2. THE BRAIN
Three-pound organ of pinkish-gray tissue.
10 billion nerve cells.
Responsible for all mental functions.
Control center for movement, sleep, hunger,
thirst and virtually other vital activity
necessary to survival.
All human emotions, including love, hate,
fear, anger, elation and sadness.
Receives and interprets the countless signals
sent from our body and environment.
3. The Brain Before and at Birth
4th month
• Medulla, Cerebellum, and Cerebrum
• All clearly separated
6th month (middle)
• A dentlike fissure appears on the surface of
the cerebrum
At birth
• Baby‘s brain contain 100 billion neurons
4.
5. Anatomy and Composition of
the Brain
• Refers to all structures lying between the cerebrum
and the spinal cord
• Diencephalon, Midbrain, Pons and Medulla
• Covered by three membranes called Meninges:
• Dura mater – outer one; tough and shiny
• Arachnoid layer – middle; encloses the brain
loosely and does not slip down into brain’s
convolutions, or ridges.
• Pia mater – inner; consists mainly of small blood
vessels that adhere to the surface of the brain.
THE BRAIN STEM
6.
7. THE CEREBRUM
The
largest
part of
the
human
brain.
85% of
the
brain’s
weight.
Cortex
- Large
surface area
- Intricate
development
account for
superior
intelligence.
Corpus
Callosum
- Slab of white
nerve fibers
that connects
the two
cerebral
hemispheres.
Cerebral
Cortex
- Outer layer
of gray matter
- 3 to 4 mm
thick
Five lobes
- Occipital,
frontal,
parietal, and
temporal
lobes.
- Insular lobe,
located
internally, not
visible at the
outside brain.
8.
9. THE CEREBELLUM
- Lies in the
posterior or
hind part of
the cranium,
underneath
the cerebral
hemispheres,
Vermins
- White fibers
that connects
the two
multiridged
hemispheres.
Cerebral peduncles
- Three band of fibers
that connects
cerebellum to the other
parts of the brain.
- Superior (top) –
midbrain
- Middle – pons
- Inferior (bottom) -
medulla
- Essential to
the control
movement of
the body.
- Reflex
center for the
coordination
and precise
maintenance
of
equilibrium.
10. THALAMUS
- Part of
diencephalon
- Consist of two
rounded mass of
gray tissue. (very
middle of the brain)
- Crucial relay station
for incoming sensory
signals and outgoing
motor signals (going
to and from cerebral
cortex)
11. HYPOTHALAMUS
- Lies just below
the thalamus on
the midline base
of the brain.
Vital activities
necessary for
survival
- eating, drinking,
temperature
regulation, sleep,
emotional
behavior, and
sexual activity.
- Appears to act
as biological
timer.
12. Pons
- Located
between
medulla and
midbrain,
directly in
front of
cerebellum.
- Consist
mainly of
transverse
and
longitudinal
white nerve
fibers.
- A transverse
bridge of
fibers arises
from the
peduncle of
the
cerebellum
and join its
two halves.
- An intricate
longitudinal
fiber system
connects the
medulla with
the cerebral
hemispheres.
13. Limbic System
Makes up o
portions of the
thalamus,
hypothalamus,
hippocampsal
formation,
amygdala, caudate
nucleus, septum,
and
mesencephalon.
Linked together in
a unique way by
fiberpaths.
Control
multifaceted
behavior, including
emotional
expression,
seizure activity,
and memory
storage and recall.
14. CEREBRAL CORTEX
Brain’s outer layer
of gray matter
3 to 4 mm. thick
It is composed of
layers of
unmyelinated
(unsheated) cells
which in turn cover
an inner mass of
myelinated (white
sheathed) fibers
called white
matter.
15. • Somatomotor area – in front of central
fissure; responsible for nearly all
voluntary movements of the body
muscles.
• Somatosensory area – behind the central
fissure; receives impulses from the skin
surface as well as from structures
beneath the skin; sensation such as
touch and taste are processed here.
16. • Frontal lobe
– Personality, behavior, emotions
– Judgment, planning, problem solving
– Speech: speaking and writing (Broca’s area)
– Body movement (motor strip)
– Intelligence, concentration, self awareness
• Parietal lobe
– Interprets language, words
– Sense of touch, pain, temperature (sensory strip)
– Interprets signals from vision, hearing, motor, sensory and memory
– Spatial and visual perception
• Occipital lobe
– Interprets vision (color, light, movement)
• Temporal lobe
– Understanding language (Wernicke’s area)
– Memory
– Hearing
– Sequencing and organization
17. • Theories of neuroscientists on cellular
mechanisms by which nerve cells store memories
(Nash, 1998) :
– A change occurs in the ribonucleic acid (RNA) in the
cells of the cortex to code the memory trace in the
brain’s protein material.
– Peptides – (hormonlike substances) in the brain are
activated as an event is being stored as a memory.
– Neurotransmitters (chemicals that relay nerve
impulses between two or more neurons) are altered
as impulses stored.
