brain

• Cerebrum


  Two large hemispheres on superior aspect of brain, origin of all complex intellectual functions
• Cerebral hemispheres


  • Left and right hemispheres separated by longitudinal fissure
  • White matter tracts like corpus callosum connect the hemispheres
  • Each hemisphere interacts with opposite side of body
  • Some higher-order functions exhibit cerebral lateralization
• Lobes of the cerebrum

  • Frontal
  • Parietal
  • Temporal
  • Occipital
  • Insular
• Frontal lobe


  Anterior part of cerebrum, responsible for motor control, concentration, verbal communication, decision making, planning, personality
• Parietal lobe


  Superoposterior part of cerebrum, serves general sensory functions like evaluating shape and texture of objects
• Temporal lobe


  Located inferior to lateral sulcus, responsible for auditory processing and memory
• Occipital lobe


  Posterior part of cerebrum, responsible for visual processing
• Insular lobe


  Not visible at surface, involved in consciousness and emotional experience
• Regions of cerebrum may exhibit multiple functions, some not easily assigned to one region
• Layers of meninges


  • Pia mater
  • Arachnoid mater
  • Dura mater
• Pia mater


  Innermost meningeal layer, adheres to brain surface
• Arachnoid mater


  Lies external to pia mater, arachnoid trabeculae extend to pia mater through subarachnoid space
• Dura mater


  Tough, outer membrane made of dense irregular connective tissue in two layers - meningeal layer and periosteal layer
• Dural venous sinuses drain blood from the brain
• The epidural space is a potential space between dura and skull, contains arteries and veins
• Epidural hematoma


  Pool of blood in epidural space, usually due to severe blow to the head
• Subdural hematoma


  Hemorrhage in subdural space, typically from ruptured veins due to fast rotational head movement
• Cranial dural septa


  • Falx cerebri
  • Tentorium cerebelli
  • Falx cerebelli
  • Diaphragma sellae
• Falx cerebri


  Largest dural septum, located on midline, projects into longitudinal fissure between cerebral hemispheres
• Tentorium cerebelli


  Separates occipital and temporal lobes from cerebellum
• Ventricles


  Cavities within the brain lined with ependymal cells and containing cerebrospinal fluid
• Ventricles of the brain

  • Lateral ventricles
  • Third ventricle
  • Fourth ventricle
• Cerebrospinal fluid (CSF)


  Clear, colorless liquid surrounding the central nervous system, provides buoyancy, protection, and environmental stability
• Choroid plexus


  Layer of ependymal cells and blood capillaries that filters blood plasma and modifies it to form CSF
• Production and circulation of CSF

  1. CSF is formed by choroid plexus

  2. Flows through ventricles and subarachnoid space

  3. Excess CSF drains into arachnoid villi and dural venous sinuses
• Hydrocephalus


  Pathologic condition of excessive CSF, often leads to brain distortion
• Blood-brain barrier (BBB)


  Regulates which substances enter brain's interstitial fluid, helps prevent neuron exposure to harmful substances
• Composition of BBB


  • Endothelial cells connected by tight junctions
  • Thick basement membrane
  • Wrapped by perivascular feet of astrocytes
• BBB is reduced in certain locations like choroid plexus and hypothalamus/pineal gland for functional reasons
• Some drugs can pass through the BBB and affect the brain, like alcohol
• The cerebrum is the origin of all complex intellectual functions
• The cerebrum is composed of left and right hemispheres
• The longitudinal fissure is the deep cleft separating the cerebral hemispheres
• The corpus callosum is the largest tract providing connection between the cerebral hemispheres
• Some higher-order functions exhibit cerebral lateralization, meaning they are primarily controlled by one side of the brain
• Speech is frequently located in the left cerebral hemisphere
• The insular lobe is not visible at the surface of the cerebrum
• The occipital lobe is responsible for visual processing
• The temporal lobe is responsible for auditory processing and memory
• The parietal lobe serves general sensory functions like evaluating shape and texture of objects