Week 5 - The Ventricular System

Question 1

What is the body of the lateral ventricle anatomy defined by?

Answer 1

From interventricular foramen to posterior thalamus

Question 2

What forms the roof of the lateral ventricle?

Answer 2

Corpus callosum

Question 3

What structures form the floor of the lateral ventricle?

Answer 3

• Body of caudate nucleus
• Lateral thalamus

Question 4

What is the medial wall of the lateral ventricle composed of?

Answer 4

Septum pellucidum

Question 5

How does the choroid plexus enter the lateral ventricle?

Answer 5

Through the choroidal fissure

Question 6

What is the anatomy of the anterior horn of the lateral ventricle?

Answer 6

• Frontal lobe
• Roof: Corpus callosum
• Floor: Round head of caudate nucleus, superior surface of rostrum of corpus callosum
• Medial wall: Septum pellucidum, anterior fornix

Question 7

What does the posterior horn of the lateral ventricle contain?

Answer 7

• Occipital lobe
• Roof & lateral wall: Fibers of tapetum of corpus callosum
• Medial wall: Superior elevation (splenial fibers), inferior elevation (calcarine fibers)

Question 8

What structures are found in the inferior horn of the lateral ventricle?

Answer 8

• Temporal lobe
• Roof: Tapetum of corpus callosum, tail of caudate nucleus
• Floor: Collateral eminence, medial floor - hippocampus

Question 9

What is the structure of the third ventricle?

Answer 9

Slit-like cleft between thalami

Question 10

What is the pathway of cerebrospinal fluid (CSF) from the lateral ventricles to the fourth ventricle?

Answer 10

Lateral ventricles → Interventricular foramina → Third ventricle → Cerebral aqueduct → Fourth ventricle

Question 11

What forms the anterior wall of the third ventricle?

Answer 11

Lamina terminalis

Question 12

What is located in the posterior wall of the third ventricle?

Answer 12

Opening of cerebral aqueduct

Question 13

What constitutes the lateral wall of the third ventricle?

Answer 13

• Thalamus superiorly
• Hypothalamus inferiorly

Question 14

What is the roof of the third ventricle composed of?

Answer 14

Tela choroidea forming choroid plexus

Question 15

What blood supply does the choroid plexus in the third ventricle derive from?

Answer 15

• Choroidal branches of internal carotid
• Basilar arteries

Question 16

What structures are found in the floor of the third ventricle?

Answer 16

• Optic chiasm
• Infundibulum
• Mamillary bodies

Question 17

What shape does the fourth ventricle have?

Answer 17

Tent-shaped anterior to cerebellum

Question 18

What is the pathway for CSF from the third ventricle to the fourth ventricle?

Answer 18

Third ventricle → Cerebral aqueduct → Fourth ventricle

Question 19

What structures are found laterally in the fourth ventricle?

Answer 19

• Caudal: Inferior cerebellar peduncles
• Cranial: Superior cerebellar peduncles

Question 20

What forms the roof of the fourth ventricle?

Answer 20

Projects into cerebellum, medial borders of superior peduncles

Question 21

What is the blood supply for the choroid plexus in the fourth ventricle?

Answer 21

PICA

Question 22

What are the lateral apertures of the fourth ventricle?

Answer 22

Openings that allow CSF to flow into the subarachnoid space

Question 23

What is the terminal vent anatomy characterized by?

Answer 23

Central canal expands as fusiform terminal vent in conus medullaris

Question 24

What is the subarachnoid space?

Answer 24

Space between arachnoid and pia that extends along cerebral blood vessels

Question 25

At what level does the subarachnoid space end?

Answer 25

At the level of the interval between 2nd & 3rd sacral vertebrae

Question 26

What are the major subarachnoid cisterns?

Answer 26

* Cerebellomedullary cistern (cisterna magna) * Pontine cistern * Interpeduncular cistern * Superior/quadrigeminal cistern of great cerebral vein

Question 27

What is the largest subarachnoid cistern?

Answer 27

Cerebellomedullary cistern (cisterna magna)

Question 28

What is the role of arachnoid villi in CSF absorption?

Answer 28

Project into dural venous sinuses and facilitate absorption

Question 29

What happens when CSF pressure is greater than venous pressure?

Answer 29

Villi compress, tubules close, leading to absorption

Question 30

What is hydrocephalus?

Answer 30

Excessive CSF

Question 31

What is a type of communicating hydrocephalus?

Answer 31

Failure of reabsorption due to raised venous pressure from obstruction in superior sagittal sinus

Question 32

What can cause non-communicating hydrocephalus?

Answer 32

* Blockage in flow * Tumors * Choroid plexus cyst blocking foramina * Meningitis & adhesions * Congenital abnormalities

Question 33

What are the treatments for hydrocephalus?

Answer 33

* Ventriculoperitoneal shunt * Ventriculoatrial shunt

Question 34

What is the blood-brain barrier?

Answer 34

Continuous lipid bilayer isolating CSF from blood

Question 35

What features are present in the lumen of blood capillaries in the blood-brain barrier?

Answer 35

* Endothelial cells * Continuous basement membrane * Astrocyte foot processes * Tight junctions

Question 36

Where is the blood-brain barrier absent?

Answer 36

* Postrema in floor of fourth ventricle * Hypothalamus

Question 37

What is the blood-CSF barrier characterized by?

Answer 37

* Closed fenestrations * Endothelial basement membrane * Pale cells with flattened processes * Epithelial basement membrane * Choroidal epithelial cells resting on basement membrane * Tight junctions

Question 38

What separates the CSF from the CNS?

Answer 38

* Pia mater * Perivascular extensions of subarachnoid space into nervous tissue * Ependymal surface of ventricles