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- 1. Brain Anatomy and Physiology Dr. Nevo Margalit – Neurosurgery Tel Aviv Sourasky Medical Center
- 2. Scalp • Skin • Connective tissue (superficial fascia) • Epicranial aponeurosis (galea aponeurotica) • Loose areolar tissue • Pericranium • Occipitofrontalis muscle
- 3. Scalp
- 4. The Skull
- 5. The Skull
- 6. The skull
- 7. The Menings The 3 layers covering the brain • Dura: covers the brain and spinal cord. The venous sinuses run through the dura. 2 additional Parts of the dura are the Tentorium and the Falx Cerebri. • Arachnoid: Transparent, thin web structure. Creates a space around the brain called the sub arachnoid space where the CSF and the main blood vessels pass. • Pia: a very thin layer. Coats the brain and spinal cord and is inseparable from them.
- 8. Dura
- 11. Tentorium
- 12. Arachnoid
- 13. Arachnoid – Basal Cisterns
- 14. Parts of the Central Nervous System • 2 hemispheres • Brainstem • Cerebellum • Spinal cord
- 15. Each hemisphere has lobes: • Frontal lobe • Parietal lobe • Temporal lobe • Occipital lobe • Insular lobe • Limbic lobe
- 16. Lateral View
- 17. Insula
- 20. Gyruses and sulci • Each lobe is composed of gyruses separated by sulci • The topography can be defined by histology, anatomical relationships or function
- 21. Map Brodmann
- 23. Functional areas
- 24. Function 2
- 25. Function 3
- 26. f-MRI
- 27. The Motor Strip
- 28. Fibers
- 30. Ventricles and CSF • CSF is produced by the choroid plexus in the ventricles • The circulation is from the lateral ventricles to the third through the Monroe- aqueduct- IV ventricle- sub arachnoid space in skull and spine- absorption in sss and other sinuses through arachnoid granulations
- 31. CSF Pathways
- 32. CSF Pathways
- 33. Arteries of the brain
- 34. Arteries of the brain • Anterior circulation – internal carotid artery, from common carotid in the neck. Bifurcates to MCA and ACA • Posterior circulation – vertebral arteries that join to form the basilar artery that will then bifurcate to 2 PCA
- 35. Circle of Willis • Communication between 2 sides – anterior communicating (a-com) • Communication between anterior and posterior circulation – posterior communicating (p-com) • Many anomalies may exist
- 36. Arteries in the neck
- 37. Arteries in the subarachnoid space
- 38. Arteries of the brain
- 39. Physiology
- 40. Blood supply to the brain • The brain gets 15% of the cardiac output and 20% of the oxygen consumption • The brain tissue gets in average 50ml of blood per 100gr of tissue per minute. The gray matter receives about 3 to 4 times more then the white matter • Total blood supply to the brain is about 500- 600ml per minute
- 41. Factors Affecting the blood supply • Autoregulation • Biochemical changes – O2 and CO2 • Blood brain barrier - BBB
- 42. Autoregulation • Maintains a regular blood supply to the brain in changing blood pressures • The range is 50-130 mm mercury • Possible mechanisms are the myogenic control, neurogenic and biochemichal control
- 43. CO2 • The most important and powerful mechanism that controls brain blood flow • A change in 1mm PCO2 changes the flow in 4-5% • PCO2 of 70 gives a maximal vasodilatation. Above that the flow is pressure dependent
- 44. Hyperventilation • Hyperventilation lowers the PCO2 • It has a strong effect but it is limited in time • Could be dangerous if not regulated- ischemia • Can be regulated with a jugular bulb oximeter
- 45. BLOOD BRAIN BARRIER • The BBB is composed of the tight junctions in the endothelium cells of the blood vessels • Prevents passage of large molecules and even small ions like Na and Cl • Specific substances pass the BBB like glucose and amino acids
- 46. BLOOD BRAIN BARRIER • Because of the BBB, in the brain hydrostatic and oncotic pressures are not significant. The important parameter is the osmotic pressure • The BBB is damages in trauma, tumor, infarct, SAH and infection
- 48. Brainstem and Cranial Nerves
- 49. Brain stem • Has 3 parts: midbrain, pons and medulla • Transports all the information to and from the brain • Centers for breathing and blood pressure • The origin or endpoint for cranial nerves • Contains the center of consciousness • Creates connections to the cerebellum
- 53. Nuclei in the brain stem
- 55. Cranial nerves • 12 pairs of nerves • All cranial nerves except I and II originate from the brainstem • The nerves are sensory, motor or mixed • There are nuclei in the brainstem that are the origin or the endpoint of the cranial nerves
- 56. CN 1- Olfactory Nerve • The sensation of smell • Pure sensory nerve • From the nose to the forebrain • Very developed in some animals • Tested an odorous substance
- 60. CN 2 - Optic N • Visual information from the eye to the brain • Pure sensory nerve • Belongs to the CNS and is not part of the PNS • Problems could result in field problem, acuity problem and more • Tested with a vision chart and field exam on confrontation
- 64. CN 3, 4, 6- occulomotor, trochlear and abbducence • Nerves that control the movement of the eyes and the constriction of the pupil • Pure motor nerves • Problems result in unsynchronized eye movements and/ or dilated pupil • Tested with the patient following a finger and with light
- 68. CN 5 – Trigeminal N • The largest CN • Sensory and motor • Sensation from the face eyes, mouth, and motor for mastication muscles • Tested with touch and pin on face
- 71. CN 7 – Facial N • Motor nerve of the face and taste from the tongue • Motor and sensory • Tested with movement of the facial muscles
- 76. CN 8 – Vestibulocochlear N • The nerves for hearing and balance • Sensory nerves • The most common origin of a schwanoma • Tested by hearing test and balance function
- 79. CN 9 – Glossopharyngeal N • Sensation from the pharynx • Mainly sensory and small motor part • Problems result in aspiration • Tested with the gag reflex
- 81. CN 10 – Vagus N • Motor to the muscles larynx and pharynx and the parasympathetic of the body • Motor nerve • Problems result in hoarseness • Tested by opening mouth wide and saying “AH“
- 83. CN 11 – Accessory N • Nerve to the trapezius and sternomastoid muscles • Motor nerve • Tested with shoulder raise or turning the head
- 85. CN 12 – Hypoglossal N • Nerve to the muscle of the tongue • Motor nerve • Tested with movement of the tongue