T6 and above
Spinal tract for pain ant temperature
Spinothalamic tract
Spinal tract for crude touch and pressure
Anterior spinothalamic tract
Spinal tract for voluntary motor
Lateral and anterior corticospinal tract
Somatotopic arrangement of lateral corticospinal and spinothalamic tract
Legs are lateral
Somatotopic arrangement of dorsal columns
Arms outside with legs inside
What type of fibers are found in the intermediate horn
Sympathetic fibers
At what spinal level is the intermediate horn located
T1 to L2/L3
How do Dorsal column fibers ascend
Ipsilaterally
Location of cell body of first neuron in Dorsal column-medial lemniscus tract
Dorsal root ganglion
Location of first synapse of Dorsal column-medial lemniscus tract
Nucleus gracilis - for fibers below T6
Nucleus cuneatus - for fibers T6 and above
How do fibers ascend in Dorsal column-medial lemniscus after first synapse
Ipsilaterally in medulla
Location of decussation in Dorsal column tract
Decussates in medulla
How do fibers ascend in Dorsal column after decussation
Contralaterally in in medial lemniscus
Where do fibers from Dorsal column-medial lemniscus terminate
In VPL of thalamus
Where do fibers from VPL of thalamus terminate
Sensory motor cortex
What is the function of the lateral spinothalamic tract
Sense pain and temperature
What sensory nerve endings are associated with lateral spinothalamic tract
A-delta and C fibers
Location of cell body of first neuron in lateral spinothalamic tract
Dorsal root ganglion
Location of first synapse in lateral spinothalamic tract
Ipsilateral gray matter in spinal cord
Location of decussation of the lateral spinothalamic tract
Anterior white commissure
How do fibers from the lateral spinothalamic tract ascend after decussation
Contralaterally in spinal cord
Where do fibers terminate after decussation in the lateral spinothalamic tract
VPL of thalamus
Which spinal tracts are descending
Lateral and anterior corticospinal tracts
Function of lateral corticospinal tract
Voluntary movement of contralateral limbs
Location of cell body of first neuron in lateral corticospinal tract
Primary motor cortex
Path fibers descend from first neuron of lateral corticospinal tract
Descend ipsilaterally through internal capsule
Location of decussation of lateral corticospinal tract
Caudal medulla (pyramidal decussation)
Path fibers descend after decussation in lateral corticospinal tract
Descend contralaterally
Location of first synapse of lateral corticospinal tract
Cell body of anterior horn in spinal cord
UMN is located where
It is the first neuron in corticospinal tract located in primary motor cortex
What is a LMN
Neuron located in anterior horn of corticospinal tract exiting spinal cord and terminating at NMJ
Spinal nerves that innervate Achilles reflex
(S1), S2 (buckle my shoe)
Spinal nerves that innervate patellar reflex
L3, (L4) (kick the door)
Spinal nerves that innervate biceps and brachioradialis
(C5), C6 (pick up sticks)
Spinal nerves that innervate triceps reflex
(C7), C8 (lay them straight)
Age primitive reflexes typically disappear
1 year old
Inhibits primitive reflexes
Mature/developing frontal lobe
Cause of loss of inhibition of primitive reflexes
Frontal lobe lesions
Abduct/extend arms when startled, and then draw together
Moro reflex
Movement of head toward side of cheek or mouth when stroked
Rooting reflex
Sucking response when roof of mouth is touched
Sucking reflex
Curling of fingers if palm is stroked
Palmar reflex
Dorsiflexion of large toe and fanning of other toes with plantar stimulation
Plantar reflex
Presence of plantar reflex in adult which qualifies for UMN lesion
Babinski sign
Stroking along one side of the spine when infant is face down causes lateral flexion of lower body toward side being stroked
Galant reflex
Sensory to posterior half of the skull
C2
Sensory to neck (high turtleneck shirt)
C3
Sensory to the nipple line
T4
Sensory to upper chest bilaterally extending to anteromedial arms ending at wrist
T1
Sensory to lateral shoulders down to thumbs
C6
Sensory to posteromedial arm including ring and pinky finger
C8
Sensory to upper chest bilaterally down anterolateral arms ending at wrist
C5
Sensory at the xiphoid process
T7
Sensory at the umbilicus
T10
Sensory at suprapubic region
T12
Erection and sensation of penile and anal zones
S2, S3, S4 (keep the penis of the floor)
Sensory at the inguinal ligament
L1
Sensory to neck (low collar shirt)
C4
Sensory to anterior leg including kneecaps
L4 (Down on ALL 4’s)
