VENTRICULAR SYSTEM by Dr. Rabia Inam Gandapore.pptx

Neuroanatomy

1. THE VENTRICULAR SYSTEM Dr. Rabia Inam Gandapore Assistant Professor Head of Department Anatomy (Dentistry-BKCD) B.D.S, M.Phil Anatomy, Dip.Implant , CHPE, CHR

2. Teaching Methodology LGF (Long Group Format) SGF (Short Group Format) LGD (Long Group Discussion, Interactive discussion with the use of models or diagrams) SGD (Short Group) SDL (Self-Directed Learning) DSL (Directed-Self Learning) PBL (Problem- Based Learning) Online Teaching Method Role Play Demonstrations Laboratory Museum Library (Computed Assisted Learning or E-Learning) Assignments Video tutorial method

3. Goal/Aim (main objective) To help/facilitate/augment the students about the: Describe structure of circle of Willis . Describe supply by circle of Willis to various structures

4. Specific Learning Objectives (cognitive) At the end of the lecture the student will able to: Describe structure of circle of Willis . Describe supply by circle of Willis to various structures

5. Psychomotor Objective: (Guided response) A student to draw labelled diagram of circle of Willis .

6. Affective domain To be able to display a good code of conduct and moral values in the class. To cooperate with the teacher and in groups with the colleagues. To demonstrate a responsible behavior in the class and be punctual, regular, attentive and on time in the class. To be able to perform well in the class under the guidance and supervision of the teacher. Study the topic before entering the class. Discuss among colleagues the topic under discussion in SGDs. Participate in group activities and museum classes and follow the rules. Volunteer to participate in psychomotor activities. Listen to the teacher's instructions carefully and follow the guidelines. Ask questions in the class by raising hand and avoid creating a disturbance. To be able to submit all assignments on time and get your sketch logbooks checked.

7. Lesson contents Clinical chair side question: Students will be asked if they know what is the function of Outline: Activity 1 Describe structure of circle of Willis . Activity 2 Describe supply by circle of Willis to various structures

8. Recommendations Students assessment: MCQs, Flashcards, Diagrams labeling. Learning resources: Langman’s T.W. Sadler, Laiq Hussain Siddiqui, Snell Clinical Anatomy , Netter’s Atlas , BD Chaurasia’s Human anatomy, Internet sources links.

9. Embryology Ventricles are developmentally derived from the cavity of the neural tube . 4 fluid-filled cavities within the brain: 2 lateral ventricles 3 rd ventricle 4 th ventricle Ventricles lined by ependymal Filled with Cerebrospinal Fluid ( CSF )

10. Forebrain Midbrain

11. Cerebrospinal Fluid ( CSF) Ventricles of brain ( 25mL ) & Subarachnoid space of cranium & Spinal cord ( 125mL ) Provides: Nourishment, waste removal & protection to brain- Shock absorber, reduce weight of brain, Homeostasis, normal neuronal function Secreated : by Choroid plexus “modified ependymal cells ” Simple cuboidal epithelium and surrounds cluster of fenestrated capillaries allowing filtration of plasma ( 400-600ML per day) Choroid plexus has microvilli with tight junctions Large substance cells, proteins & glucose= do not pass I ons, vitamins, nutrients do= pass

12. Electric potential pulls Na+ , Cl -, HCO3 from plasma into CSF creating osmotic gradient and pulls H2O. CSF h as low K+ & Ca + , traces of proteins, immunoglobulins CSF produced via Choroid plexus f ormed by Tela Choroidea

13. Ventricular system CSF Flow

14. Lateral ventricle Inter- Venticular Foramen of M onro 3 rd ventricle Cerebral Aqueduct ( Sylvius ) 4 th ventricle CSF goes through 3 foramina (2 laterally foramen of Luschka and one posteriorly foramen of M agenda into the sub-arachnoid space. Tela choroidea : plexus from posterior inferior cerebellar arteries Communicates Central canal of Spinal C ord Terminal Ventricle Choroid plexus: projects into body of the ventricle through the choroidal fissure f ormed by Tela Choroidea , Function: Produce CSF . Arterial supply: choroidal branches of the internal carotid and basilar arteries . Venous drainage: into internal cerebral veins: unites to form great cerebral veins, this vein joins the inferior sagittal sinus and then drains into the straight sinus

15. Choroid Plexus

16. Lateral Ventricles And Its Relations

17. Lateral ventricle Two lateral ventricles (1 in each cerebral hemisphere lined by Ependyma ) C – shaped with a body and 3 horns Body is in P arietal lobe 3 horns Flash Card Lateral Ventricle communicates with which ?? ventricle and through which formina ?

