1 and 2. CNS anatomy I Flashcards
True or false: A longitudinal band of endoderm thickens to form the neural plate
False - it is the ectoderm which does this
True or false: Neural crest cells form peripheral neural structures such as adrenal medulla cells
true
which end does the neural tube fuse first?
rostral (head) end
Protrusion of the meninges and the brain tissue through the skull, due to incomplete closure of the neural tube is known as..?
Meningo-encephalocele
which of the following is not a primary brain vesicle?
prosencephalon
mesencephalon
mylencephalon
rhombencephalon
mylencephalon
from which primary brain vesicle does the cerebellum arise?
rhombencephalon
which of the following arises from the metencephalon?
pons basal ganglia dorsal thalamus brainstem cerebral hemisphere
pons
what is the innermost meningeal layer?
pia mater
The CSF is produced in the choroid plexus of what ventricle?
Lateral ventricle
True or false- the lateral ventricles communicate directly with each other and the third ventricle?
false
which artery supplies the temporal lobe?
middle cerebral artery
how many arteries supply the brain? what are they?
2
internal carotid & vertebral
in which way does differentiation occur?
dorsal to ventral (back to front)
3 germ cell layers
ectoderm, mesoderm, endoderm
what organs does the ectoderm form?
skin and nervous system
what organs does the mesoderm form?
muscle, CT, skeleton
what organs does the endoderm form?
digestive/respiratory tubes
what produces signalling chemicals which cause the differentiation of the ectoderm?
notochord
what ectoderm is formed by the signalling chemicals?
neuroectoderm
which two signalling chemicals form skin?
retinoic acid and Shh
which two signalling chemicals form neural tissue?
BMP - bone morphogenic proteins - noggin and chordin
when the neural tube is being fused, which part fuses first?
top - rostral
in terms of signalling molecules, how is skin formed?
BMPs are switched off
3 clinical implications which cause alterations of neural tube closure?
- spina bifida
- vit a deficiency
- folic acid deficiency
what is spina bifida?
incomplete closure of the neural tube
what is anencephaly?
being headless
what is holoprosencephaly?
where right and left hemispheres of the brain dont form
define meningocele
meninges protruding into skull
define meninogoencephalocele
meninges + brain tissue protruding the skull
meningohydroencephalocele
meninges + brain tissue + CSF/ventral system protruding the skull
why is vit A deficiency/excess a problem in terms of neural tube formation?
The RA concentration differs - which causes the differentiation of different tissues. If there is excess/deficiency it can disrupt the gradient concentration.
when is folic acid taken and what for?
pregnancy - prevent dystrophic defects to neural tube
Neural crest cells break off from the neural tube and travel around the body. What do they join to which determines their future?
chemical stimulators or chemical inhibitors
what 4 types of cell do neural crest cells become?
- sensory ganglia
- autonomic ganglia
- dorsal kidney - adrenal medulla cells
- non-neural cells (melanocytes)
4 primary vesicles
- prosencephalon
- mesencephalon
- rhombencephalon
- spinal cord
name the embryonic brain parts for each of the 4 primary vesicles
pros - telencephalon - diencephalon mesencephalon rhomb - metencephalon - myeloncephalon spinal cord
what adult brain derivatives are formed by the telencephalon? (5)
- cerebral cortex
- basal ganglia
- hippocampus
- olfactory bulb
- basal forebrain
what adult brain derivatives are formed by the diencephalon? (2)
dorsal thalamus and hypothalamus
what adult brain derivatives are formed by the metencephalon?
cerebellum and pons
what adult brain derivatives are formed by the myelencephalon?
medulla
what cerebral spaces are associated with the following;
- telencephalon
- diencephalon
- mesencephalon
- rhombencephalon
- spinal cord
- lateral ventricle
- third ventricle
- cerebral aqueduct
- 4th ventricle
- central canal
4 things which make up forebrain
- cerebral cortex
- thalamus
- hypothalamus
- cortical white matter
which embryonic derivative makes up the forebrain?
telencephalon
what does the tectum form in the midbrain?
superior and inferior colliculi
what does the tegmentum form in the midbrain?
substantia nigra and red nucleus
what is lost in parkinson’s disease
substantia nigra
what flows in the cerebral aqueduct?
