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THE BRAIN
Chapter 7
Major Divisions of the Brain
• 1. Cerebrum
• 2. Diencephalon
• 3. Brain Stem
• 4. Cerebellum
The Cerebrum
• Location: The most superior part of the brain (the
top part). Takes up the most room. Has all the
wrinkles in it.
The Cerebrum
What are all the bumps in it?
Gyrus = bump
Sulcus = shallow groove
Fissures = deep grooves that
separate the lobes of the brain
1. Longitudinal fissure - separates right and left sides
2. Transverse Fissure –
separates cerebrum from cerebellum
3. Lateral Fissure separates the temporal lobe from
the Frontal and Parietal lobes
The Cerebrum
• Functions of the Cerebral Cortex:
– Controls speech, memory, logical and
emotional response, consciousness,
interpretation of sensation, and voluntary
movement
• It is split into 4 major lobes
The Cerebrum
• Lobes of the cerebrum:
– Frontal – reasoning,
thinking, language
– Parietal – touch, pain,
relation of body parts
(somatosensory)
– Temporal Lobe – hearing
– Occipital – vision
The Cerebrum
• Specialized areas of the cerebrum
– Broca’s area- responsible for speech usually located
only in the left side. Damage to this area causes the
inability to say words properly (you know what you
want to say but you can’t vocalize the words)
.
The Cerebrum
• Specialized areas of the cerebrum
– Basal Ganglia- help regulate volunteer motor
activities by stopping or starting movement. It
modifies instructions sent to the skeletal muscles.
– Parkinson’s disease and Huntington’s disease are
disorders of the basal ganglia. (page 253-254)
The Cerebrum
• Specialized areas of the cerebrum
– Corpus Collosum-connects the left and right hemispheres
Take the Left Brain – Right Brain Test
The Diencephalon
• Location: Under the cerebrum, in the middle of
the brain. It sits on top of the brain stem.
Parts of the
Diencephalon
1. Thalamus - relay station for sensory impulses
passing to the sensory cortex for interpretation
Parts of the
Diencephalon
2. Hypothalamus – most important regulatory
center of the autonomic nervous system
-controls temperature, water balance, &
metabolism
- also controls many drives and emotions (thirst,
appetite, sex, pain, and pleasure centers)
Parts of the
Diencephalon
-Pituitary Gland:
The "master gland" of the endocrine system. It
controls hormones. Ex: growth hormone
-Pineal Gland: secretes melatonin (for sleep)
Thalamus
Pineal gland
Hypothalamus
Corpus callosum
THE BRAINSTEM
Location: Bottom of the brain leading to the spinal
cord. Is about 3 inches long and the width of your
thumb.
THE BRAINSTEM
Parts of the Brainstem:
Midbrain- visual reflexes, eye movements
Pons- relay sensory information
Medulla Oblongata- regulates breathing, heart rate,
blood pressure
Medulla
Oblongata
Pons
Midbrain
CEREBELLUM
Location: lower, back of brain. It is under
the occipital lobe.
CEREBELLUM
• Function: Balance and coordination
Protection of the Brain
The Meninges & Cerebral Spinal Fluid
The Meninges
Dura mater – Means “tough
mother”. It is the outermost
layer.
Arachnoid mater - no
blood vessels, in between
layer (resembles a spider
web)
Pia mater -inner membrane,
contains nerves and blood
vessels to nourish cells
Dura mater is being
peeled away in this
photo.
The Meninges
Figure 13.25a
Cerebrospinal Fluid
• Is a watery broth similar to blood plasma, from
which it forms.
• It forms a watery cushion that products the
fragile nervous tissue from blows and other
trama.
Cerebrospinal Fluid (CSF)
Problems
• Meningitis- inflammation to the meninges. It is
a serious threat because the bacteria or virus can
spread to the CNS.
• Encephalitis- is inflammation of the brain
• Hydrocephalus- is water on the brain because a
tumor (or something) is blocking drainage of the
CSF. Treated with a shunt.
• A spinal tap is done to test CSF