B&B Anatomy Flashcards
What structures are derived from the Telencephalon
Cerebral Hemispheres Basal Forebrain Basal Ganglia Hippocamus Amygdala
What structures are derived from the Diencephalon
Thalamus
Hypothalamus
Epithalamus
Subthalamus
What structures are derived from the Mesencephalon
Midbrain
Metencephalon
Pons, Cerebellum
Myelencephalon
Medulla
White matter consists of
Myelinated axons
Gray matter consists of
Neuronal Cell Bodies
Choroid Plexus
Cells in Ventricular walls that produce CSF
Infundibulum
Stalk of the pituitary
Links hypothalamus with thalamus
Infundibulum
Location?
Stalk of the pituitary
Links hypothalamus with thalamus
Behind the optic chiasm! (David and Goliath)
Brodmann Area 4
M1, primary motor cortex
Brodmann Area 6
Premotor cortex
Brodmann Area 8
Frontal Eye Fields
Brodmann Area 3, 1, 2
S1, somatosensory cortex
Brodmann Area 17
V1, primary visual cortex
Brodmann Area 18
Secondary visual area (V2)
Tentorium
Sheet of dura that separates Cerebellum from the cerebral hemispheres
What is the epithalamus? Where is it located?
Epithalamus = Pineal Gland + Posterior Commisure
Located Posterior limit of 3rd ventricle
What is the subthalamus? Where is it located?
Subthalamus is transition from Thalamus to midbrain
Contains: Subthalamic nuclei!!! (Whattaya know?)
Magendie and Luschka
Midline and Lateral apertures of CSF flow from 4th ventricle, respectively
Longitudinal Fissure
Separates right and left hemispheres
Usually contains the falx cerebri
Septum Pellucidum
Membrane that separates the lateral ventricles
Insula
The “fifth” cerebral lobe located within Sylvian fissure
Involved in Taste
Relationship between optic chiasm, infundibulum and mamillary bodies
From anterior to posterior:
chiasm, infundibulum, mamillary bodies
Mamillary bodies
Most posterior part of the hypothalamus
Behind infundibulum
Involved in memory
Anterior Commisure
Connects the uncus of the two temporal lobes
Similar to corpus callosum in the sense that it is a WHITE MATTER structure that connects shit
Massa Intermedia
Interthalamic adhesion
What connects the two thalami
Supramarginal gyrus
Part of parietal lobe
First part of the “m” in M is for Language
Angular Gyrus
Part of parietal lobe
Second part of the “m” in M is for language
Heschl’s gyrus
Located on the superior portion of temporal lobe
Runs from lateral temporal lobe to medial INSULA
Is the primary AUDITORY cortex
What is only modality to bypass thalamus and reach cortex directly?
Smell (olfactory tract)
Mossy fibers
Synapse with Granular cells in cerebellum (and deep cerebellar nuclei)
Climbing fibers
Synapse with Purkinje Cells in cerebellum (and deep cerebellar nuclei)
Come from the inferior olive
Vestibulocerebellum
Includes Flocculonodular Lobe Function: ocular reflexes -balance and equilibrium DCN: Vestibular nuclei Input through ICP
Spinocerebellum
Includes Vermis AND paravermis DCN: Fastigial and Interposed Function: Basic Trunk and Limb movements Example: walking Input through ICP
Cerebrocerebellum
Includes: Lateral Hemisphere
DCN: Dentate
Function: Complex movement, praxis, tying your shoes
Input: MCP
Where is the primary olfactory cortex?
Uncus
Lenticulostriate arteries
Supply the striatum and internal capsule of basal ganglia
Comes from MCA
What are lacunar strokes?
