Neuro Anatomy and Science Flashcards
Central Nervous System (CNS)
Brain and spinal cord
Peripheral Nervous System (PNS)
Cranial Nerve and Spinal nerve
Gyrus
ridge on the surface of the cerebral cortex
Sulcus
depression in the surface of the cerebral cortex
Gray matter
the cell bodies, Nuclei in CNS, ganglia in PNS
White matter
Axon tract - majority is myelinated
Meniges
Dura matter: tough outer layer
Arachnoid: middle layer
Pia matter: attached to the surface of the brain and spinal cord
Lobes
Frontal
Parietal
Temporal
Occipital
Brain stem
Frontal Lobe
Primary Motor Cortex
Prefrontal Cortex: personality, Executive function, social behavior, and judgement
Broca’s Area: Language output
Parietal Lobe
Primary Sensory Cortex
Perception and integration
Visual and auditory processing
Temporal Lobe
Primary Auditory Cortex
Wernicke’s Area: Language Comprehension
Memory
Identification of Object
Occipital Lobe
Primary Visual Cortex
Visual Association Cortex
Venticular System
Containing cerebrospinal fluid, that is produced by the choroid plexus, fills the subarachoroid space
Lateral ( L and R)
Third
Fourth
The flow of CSF
Lateral ventricles →Interventicular Foramen( Foramen of Monro)→Third venticle→Cerbral Aqueduct
→Fourth ventricle→Subarachoroid space→Dural venos sinuses→Blood stream
Limbic System
Hippocampus
Amygdala
Hypothalamus
Anterior and medial nuclei of the thalamus
Limbic cortex(Cingulate gyrus, parahippocampal gyrus, uncus)
Amygdala
Control Emotions
Instincts, initiation, motivation, aggression
Hippocampus
Declartive( explit) memory
Diencephalon
Thalamus
Hypothalamus
Epithalamus
Subthalamus
Thalaramus
Collection of nuclei located above the brainstem
Function: relay of sensory and motor signals to the cerebral cortex
sensory - all except olfactory
motor - from the cerebellum and basal ganglia
Regulation of consciousness, arousal, and attention
Assists in integration of Visceral and somatic functions
Hypothalamus
Located below thalamus
Conntected to endcrine system and pituitary gland
Function: maintian homeostasis, regulate body temp, metabolic rate, BP, hunger, digestion, water balance etc.
Regulate circadian rhythm
Emotional expressions
Involved in functions of Autonomic nervous system
Epithalamus
Located above thalamus
Major componet is the pineal gland
Functions: secretes hormones that influence pituitary gland
helps regulate circadian rhythm
Subthalamus
Located below thalamus
part of basal ganglia
Function: control movements
Internal Capsule
Axon connecting the cerebral cortex and subcortical structure
Fiber tracts separate thalamus and basal ganglia
Basal ganglia
Caudate
Putaman
Globus pallidus
Subthalamic nucleus (diencephalon)
Substantia nigra(midbrain)
Lentiform nucleus
globus pallidus + putamen
Striatum
Caudate + putamen
Basal ganglia function
Regulates movement via control of sequencing, muscle tone, and muscle force
Comminucates with motor planning areas of the cerebral cortex via the thalamus
Influences LMN via connections with the pedunculopontine nucleus of the midbrain
Cerebellum Lobes
Anterior
Posterior
Flocculonodular
Cerebellum Vertical divisions
Vermis
Paravermal hemispheres
Lateral hemispheres
Cerebellum: Deep cerebellar nuclei
Fastigial
Globose
Emboliform
Dentate
Cerebellum: Functional regions
Vestibulocerebellum(Flocculonodular lobe)
Spinocerebellum(vermis and paravermal hemisphere)
Cerebrocerebellum(lateral hemisphere)
Cerebellum: conection to brainstem
Superior cerebellar peduncle: attaches to the midbrain; contain cerebellar efferent fiber
Middle cerebellar peduncle: attaches to the pons; contains afferent fibers from the cerebral cortex
Inferior cerebellar peduncle: attaches to the medulla; contains afferent fiber from the brainstem and spinal cord, efferent
fibers to the vestibular and reticular nuclei in the brainstem
Cerebellum pathway
Mostly ipsilateral
Vistibulocerebellum includes some bilateral control
Cerebellum Primary Function
