More neuro anatomy

Question 1

4 key elements of BBB

Answer 1

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)

Question 2

Which vessel divides the anterior to posterior circulation of the brain?

Answer 2

The posterior communicating artery

Question 3

What does the anterior cerebral artery supply?

Answer 3

frontal lobe, between 2 hemispheres

Question 4

What does the middle cerebral artery supply?

Answer 4

Temporal lobes and part of parietal lobe, lateral sides

Question 5

What does the posterior cerebral artery supply?

Answer 5

Occipital lobe and part of parietal lobe

Question 6

Which vein which follows the falx cerebri?

Answer 6

Superior sagittal sinus

Question 7

What path does the CSF follow?

Answer 7

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.

Question 8

What are the ventricles lined by?

Answer 8

Ependymal cells.
Look like epithelial cells but are glial cells.
Has cilia which beat to help move CSF.

Question 9

Choroid plexus

Answer 9

Highly vascular (look at picture for histology of this)

Question 10

How does CSF get reabsorbed?

Answer 10

Arachnoid granulations drains into the superior sagittal sinus

Peripheral nerves to lymphatics (nasal mucosa lymphatics deep cervical lymph nodes)

Question 11

**Brainstem **

Answer 11

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

Question 12

What does the thalamus do?

Answer 12

Sensory relay station (simplified)

Question 13

Floor of fourth ventricle

Answer 13

Is upright, only in animals is it the inferior border!

Question 14

Midbrain

Answer 14

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.

Question 15

Medulla

Answer 15

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.

Question 16

Pons

Answer 16

Superior, middle and inferior peduncles carry fibres into the cerebellum

Question 17

Cerebellum

Answer 17

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.

Question 18

Limbic system

Answer 18

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

Question 19

Hippocampus

Answer 19

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.

Question 20

Diencephalon and internal capsule`

Answer 20

Anteriorly to posteriorly:
head of caudate nucleus
Anterior limb and posterior limb of internal capsule. V-shaped.
Thalamus

Question 21

Thalamus

Answer 21

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.

Question 22

Basal ganglia

Answer 22

Striatum - initiates movement. Made of caudate nucleus and putamen with white stripe dividing them (ventral striatum).

There is more to this, look up

Question 23

Hypothalamus

Answer 23

Sits on top of pituitary gland, inferior to thalamus.

Main output is to pituitary gland to produce hormones.

Question 24

Septum pellucidum

Answer 24

Divides 2 lateral ventricles from each other

*Know where there is for anatomy.

Question 25

Amygdala

Answer 25

Fight or flight

Question 26

Spinal cord

Answer 26

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.

Question 27

Dorsal column function test

Answer 27

Patient eyes closed. Move finger up or down. Ask patient to say whether you are moving it up or down.

Question 28

Main sensory tracts in spinal cord

Answer 28

Dorsal column-medial lemniscus system, spinothalamic (or anterolateral) system, and spinocerebellar system

Question 29

Motor tract in spinal cord

Answer 29

lateral corticospinal tract (degenerates in MND)

Question 30

Spinothalamic tract

Answer 30

Crude touch, pain, temperature.

Dorsal root ganglia, cross midline low down in spinal cord. Then goes up.

Question 31

Pathway of dorsal column-medial lemniscus system

Answer 31

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.

Question 32

A lesion in spinal cord causes

Answer 32

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.