CSF
what moves up to form the cerebellum?
rhombic lips
what lies between the pons and cerebellum?
4th ventricle
which part of the brain contains sensory and motor nuclei?
medulla
what part of the spinal cord is motor and which is sensory?
motor - ventral
sensory - dorsal
3 cranial meninges (inner to outer)
- pia mater
- arachnoid mater
- dura mater
which cranial meninge has a membrane which dips to form the sagittal sinus?
dura mater
describe composition of each of the cranial meninges
dura = tough fibrous loose membrane arachnoid = soft loose membrane pia = thin
where can brain bleeds occur? what are they?
CSF - leaking into gaps between the cranial meninges
where is CSF produced - specifically?
chloroid plexus of lateral ventricles
what is hydrocephalus
when the ventricular system becomes blocked and CSF builds up - causing it to build up in the sagittal sinus - where it can enter the blood stream
state the CSF flow
- lateral ventricle
- third ventricle
- aqueduct
- 4th ventricle
- around cerebellum / spinal cord
what is meningitis ?
inflammation of meninges
what type of meningitis is fatal?
bacterial
what causes meningitis?
a chemical reaction where a foreign substance enters the CSF to cause inflammation
what is a haematoma
clotted blood
a haematoma can occur in 4 places in the brain - what are they? and where?
- intracerebral - inside brain
- subarachnoid - between arachnoid and pia mater
- subdural - between dura and arachnoid mater
- extradural - between dura mater and skull
what is shaken baby syndrome ? where does it occur?
shaking a baby causing damage to blood vessels - subdural
what is hydrocephalus?
increased fluid pressure due to obstruction of CSF
treatment for hydrocephalus
drainage
2 main blood vessels supplying the brain
- common carotid
2. vertebral
2 branches of common carotid - what do each of them supply
external = skull internal = brain
3 branches of internal carotid
- posterior communicating artery
- middle cerebral artery
3 . anterior cerebral artery
what artery connects the right and left anterior cerebral arteries?
anterior communicating artery
2 branches of vertebral artery
- posterior inferior cerebellar artery
2. basilar artery
3 branches of basilar artery
- ant inf cerebellar artery
- superior cerebellar artery
- posterior cerebral artery
name of structure which allows dual circulation to the brain
circle of willis
3 arteries which make up circle of willis
- basilar artery
- posterior cerebral artery
- anterior communicating artery
which artery supplies the visual cortex and inferior temporal lobe
posterior cerebral artery
which 2 arteries supply anterior brain
middle cerebral artery and anterior communicating artery
3 veins draining brain
- superficial
- deep
- dural venous sinuses
what does the superficial vein drain?
subarachnoid space
what does the deep vein drain?
internal structures
where does the deep vein drain into
great cerebral vein
what does the dural venous vein drain?
channels between 2 layers of dura mater - superior and inferior sagitall sinuses
where do all veins meet
confluence of the sinuses
describe venous flow from the confluence of sinuses
transverse + sigmoid sinus
jugular vein
vena cava
what can the occlusion/blockage of the cerebral artery cause
infarction/embolism
what is cerebral haemorrhage
rupture of blood vessel
what is an aneursym
swelling of a blood vessel
what is arteriovenous malformation
a congenital abnormality which causes arterial and venous blood to mix
what structure arises from the prosencephalon and is sometimes known as the relay centre for motor & ssensory info?
thalamus
In which structyre would you find superoir and inferior colliculi?
midbrain
In which brain structure would u find substantia nigra?
midbrain
which of the cerebellar peduncles is the largest and mainly incoming?
middle
true or false - Large cell bodies of descending motor neurones lie in the ventral horn of the spinal cord?
true