Postural adjustment(anticipatory and reactive)
Coordination of movement
Cerebellum
Input: Mossy fibers(information), Climbing fibers( timing)
Output: Purkinje cells
Vistibulocerebellum
Function: Regurates equilibrium
Input: Vestibular nuclei and superior collius - eye and head position/movement
Output: medial vestibular nucleus - VOR and eye coordination
lateral vestibular nucleus, reticulospinal system, primary motor cortex - postural reactions
Deep cerebellar nucleus : Fastigial
Spinocerebellum
Function: Regulate gross limb movements
Inputs: spinocerebellar tracts
Output: Vestibulospinal and reticulospinal tracts
Motor cortex and red nucleus
Deep cerebellar nuclei: Emboliform, Globose
Cerebrocerebellum
Function: Regulates distal limb voluntary movements
motor planning
Timing/Rhythum
Input: Cerebral cortex via pontine nuclei
Output: Motor and premotor cortices via thalamus
Red nucleus to activate rubrospinal tract
Deep cerebral nucleus: Dentate
Brainstem
Midbrain
Pons
Medulla
Brainstem: function
Communication pathway between the cerebrum, cerebellum, and spinal cord
Location of cranial nerve III-XII nuclei
Regulates cardiovascular, respiratory, and visceral activity
Regulates arousal and awareness through the ascending reticular activating system
Midbrain
Cerebal peduncle located anteriorly -Descending tracts from the cerebral cortex
Substantia nigura - part of the basal ganglia
Red nucleus
Superior collicuous - reflective eye-head movements
Infeiror collicuous - Relays auditiory information
Cranial nerve nuclei: III, IV, V
Pons
Corticopontine tracts synapse on pontine nuclei
Most cerebellar peduncles
Cranial nerve nuclei: V, VI, VII
Medulla
Pyramids located anteriorly - Descending axons of corticospinal tract
Olives located lateral to pyramids
Inferior cellebelar peduncle posterirorly
Decussation of corticospinal cord and dorsal column-medial lemniscus tract
Medial longitudinal fasciculus connects vestibular nuclei and oculomotor nuclei
Infeiror olivary nucleus located deep to the olive
Cranial nerve nuclei: VII, VIII, IX, X, XI, XII
Spinal cord
Extends from medullar to the L1-2 vertebral level
Conus medullaris : the termination of spinal cord
Cauda equina consists of nerve roots that exit spinal canal in the lumbar and sacral regions
Spinal Cord
8 Cervical
12 Thoracic
5 Lubar
5 Sacral
1 Coccygeal
Meninges
Continous with those surrounding the brain
Dura matter, archnoid, pia matter
White matter
Axon tracts conveying ascedning and descending information
Gray matter
Cell bodies and reflex circuts
Dorsal roots
Sensory information enterning spinal cord
cell bodies in dorsal root ganglia outside spinal cord
Ventral roots
Motor commads exiting spinal cord
Cell bodies within spinal cord
Spinal nerves
Fusion of dorsal and ventral roots that exit through the intervertebral foramina
Ascending Tracts
Doral Colum Medial Lemniscus tract: discrminative touch, conscious propiroception
Spinothalamic tract: pain, temprature
Divergent pathway
Unconsious relay tracts
Dorsal Colum Medial Lemniscus tract
First order neuron: peripheral receptor to medulla
Enters spinal cord in Lissauer’s tract
Ascends in the dorsal spinal cord
Fasciculus cuneatus: information from upper trunk and arm
Fasciculus gracilis: information from lower trunk and leg
DCML tract
Second order neuron: medulla to thalamus
Synapse in lower medulla at the nucleus gracilis and cuneatus
Decussate and form medial lemniscus that ascends through brainstem
DCML tract
Third neuron: Thalamus to cerebral cortex
Synapse in thalamus in vertrolateral posteiror nucleus(VPN)
Ascend through internal capusle to primary somatosensory cortex
Spinothalamic tract
First order neuron: periperal receptor to spinal cord
Enters spinal cord in Lissauer’s tract
Synapses in spinal cord
Spinothalamic tract
Second order neuron: spinal cord to thalamus
Decussates in anterior white commissure
Ascends contralaterally in anterolateral spinal cord