18. A. Body of lateral ventricle Origin: Foramen Monro & upto posterior end of thalamus Roof : under the surface of the corpus callosum Floor: Body of the caudate nucleus Lateral margin of the thalamus 3. Medial Wall: Anterior: septum pellucidum Posterior: roof & floor come together on medial wall

19. B. Horns of lateral ventricle Anterior horn : F rontal Lobe Posteriorly : Inter-ventricular foramen (Monro-3 rd Ventricle) and then into the body of the ventricle. Roof: genu of corpus callosum Floor : head of caudate nucleus Superior surface of rostrum of corpus callosum Medial wall: Septum pellucidum Anterior c olumn of fornix

20. 2. Posterior horn : O ccipital Lobe Roof and lateral wall: F ibers of Tapetum of corpus callosum Lateral to it is fibers of optic radiation b. Medial wall has two elevations: Superior swelling: Forceps major Inferior swelling: C alcus avis

21. Contd.

22. Contd. 3. Inferior horn : T emporal lobe Roof : Inferior surface of tapetum of corpus callosum T ail of caudate nucleus Stria Terminalis b. Floor : Laterally: C ollateral eminence Medially: hippocampus

23. Third Ventricle And Its Relations

24. Third ventricle Derived from forebrain vesicle Present between two thalami (slit-like cleft ) Anteriorly: Communicates with the lateral ventricle via interventricular foramen ( Monro ) Posteriorly: Communicates with 4 th ventricle via cerebral aqueduct of Sylvius .

25. Walls of the 3 rd ventricle Walls are lined by ependyma 5 walls: Anterior wall : Lamina terminalis (grey matter) Posterior wall: Cerebral A queduct Lateral wall: Superiorly : Thalamus ( medial surface ) Inferiorly: Hypothalamus

26. Cerebral Aqueduct

27. 4. Roof/ Superior wall: Ependyma layer , T ela choroidea of 3 rd ventricle (choroid plexuses) Fornix Corpus callosum 5. Floor/ Inferior wall: Optic chiasma Tube cinereum Infundibulum ( hypophysis ) and Recess Mammillary bodies Hypophysis which is attached to the infundibulum

28. Cerebral A queduct (Aqueduct Of Sylvius )

29. Cerebral aqueduct ( S ylvius ) Narrow channel about 1.8cm. C onnect 3 rd ventricle to 4 th ventricle for CSF flow. Lined by ependyma . Surrounded by grey matter (central gray) No choroid plexus .

30. Fourth Ventricle And its relations

31. 4 th ventricle Tent shaped cavity: Lined by ependyma , filled with CSF Posteriorly: C erebellum Anteriorly: Pons Superior half of medulla oblongata Above: cerebral aqueduct (midbrain) Below: central canal (medulla oblongata and spinal cord)

32. Boundaries of 4 th ventricle Lateral boundaries ( C erebellar Peduncles ) Cranial part: Superior cerebellar peduncle ) Caudal part: I nferior cerebellar peduncle) 2. Roof / posterior wall Projects into the cerebellum Superior : 2 superior cerebellar peduncles Superior medullary velum

33. ContD. Inferior : Inferior medullary velum Foramen magenda ( posterio -inferior) Laterally: foramina of Luschka Note: 4 th ventricle communicates with subarachnoid space through foramen magenda and two foramina Luschka (CSF flows from ventricular system into subarachnoid space).

34. 3. Floor / rhomboid fossa . Posterior surface of pons Cranial half of medulla oblongata Divided by Median sulcus on sides is Median eminence bounded lateral by Sulcus limitans = Vestibular area with nuclie Hypoglossal Triangle (nuclei) Vagal Triangle ( vagus nuclie )

35. Central Canal Spinal Cord and Medulla Oblongata

36. Central Canal (Spinal C ord and Medulla Oblongata) 4 th ventricles open into central canal (CSF and lined by ependymal) S pinal cord & then terminal ventricle No choroid plexus

37. Flash Card Revision

38. Clinical Relevance Hydrocephalus : abnormal collection of CSF in ventricles-Brain. Chronic hydrocephalus cause raised intracranial pressure & cerebral atrophy . 3 classifications : 1. Communicating (Non-obstructive) Hydrocephalus  – Abnormal collection of CSF, No-obstruction in ventricles . Causes: functional impairment of arachnoid granulations , i.e. fibrosis of subarachnoid space following a haemorrhage. 2. Non-communicating (Obstructive) Hydrocephalus  – Abnormal collection of CSF , flow obstructed within ventricular system. C ommon site: obstruction cerebral aqueduct . 3. Hydrocephalus ex vacuo   – ventricular expansion, secondary to brain atrophy in patients with neurodegenerative conditions i.e. Alzheimer’s disease . Treatment: Reversing cause. shunt inserted & drains fluid into right atrium/ peritoneum.

39. Optic Nerve, Raised CSF Pressure & Papilledema Optic nerves= surrounded by sheaths derived from pia mater, arachnoid mater & dura mater. Extension of intracranial subarachnoid space around optic nerve to back of eyeball . Rise of CSF caused by an intracranial tumor will compress thin walls of retinal vein as it crosses the extension of subarachnoid space to enter optic nerve. Result in congestion of retinal vein , bulging of optic disc & edema of disc called Papilledema . Persistent papilledema cause optic atrophy & blindness Papilledema optic atrophy

40. C alcification of C horoid Plexus Choroid plexus of lateral ventricle is continuous with 3 rd ventricle through interventricular foramen. Choroid plexus is largest where the body+ posterior + inferior horns of lateral ventricle join & it may become calcified with age . S ize & shape of lateral ventricle investigated clinically CT & MRI

41. Difficulty concentrating M emory loss Changes in personality D istorted view of reality ( psychosis) D ecline in intellectual function (dementia).

42. Any Questions? Thank You!