Transcript The Nervous System Part II

The Nervous System
Part II

Cerebrum

Largest part of the brain
 CEREBRAL CORTEX –
layer of gray matter that
covers the upper and
lower surfaces of the
cerebrum – most highly
evolved portion of the
brain
 Divided into R and L
hemispheres by a deep
grove called the
longitudinal fissure
Cerebral Cortex


The most recently
evolved animals have a
larger proportion of the
brain taken up by the
cerebral cortex
In the “higher” animals
(especially the higher
mammals), the surface of
the cerebral cortex
becomes folded
Cerebrum (continued)

If the right or left side of your
cerebral cortex was rolled out
flat, it would be the size of an
extra large pizza

CONVOLUTIONS – elevated
folds on the surface of the
cerebrum, they increase the
surface area of the brain.

Sulci – fissures or grooves
separating cerebral
convolutions
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Lobes of the Cerebrum

Frontal Lobe
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Located in front of the
central sulcus
 Motor cortex of frontal
lobe controls skeletal
muscles
 Concerned with:
reasoning
planning
parts of speech
emotions
problem solving
Frontal Lobe (continued)

Responsible for personality

Damage to frontal lobe can cause
changes in personality

Broca’s Speech Area – allows a
person to forms words

Damage to Broca’s Area – person
can still understand language but
cannot produce speech. If can
talk at all – speech will be slow
and slurred
Temporal Lobe

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Located below the lateral
fissure
 Auditory area –
interprets the sounds we
hear
 Olfactory area is located
here – interprets the
odor we smell from our
nose
Temporal Lobe (continued)
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Houses Wernicke’s Area –
ability to understand
language.
Damage to this area can
result in the ability to
understand language –
person can speak clearly, but
the words that are put
together make no sense
In 97% of people, both
Broca’s area and Wernicke’s
area are found only in the left
hemisphere of the brain
Parietal Lobe

Located behind the
central sulcus between
frontal and occipital
lobes
 Sensory center where
impulses from skin such
as pain, pressure, and
temperature are
interpreted
 Area for estimation of
distances, sizes, and
shapes
Occipital Lobe


Located at the back
of the brain behind
the parietal lobe and
the temporal lobe
 Primary visual area
 Trauma can result in
blindness
 Lesions can cause
visual hallucinations
Diencephalon

Located between
cerebrum and
midbrain
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Composed of
THALAMUS AND
HYPOTHALAMUS
Thalamus
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Thalamus acts as a relay
station for incoming and
outgoing nerve impulses
All sensory imput expect
olfactory (smell) is routed
to the thalamus for
processing and then
transmitted to the
cerebral cortex for
interpretation
Damage to the thalamus
may result in increased
sensitivity to pain, or total
loss of consciousness

Nine Vital Functions of the
Hypothalamus

1. Autonomic nervous
control
 2. Cardiovascular control
 3. Temperature control
 4.Appetite control
 5. Water balance
 6. Manufacture of oxytocin
 7. Gastrointestinal control
 8. Emotional state
 9. Sleep control
Cerebellum

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Located behind the pons and
below the cerebrum

Composed of two
hemispheres
Controls all body functions
related to skeletal muscles,
including:
1. Balance
2. Muscle Tone
3. Coordination of muscle
movements
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Brain Stem

Made up of PONS,
MEDULLA, and
MIDBRAIN

Pathway for ascending
and descending tracts

Sensory fibers conduct
impulses up from the cord
to other parts of the brain
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Motor fibers conduct
impulses down from the
brain to the spinal cord
Pons

Located above the
medulla. Located
below the midbrain in
the brain stem
 “Pons” means bridge
and the pons is the
bridge between the
cerebrum and the
cerebellum
 Consists of white
matter with scattered
bits of gray matter
Pons

Responsible for
conduction messages
to other parts of the
brain and for certain
reflex actions
including:
chewing
tasting
production of saliva
Midbrain

Superior to the pons
and the smallest
region of the
brainstem
 Two-way conduction
pathway ; relay for
visual and auditory
impulses
Medulla Oblongata
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Bulb-shaped structure
between pons and spinal
cord, inside the cranium
above foramen magnum
Responsible for
1. Heart rate
2. Rate and depth of
respiration
3. Blood pressure
4. Swallowing and
vomiting
Spinal Cord
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Begins at foramen
magnum and continues
down to 2nd lumbar
vertebrae
White and soft in spinal
canal
Surrounded by
cerebrospinal fluid
Spinal Cord

Functions as:
1. Refelex center
2. 2. Conduction
pathway to and
from the brain
The End