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A 61 year old man with history of alcohol abuse who suffered a stroke lost…

- - - - shallow depressions called sulci
        
        deeper grooves called fissures
    - - anterior = rostral
        
        (“toward the nose”)
      - posterior = caudal
        
        (“toward the tail”)
  - - - color from motor and interneuron cell bodies, dendrites, and unmyelinated axons
    - - color from myelin on axons
  - - - provides rigid support
    - - surround and partition
    - - cushions the brain
    - - prevents entry of harmful materials
    - - three connective layers that
        
        enclose and protect blood vessels supplying the brain
        
        subdural space
        
        potential space between arachnoid and dura mater
        
        becomes actual space if blood or fluid accumulates there
        
        help contain and circulate cerebrospinal fluid
        
        arachnoid mater
        
        Lies external to pia mater
        
        Partially composed of collagen and elastic fibers (arachnoid trabeculae)
        
        Trabeculae extend through subarachnoid space
        
        contains cerebrospinal fluid
        
        separate and support soft tissue of brain
        
        pia mater
        
        Thin layer of loose areolar connective tissue
        
        Tightly adheres to brain and follows contours of brain surface
      - Dura Mater
        
        tough, dense layer that lies external to arachnoid mater
        
        meningeal layer
        
        immediately superficial to arachnoid
        
        periosteal layer
        
        more superficial layer that forms the periosteum on internal surface of cranial bones
        
        Layers usually fused but separate in specific areas where form large, blood-filled spaces called dural venous sinuses
        
        lack valves and drain blood from the brain
        
        epidural space
        
        potential space between dura mater and bones of skull
        
        contains arteries and veins nourishing meninges and cranium
        
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  - - - Lined with ependymal cells and contain cerebrospinal fluid
        
        Third ventricle
        
        smaller, thinner cavity within diencephalon
        communicate with each lateral ventricle through interventricular foramen
        
        Fourth ventricle
        
        located between pons and cerebellum
        
        communicates with third ventricle through cerebral aqueduct
        
        opens to subarachnoid space
        
        via medial aperture and paired lateral apertures
        
        narrows before merging with central canal in the spinal cord
  - - - functions:
        
        protection
        
        provides liquid cushion
        
        protects delicate neural structures from sudden movements
        
        environmental stability
        
        transports nutrients and chemical messengers to brain
        
        removes waste products (to venous circulation)
        
        protects tissue from chemical fluctuations
        
        buoyancy
        
        brain floating reduces apparent weight by 95%
        
        prevents collapse of brain through foramen magnum
    - - Produced by secretion from ependymal cells
        
        Originates from blood plasma
        
        Composition somewhat similar to plasma
      - a specialized tissue in each ventricle that is composed of a layer of ependymal cells and blood capillaries (within pia)
      - CSF circulation
        
        Flows through subarachnoid space
        
        Excess CSF removed from subarachnoid space
        
        flows into arachnoid villi
        
        Then enters subarachnoid space
        
        passes into central canal of spinal cord
        
        fingerlike extensions of arachnoid mater
        
        Circulates through ventricles
        
        from lateral ventricles to third ventricle
        
        through aqueduct into fourth ventricle
        
        project through dura into dural venous sinuses
        
        drains into dural venous sinuses
        
        conduit for one-way flow of excess CSF into blood
        
        Produced by choroid plexus
  - - - Helps prevent neuron exposure to harmful substances, e.g., drugs, blood waste products, and variations in levels of normal substances (e.g., ions, hormones)
    - - Most capillaries in brain wrapped by perivascular feet of astrocytes
      - Tight junctions between adjacent endothelial cells reduce capillary permeability
      - barrier not absolute
        
        Lipid-soluble compounds can diffuse across endothelial plasma membranes e.g., nicotine, alcohol, some anesthetics
        
        Can be damaged by drugs such as cocaine
        
        Missing or reduced in 3 locations:
        
        choroid plexus – needs to be permeable to produce CSF
        
        hypothalamus and pineal gland
        produce hormones requiring access to bloodstream
- - - - reduced blood supply to part of brain
        due to blocked arterial blood vessel or hemorrhage
        
        affects opposite side of body
        
        brief episode called a transient stroke
        
        symptoms include :
        
        headache
        
        dizziness
        
        weakness
        
        walking difficulty
        
        blurred vision
        
        every stroke is different for every person that has one
        
        ex: one person may experience a stroke for a short amount of time and symptoms are mild
        
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        indicates more serious vessel blockage
      - may cause brain tissue death if greater than 10 minutes
- - - - loss of balance and posture
        
        difficult/unable to stand on one foot
      - inability to detect proprioceptive information
        
        inability to close eyes and touch the nose
      - disturbance of gait (manner of walking)
        
        rarely walks in straight line but appears to sway and stagger
- - - - Third ventricle
        
        Fourth ventricle
        
        located between pons and cerebellum communicates with third ventricle through cerebral aqueduct
        
        opens to subarachnoid space
        
        via medial aperture and paired lateral apertures
        
        narrows before merging with central canal in the spinal cord
      - smaller, thinner cavity within diencephalon
        communicate with each lateral ventricle through interventricular foramen
  - - - overlapping and indistinct boundaries
      - some aspects not easily assigned to any single region, e.g., memory
      - Usually difficult to assign precise function to specific region
      - Innervation
        
        hemispheres projecting motor commands to opposite side of body
        
        e.g., right cerebral hemisphere controlling the left side of body
        
        Functional differences between hemispheres termed cerebral lateralization
        
        hemispheres receiving information from opposite side of body
        
        Lobes
        
        Four visible on external surface named for overlying cranial bones
        
        Four visible on external surface named for overlying cranial bones
        
        frontal lobe
        
        forms anterior part of cerebral hemisphere
        
        forms anterior part of cerebral hemisphere
        
        Parietal lobe
        
        forms superoposterior part of cerebral hemisphere
        
        terminates anteriorly at central sulcus, posteriorly at parieto-occipital sulcus,
        and laterally at lateral sulcus
        
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        Temporal lobe
        
        inferior to lateral sulcus
        
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        Occipital lobe
        
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        Specific structural areas with distinct motor and sensory functions
        
        Higher mental functions dispersed over large areas
        
        Three categories of functional areas – motor, sensory, and association areas
        
        Motor Areas
        
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        Association Areas
        
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        Sensory areas
        
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        Central white matter
        
        lies deep to gray matter of cerebral cortex
        
        Composed primarily of myelinated axons grouped into bundles called tracts
        
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        Hemisphere specialization
        
        aka cerebral lateralization
        
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        Categorical hemisphere
        
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- - - - Alcohol increases the level of HDL in the blood it reduces the amount of atherom which narrows our arteries and makes them more likely to clog
  - - - patient probably had a stroke in his Premotor cortex (somatic motor association area) within frontal lobe
        
        responsible for coordinating skilled motor activities