1. The Brain & The Spinal Cord I- The brain: 1- The Meninges: Dura Matter Dura Matter Arachinoid Matter Arachinoid Matter Pia Matter Pia Matter 2- The forebrain CerebrumDiencephalon 4- The Hind Brain PonesMedullaCerebellum II- The spinal cord 3- Midbrain

2. Midbrain –Connect the diencephalon to the pons and lies in the posterior cranial fossa. –Consist of right and left halves each forming the cerebral peduncle, –Divided into ventral and dorsal part with a narrow cavity running through the dorsal part, the aqueduct

3. The Brain & The Spinal Cord I- The brain: 1- The Meninges: Dura Matter Arachinoid Matter Pia Matter 2- The forebrain CerebrumDiencephalon 3- Midbrain II_ The spinal cord 4- The Hind Brain PonesMedullaCerebellum

4. Hindbrain The Pons:The Pons: Lie on the anterior surface of the cerebellum below the midbrain and above the medulla.Lie on the anterior surface of the cerebellum below the midbrain and above the medulla. –Fibres Composed mainly of:Composed mainly of: – nerve fibres connecting the two halves of the cerebellum –ascending and descending fibres connecting the forebrain, midbrain and spinal cord The sensory and motor roots of the 5 th cranial nerveThe sensory and motor roots of the 5 th cranial nerve

5. Hindbrain Cells:Cells: –Some serve as relay stations while others form cranial nerve nuclei. Pontine nuclei, relay station in the ventral surfacePontine nuclei, relay station in the ventral surface 5 th – 8 th cranial nerves nuclei, dorsal part5 th – 8 th cranial nerves nuclei, dorsal part Trigeminal, abducent, facial, vestibulotrochlearTrigeminal, abducent, facial, vestibulotrochlear Motor nucleus of the 5 th nerve, upper ponsMotor nucleus of the 5 th nerve, upper pons Sensory nucleus of the 5 th nerve lateral to the motorSensory nucleus of the 5 th nerve lateral to the motor Superior salivary nuclei (Parasympathetic), fibres join nervus intermediusSuperior salivary nuclei (Parasympathetic), fibres join nervus intermedius Inferior salivary nucleus, fibres join glossopharyngeal NInferior salivary nucleus, fibres join glossopharyngeal N Pons

6. Hindbrain oblongata:Medulla oblongata: –Conical in shape and lie vertically connecting the Pons to the spinal cord, passes through foramen magnum PyramidPyramid –a deep groove in the midline on the ventral surface, contain the corticospinal fibres. OliveOlive –convex structure, lateral to the pyramid, contain the inferior salivary nucleus Inferior cerebellar peduncleInferior cerebellar peduncle –behind the olive, connect the medulla to the cerebellum Medulla

7. Hindbrain Structures:Structures: – –Nucleus: 9 th –12 th cranial nerves –Reticular formation: is an irregular mass of cell and fibres that extend up into the pons and down into the spinal cordis an irregular mass of cell and fibres that extend up into the pons and down into the spinal cord –The cells: Cardiac and respiratory centersCardiac and respiratory centers vomiting centervomiting center Chemoreceptor trigger zone communicate with the cardiac and respiratory centers.Chemoreceptor trigger zone communicate with the cardiac and respiratory centers. Medulla

8. Hindbrain Cerebellum:Cerebellum: –Occupy the posterior cranial fossa posterior to the pons and medulla –Consist of two hemisphere united in the midline by the vermis. Each hemisphere consist of a small anterior and a large posterior lobe separated by shallow groove, primary fissureEach hemisphere consist of a small anterior and a large posterior lobe separated by shallow groove, primary fissure –Connected to the midbrain, pons and medulla by the superior, middle and inferior cerebellar peduncles Cerebellum:

9. Hindbrain Structure: –Surface layer is the cortex of grey cells, with white matter internal. –The cortex is thrown into folds or folia, separated by transverse fissures –The dentate nucleus is a mass of grey matter Control of muscle tone and co-ordination of muscle movement on the same sideControl of muscle tone and co-ordination of muscle movement on the same side Cerebellum:

10. Hindbrain The fourth ventricle:The fourth ventricle: –Is the cavity of the hindbrain and bounded in front by the pons and medulla and from behind by the cerebellum. –It is connected above to the third ventricle by the cerebral aqueduct, and below it is continuous with central canal of the spinal cord. –It communicate with subarachnoid space by three openings in the lower part of the roof, a median and two lateral openings.

11. The Brain & The Spinal Cord I- The brain: 1- The Meninges: Dura Matter Arachinoid Matter Pia Matter 2- The forebrain CerebrumDiencephalon 3- Midbrain 4- The Hind Brain PonesMedullaCerebellum II- The spinal cordII- The spinal cord

12. The spinal cord Is cylindrical in shape, begins at the foramen magnum and terminate inferiorly at the lower border of the 1 st lumber vertebra.Is cylindrical in shape, begins at the foramen magnum and terminate inferiorly at the lower border of the 1 st lumber vertebra. –Surrounded by the three meninges, Dura, Arachnoid and Pia matter. –CSF fills the Subarachnoid space, add protection. –31 pairs of spinal nerves are attached to the spinal cord by an anterior (motor) and posterior (sensory) roots

13. The spinal cord (cont) :Structure: –Consist of a central mass of grey matter surrounding a central canal, a downward continuation of the fourth ventricle, enclosed in a cylindrical mass of white matter. –The anterior fissure and the posterior septum divide the cord into two halves –Both the grey & white matter are divided into anterior, lateral and posterior horns & columns of cells and fibres.

14. The spinal cord (cont) – –Grey matter: H-shaped, enlarged in the cervical and lumbosacral region due to increase in the number of the cells in the anterior horn rootH-shaped, enlarged in the cervical and lumbosacral region due to increase in the number of the cells in the anterior horn root – –White matter. contain three types of fibres, ascending, descending and intersegmentalcontain three types of fibres, ascending, descending and intersegmental