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Ventricular system of brain final


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Ventricular system of brain final

  1. 1. Ventricular system of brain Dr. Syed Imad FCPS, MRCS
  2. 2. VENTRICULAR SYSTEM <ul><li>What are the ventricles ? </li></ul><ul><li>How do they develop ? </li></ul><ul><li>What do they contain ? </li></ul>
  3. 3. VENTRICULAR SYSTEM <ul><li>Communicating system of cavities </li></ul><ul><li>Cavity of neural tube that persists </li></ul><ul><li>Ependyma, a single epithelial-like layer of cells. </li></ul><ul><li>Cerebrospinal fluid (CSF) </li></ul>
  4. 4. Neural tube
  6. 6. VENTRICULAR SYSTEM <ul><li>Comprises of: </li></ul><ul><ul><li>two lateral ventricles </li></ul></ul><ul><ul><li>the third ventricle </li></ul></ul><ul><ul><li>the cerebral aqueduct </li></ul></ul><ul><ul><li>and the fourth ventricle </li></ul></ul>
  7. 7. VENTRICULAR SYSTEM from the right from above Central canal
  8. 9. VENTRICULAR SYSTEM <ul><li>Is CSF stagnant or it circulates ? </li></ul><ul><ul><li>What is the path of CSF flow ? </li></ul></ul><ul><ul><li>Where does it come from ? </li></ul></ul><ul><ul><li>Where does it go ? </li></ul></ul>
  9. 10. VENTRICULAR SYSTEM <ul><li>Interventricular foramen (of Monro) --- leads from the lateral into the third ventricle. </li></ul><ul><li>Ventricles communicate with subarachnoid spaces and cisterns via apertures of the fourth ventricle. </li></ul>
  10. 11. External CSF circulation Internal CSF circulation Interventricular foramen 3rd Ventricle Choroid plexus Venous Sinus Lateral ventricle Subarachnoid space
  11. 12. Subarachnoid space and cisterns
  12. 14. Choroid Plexus <ul><li>The lining ependyma of each ventricle comes into contact with the surface pia mater allowing the invagination of a mass of blood capillaries --- combination of these capillaries , pia and ependyma constitutes the choroid plexus . </li></ul>
  13. 15. Choroid Plexus <ul><li>lateral ventricles </li></ul><ul><ul><li>continuous through Interventricular foramen with the small plexus in the third ventricle. </li></ul></ul><ul><ul><li>secretes the bulk of the CSF </li></ul></ul><ul><li>fourth ventricle </li></ul><ul><ul><li>separate from that in the third and lateral ventricles </li></ul></ul><ul><ul><li>only makes a small contribution to the total amount of CSF </li></ul></ul>
  14. 17. CSF <ul><li>CSF is clear, colorless, and odorless fluid </li></ul><ul><li>produced within the ventricles secreted by the Choroid plexus </li></ul><ul><li>provides mechanical support – protection from pressure changes. </li></ul><ul><li>In adults, the total volume of CSF is about 150 ml </li></ul><ul><li>Between 400 and 500 mL of CSF is produced and reabsorbed daily. </li></ul>
  15. 18. CSF Flow
  17. 20. VENOUS SINUSES OF THE DURA MATER <ul><li>Venous sinuses are network of channels that receive all the venous blood from the brain </li></ul><ul><li>Venous sinuses lie b/w the inner and outer layers of the dura ---- Inferior sagittal and straight sinuses are the exceptions </li></ul><ul><li>Arachnoid granulations also project into the venous sinuses to return CSF to the bloodstream </li></ul>
  18. 23. Dural venous sinuses
  19. 24. Lateral ventricles
  20. 25. Central canal
