Memmler’s
The Human Body in Health and Disease
11th edition
Chapter 10
The Nervous System: The
Brain and Cranial Nerves
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The Brain
•Cerebrum
–
Cerebral hemispheres
–
Longitudinal fissure
–
Lobes
•Diencephalon
–
Thalamus
–
Hypothalamus
•Brain stem
–
Midbrain
–
Pons
–
Medulla oblongata
•Cerebellum
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Brain, sagittal section. Main
divisions are shown.
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External
surface of
the brain,
superior
view.
The division
into two
hemispheres
and into
lobes is
visible.
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Checkpoint 10-1: What are the main divisions of the
brain?
Question:
True or False?: The pons is a part of the brainstem.
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Answer:
True: The pons is one of three parts of the
brainstem
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Protective Structures of the
Brain and Spinal Cord
•Meninges
– Dura mater
• Dural sinuses
– Arachnoid
– Pia mater
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Frontal (coronal)
section of the top
of the head. The
meninges and
related parts are
shown.
• What is located in
the spaces where
the dura mater
divides into two
layers?
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Checkpoint 10-2: The meninges are protective
membranes around the brain and spinal cord. What are the
names of the three layers of the meninges from the
outermost to the innermost?
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Cerebrospinal Fluid
•Supports nervous tissue, cushions from shock
•Carries nutrients to cells
•Transports waste products from cells
•Produced in ventricles
– Choroid plexus
– Lateral ventricles
– Foramina
– Cerebral aqueduct
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Flow of cerebrospinal
fluid (CSF). Black arrows
show the flow of CSF
from the choroid
plexuses and back to the
blood in dural sinuses;
white arrows show the
flow of blood. (The actual
passageways through
which the CSF flows are
narrower than those
shown here, which have
been enlarged for
visibility.)
ZOOMING IN
• Which ventricle is
continuous with the central
canal of the spinal cord?
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Checkpoint 10-3: In addition to the meninges, CSF helps
to support and protect the brain and spinal cord. Where is
CSF produced?
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Ventricles of the brain.
Three views are shown.
• Which are the largest
ventricles?
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The Cerebral Hemispheres
•Lobes
–
Frontal
–
Parietal
–
Temporal
–
Occipital
–
Insula (within the hemisphere)
•Cerebral cortex
–
Gyri
–
Sulci
• Central sulcus
• Lateral sulcus
•Basal nuclei (basal ganglia)
•Corpus callosum
•Internal capsule
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External
surface of the
brain, lateral
view. The lobes
and surface
features of the
cerebrum are
visible.
• What structure
separates the
frontal from the
parietal lobe?
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Question:
The cerebral cortex is an arrangement of
elevated portions of tissue separated by
shallow grooves. What is the name for the
elevated portions?
a. sulci
b. gyri
c. villi
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Answer:
b. gyri
Checkpoint 10-4: What are the four
surface lobes of each cerebral
hemisphere?
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Functions of the Cerebral Cortex
•Frontal lobe
–
Motor area
–
Speech centers
•Parietal lobe
–
Sensory area
–
Estimation of distances, sizes, shapes
•Temporal lobe
–
Auditory area
–
Olfactory area
•Occipital lobe
–
Visual receiving area
–
Visual association area
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Functional areas
of the cerebral
cortex.
• What cortical
area is posterior
to the central
sulcus? What area
is anterior to the
central sulcus?
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Checkpoint 10-5: Higher functions of the brain occur in a
thin layer of gray matter on the surface of the cerebral
hemispheres. What is the name of this outer layer of gray
matter?
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Communication Areas
•Auditory areas
– Auditory receiving
– Auditory association
– Speech comprehension (Wernicke area)
•Motor areas
– Motor speech (Broca area)
– Written speech center
•Visual areas
– Visual language images receiving
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Memory and the Learning Process
•Short-term memory
– Information lost unless reinforced
•Long-term memory
– Rehearsal (repetition)
– Alertness
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The Diencephalon
•Thalamus
– Sorts sensory impulses
– Directs impulses within cerebral cortex
•Hypothalamus
– Maintains homeostasis
– Controls sympathetic and parasympathetic divisions
of autonomic nervous system
– Influences heartbeat, blood flow, hormone secretion
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Regions of the diencephalon. The figure shows the relationship among the
thalamus, hypothalamus, and pituitary gland (hypophysis).
ZOOMING IN • To what part of the brain is the pituitary gland attached?
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Checkpoint 10-6: What are the two main portions of the
diencephalon and what do they do?
