Ventricle of Brain and Cerebral Aqueduct



Download 14.81 Kb.
Date26.11.2017
Size14.81 Kb.
4th Ventricle of Brain
and Cerebral Aqueduct

Learning Objectives



  • At the end of lecture student should able to:

  • Describe the location of different ventricles.

  • Discuss the boundaries of 4th ventricle.

  • Describe the structure present in the floor of 4th ventricle.

  • Explain the location of cerebral aqueduct.

  • Explain the formation and circulation of CSF.

  • Define the blood brain barrier.

  • Discuss the appllied anatomy of CSF circulation.

The Ventricular System.

The Ventricular System.

Ventricles are fluid filled cavities located within the brain; 2 lateral ventricles, 3rd ventricle and 4th ventricle.

2 lateral ventricles communicate through interventricular foraminaà 3rd ventricleà4th ventricle by the cerebral aqueduct.

The 4th ventricle à central canal of spinal cord and subarachnoid space through 3foraminea.

Forth Ventricle

Diamond shape when viewed superiorly and tent-à shaped when viewed laterally.

Last and lowest ventricle .

Cavity of hindbrain.

Situated b/w pons ad medulla infront and


cerebellum behind.

Communication

With 3rd ventricleà cerebral aqueduct.

Inferiorly communicate with central canal of


medulla and spinal cord.

Dorsally---median aperture(FORAMEN OF


MAGENDI) ad lateral aperture(FORAMEN
OF LUSCHKA) communicate with
subarachnoid space.

Fourth Ventricle



  • ROOF----tent shaped, projects into
    cerebellum.

  • Superior –lateral: formed by supr.cerebellar

  • Peduncle

  • Connecting sheet of white matter—superior medullary vellum.

  • Inferior part– inferior medullary vellum

  • Tela choroidea of 4th v.

  •  Median aperture—foramen of Magendie.

  • Lateral aperture—foramina of Luschka.

FLOOR --RHOMBOIDAL FOSS

  • Median sulcus.

  • Median eminence—elevation on either side of Median sulcus.

  • Lateral sulcus/sulcus limitansàVESTIBULAR AREA– vestibular nuclei.

  • Superior end of sulcus limità Substantia ferruginea

  • Facial colliculusàinferior end of medial eminence--produced by fibres of facial nerve loop around the abducent nuclues.

  • VAGAL TRIANGLE---dorsal nucleus of vagus.

  • HYPOGLOSSAL TRIANGLE-----hypoglossal nucleus.

Choroid Plexus of 4th ventricle

Cerebral Aqueduct

The cerebral aqueduct is about—1.8 cm long.

Connects 3rd to 4th ventricle.

It lined with ependyma cells with central gray area.

The direction of flow is from 3rdà4th ventricle.

There is no choroid plexus in the cerebral aqueduct.

Tela Choroidea

CSF Circuration

CSF produced by choroid plexus of ventricles and


circulates thru subarachnoid space ad
ventricles, before being absorbed into Dural
venous sinuses.

Choroid plexus is located in roof of 3rd &4th


ventricles &floor and body of inferior horn of lateral ventricle.

Choroid plexus is composed of highly vascular


tissue called TELA CHOROIDEA

Total volume of CSF—130ml .

Normal pressure is 60—150 mm of water.

Colorless contain:

Glucose ½ of blood.

Traces of protein.

Few lymphocytes (0—3 cells/cmm)

Functions:

Nourishes the brain tissue.

Protection.

Cushion and mechanical buoyancy—brain.

Removal of products—neuronal metabolism.

Pathway for the pineal gland secretion –pituitary gland.

Circulation

Blood Brain Barrier



  • The isolation of nervous tissue of brain and spinal cord from blood is called –blood brain barrier.

  • Permeability of BBB is inversely related to the size of molecule and directly to the lipid solubility of molecule.

  • Structure:

  • Endothelial cells of capillary.

  • Continuous basement membrane.

  • Foot process of astrocytes.

Hydrocephalus

Types of Hydrocephalus



Pathophysiology and Etiology

Treatment


Share with your friends:


The database is protected by copyright ©dentisty.org 2019
send message

    Main page