  21. 26. Lateral ventricles <ul><li>C-shaped cavity </li></ul><ul><li>within each cerebral hemisphere </li></ul><ul><li>Consists of: </li></ul><ul><ul><li>anterior horn - frontal lobe </li></ul></ul><ul><ul><li>body --- parietal lobe </li></ul></ul><ul><ul><li>posterior horn ---- occipital lobe </li></ul></ul><ul><ul><li>inferior horn ---- temporal lobe </li></ul></ul>
  22. 30. Lateral ventricles <ul><li>Anterior horn and Body: </li></ul><ul><ul><li>Roof: </li></ul></ul><ul><ul><ul><li>Corpus callosum and the fornix </li></ul></ul></ul><ul><ul><li>Medial surface: </li></ul></ul><ul><ul><ul><li>Septum pellucidum (thin partition between the fornix and corpus callosum) </li></ul></ul></ul>
  23. 32. Thalamus and Basal ganglia Brain stem
  24. 33. Thalamus Thalamus and Basal ganglia Brain stem
  25. 34. Amygdaloid body Thalamus Tail of Caudate nucleus Head of Caudate nucleus Lentiform nucleus Body of Caudate nucleus
  26. 35. Lateral ventricles <ul><ul><li>Anterior horn and Body: </li></ul></ul><ul><ul><ul><li>Floor: </li></ul></ul></ul><ul><ul><ul><ul><li>Caudate nucleus, thalamus </li></ul></ul></ul></ul>
  27. 36. Fibers of Internal capsule Corpus callosum Left thalamus and basal nuclei, viewed from behind
  28. 37. Lateral ventricles <ul><li>Posterior horn </li></ul><ul><ul><li>is the most variably developed and may even be absent. </li></ul></ul>
  29. 38. Lateral ventricles Cingulate sulcus Posterior horn of lateral ventricle Collateral eminence Collateral sulcus Splenium of corpus callosum Tapetum of corpus callosum Optic radiation Callosal radiation
  30. 39. Lateral ventricles <ul><ul><li>Posterior Horn </li></ul></ul><ul><ul><li>Roof and lateral wall </li></ul></ul><ul><ul><ul><li>Tapetum of the corpus callosum </li></ul></ul></ul><ul><ul><ul><li>Optic radiation lying against the tapetum in the lateral wall. </li></ul></ul></ul><ul><ul><li>Medial wall --- two convexities: </li></ul></ul><ul><ul><ul><li>Upper (bulb of the posterior horn) </li></ul></ul></ul><ul><ul><ul><ul><li>Splenium of the corpus callosum </li></ul></ul></ul></ul><ul><ul><ul><li>Lower (Calcar avis) </li></ul></ul></ul><ul><ul><ul><ul><li>Calcarine sulcus. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>If Calcar avis is well developed, it obliterates the posterior horn. </li></ul></ul></ul></ul><ul><ul><li>Floor </li></ul></ul><ul><ul><ul><li>Collateral eminence, produced by the collateral sulcus </li></ul></ul></ul>
  31. 41. Lateral ventricles Inferior horn -- Largest horn
  32. 42. Lateral ventricles <ul><ul><li>Inferior Horn </li></ul></ul><ul><ul><li>Floor </li></ul></ul><ul><ul><ul><li>medially </li></ul></ul></ul><ul><ul><ul><ul><li>hippocampus </li></ul></ul></ul></ul><ul><ul><ul><li>laterally </li></ul></ul></ul><ul><ul><ul><ul><li>collateral eminence </li></ul></ul></ul></ul><ul><ul><li>Roof </li></ul></ul><ul><ul><ul><li>tail of the caudate nucleus, amygdaloid body </li></ul></ul></ul><ul><ul><li>Lateral wall </li></ul></ul><ul><ul><ul><li>Tapetum of corpus callosum </li></ul></ul></ul>
  33. 43. Lateral ventricles <ul><li>Convexities within Lateral ventricles: </li></ul><ul><li>The grey matter at the bottom of a sulci indents the cavity </li></ul><ul><li>Such sulci are </li></ul><ul><ul><li>Parahippocampal </li></ul></ul><ul><ul><li>Calcarine </li></ul></ul><ul><ul><li>Collateral </li></ul></ul><ul><li>Caudate nucleus and thalamus also project into the cavity </li></ul><ul><li>Elsewhere the walls of the cavity are formed by white matter of the cerebral hemisphere </li></ul>
  34. 44. Third Ventricle <ul><li>Cavity within Diencephalon </li></ul><ul><li>slit-like space, lying in the sagittal plane </li></ul>