Lacunar is a GENERAL term for any perforating artery…
So it can lead to a shitload of syndromes, INCLUDING a stroke to the lenticulostriate arteries
Great vein of Galen
main drainage area for all veins that serve the INTERNAL aspects of the cerebrum
Empties into straight sinus (joins with inferior sagittal sinus
Clarke’s nucleus
Origin of the dorsal spinocerebellar tract
Input: proprioceptive/stretch receptors from LEGS
Output: dorsal spinocerebellar tract
Location: T1-L2 (makes sense because this is just the legs mothafuckaaa)
Is the second order sensory neuron as part of one of the proprioceptive pathways
Dorsal Spinocerebellar Tract
Starts from Clarke’s nucleus, goes up in the most dorsolateral part of spinal cord (T1-L2) up to ICP up to Vermis/paravermis (fastigial/dentate nuclei)
Ipsilateral cerebellum
Lateral Horn
Where the Preganglionic SYMPATHETIC neurons run
Location: From T1-L2
-Looks like an outpouching of the intermediate zone
Funiculus vs. Fasciculus
Cord-like structure vs. bundle like structure
Medial Division Dorsal Root Fibers
Largest diameter, most heavily myelinated
I-a, I-b, II, A-beta fibers
(the shit that is in your dorsal columns)
Sensitive to anoxia, resistant to anesthesia
Ia fibers (and II fibers)
Muscle Spindles
Senses stretch
Ib fibers
Golgi Tendon organs
Senses Force
Proprioception
A-beta
Touch (two point touch)
Lateral Division Dorsal Root Fibers
Smaller, less heavily myelinated
A-delta
C-fibers
(the shit that is in your spinothalamic tract)
Resistant to anoxia, sensitive to anesthesia
A-delta
Sharp pain and Cold (spinothalamic tract)
C fibers
Dull pain and Warmth (spinothalamic tract)
What are the three types of motor axons that exit from ventral root?
- alpha-motor neurons
- gamma-motor neurons
- pregang. autonomic axons
Alpha-motor neurons
make skeletal muscle contract
innervates extrafusal fibers
Gamma motor neurons
increase sensitivity to muscle spindle
innervates intrafusal fibers
Topographic organization of cell bodies in ventral horn
From Posterior to Anterior (Flexor to Extensor)
-flexor seems to always be on the side where your palms are pointing up during flexion
From medial to lateral (trunk to arms or Proximal to distal muscles)
-this makes sense because the biggest muscles (legs) need more motor neurons to innervate them
Renshaw cells
Inhibitory interneurons that release glycine to inhibit and regulate alpha motor neurons
What structures contain UMN cell bodies?
M1, Red nucleus, pontine and medullary reticular formation, lateral/medial vestibular nuclei
Spinal cord segments involved in
a. biceps brachii stretch reflex
b. triceps brachii stretch reflex
c. patellar tendon (quadriceps femoris) stretch reflex
d. achilles tendon (gastroc/soleus) stretch reflex
a. C5, C6
b. C7, C8
c. L3, L4
d. S1, S2
Epicritic
Sensation felt by dorsal column MINUS proprioception
(mnemonic is the E in epicritic comes before the P in protopathic, just like dorsal column is before spinothalamic tract in alphabetical order…)
Where is the fasciculus cuneatus found?
T5 and above
Protopathic
Sensation felt by spinothalamic tract
What are the two neurons used to convey info to spinocerebellum?
- External cuneate nucleus (arms)
2. Clarke’s nucleus (legs)
External cuneate nucleus
Located in medulla
Origin of the cuneocerebellar tract (CCT)
carries ARM and UPPER TRUNK proprioception to spinocerebellum
How do you identify the level of a cord section?
Is there a fasciculus cuneatus present?
-Yes = above T5
-No = Below T5
Is there a lateral horn present?
-Yes = T1-L2
-No = Not T1-L2 lol
Is there a large ventral horn?
-Yes = C5-T1 (brachial blexus) or L2-S2 (sacrolumbar plexus)
-No = T2-L1 or C1-C4
Also, spinal cord segments gets bigger as they get closer to brain
What is the significance of Lissauer’s Tract?
So that upon a painful stimulus, the pain fibers can mobilize multiple spinal cord segments to withdraw from the pain
Central Tegmental Tract
Runs centrally through each side of the brainstem reticular formation
Function:
-Contains TASTE FIBERS ascending from solitary nucleus fibers to VPM
-sends projections from RED NUCLEUS to the INFERIOR OLIVARY NUCLEUS (crosses) and the fibers from inferior olive will send axons to cerebellum (crosses again here so that’s why these guys cross twice)
Branchiomeric muscles.
Muscles that are derived embryologically from the branchial (gill) arches, notably the larynx, pharynx, palate, jaw and face
What are the four cranial nerves that contain pharyngeal arch motor neurons?
5, 7, 9, 10
Sulcus limitans
Separation between the sensory and motor plates in brainstem
At what cross section level do we start seeing periaqueductal gray?
