Neuroanatomy Flashcards
What are ascending tracts?
Sensory info from peripheral nerves is transmitted to the cerebral cortex. Also called somatosensory pathways.
Two types of ascending tracts?
Conscious: Dorsal column lemniscal and anteriolateral
Unconscious: spinocerebellar tracts
How are the two cerebral hemispheres connected?
Via the corpus collosum,
What are the ventricles? Route the CSF takes?
The lateral ventricle, with inferior, Anterior, Dorsal and Posterior horn.
Through the interventricular foramen (or foramen of monroe), to the third ventricle.
Down the aquaduct to the forth ventricle.
Down the central canal to spinal cord.
What is the function of the CSF?
- Buoyancy- reduces the weight of the brain from 1.4kg (male) or 1.2kg female to 25g.
- Protection- cushions from physical damage
- Chemical homeostasis- keeps exc K+ low
Where is CSF produced?
Ependymal cells in Choroid plexus found in all the ventricles
How is the CSF recycled?
500ml made but only 150ml present.
reabsorbed through arachnoid granulations into the superior sagittal sinus to venous circulation.
Where is the third ventricle? e.g. structures near
Either side of the third ventricle is the thalamus, connected by the interthalamic adhesion.
Where is the forth ventricle? e.g. structures near
located in the brainstem, between the pons and the medulla oblongata, cerebellum posterior to
What is the Diaphragma sellae?
Flat piece of dura mater that roofs the pituitary gland (held in the hypophyseous fossa or sellae turcica of sphenoid)
What spaces surround the dura mater in the spinal canal?
Extradural space above the dura mater
Subdural space below the dura mater
What space is there in both the spinal canal and brain meninges?
Subarachnoid space below the arachnoid (so above the pia)
If the lateral sulcus is pulled apart what can be seen?
Insula
What are the layers brain to scalp?
Brain, Pia, arachnoid, dura (meningeal then endosteal), skull, periosteum, epicranial aponeurosis, scalp.
Area where neurons enter the thalamus?
fornix (from the hippocampus to hypothalamus)
Anterior to posterior areas of the corpus collosum?
Rostrum, Genu, body, Splenium
What separates the anterior horns of ventricles?
Septum pellucidum
Where is the parietal-occipital sulcus?
separating the parietal and occipital lobes.
Where is the lateral aperture located? Median?
The forth ventricle from posterior makes a diamond shape, the two lateral points are named the lateral aperture.
The median is the inferior point where it converges onto the central canal.
Where is the brains longitudinal fissure?
in midsagittal plane, splits the two hemispheres in two.
Where is the brains lateral fissure/ sulcus?
Separates the temporal lobe from parietal and frontal. (if pull apart can see insula)
Function of insula?
Body homeostasis
Wheres the central sulcus?
Coronal cross section splitting the frontal lobe from the parietal. Before this sulcus is the precentral gyrus, and posterior to is the postcentral gyrus
The cerebellum derives from which developemental structure?
metencephalon
The cerebellum lies at the same level just posterior to what structure?
the pons, separated by the forth ventricle.
The two cerebellum hemispheres are connected by?
the vermis
Distribution of white and grey matter in the brain, cerebellum and spinal cord?
Brain and cerebellum grey is on surface and white in centre, but for the spinal cord this is the opposite so grey butterfly structure surrounded by the white matter.
What are the three cerebellal lobes?
anterior, posterior(or middle) and flocculonodular
What fissures divide the cerebellal lobes?
Primary fissure between anterior and posterior
Posterolateral between the flocculonodular and posterior
Functional divisions of the cerebellum?
Cerebrocerebellum (Pontocerebellum), spinocerebellum, vestibulocerebellum
Function of the largest functional division of the cerebellum?
cerebrocerebellum: lateral hemisphere forms, planning movements and motor learning, inputs via cerebrum and pontine nucleus, outputs to thalamus and red nucleus. Fine co-ordination of movement by inhibiting excess.
spinocerebellum function?
Vermis and intermediate zones make up. Regulating body movements allowing body and posture corrections, and recieves proprioception info
Vestibulocerebellum function?
Involved in balance, occular reflexes, and fixation on a target, spatial orientation and muscle tone. Recieves Inputs from the vestibular system and outputs to the vestibular nuclei.
What are the structures that join the cerebellum to the
Cerebellar Peduncles: Superior, inferior and middle
flocculonodular lobe is made up of which two structures?
Flocculus and Nodulus
Middle cerebellar peduncle function?
Joins the cerebellum to the pons. Fibres from the pontine nucleus run through.
Inferior cerebellar peduncle function?
Connects cerebellum to the medulla oblongata and spinal cord.
Spinocerebellar Tracts go through and axons from the olivary nucleus
Superior cerebellar peduncle function?
connects the cerebellum to the midbrain.
contains cerebellothalamic fibres and cerebellorubral
What is the infundibulum?
The pituitary stalk, which connects it to the hypothalamus
Superior (or upper) sinus position? Function?
Runs along the margin of falx cerebri, allowing blood to drain from lateral of anterior hemispheres to the confulence of sinuses.
e.g. CSF drains through arachnoid granules into, and back to venous circulation.
Inferior or lower sagittal sinus position? Function?
Vein beneath the cerebral hemispheres, along the inferior boarder of the falx cerebri, just above the corpus callosum. Blood drains posterior through, converging with the great cerebral vein to become the straight, and to the confluence of sinuses.
What is the confluence of sinuses?
Where the superior sagittal sinus, straight sinus (inferior sagittal and great cardiac converge to) and occipital sinus drain to.
Located at the internal occipital protuberance
Where does the blood/CSF drain to after the confluence of sinuses?
Transverse sinus, to sigmoid then internal jugular vein
What are the cavernous sinuses?
Drains into the inferior and superior petrosal sinuses into the sigmoid, and eventually the internal jugular vein.
Recieves blood from the inferior and superior ophthalamic veins.
What are the cerebellar folia?
Folds of cortex, increases the surface area
What is the cerebellar vermis?
Separates the two hemispheres. Associated with the body posture and locomotion. Part of the spinocerebellum.
Can’t be seen when brain is in tact, as is on superior surface.
Function of the anterior cerebellum lobes?
Unconcious proprioception.
Function of the posterior cerebellum lobes?
Fine motor control, terminating excess involuntary movements via the GABA inhibition.
Where is the flocculonodular lobe?
Made up of flocculus + Nodule (connecting the two more lateral flocculus together)
Located on the anterior inferior of the cerebellum.
Function of the floculonodular lobe of cerebellum?
Connects to the vestibular nuclei, integrates vestibular info and body position to influence eye movements and balance.