Download Ativity 15

Lab Activity 14
The Brain
Portland Community College
BI 232
Brain Regions
• Cerebrum
• Diencephalon
(thalamus,
hypothalamus, pineal
gland)
• Cerebellum
• Brainstem (midbrain,
pons, medulla
oblongata)
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Cerebrum
• Frontal lobe
• Motor, speech (usually left lobe), personality
• Parietal lobe
• Sensation (except smell), language
• Occipital lobe
• Vision
• Temporal lobe
• Hearing, smell, language
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Cerebral Cortex
• The superficial
layer/rim of gray
matter in the
cerebral
hemispheres
• Gray matter
consists of cell
bodies, dendrites,
and unmyelinated
axons.
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Sulci & Gyri
• Sulci: Shallow depressions of the cerebral
cortex
Sulci
• Central sulcus is between the frontal and parietal
lobes
• Lateral sulcus is between the parietal lobes and
temporal lobes.
• Fissures: Deep grooves
• Longitudinal: separates cerebral hemispheres
• Transverse: separates cerebrum form the
cerebellum
• Gyri: The elevated ridges of the cerebral cortex
• Serve to increase the surface area
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Longitudinal
Fissure
Transverse
fissure
Transverse
Fissure
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Central
Sulcus
Lateral
Sulcus
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Precentral Gyrus:
(frontal lobe)
contains the
primary motor area
Central Sulcus
Postcentral Gyrus:
(parietal lobe)
contains the primary
somatosensory area.
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White Matter & Basal Nuclei
• White matter consists primarily of myelinated axons
• Is beneath the gray matter cortex
• Notice how it is the opposite arrangement from the spinal cord
(Spinal cord: white matter is on the outside and gray matter is
on the inside.)
• Corpus callosum: Connects the right and left hemispheres
• Basal nuclei: Islands of gray matter within the white
matter.
• Function: Involved in the subconscious control of skeletal
muscle tone and the coordination of learned movement
patterns
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White Matter
& Basal Nuclei
White Matter
Basal Nuclei
Corpus
Callosum
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Diencephalon
Structures
• Thalamus
• Hypothalamus
• Epithalamus
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Diencephalon: Epithalamus
• Superior to the third ventricle, contains the
pineal gland
Pineal gland
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Diencephalon: Thalamus
• Relay station for sensory input
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Diencephalon: Hypothalamus
• Pituitary gland: Attaches to the hypothalamus via
the infundibulum
• Mamillary bodies: Process olfactory sensations.
Pituitary gland
(not in this
picture) would
be hanging here
Mamillary
body
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Diencephalon: Hypothalamus
•
Major Functions:
1. Controls somatic motor activities at the
subconscious level
2. Controls autonomic function
3. Coordinates activities of the nervous and endocrine
systems
4. Secretes hormones
5. Produces emotions and behavioral drives
6. Coordinates voluntary and autonomic functions
7. Regulates body temperature
8. Coordinates circadian cycles of activity
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Cerebellum
• Functions:
• Coordination of
movements
• Adjustment of
postural muscles
Arbor Vita (white
matter that looks
like a leaf)
Vermis
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Brainstem
3 Structures:
• Midbrain
Corpora
quadrigemina
(mesencephalon)
• Pons
• Medulla
oblongata
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Midbrain
Pons
Medulla
Corpora
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quadrigemina
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Brainstem: Pons
• Functions:
• Sensory and motor nuclei of Cranial nerves V,
VI, VII, and VIII
• Respiratory control:
• Apneustic center and pneumotaxic center to
modify the activity of the respiratory
rhythmicity center in the medulla
• Nuclei and tracts that process and relay
information to and from the cerebellum
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Brainstem: Midbrain
• Functions:
• Connects pons to cerebellum
• Superior colliculi: visual reflex centers
• Inferior colliculi: auditory reflex centers
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Brain Meninges: Dura Mater
• Continuous with the spinal meninges
• Dura mater: An outer and inner fibrous
connective tissue
• Outer later is fused to the periosteum of the
cranial bones (no epidural space)
• Between the layers are tissue fluids, blood
vessels and venous sinuses.
• Venous sinuses are large collecting veins.
• Venous sinuses drain into the internal jugular
veins
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Dural Folds
• The inner layer of dura mater that extends
into the cranial cavity.
• Provide additional stabilization and support
for the brain
• Contain the dural sinuses
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Dural Folds
• Falx cerebri projects between the cerebral
hemispheres in the longitudinal fissure
• Superior sagittal sinus & inferior sagittal sinus
• Tentorium cerebelli separates the cerebellar
hemisphere from the cerebrum
• Transverse sinus
• Falx cerebelli divides the cerebellar
hemispheres
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Brain Meninges:
Arachnoid & Pia Mater
• Arachnoid mater consists of the arachnoid
membrane and fibers of the arachnoid
trabeculae that attach to the pia mater
• Pia mater: attached to the surface of the
brain, anchored by processes of astrocytes
• Contains branches of cerebral blood vessels that
penetrate the surface of the brain.
• CSF is between these two membranes in the
subarachnoid space
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Ventricles
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Brainstem: Medulla Oblongata
• Functions:
• Center for the coordination of complex
autonomic reflexes (heart rate, respiratory
rhythm, blood pressure)
• Control of visceral functions (vomiting,
swallowing)
• Decussation of pyramids: a crossover point for
the major motor tracts
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Cranial nerves
• 12 pairs of cranial
nerves
• Originate from the
nervous tissue of the
brain
• Some are mixed
nerves while some are
only sensory.
• We will learn more
later
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Sheep Brain Dissection
• Follow instructions in book for the sheep
brain dissection.
• When finished discard brain in the container
provided.
Wash utensils and put back so other classes
can use the materials.
• ID structures on the brain models for next
week’s quiz.
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The End
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