BHSC MOD 2 Brain

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BHSC MOD 2 Brain
2012-01-25 22:42:47
BHSC MOD brain

BHSC MOD 2 brain
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  1. What is contained in the ventricles of the brain?
  2. What are the 4 regions of the Brain?
    1.Cerebral hemispheres (cerebrum)



  3. Growth of the cerebral hemispheres
    •As the brain grows the outer gray matter of the brain grows at a faster rate than the inner white matter

    •The surface becomes covered with ridges (gyri;sing. gyrus) and grooves (sulci;sing.sulcus) caused by its greater rate of growth

    •The constricted space within the skull also cause the brain and the brainstem to begin folding in on themselves
  4. Cerebrum
    •Cerebral Hemispheres (Cerebrum)

    •Paired (left and right) superior parts ofthe brain

    •Right side of brain controls left side of body while left side of brain controls right side of body
  5. Lobes of the cerebrum
    Fissures (deep grooves) divide the cerebrum into lobes

    • Surface lobes of the cerebrum
    • 1.Frontal lobe
    • 2.Parietal lobe
    • 3.Occipital lobe
    • 4.Temporal lobe

    • •Deep lobe of the cerebrum
    • 5. The insula (inside temporal lobe)
  6. Which lobes does the lateral sulcus divide?
    Temporal and Parietal
  7. Layers of the cerebrum
    • Gray matter
    • •outerlayer in the cerebral cortex composed mostly of neuron cell bodies

    • White matter
    • •fiber tracts deep to the gray matter
    • (Eg Corpus callosum connects hemispheres)

    • Basal nuclei
    • •islands of gray matter buried within the white matter
  8. The Cerebral Cortex
    • •Outterlayer of the brain, is called gray matter
    • •40% of brain mass
    • •2-4mm thick
    • •Conscious mind found here
    • •Awareness, sensations
    • •Enables us to communicate, remember and understand
    • •Initiates voluntary movement
  9. Neural Structures of the Cerebral Cortex
    • •Neural cell bodies
    • •Dendrites
    • •Glial cells
    • •Blood vessels
    • •NO FIBRE TRACTS (in gray matter)
    • •There are only white matter fibre tracts
  10. Functional regions of the cerebral cortex
    • There are 3 functional areas
    • •Sensory (post central gyrus)
    • •Motor (pre central gyrus)
    • •Association (interneuron equivalent) eg. corpus callosum
  11. Specialized areas of the Cerebral cortex
    • Primary somatic sensory area
    • •Receives impulses from the body’s sensory receptors
    • •Located in parietal lobe
    • •Posterior to the central sulcus

    • Primary motor area
    • •Sends impulses to skeletal muscles
    • •Located in frontal lobe
    • •Anterior to the central sulcus

    • Association areas
    • •Regions that are not primary motoror primary sensory areas
    • •Widespread throughout the cerebral cortex
    • •Analyze and interpret sensory experiences
    • •Provide memory, reasoning,verbalization, judgement, emotions, goes out via motor
    • (smell, taste, touch, hearing)
  12. Cerebral areas involved in special senses
    • 1.Gustatory area (taste)
    • •base of the post central gyrus(part of insula)

    • 2.Visual area
    • •Occipital lobe

    • 3.Auditory area
    • •Temporal lobe

    • 4.Olfactory area (smell)
    • •Temporal lobe
  13. Interpretation areas of the cerebrum
    • Speech/language region
    • Broca’s area (motor above temporal)
    • •Anterior to primary motor cortex
    • •Usually in the left hemisphere
    • •Controls muscles needed for speech
    • •Generates motor signals for larynx,tongue, cheeks and lips

    • Language comprehension region
    • Wernicke area (sensory part of temporal and parietal)
    • •Permits recognition of spoken andwritten language and creates plan of speech
  14. Association Areas of the Cerebral Cortex
    • 1.Frontal Lobe Association Areas (labotomy region)
    • •Concentrating
    • •Planning
    • •Complex problem solving

    • 2.Parietal Lobe Association Areas
    • •Understanding speech
    • •Choosingwords to express thought

    • 3.Temporal Lobe Association Areas
    • •Interpret complex sensory experiences
    • •Store memories of visual scenes, music and complex patterns

    • 4.Occipital Lobe Association Areas
    • •Analyze and combine visual images with other sensory experiences
  15. Pre-motor Area
    •Made up of the remainder of the pre central gyrus together with adjacent portion of the superior and middle frontal gyri

    •Functionally related to the initiation of voluntary contralateral movements

    •Controls learned motor skills of a repetitious or patterned nature such as playing a musical instrument or typing on a keyboard

    •Co-ordinates the movement of several muscle groups either simultaneously or sequentially

    • •Mostly done by sending activating
    • impulses to the primary motor cortex

    • •More like a memory bank of skilled
    • motor movements

    •Involved in planning movements
  16. Cerebral Lateralization
    • Left Hemispherecategorical hemisphere
    • (dominant in most people)
    • •Specialized for spoken and written language, sequential and analytical reasoning (math andscience) and analyzing data in a linear way

    • Right Hemisphererepresentational hemisphere
    • •Perceives information more holistically
    • •Perceptionof relationships
    • •Pattern
    • •Comparison of special senses
    • •Imagination and insight
    • •Music and artistic skill
  17. Organization of the White Matter of the Brain
    • -Association tracts
    • -Commissural tracts
    • -Projection tracts
  18. Cerebral White Matter
    • •Made up of glia and myelinated nerve fibres
    • carrying signals from one region to another within the brain

    •The white matter within the cerebrum consists of a complex mass of intermingling nerve fibres, most of them myelinated, running in all directions

    •Fibres travel in bundles called tracts
  19. Association Tracts
    • •Confined to the same hemisphere
    • •Gyrus to gyrus and lobe to lobe in the same hemisphere

