Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
106 Cards in this Set
- Front
- Back
|
What are the three germinal layers
|
Matrix
Mantle Marginal |
|
|
What exactly do the germinal layers make together?
|
The walls of the neural tube
|
|
|
What is another name for the germinal layers?
|
Ectoderm
Endoderm Mesoderm |
|
|
What comes from the ectoderm?
|
Central Nervous system (modified skin!)
|
|
|
What comes from the endoderm?
|
Internal organs develop from here
|
|
|
What comes from the Mesoderm?
|
Muscles, tendons, skeleton and ligaments, blood, vessels, etc.
|
|
|
Where is the neuroectoderm located? What happens to the neuroectoderm?
|
It is located in the centre of the back of the embryo (it is basically a strip of skin).
Early on (2 weeks in), it goes to invagination. It forms a groove and then forms a tube. |
|
|
The skin and inner lining of the _________ is all ________.
|
ventrical
ectoderm |
|
|
When the neural tube forms you have what components?
|
The tube is the ventricular system and it has an ependymal lining.
The walls of the tube is the neural tissue: - Matrix - Mantle - Marginal |
|
|
Describe the matrix:
|
They are cells just outside of the ependymal layer (SUB-ependymal).
The deepest systems will develop from here and will be close to the ependymal lining. |
|
|
What is the ependyma
|
It is made up of ependymal cells. These are the epithelial cells that line the CSF-filled ventricles in the brain and the central canal of the spinal cord.
|
|
|
Describe the mantle and what it will form.
|
It is the layer between the matrix and the marginal layer. It will form the thalamus, basal ganglia fibre tracks, etc.
|
|
|
Describe the marginal layer and what it will form
|
It is the outer germinal layer. Cerebral cortex but it's cells don't come from here. It is to do with the external world.
|
|
|
What is the common cause of epilepsy?
|
Dysplasia - an abnormality of the developmental brain tissue. It is a malconnection that becomes highly epileptogenic.
|
|
|
What are the external and internal (core) receptor surfaces of the neural tube?
|
The skin on the outside is the external receptor and the skins that gets captured in the cavity is the internal receptor. There's a continuity here between the inside and the outside of the tube.
|
|
|
Transmantle dysplasia
|
A malformation of cortical development (MRIs show signal abnormality extending from the cortex to the superolateral wall of the lateral ventricle)
|
|
|
Transmantle dysplasia is what?
|
it is the regional abnormality of mantle.
It extends from the ventricle to the cortex. Lots of transmantle problems can arise! |
|
|
- itis means?
|
inflammation!
|
|
|
What does the neural crest consist of?
|
Mirgratory cells that become ectodermal and mesodermal origin i.e. peripheral vervous system, dental enamel, blood vessels, bone and eyes, etc.
They differentiate fully at the end point |
|
|
What are the neurocutaneous syndromes?
|
Horrific deformities due to the neural tube.
1) Neurofibromatosis - skin pigmentation lesions and tumours of the peripheral nerves. 2) Tuberous sclerosis - highly epileptogenic |
|
|
What is a syndrome?
|
A set of clinically observable signs that reliably co-occur
|
|
|
What is a symptom?
|
A subjective experience of a disorder?
|
|
|
What are the three primary brain vesicles?
|
Prosencephalon
Mesencephalon Rhombencephalon |
|
|
What are the five secondary brain vesicles?
|
Telencephalon
Diencephalon Mesencephalon Metencephalon Myelencephalon |
|
|
What is the forebrain?
|
The prosencephalon which becomes the telencephalon and the diencephalon.
|
|
|
What is the midbrain?
|
The Mesencephalon which stays the same
|
|
|
What is the hindbrain?
|
The rhombencephalon which becomes the metencephalon and the myelencephalon.
|
|
|
What does the metencephalon mean?
|
The brain above (the cerebellum)
|
|
|
What does the myelencephalon
|
The white brain (medulla oblongata)
|
|
|
What will be contained in the telencephalon?
|
The left and right cerebral hemispheres and the lateral ventricals and foramen of monroe.
|
|
|
What will be contained in the diencephalon?
