The ventricular system and circulation of cerebrospinal fluid Flashcards
What does a ventricle mean?
- small cavity/chamber
How do ventricles form?
- forms from the neural canal
- neural canal dilates within the prosencephalon, leading to the formation of the lateral ventricles and third ventricle
What is the purpose of the ventricles?
- to produce and circulate CSF

Neurolation is the formation of the neural plate, which then bends up and later fuses to form the hollow tube that will eventually differentiate into the brain and the spinal cord of the central nervous system. In the image below, label the items numbered 1-3 using the labels below?
- neural crest
- neural plate
- notochord

1 - notochord
2 - neural plate
3 - neural crest

The neural crest cells begin to seal the remaining space at the cranial (top) and caudal (bottom) ends of the neural tube, what are the ends called and what can happen if these are not sealed correctly?
- neuropores and can cause congenital abnormalities (spina bifida/anencephaly)
- nanapores and can cause congenital abnormalities (spina bifida/anencephaly)
- neural ends and can cause congenital abnormalities (spina bifida/anencephaly)
- caudal pores and can cause congenital abnormalities (spina bifida/anencephaly)
- neuropores and can cause congenital abnormalities (spina bifida/anencephaly)

What is spina bifida?
- neural tube fails to seal correctly at the caudal end and there is no skin, can be:
- occulta = vertebral arch defects (not able to be seen as in the latin name
- cystica = meninges (and sometime the nerves) project out of vertebrae

What is anencephaly?
- where the neural tube has not sealed correctly at the cranial end
- a serious birth defect in which a baby is born without parts of the brain and skull

What do the neural crest cells associated with the nervous system go on to develop?
- PNS
The neural tube will develop into the CNS. What are the 3 primary vesicles called?
- diencephalon, prosencephalon, mesencephalon
- rombencephalon, prosencephalon, mesencephalon
- diencephalon, prosencephalon, mesencephalon
- telencephalon, prosencephalon, mesencephalon
mesencephalon
- rombencephalon, prosencephalon, mesencephalon
- Prosencephalon (forebrain)
- Mesencephalon (midbrain)
- Rombencephalon (hindbrain)

The neural tube will develop into the CNS. There are 3 primary vesicles called the Prosencephalon (forebrain), Mesencephalon (midbrain) and the Rombencephalon (hindbrain). What are the secondary vesicles these will go on to develop?
1 - telencephalon (Prosencephalon)
2 - diencephalon (Prosencephalon)
3 - mesencephalon (Mesencephalon)
4 - metencephalon (Rombencephalon)
5- myelencephalon (Rombencephalon)

As the brain continues to develop, label the key parts of the brain that from from the 5 secondary vesicles (telencephalon, diencephalon, mesencephalon, metencephalon, and myelencephalon), numbered in the image 1-8 using the labels below?
- spinal cord
- cerebellum
- left and right hemisphere
- thalamus
- pons
- midbrain
- hypothalamus
- pons
- medulla oblongata

- left and right hemisphere
- thalamus
- hypothalamus
- midbrain
- cerebellum
- pons
- medulla oblongata
- spinal cord

As the brain continues to develop from from the 5 secondary vesicles (telencephalon, diencephalon, mesencephalon, metencephalon, and myelencephalon), 4 ventricles form. What are these called and what connects them
- lateral, 2nd, aqueduct of slyvius and 5th ventricle
- medial, 3rd, aqueduct of slyvius and 4th ventricle
- lateral, 3rd, aqueduct of slyvius and inferior ventricle
- lateral, 3rd, aqueduct of slyvius and 4th ventricle
- lateral, 3rd, aqueduct of slyvius and 4th ventricle
- 1 - lateral ventricles (one on each side of hemisphere)
- 2 - 3rd ventricle (below thalamus)
- 3 - aqueduct of slyvius (connects 3rd and 4th ventricle)
- 4 - 4th ventricle (between pons and cerebellum)

As the brain continues to develop from from the 5 secondary vesicles (telencephalon, diencephalon, mesencephalon, metencephalon, and myelencephalon), 4 ventricles form. What connects the 3rd and 4th ventricles?
- aqueduct of slyvius (also called cerebral aqauduct)
- arachnoid granulocytes
- glymphatic system
- vein
- aqueduct of slyvius (also called cerebral aqauduct)