    I.Short association fibres connect cortical areas in adjacent gyri

    II.Long association fibres pass between cortical areas that are further removed from each other
  20. Commissural tracts
    •Originate from cell bodies in the cortex of one hemisphere, cross the midline and synapse with neurons in corresponding areas of cortex of the other hemisphere

    •Thelargest bundle of commissural fibres is the corpus callosum

    •The anterior commissure and posterior commissure connect the temporal lobes
  21. Projection Tracts
    •Project to and from the cortex

    •They enter the cerebral hemispheres from lower brain or spinal cord centres or

    •leave the cortex of the cerebrum to travel to lower areas including the spinal cord

    •They tie the cortex to the rest of the nervous system and to the body’s receptors and effectors

    •These tracts run vertically

    •The internal capsule forms aprojection tract called the pyramidal tract that descends into the spinal cord
  22. Basal Ganglia (Nuclei)
    • •Gray matter nuclei within the white matter
    • •Clusters of gray matter deep within the white matter of the brain

    • Thereare 3 basal nuclei:
    • 1.The caudate nucleus
    • 2.The putamen
    • 3.The globus pallidus
  23. Important Roles of Basal Ganglia (Nuclei)
    • •Play an important role in initiating and terminating movements
    • •Inhibit antagonistic movements
    • •Inhibit unnecessary movements
    • •Controlof subconscious contraction of skeletal muscles
    • Damage to basal ganglia can cause uncontrollable shaking as in Parkinson’s disease
  24. Basal Ganglia (Nuclei) and Injury
    •If the motor cerebral cortex of one cerebral hemisphere is destroyed, the injury will prevent fine discrete movements of the hands and feet on the opposite side of the body but crude movements of the opposite limbs will still occur

    •If the basal ganglia are also destroyed then paralysis of the remaining movements of the opposite side of the body will occur
  25. Diencephalon
    • •Sits on top of the brain stem
    • •Enclosed by the cerebral hemispheres

    • Made of three parts
    • 1.Thalamus
    • 2.Hypothalamus
    • 3.Epithalamus
  26. Thalamus
    • •Surrounds the third ventricle
    • •The relay station for sensory impulses
    • •All sensory input except olfaction(smell) enters the thalamus, hits mmillary body first
    • •Transfers impulses to the correct part ofthe cortex for localization and interpretation
  27. Hypothalamus
    • •Under the thalamus
    • •Important autonomic nervous system center
    • •Helps regulate body temperature
    • •Controls water balance
    • •Regulates metabolism
    • •Houses the limbic center for emotions
    • •Regulates the nearby pituitary gland
    • •Pituitary hangs from the anterior floor of the hypothalamus by a slender pituitary stalk
    • Produces two hormones of its own
    • •Antidiuretic hormone (causes water retention)
    • •Oxytocin (causes uterus to dilate)
  28. Epithalamus
    • •Forms the roof of the third ventricle
    • •Houses the pineal body (an endocrinegland)
    • •Includes the choroid plexus responsiblefor formation of cerebrospinal fluid (a collection of ependymel cells)
  29. The mamillary bodies
    • •These structures are found bulging from the floor of the hypothalamus, posterior to the pituitary gland
    • •Reflex centres in olfaction (smell)
  30. Regions of the Brain Stem
    •Attaches to the spinal cord, cranial nerves 3-12 come from brain stem

    Parts of the brain stem



    3.Medulla oblongata
  31. Midbrain
    • •Mostly composed of tracts of nerve fibers
    • •Has two bulging fiber tracts
    • •cerebral peduncles
    • •Has four rounded protrusions
    • •corpora quadrigemina
    • •Reflex centers for vision and hearing
  32. Pons
    • •The bulging center part of the brain stem
    • •Mostly composed of fiber tracts
    • •Includes nuclei involved in the controlof breathing
    • -comminucates between 2 cerenellar lobes
    • -controls respiratory rate and depth
  33. Medulla Oblongata
    • •The lowest part of the brain stem
    • •Merges into the spinal cord
    • •Includes important fiber tracts

    • Contains important control centers
    • 1.Heartrate control
    • 2.Bloodpressure regulation
    • 3.Breathing
    • 4.Swallowing
    • 5.Vomiting
  34. Reticular Formation and RAS
    • Formation
    • •Diffuse mass of gray matter along the brain stem
    • •Involved in motor control of visceral organs •Vasomotor
    • •Cardiac
    • •Respiratory centers

    • Reticular activating system (RAS)
    • •plays arole in awake/sleep cycles and consciousness
    • •Sends impulses to the cerebral cortex to keep it conscious and alert
    • •Causes a sleeping person to awaken
    • •Severe injury results in permanent unconsciousness (coma) Filtersout repetitive and weak stimuli (~99% of all stimuli!)
  35. Structure of Cerebellum
    • •2 hemispheres joined in the midline
    • •Convoluted surface of cortex
    • •Pleat-like gyri called folia
    • •Inner white matter
    • •Distinctive pattern called Arbor Vitae (receives info from joints and muscles)

    • Fissures divide it into lobes
    • 1.Anterior
    • 2.Posterior
    • 3.Floculonodular
  36. Cerebellum
    • •Provides involuntary coordination of body movements
    • •Cerebellum sorts info, evaluates and calculates the best way to co-ordinate movements
    • •Proprioceptors throughout the body
    • •Info to cerebellum regarding muscle and tendon position and joint position
    • •Visual and equilibrium info also sent to cerebellum
  37. Cerebellar Injury
    • •Cerebellar injury means loss of muscle tone and clumsy movements
    • •Called ataxia
    • •Deficits also include decreased sensory, linguistic, emotional and cognitive functions, ability to recognize.