|
The thalamus and hypothalamus and the third ventrical
|
|
|
Where is the cerebral aqueduct located?
|
In the mesencephalon
|
|
|
Where is the fourth ventricle located?
|
in the myelencephalon
|
|
|
What is the laminar terminalis?
|
It is the most anterior wall of the diencephalon (the brain between). In the earliest picture that Michael shows us, it is Micky Mouse's head between Micky Mouse's ears!!! It is the anterior boundary of the 3rd ventricle.
|
|
|
What is so cool about the laminar terminalis?
|
The commissural tracts come from here. It and the roof and floor of the diencephalon are very productive! i.e. glandular structures and commissures.
|
|
|
What is the cephalic flexure?
|
happens in week 5 of gestation - it is where the brain bends almost 90 degrees.
|
|
|
The lamina terminalis gives rise to what?
|
The corpus callosum, the anterior commissure (joins the limbic system), the optic chiasm, etc.
|
|
|
What is so special about the roof of the dien?
|
It gives rise to the pineal gland and the habenular commissure (which joins the midbrain).
|
|
|
What is so special about the floor of the dien?
|
It gives rise to the pituitary gland (the non-neural section is in the roof of the mouth and the neural section is the outpouching of the floor of the dien).
|
|
|
What structure is the corpus callosum?
|
A diencephalic structure
|
|
|
What are the neuropils of the forebrain (i.e. the prosencephalon which forms the telen and dien).
|
The reticulate
The nucleate The stratilaminate |
|
|
What is the reticulate neuropil?
|
It is part of the reticulate formation. It forms part of the MATRIX ZONE. It is periventricular (i.e. around the ventricle) and it is the deepest layer.
It has rostral extensions into the midline forebrain structures (thalamus, hypothalamus and septal area). |
|
|
What is the point of the neuropils?
|
The are neuronal zones that have direct relationship with embryonic layers of the neural tube.
|
|
|
What is the nucleate neuropil?
|
It is a translator between the reticulate and the stratilaminate layers. It is essentially the MANTLE zone. It is an intermediate, grey matter.
|
|
|
What is the stratilaminate layer?
|
It is the transition between MARGINAL and MANTLE zones where the cerebral cortex develops.
|
|
|
How is reticulate neuropil different from stratilaminate?
|
1) Responsive to internal environment
2) It is an ependymal structure 3) It is genetically preprogrammed 4) It can't change or learn 5) it is analogue i.e. no nerve impulses i.e. NO INFORMATION IS CONVEYED. It's like a battery! 6) It functions slowly in order to pick up biochemical changes in the environment 7) It is non-linear because it is a network. IT IS INTEROFACIENT |
|
|
How is stratilaminate different from reticulate neuropil?
|
1) NOT pre-programmed
2) Neurons are linearly organised 3) Has 6 layers 4) It is digital 5) Rapidly activating due to changes in the external environment IT IS EXTEROFACIENT |
|
|
How does the Triune Brain model fit with the neuropil model?
|
Reptillian = Reticulate
Neomammalian = Stratilaminate Paleomammalian = limbic (a disease here is said to cause psychiatric disease) |
|
|
What is pia mater?
|
It is a soft covering just above the brain. It follows the contours of the brain.
|
|
|
What are the layers of the meninges?
|
1) Pia mater
2) Sub-arachnoid space 3) Arachnoid 4) Dura-mater 5) Cranium 6) Scalp |
|
|
What is sub-arachnoid space?
|
It is filled with little trabechulations of veins and arteries. CSF circulates through here.
|
|
|
What are the layers of protection for the brain?
|
1) Bone
2) Dura mater a) Periosteal Layer b) Meningeal Layer 4) Arachnoid 5) Sub-arachnoid 6) Pia BRAIN |
|
|
Meningitis is what?
|
An inflammation of the meninges
|
|
|
The meningeal dives between the two halves of the brain and forms a barrier between the cerebellum and the cerebral cortex - what is it called?
|
The falx cerebri and the tentorium cerebelli.
|
|
|
What is the falx cerebri?
|
A flat sheet of dura that is suspended from the roof of the cranium and separates the right and left cerebral hemispheres, running in the interhemispheric fissure.
