Anatomy of the Brain

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Transcript Anatomy of the Brain

Anatomy of the Brain
• Size: ~ 3 pounds (~size of 2 fists)
• Appearance: pinkish gray & wrinkled
with a texture of cold oatmeal
• # of Neurons: ~100 billion
Miscellaneous Facts
• Brain = organ
• Mind = abstract mental activity
• Most of what we know of brain & mind
learned through animal experiments
and studying people with disease or
head trauma
• The brain has no pain receptors
Basic Definitions
• Ventricles - cavities in the brain that contain
• Gyri (“twisters”) - elevated ridges of
brain tissue
• Sulci (“furrows”) - shallow grooves in
brain tissue
• Fissures - deep grooves that separate large
regions of the brain
Basic Definitions (cont.)
• Center - group of functionally related neurons
that may or may not be closely grouped
• Tract - a bundle of axons in the CNS that have
the same origin & function
• Basal nuclei - “islands” of gray matter located
deep within the white matter of the cerebral
hemispheres; help regulate voluntary motor
4 Major Parts of the Brain
• There are 4 major parts: cerebrum,
diencephalon (interbrain), brainstem, &
Parts of the Brain
1. Cerebrum - largest part of brain ~2
a. Consists of right & left
hemispheres, separated by a
longitudinal fissure
Parts of the Brain
1. Cerebrum - largest part of brain ~2
b. Contains the corpus callosum:
a large fiber tract that connects
the right & left hemisphere
(Split-brain experiments)
Video Clip
• Split Brain
Parts of the Brain
c. Lobes of each cerebral hemisphere
1. Frontal - speech, voluntary
movement, & personality
Video Clip
Phineas Gage
Parts of the Brain
c. Lobes of each cerebral hemisphere
2. Parietal - interprets sensory
functions such as touch (hot,
cold, pain, pressure, &
position of other body parts)
Parts of the Brain
Lobes of each cerebral hemisphere
3. Occipital - interpretation of vision
4. Temporal - interpretation of hearing,
smell, & taste
Parts of the Brain
d. Cerebral cortex:
- layer of gray matter that covers the
cerebrum - highly wrinkled to increase
surface area
-main area of judgment, intelligence,
creativity, memory, learning, & reasoning
(Contains Broca’s area & Wernicke’s area important speech centers)
Parts of the Brain
2. Diencephalon (Interbrain) - enclosed by
the cerebral hemispheres and sits on top
of the brain stem
a. Thalamus - relay station for sensory
impulses (recognize
whether a sensation
being passed along is
pleasant or unpleasant)
Parts of the Brain
b. Hypothalamus (“under the thalamus”)
-responsible for autonomic/visceral
control such as regulating body
temperature, water balance, &
-Limbic system “emotional-visceral
brain”: controls hunger, thirst, sex,
pain, & pleasure centers
-Also allows for physical expression of
-Regulates the pituitary gland
Parts of the Brain
c. Epithalamus - contains the pineal
body (part of endocrine
system) and a choroid
plexus (helps form
Parts of the Brain
Brainstem - ~3 inches long & thumb size
in diameter
a. Midbrain - contains visual & auditory centers
& nerve pathway crossing
b. Pons (“bridge”) - responsible for
autonomic functions
such as respiration,
jaw movement, &
facial senses
Parts of the Brain
c. Medulla oblongata - enlarged continuation of
spinal cord; respiratory & cardiac
control; autonomic reflexes such
as sneezing, coughing, blinking,
swallowing, & vomiting
*Reticular Activating System (RAS) - sleep/wake
Lack of dreams = heading for severe psychological
Lack of sleep = may result in insanity &/or death
Parts of the Brain
4. Cerebellum - 2nd largest part of brain;
cauliflower-like structure
-is also divided into right & left
-controls balance, posture, muscle
tone, & coordination of movement
Parts of the Brain
*Ataxia - damage to cerebellum (blow
to head, tumor, stroke);
movements are clumsy &
disorganized; victims appear
drunk due to loss of muscle
coordination; cannot touch
finger to nose with eyes
Review Song
• Parts of the Brain Song