Transcript Cerebrum

Cerebrum
Chapter 12 and 13 p. 430
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Cerebrum – surrounded by a thin layer
of gray matter called cerebral cortex
(rind or bark)
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Consists of six layers of nerve cell bodies
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Beneath the cortex lies cerebral white matter
Embryonic Development of the
brain
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During development, the gray matter
of the cerebral cortex increases faster
than the underlying white matter
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Folds upon itself – Gyri pl.(gyrus =sing.)
Deep folds are fissures with the grooves
called sulci pl. (sulcus=sing.)
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Longitudinal Fissure = separates the
cerebrum into 2 hemispheres
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Development of the brain
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Corpus callosum - connects the two
hemispheres
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Composed of bundles of transverse
fibers made of white matter
Larger in females than males
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Males only have emotional capacities in just
one hemisphere (right side)
Female has emotional capacities in both
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Info flow in males is slower between the emo right
side and the verbal left side of the male brain
Agenesis of the corpus callosum
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AGCC – Born without a corpus
callosum
Lobes
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4 lobes – frontal, parietal, temporal,
occipital
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Central sulcus – divides frontal and
parietal lobes
Precentral gyrus – anterior to central
sulcus. Controls primary motor area of
cerebral cortex
Postcentral gyrus – posterior to central
sulcus. Contains somatosensory area.
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The brain of a genius – Discovery
Channel
Limbic System
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Portions of the cerebral hemisphere and
diencephalon
Wishbone shaped group of structures
surrounding the brainstem, functions in
emotions such as
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Pain, pleasure, anger, rage, fear, sorrow sexual
feelings, affection
Controls involuntary aspects of emotion such as
survival and also functions in memory
The limbic system of the brain is a group of structures which govern emotions and
behavior. The limbic system, and in particular the hippocampus and amygdala, is
involved in the formation of long-term memory, and is closely associated with the
olfactory structures (having to do with the sense of smell).
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Memory and stress
Functional Areas of the
Cerebral Cortex
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3 Areas –
Motor – muscular movement
Sensory – receiving and interpreting
sensory impulses
Association – memory, emotions,
reasoning, will, judgment, personality
and intelligence
Sensory
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Sensory input into the cerebral cortex
flows mainly to the posterior half of the
cerebral hemispheres
1. Primary somatosensory – receives
sensations from cutaneous (skin) and
muscular receptors
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Function – localize exactly the points of
the body where the sensations originate
Sensory
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2. Primary Visual – occipital lobe,
receives sensory impulses from the
eyes and interprets shape, color, and
movement
3. Primary auditory – temporal lobe,
interprets basic characteristics of
sound such as pitch and rhythm
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Article – Discovery News
Sensory
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4. Primary Gustatory area – base of
postcentral gyrus, interprets
sensations related to taste
5. Primary olfactory – temporal lobe,
interprets sensations related to smell
Motor Areas
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Motor cortex are found in both
hemispheres
1. Primary motor area – in precentral
gyrus of frontal, consists of regions
that control muscle groups
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Stimulation of a specific point results in a
muscle contraction
Motor Area
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2. Motor speech area – broca’s area, frontal
lobe (left) superior to the lateral cerebral
sulcus
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Damage to this area can result in –
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Aphasia – inability to speak
Agraphia – inability to write
Word deafness – inability to understand spoken words
Word blindness – inability to understand written words
Association Areas
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Association tracts that connect motor
and sensory areas and large parts of
the occipital, parietal, and temporal
lobes anterior to motor areas
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1. Somatosensory association area –
posterior to primary somatosenory
area
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Determine shape and texture of an object
without looking at it, sense relationship of
one body part to another, and orientation
of one object to another as they are felt
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2. Visual association area – occipital
lobe
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Relates present to past visual
experiences with recognition and eval of
what is seen
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3. Auditory association area – below
primary auditory area in temporal
cortex
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Determines if sound is speech, music,
noise
Translates words into thoughts
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4. Gnostic – integrates sensory
interpretations from the association
areas and impulses from other areas
so that a common thought can be
formed from various sensory inputs
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5. Premotor Area – in front of the
primary motor area
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Deals with learned motor activities of
complex and sequential nature
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Ex: specific muscles contract in order to
write a word
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6.Frontal eye field area – frontal cortex
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Controls voluntary scanning movements
of the eyes
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Searching for a word in a dictionary
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7. Language areas – broca’s area
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Nerve impulses pass to premotor regions
that control the muscles of the larynx,
pharnyx, and mouth
Impulses reach your breathing muscles
to regulate the proper flow of air past the
vocal cords
Memory
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Short term and long term
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Associated with association cortex of the
frontal, parietal, occipital, and temporal
lobes; part of the limbic system; and the
diencephalon
Dori
Cerebellum
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Second largest portion of the brain
Behind the medulla and pons and
below the occipital lobes of the
cerebrum
Cerebellum
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Compares the intended movement
programmed by motor areas in the
cerebrum with what is actually
occurring.
Helps to smooth and coordinate
skeletal muscle contractions
Main region that regulates posture,
balance and skills for motor activities
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Video