|
|
|
What is the tentorium cerebelli?
|
A tent-like sheet of dura that covers the upper surface of the cerebellum.
|
|
|
What is the portion of the intracranal cavity above the tentorium? And below?
|
Supratentorial? Infratentorial
|
|
|
What is a epidural haematoma?
|
It is a bleed under the skull i.e. between the bone and dura. The dura is pushed in to the brain but there is NO blood related damage. It can be normal but pressure onto the brain is a dangerous thing. BITS OF BRAIN CAN HERNEATE IF LONG-STANDING AND UNTREATED. It has a smooth boundary too it on MRIs.
|
|
|
What is a subdural haematoma?
|
Blood between the dura and pia. This is a lot more scary as the blood will follow the contours of the brain. It follows a crazy pattern of the contour of the brain because only pia is the barrier.
|
|
|
What is a meningioma?
|
A tumor that is SUBdural (between the dura and pia most likely). It has a smooth boundary to it as it is not invading anything. It compresses the brain but it is NEUROPSYCHOLOGICALLY ASYMPTOMATIC.
It is very slow growing. |
|
|
What divides the lateral ventricles?
|
The septum pallucidum (it's a membrane)
|
|
|
What is the choroid fissure?
|
Where the meninges are in direct contact with the ependymal lining of the ventricle (meningeal-ependymal contact). There are blood vessels here.
THIS GIVES RISE TO CSF. |
|
|
The choroid plexus does what?
|
It gives rise to the CSF.
|
|
|
What bad thing can happen from the choroid fissure? What is not there to protect the brain?
|
An intraventricular meningioma. It can be symptomatic neuropsychologically. There is NO DURA to protect the brain here!!!
|
|
|
What are the arachnoid granulations?
|
They are outpouchings that extend up through the meninges and into blood vessels that connect with the veins of the brain. i.e. they connect the venus system with the sub-arachnoid space?
|
|
|
What is the arachnoid villus?
|
It is the link between the venus system and the subarachnoid space.
|
|
|
Where does the subarachnoid space extend to? What can form?
|
Around the brain and the spinal cord. Sometimes this area widens to form a cistern i.e. in the cerebellomedullary area or the pontine.
|
|
|
What is the foramen of Magendie-Luschka?
|
They are tiny holes in the roof of the fourth ventricle. Plugging of these can be caused by debris from TBI or encephalitis and can cause a SECONDARY HYDROCEPHALUS. This can push the brain against the skull.
|
|
|
What is the main venus sinus? What can go wrong there?
|
The superior sagittal sinus (it is thin and floppy - but HUGE!
Thromboses can develop here due to severe dehydration. |
|
|
What can go wrong in the foramen of monroe?
|
Hydrocephalus due to a cyst that can block it. Septum pallucidum can be pushed sideways.
|
|
|
What are the parts of the base of the skull?
|
The anterior fossa (the base of the frontal lobes).
The middle fossa (the temporal lobes) The posterior fossa (the cerebellum) The foramen magnum is the hole for the spinal cord |
|
|
What is the sphenoid bone?
|
Between the anterior middle fossa, there is a bony ridge (or wing). There is a greater wing and a lesser wing. The LESSER wing is a very good anatomical landmark!
|
|
|
How is the posterior fossa divided from the rest of the cranial vault?
|
By the tentorium cerebelli and the petrous portions of the temporal bones.
|
|
|
What is important about the midbrain in terms of the tentorium cerebelli?
|
It passes through an important narrow opening in the tentorium cerebelli, the tentorial incisura (or the tentorial notch).
|
|
|
What is epidural space? What artery runs through here?
|
The space located between the inner surface of the skull and the tightly adherent dura. the middle meningeal artery runs through here. It is a branch off the external carotid artery and supplies the dura.
|
|
|
What artery supplies the dura?
|
The middle meningeal artery (part of the external carotid artery) that sits in epidural space.
|
|
|
What is subdural space?
|
Potential space between the inner layer of the dura (meningeal dura) and the arachnoid and pia.
|
|
|
What things traverse the subdural space?