Divergent Patheays(slow pain)
Spinomesencephalic tract: Turns eyes toward souse of pain
Spinoretucular tract: Arousal, withrawal, and autonomic respose to pain
Spinolimbic tract: Affective responses to pain
Unconsious Relay tract
Send proprioceptive information to cerebellum for adjusting movements
High-fidelity pathways: posterior spinocerebellar pathway
Cuneocerebeller pathway
Internal feedback tracts: Anterior spinocerebellar tract
Rostral spinocerebellar tract
Descending(motor) tracts
Descending to all spinal levels: Corticospinal tracts
Rubrospinal tract
Reticulospinal tract
Laterl vestibulospinal tract
Head and neck control: Tectospinal tract
Medial vestibulospinal tract
Nonspecific tract: Ceruleospinal tract
Raphespinal tract
Lateral corticospinal tract
Origination: primary cortex, supplymentary motor area, other frontal and perietal areas
Termination: spinal gray matter
Laterality: Contralateral
Decussation - lower medulla at the decussation of the pyramid(1-2% remains ipsilateral)
Function: fractionation of movement
ability to activate individual muscles independently of other muscles
Medial corticaspinal tract
Origination: primary cortex, supplymentary motor area, other frontal and perietal areas
Termination: Bilaterally in ventromedial gray of spinal cord
Laterality: mostly ipsilatral
Decussation - small percentage of contralateral fibers decussate in the spinal cord
Function: neck, shoulder, trunk muscules
prepares postural system for intended movements
Rubrospinal tract
Origination: Red nucleus of midbrain with inputs from cerebellum and motor cortex
Termination: ventromedial gray of cervical spinal cord
Laterality: Contralateral
Decussation - midbrain
Function: Extremity muscle(especially wrist extensors), shaping the hand
Lateral Reticulospinal tract
Origination: Reticular formation in medulla
Termination: ventromedial gray of spinal cord
Laterality: ipsilateral
Decussation - N/A
Function: Psotural control and proximal limb musculature
Medial reticulospinal tract
Origination: Reticular formation in pons
Termination: ventromedial gray of spinal cord
Laterality: ipsilateral
Decussation - N/A
Function: Postural control and limb extensors
Lateral Vestibulospinal tract
Origination: Lateral vestivular nuclues
Termination: ventral and intermediate gray
Laterality: ipsilateral
Decussation - N/A
Function: Facilitate Extensors and inhibit flexors for balance reactions
Medial Vestibulospinal tract
Origination: Medial vestibular nucleus
Termination: bilatral ventromedial gray in cervical and thoracic spinal cord
Laterality: bilateral
Function: Neck and upper back musculature
Tectospinal tract
Origination: superior colliculus in midbrain
Termination: ventromedial gray of cervical spinal cord
Laterality: Contralateral
Decussation - midbrain
Function: Turn head toward visual and auditory stimuli
Nonspecific tracts
Ceruleuospinal tract and raphespinal tract
Function: enhance activity of interneurons and motor neurons
Cranial Nerves
12 pairs of specialized lower motor neurons providing communication between the brain and periphery
I - Olfactory Nerve
Function: Smell
Examination: Identify distictive smells
Additional notes: Projects directly to temporal lobe of cortex(bypass thalamass)
II - Optic Nerve
Function: Vision
Examination: Snellen Chart, conforntation
Additional notes: Optic nerve from each eye projects to optic chiasm, from which optic radiations projects to the visual
cortex
Information from right visual field(nasal retina from right eye, temporal retina from left eye) goes to left
cortex vice versa
III - Oculomotor nerve
Function: Eye movements; innervation of superifor rectus, medial rectus, inferior rectus, inferior oblique
Raises upper eye lid; innervation of levator palpebrae superioris
Constrict pupil ; innervation of pupillary sphincter
Adjust shape of lens of eye: innervation of ciliary muscle
Examination: Smooth pursuits
