More neuro anatomy Flashcards
4 key elements of BBB
1) Endothelial cell tight junctions
2) Lack of basement membrane fenestrations
3) Astrocytic end feet (form layer called glia limitans)
4) Pericytes (regulate the BBB, unknown what way but can effect permeability)
Which vessel divides the anterior to posterior circulation of the brain?
The posterior communicating artery
What does the anterior cerebral artery supply?
frontal lobe, between 2 hemispheres
What does the middle cerebral artery supply?
Temporal lobes and part of parietal lobe, lateral sides
What does the posterior cerebral artery supply?
Occipital lobe and part of parietal lobe
Which vein which follows the falx cerebri?
Superior sagittal sinus
What path does the CSF follow?
Made in choroid plexus in floor of lateral ventricles, interventricular foramen, 3rd ventricle, cerebral aqueduct (AKA aqueduct of Sylvius), 4th ventricle, foramen of Magendie or the 2 foramen of Luschka.
What are the ventricles lined by?
Ependymal cells.
Look like epithelial cells but are glial cells.
Has cilia which beat to help move CSF.
Choroid plexus
Highly vascular (look at picture for histology of this)
How does CSF get reabsorbed?
Arachnoid granulations drains into the superior sagittal sinus
Peripheral nerves to lymphatics (nasal mucosa lymphatics deep cervical lymph nodes)
**Brainstem **
Gives rise to all cranial nerves (except I, the olfactory nerve)
Medulla, pons, midbrain and mamillary body.
*Learn where the mamillary bodies are - very useful as anatomy landmark.
Pons has lots of white matter for fibres running laterally between cerebellum
What does the thalamus do?
Sensory relay station (simplified)
Floor of fourth ventricle
Is upright, only in animals is it the inferior border!
Midbrain
Tectum (posterior) and tegmentum.
Superior colliculi in tectum.
Raised intercranial pressure can affect this
Crus crebrie AKA cerebri peduncles, carries fibres.
Substantia nigra - melanin present as waste product of production of dopamine. Gives black pigmentation. In Parkinson’s these cells die and macrophages mop up the pigment.
Cerebral aqueduct runs through tectum. Potential point of blockage.
Medulla
Anteriorly have pyramids. Carry fibres down.
Posteriorly, fibres coming up. Synapses, relay station.
Medial lemniscus tells what direction your joints are.
Middle have central canal with some CSF in.
Inferior olive talks with cerebellum for co-ordination.
Various nuclei.
Pons
Superior, middle and inferior peduncles carry fibres into the cerebellum
Cerebellum
Means small brain.
Tested by rapidly altering movements (turning hand dorsally and rapidly).
Alcohol effects cerebellum.
2 main fissures called primary and horizontal fissures. Vermis down middle.
Flocculonodular lobe formed by flocculus and nodule. To do with balance.
Vermis to do with posture.
Cerebellum hemispheres to do with co-ordination, sophisticated movements.
Molecular layer, many synapses. Granule cells to Purkinje cells via synapses.
Limbic system
Important for memory and emotion, motivation and fight or flight
(limbus means edge in Latin)
Cingulate gyrus, mammillary body, column of fornix, singulum, cyrus of fornix, parahippocampal gyrus, fimbria, hippocampus
Hippocampus
Important in making memories. If damaged, won’t be able to make memories from then on.
Involved with epilepsy. One side can be removed to help treat as long as other side can still make memories and won’t cause amnesia.
Diencephalon and internal capsule`
Anteriorly to posteriorly:
head of caudate nucleus
Anterior limb and posterior limb of internal capsule. V-shaped.
Thalamus
Thalamus
Cranial nerves travel via thalamus.
3 main groups of nuclei.
Sensory relays
Cerebellar and basal ganglia relates to motor frontal lobe
Connected to associative and limbic areas of cerebral cortex
Damage causes loss of sensation, causes pain or causes movement disorders.
There are many thalamic connections to different cortexes.
Basal ganglia
Striatum - initiates movement. Made of caudate nucleus and putamen with white stripe dividing them (ventral striatum).
There is more to this, look up
Hypothalamus
Sits on top of pituitary gland, inferior to thalamus.
Main output is to pituitary gland to produce hormones.
Septum pellucidum
Divides 2 lateral ventricles from each other
*Know where there is for anatomy.
Amygdala
Fight or flight
Spinal cord
Grows more slowly than spine itself. Ends around L1.
Covered by dura meta, arachnoid mater, pia mater.
Grey matter in middle (amount relates to complexity of movement and fineness of control), white around.
Lumbar cord to leg so lots of grey matter.
Same with hands in cervical cord.
But thoracic less as only needs to twist and bend trunk.
In general, sensory enters spine from back, motor impulses comes out front of spine.
Motor/ ventral root cell bodies are in the ventral horns.
Sensory / dorsal root cell bodies are in dorsal root ganglion.
Dorsal column function test
Patient eyes closed. Move finger up or down. Ask patient to say whether you are moving it up or down.
Main sensory tracts in spinal cord
Dorsal column-medial lemniscus system, spinothalamic (or anterolateral) system, and spinocerebellar system
Motor tract in spinal cord
lateral corticospinal tract (degenerates in MND)
Spinothalamic tract
Crude touch, pain, temperature.
Dorsal root ganglia, cross midline low down in spinal cord. Then goes up.
Pathway of dorsal column-medial lemniscus system
2 columns. One for arms, one for legs. Goes up first and then across midline of spinal cord at medulla. Synapse onto relevant nuclei. To somatosensory cortex.
A lesion in spinal cord causes
Joint position sense and pain and temperature sense lost.
Weakness / paralysis on one side of body.
Loss of sensation on other side of body.
Brown sequard.