  35. 45. Neural tube
  36. 46. Third Ventricle <ul><li>Comprises of: </li></ul><ul><ul><li>Anterior wall </li></ul></ul><ul><ul><li>Two side walls </li></ul></ul><ul><ul><li>Floor </li></ul></ul><ul><ul><li>Roof </li></ul></ul>
  37. 47. Third Ventricle
  38. 48. Third Ventricle
  39. 49. Third Ventricle <ul><li>Anterior wall: </li></ul><ul><ul><li>lamina terminalis </li></ul></ul><ul><ul><li>anterior commissure </li></ul></ul><ul><li>Floor: </li></ul><ul><ul><li>optic chiasma </li></ul></ul><ul><ul><li>tuber cinereum median eminence </li></ul></ul><ul><ul><li>infundibulum </li></ul></ul><ul><ul><li>mamillary bodies </li></ul></ul><ul><ul><li>posterior perforated substance </li></ul></ul><ul><ul><li>tegmentum of the cerebral peduncles </li></ul></ul><ul><li>Two side walls: </li></ul><ul><ul><li>Thalamus Interthalamic adhesion (60% of brains) </li></ul></ul><ul><ul><li>Hypothalamus Supraoptic nucleus – ADH </li></ul></ul><ul><ul><li>Paraventricular nucleus – Vasopressin/Oxytocin </li></ul></ul><ul><ul><li>Subthalamus Subthalamic nucleus </li></ul></ul>
  40. 50. Tuber cinerum Median eminence Infundibulum Posterior pitutary
  41. 51. Third Ventricle
  42. 52. Aqueduct (of Sylvius) <ul><li>Cavity within midbrain </li></ul><ul><li>Continuous above with third ventricle </li></ul><ul><li>leads through the midbrain into the cavity of the fourth ventricle </li></ul>
  43. 54. Choroid fissure <ul><li>C-shaped slit in the medial wall of the cerebral hemisphere </li></ul><ul><li>convexity – fornix </li></ul><ul><li>concavity – thalamus, tail of the caudate nucleus </li></ul><ul><li>Invaginated by choroid plexus of lateral ventricle </li></ul>
  44. 56. Tela choroidea (double fold of pia) Pitutary stalk (solid) Infundibulum (hollow )
  45. 57. Tela choroidea <ul><li>Reflection of two layers of pia matter </li></ul><ul><ul><li>Medially b/w interventricular foramina </li></ul></ul><ul><ul><li>Laterally across the upper surface of thalamus </li></ul></ul>
  46. 58. Fourth ventricle
  47. 60. Blood-Brain Barrier <ul><li>Collectively, the blood vessels within the brain have a very large surface area that promotes the exchange of oxygen, carbon dioxide, amino acids, and sugars between blood and brain. </li></ul><ul><li>The blood-CSF barrier is formed by active transport from the blood vessels to the brain- Epithelial cells of joined by tight junctions, form a continuous layer that selectively permits the passage of some substances but not others. </li></ul><ul><li>Why do we need this? </li></ul>
  48. 61. <ul><ul><li>no blood/brain barrier </li></ul></ul><ul><ul><li>corpora amylacea --- calcify ---- after the age of forty years they normally throw a shadow in radiographs of the skull </li></ul></ul><ul><ul><li>displaced calcified pineal indicates a space-occupying lesion above the tentorium </li></ul></ul><ul><ul><li>melatonin (a hormone related to serotonin), which in animals and probably in man also has an antigonadotrophic action. </li></ul></ul><ul><li>part of the tuber cinereum at the base of the infundibulum is the median eminence — highly important as the site of the neurosecretory cells that control the anterior pituitary, and one of the few regions with no blood/brain barrier </li></ul>
  49. 62. Clinical correlates <ul><li>Hydrocephalous </li></ul><ul><li>Arnold Chiari malformation </li></ul><ul><li>Intraventricular hemorrhage </li></ul><ul><li>Ependymal tumors </li></ul><ul><li>Subarachnoid hemorrhage </li></ul>