Additional notes: Pupillary reflex: light enterning eyes is detected by optic nerve and oculomotor nerve causes pupil
constriction
IV - Trochlear nerve
Function: Eye movement; innervation of superior oblique muscle (inferior and medial eye movement)
Examination: Smooth pursuits
Additional notes: Only cranial nerve to emerge from the dorsal brainstem
V - Trigeminal nerve
Function: Sensory - facial and temporomandibular joing sensation
Motor - muscles of mastication(temporalis, masseter)
Examination: Light touch to face
Palpate temporalis and masseter as patient crutch teeth
Additional notes: 3 branches; Ophthalamic(sensory), maxillary(sensory), mandibular(sensory and motor)
Jaw jerk reflex
VI - Abducens nerve
Function: Eye movement; innervation of lateral rectus(lateral eye movements)
Examination: Smooth pursuits
Additional notes: Right abducens nerve palsy( right eye shift to medial side)
VII - Facial nerve
Function: Motor - muscles of facisal expression and eye closure
Sensory - salivation, taste of anterior of 2/3 of tongue
Examination: Obseve facial symmetry, facial movement( eyebrow elevation, eye closure, smile, puff cheecks)
Additional notes: Five braches; Temporal, zygomatic, buccal, madinbular, cervical
VIII - Vestibulocochlear nevre
Function: hearing and vestibular function
Examination: Finger rub beside ears, vestibular screen
Additional notes: Vestibular nuclei projects to the spinal cord, cerebellum, and nuclei of cranial nerves III, V and VI
IX - Glossopharyngeal nerve
Function: Taste of posterior 1/3 of tongue, salivation, swallowing(sensation from soft palate and pharynx)
Examination: Gag reflex
Additional notes: sensory portion of gag reflex
X - Vagus nerve
Function: Speech, swallowing, thoracic and abdominal viscrea( especially heart)
Examination: Gag reflex, say “ahh” and observe palate elevation ( uvula deviation away from affected side)
Additional notes: Motor portion of gag reflex
XI - Accessory nerve
Function: Inneravation of sternocleidomastoid and upper trapezius
Examination: Turn heard and shrug shoulder
Additional notes:
XII - Hypoglossal nerve
Function: Tongue movement
Examination: Tongue protrusion(deviation toward affected side)
Additional notes: Left hypoglossal nerve palsy - tongue deviated to Left
Peripheral nerve anatomy
Bundles of axons surrounded by connective tissue
Epineurium: surrounds entire nerve trunk
Prineurium: separates bundles of axons
Endoneurium: separates indiviual axons
LMN
Alpha motor neuron: large, myelinated axons
Gamma motor neuron: medium, myelinated axons
Motor unit
Definition: an alpha motor neuron and the muscle fibers it innervates
Fast twitch - large diameter, faster alpha motor neuron
Slow twitch - smaller diameter, slower alpha motor neuron
Motor unit Recruitment
Henneman’s size principle : smaller motor neuron(slow twitch) activated first, followed by larger motor neuron(fast twitch)
oppsite recruitment pattern with electrical stimulation
Myotomes - groups of muscles innervated by a single spinal nerve
C5 : Elbow flexors
C6 : Wrist extensors
C7 : Elbow extensors
C8 : Finger flexors
T1 : Deep finger abductors
L2 : Hip flexors
L3 : knee exntors
L4 : ankle dorsiflexors
L5 : Great toe extensors
S1 : ankle plantor flexors
Dermatomes
Area of skin for which sensation is relayed by a single spinal nerve
Autonomic nervous system
Responsible for homeostasis
Regulates cardiovascular system, gastrointestinal system, genitourinary system, body temperature, metabolism,
pupillary adjustments and reproduction
Afferent pathways
Information from visceral receptors sent to CNS via spinal cord and cranial nerve(VII, IX, X)
Visceral receptors - Mechanoreceptors
Chemoreceptors
Nociceptors
Thermoreceptors
Central regulation
Solitary nucleus : convergence of afferent information from cranial nerve VII, IX, X
Pons and medulla: Heart rate, respiration, circulation(vasoconstriction/dilation)
Hypothalamus, thalamus, and limbic system: Modulate brainstem control