At the level of the midbrain
What will be found in every brainstem section?
- The three main tracts + hypothalamic
- MLF
- Central tegmental tract
- At least one peduncle
- At least one cranial nerve nucleus
What is the point of corticobulbar tracts?
They provide UMN innervation to LMNs of cranial motor nuclei
-synapse with facial motor nuc, trigem motor nuc, nucleus ambiguus, hypoglossal nucleus and accessory nucleus in cervical spine
Significance of bilateral vs. unilateral:
Bilatearl innervation to everything except the muscles that are below the eye
Unilateral innervation is where you’ll see a weakness in a unilateral corticobulbar lesion
(in contrast, corticospinal tract just provides UMN innervation to motor nuclei present in the spinal cord)
Internal Arcuate fibers
Fibers that link nucleus gracilis/cuneatus to medial lemniscus
At what level do spinothalamic and medial lemniscus run together in brainstem?
Rostral pons
Medial Longitudinal Fasciculus
Links vestibular nuclei with abducens, trochlear and oculomotor nuclei
-contains both the tectospinal and vestibulo spinal axons in medulla
Where can mossy fibers come from?
Dorsal spinocerebellar tract (Clarke)
Cuneocerebellar tract (external cuneate)
Vestibular nuclei
Pontine nuclei
Where do axons from deep cerebellar nuclei synapse in the thalamus?
VL
Which fibers cross before reaching cerebellar peduncles and which stay ipsilateral?
Spinocerebellar shit is ipsilateral
Inferior olive crosses at midline of medulla to ICP
MCP shit like pontine nuclei cross too
At what level does the trapezoid body of auditory fibers cross?
Caudal Pons (ventral to the medial lemniscus)
At the level of the pons, what’s the easiest peduncle to find? Why?
Middle cerebellar peduncle…all you have to do is follow the Efferent corssing fibers of the pontine nuclei and where ever that leads you (i.e. right next to the pontine nuclei…Hint Hint), that’s where the MCP is
Can you see all 3 peduncles in one slide?
Yes! Caudal pons is a good example of it. SCP is right next to deep cerebellar nuclei
What is the lateral lemniscus and where do you see it?
Lateral lemniscus connects cochlear nuclei with inferior colliculi
So at level of ROSTRAL PONS (right before lateral lemniscus makes its connection), you see it start to come up lateral and superior to the spinothalamic tract
Function: responsible for carrying auditory fibers
What the fuck is the “brachium of the inferior colliculus”???
It is the tract that carries auditory fibers from the inferior colliculus up to the MGN in the thalamus
Appears in Mid-midbrain section (right above inferior colliculus) on the lateral side as you would expect for a tract carrying shit superiorly from the inferior colliculus
How can you tell difference between oculomotor and trochlear nucleus in midbrain sections?
Oculomotor nucleus is at level of superior colliculus while trochlear is between the colliculi
How can you distinguish between the levels of superior and inferior colliculus?
there periaqueductal gray has a distinct “V” shape at the level of the superior colliculus
What is the purpose of the nucleus accumbens?
Basal ganglia
Anterior joining of putamen and caudate
Implicated in reward behavior (e.g. getting into medical school lmao)
What is the superior longitudinal bundle?
A band of fibers that connects Broca’s area to the aarcuate fasciculas (angular gyrus)
What is the claustrum?
A thin extensive layer of gray between the external and the extreme capsule.
Function not understood.
What is the uncinate fasciculus?
The bundle of fibers that connects the frontal and temporal lobes
In a coronal myelin stained section, at a region just posterior to the optic chiasm, what are the layers (from superior to inferior) below the thalami
Superior Cerebellar Peduncle
Subthalamic Nucleus
Substantia Nigra
Cerebral Peduncle (just trace the internal capsule and you have the cerebral peduncle..)
Where can you see the posterior commisure on a coronal section?
Separates third ventricle from cerebral aqueduct
-you see posterior commisure at level in which LGN and MGN are visible
Where do you localize the lesion when you lose all sensory modality on one side WITHOUT cranial nerve signs or other loses?
Thalamus (VPL and VPM or VB)
This is because in a patient with risk factors for stroke (hypertension, diabetes), thalamoperforators are one of the first to go