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The Limbic System
•Between cerebrum and diencephalon
•Involved in emotional states, behavior
•Involved in learning, long-term memory
•Stimulates the reticular formation
•Links functions of cerebral cortex and brain stem
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The Brain Stem
•Connects cerebrum and diencephalon with the spinal cord
•Composed of midbrain, pons, and medulla oblongata
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The Midbrain
•Superior part of brain stem
•Four masses form superior part of midbrain
•Reflexes involving eyes and ears
•Conducts impulses between higher centers of cerebrum
and lower centers of pons, medulla, cerebellum, spinal cord
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The Pons
•Connecting link between cerebellum and rest of nervous
system
•Some reflexes involving respiration
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The Medulla Oblongata
•Respiratory center
•Cardiac center
•Vasomotor center
•Contralateral (opposite side) control
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Checkpoint 10-7: What are the three subdivisions of the
brain stem?
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The Cerebellum
•Three parts
– Vermis
– Left hemisphere
– Right hemisphere
•Functions
– Help coordinate voluntary muscles
– Help maintain balance
– Help maintain muscle tone
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Question:
What portion of the brainstem houses the
respiratory, cardiac, and vasomotor
centers?
a. medulla oblongata
b. midbrain
c. pons
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Answer:
a. medulla oblongata
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The cerebellum.
(A) Posterior view
showing the two
hemispheres.
(B) Midsagittal
section showing
the distribution of
gray and white
matter.
The three parts of
the brain stem
(midbrain, pons,
and medulla
oblongata) are
also labeled.
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Checkpoint 10-8: What are some functions of the
cerebellum?
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Brain Studies
Imaging techniques to study the brain without surgery
•Computed tomography (CT) scan
•Magnetic resonance imaging (MRI)
•Positron emission tomography (PET)
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Electroencephalograph
•Record electric currents given off by brain nerve cells
•Study sleep patterns
•Diagnose disease
•Locate tumors
•Study drug effects
•Determine brain death
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Question:
Which brain imaging study shows images
of the brain “in action”?
a. CT scan
b. MRI
c. PET scan
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Answer:
c. PET scan
Bonus Question:
What does PET stand for?
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Answer:
Positron emission tomography
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Disorders of the Brain and
Associated Structures
•Meningitis
–
Inflammation of brain and spinal cord coverings
–
Bacterial causes
–
Viral causes
•Encephalitis
–
Inflammation of the brain
–
Viral causes
–
Toxic substances causes
–
Viral vaccine causes
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Hydrocephalus
•Abnormal CSF accumulation within brain
•Causes
– Congenital malformation
– Tumor
– Inflammation
– Hemorrhage
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Stroke and Other Brain Disorders
•Stroke
– Most common brain disorder
•Cerebral palsy
•Epilepsy
•Brain tumor
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Checkpoint 10-9: What is the common term for
cerebrovascular accident (CVA)?
Checkpoint 10-10: What type of cells are commonly
involved in brain tumors?
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Injury
Head trauma can lead to injury within skull
•Epidural hematoma
•Subdural hematoma
•Intracerebral hematoma
•Cerebral concussion
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Degenerative Diseases
•Alzheimer disease
•Multi-infarct dementia
•Parkinson disease
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Cranial Nerves
•12 pairs
•Four categories
– Special sensory impulses
– General sensory impulses
– Somatic motor impulses
– Visceral motor impulses
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Cranial nerves.
The 12 pairs of
cranial nerves
are seen from the
base of the brain.
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Names and Functions of the Cranial
Nerves
•I Olfactory
•II Optic
•III Oculomotor
Your homework tonight is to
develop your own, ‘tasteful’ saying
that will help you remember the 12
Cranial nerves.
•IV Trochlear
•V Trigeminal
•VI Abducens
•VII Facial
•VIII Vestibulocochlear
•IX Glossopharyngeal
•X Vagus
•XI Accessory
•XII Hypoglossal
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Checkpoint 10-11: How many pairs of cranial nerves are
there?
Checkpoint 10-12: The cranial nerves are classified as
being sensory, motor, or mixed. What is a mixed nerve?
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Question:
This cranial nerve is the large
sensory nerve of the head and
consists of three smaller branches.
What nerve is it?
a. trochlear nerve
b. trigeminal nerve
c. abducens nerve
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Answer:
b. trigeminal nerve
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Disorders Involving the Cranial Nerves
•Destruction of optic fibers
•Damage to hearing nerves
•Paralysis of muscles
•Bell palsy
•Neuralgia
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Aging of the Nervous System
•Decreased brain size and weight
•Decreased speed of information processing
•Slowed movements
•Diminished memory
•Reduced blood flow to brain
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QUESTIONS?
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