|
The bridging veins that drain the cerebral hemispheres and pass through en route to several large dural venous sinuses.
|
|
|
What are dural sinuses?
|
Large venous channels that lie enclosed within the two layers of dura. They drain blood mainly via the sigmoid sinuses to reach the internal jugular veins.
|
|
|
The inner walls of the ventricles are lined with a layer of ----- cells.
|
ependymal
|
|
|
What are the blood vessels of the choroid plexus lined with?
|
Choroid epithelial cells.
|
|
|
What is the fourth ventricle surrounded by?
|
The pons, medulla and cerebellum. hindbrain (rhombencephalon)
|
|
|
What are the horns of the lateral ventricle?
|
The frontal (anterior) horn and it begins anterior to the foramen of Monroe. The occipital horn (or posterior horn). The temporal (inferior) horn).
|
|
|
What are the C-shaped structures in the brain?
|
caudate nucleus
corpus callosum lateral ventricle fornix stria terminalis they follow the C-shape of the lateral ventricle. |
|
|
How does CSF leave the ventricular system? What happens then?
|
via the lateral foramina of Luschka and the midline foramen of the Magendi.
|
|
|
What happens after the CSF leaves the foramen of Magendie-Luschka?
|
CSF percolates around the brain and spinal cord in the subarachnoid space and is ultimately reabsorbed by the arachnoid granulations into the dural venous sinuses and thus back into the bloodstream.
|
|
|
Why doesn't blood enter the brain? i.e. what is the blood-brain barrier?
|
Capillary enothelial cells are linked by tight junctions and substances entering or leaving the brain must travel through the endothelial cells, mostly by active transport.
|
|
|
What is the similar to the blood-brain barrier?
|
The blood-CSF barrier between the choroid plexus and CSF. The capillaries of the choroid plexus are freely permeable but the choroid epithelial cells form a barrier between the capillaries and the CSF.
|
|
|
Substances can pass relatively freely where?
|
Across the ependymal layer between the CSF and brain parenchyma.
|
|
|
Where is CSF reabsorved
|
At the arachnoid granulations where arachnoid villus cells mediate one-way bulk transport of CSF through giant vacuoles large enough to engulf entire red blood cells.
|
|
|
What lies in the telencephalon
|
Cerebral hemispheres
Cerebral cortex Subcortical white matter Basal ganglia basal forebrain nuclei |
|
|
What lies in the diencephalon?
|
Thalamus
Hypothalamus Epithalamus |
|
|
What lies in the mesencephalon
|
Cerebral peduncles
Midbrain tectum Midbrain tegmentum |
|
|
What lies in the metencephalon
|
Pons
Cerebellum |
|
|
What lies in the myelencephalon
|
Medulla
|
|
|
What is referred to as the brainstem?
|
The midbrain, pons and medulla.
|
|
|
How do cells migrate?
|
1) Radial process - deep within the matrix (periventricular to superficial layers)
2) Horizontal process |
|
|
_____ layer becomes white matter and ______ cortex develops between _____ and ____ layer
|
Marginal
cerebral marginal mantle |
|
|
Problems with migration can cause what?
|
dysplasia
|
|
|
What is white matter?
|
Myelinated axons of the CNS.
|
|
|
What is the gray matter?
|
Cell bodies. Most of the local synaptic communication between neurons in the CNS occurs here.
i.e. thalamus, basal ganglia and cortex |
|
|
What is ganglia?
|
Clusters of cell bodies
|
|
|
What are the boundaries of the frontal lobe?
|
They extend back to the central sulcus of Rolando. They are separated inferiorly and laterally from the termporal lobes by the Sylvian fissure.
|
|
|
What are the parietal lobes bounded by?
|
Anteriorly by the central sulcus but there is not sharp demarcation from the temporal lobes or occipital lobes when viewed laterally. Medially, the parieto-occipital sulcus separates the parietal from the occipital lobes.
|
|
|
What is the insular cortex covered by?
|
A lip of frontal cortex called the frontal operculum and parietal operculum (anterior and parietal cortex posteriorly).
|
|
|
The two cerebral hemispheres are separated in the midline by what?
|
The interhemispheric fissure.
|