If the ventricle system is damaged or it does not develop properly then this can cause problems. One such problem is the Dandy-Walker malformation, what is this?
- congenital abnormality
- expansion of the 4th ventricle (huge in image) means little or no cerebellum develops

What are choroid plexus and where can this be found in the brain?
- plexus of cells arising from ventricles
- arachnoid granules
- ventricular zone
- subarachnoid space
- plexus of cells arising from ventricles
- ependymal cell (form of glial cell) line the ventricles of the brain
- collectively the ependymal cells make up the choroid plexus

Ependymal cells become specialised turning into choroid cells, which make up the choroid plexus. What do these cells produce in the brain and interact with in the brain?
- capillaries invaginate within the choroid plexus and CSF is formed here
- choroid plexus cells filter fluid to form the CSF
The choroid plexus, is responsible for CSF production. Where can the choroid plexi be found?
- in each of the 4 ventricles inside the brain

CSF is created in the choroid plexus of the ventricles in the brain. Using the labels below, order the process of how CSF is created:
- ultrafiltrte collects in choroid stroma
- arterial blood is filtred creating an ultrafiltrate of plasma
- once it passes choroid cells it enters the CSF
- ultrafiltarte has to actively or passively diffuse across choroid cells due to tight junctions
- arterial blood is filtred creating an ultrafiltrate of plasma
- ultrafiltrte collects in choroid stroma
- ultrafiltarte has to actively or passively diffuse across choroid cells due to tight junctions
- once it passes choroid cells it enters the CSF

Where is the Na/K+ pump on the choroid epithelium cells of the ventricles?
- located on the apical side (closest to CSF) of the cell instead of the basal lateral membrane
- creates a net effect of Na+ crossing into CSF creating an osmotic gradient

The Na/K+ pump on the choroid epithelium cells of the ventricles is located on the apical side (closest to the CSF) of the cell instead of the basal lateral membrane. The Na/K+ pump creates an osmotic gradient due to the flow of Na+ into the CSF inside the ventricles. This means that H2O will also want to flow, which can be used to create CSF. How is H2O transported into the CSF?
- aquaporin 1 (choroid cells) and aquaporin 4 (ependymal cells)
- diffusion passively between tight junctions
- with Na+/H2O ATPase pumps
- by binding to K+
- aquaporin 1 (choroid cells) and aquaporin 4 (ependymal cells)
What can happen to the aquaporin 4 channels in neuromyelitis optica (NMO), also known as Devic’s disease, a rare condition where the immune system damages the spinal cord and the nerves of the eyes (optic nerves)?
- increased number of aquaporin 4 channels
- decreased number of aquaporin 4 channels
- damage to aquaporin 4 channels so H2O cannot pass
- damage to aquaporin 4 channels so H2O cannot pass
- bodies immune system (IgG) attacks host cells including aquaporin 4 channels and the optic nerve
What enzyme present inside the choroid epithelial cells that helps transport ions in and out of the cells? This is also important for maintaining pH in the body?
- lactate dehydrogenase
- creatine kinase
- carbonic anhydrase enzymes
- phosphocreatine
- carbonic anhydrase enzymes
- facilitate the following:
- CO2 + H2O arrow ➡️ H2CO3 ➡️ H+ + HCO−3

Bicarbonate can be created in the choroid epithelial cells due to carbonic anhydrase and pass into the CSF along with a Na+ cation. Why is this important?
- draws H20 so important for making CSF
- ensures balance between Na+ and K+ in
- acts as a buffer, maintaining pH of CSF
- involved in maintaining osmosis
- acts as a buffer, maintaining pH of CSF
- able to buffer any acid produced in the brain ensuring optimal pH for the brain
Furosemide generally affects the distal tubules in the kidneys. Furosemide acts by blocking Na+/Cl-/K+co-transporter being re-absorbed in the kidney tubules, meaning H2O is also not re-absorbed, thus increasing urine output. Why might this be useful in the brain?
- less Na+ in the body, so less can be absorbed into CSF
- less Na+ means less H2O and a reduction in the production of CSF
- important in patients who have increased inter-cranial pressure









