The Human Brain
Basic Brain Structure
• Composed of 100 billion cells
• Makes up 2% of bodies weight
• Contains 15% of bodies blood
supply
• Uses 20% of bodies oxygen and
glucose
Brain Protection
• Surrounded by the cranium
• Surrounded by protective
membranes called meninges
• Fluid within the spaces of the
meninges called, cerebral spinal
fluid (CSF)
Major Parts of The Brain
Medulla Oblongata
• Attached to the spinal cord at
the base of the brain
• Contains reflex centers for
vomiting, hiccupping,
coughing, and swallowing.
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Contains control centers for:
Heart rate
Force of heart contractions
Blood pressure
Breathing rate
Cerebellum
• The cerebellum processes input
from other areas of the brain,
spinal cord and sensory
receptors to provide precise
timing for coordinated, smooth
movements of the skeletal
muscular system.
Thalamus
• The sensory relay center of the
brain.
• Receives sensory information
from parts of the body and
directs these messages to the
appropriate parts of the brain
Hypothalamus
• Main control center for the
autonomic nervous system.
• Also controls feelings of hunger,
body temperature, aggression, sex
drive, thirst, circadian rhythms,
fear, control of sex hormones
• Secretes hormones that control the
pituitary gland
Midbrain
• Important visual and auditory
functions
• Controls eye movements
• Important functions dealing
with movement.
Pons
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Functions include:
Arousal
Sleep
Level of consciousness
Assist in control of autonomic
functions.
Limbic System
• The limbic system
encompasses structures that are
critical for forming memories
and experiencing pleasure, as
well as for various motivational
and emotional activities.
The Cerebrum
• Largest part of the Human
Brain
• This part of the Brain has
many convolutions that give
it a very large surface area.
Functions of the Cerebrum:
• All information from our
senses are sorted and
interpreted in this part of the
brain
• Voluntary muscles that
control movement and
speech are contained in the
cerebrum
• Memories are stored in the
cerebrum
• The cerebrum is the decision
making part of the brain.
• The cerebrum is thought to be
the center of human
consciousness
Regions of the
Cerebrum
Cerebral Cortex – The outer
lining of the cerebrum
• The cerebral cortex has
several important functions
1. Experience of sensation
2. Voluntary movement
3. All thought processes
associated with
consciousness
Cerebral Hemispheres
• The cerbral cortex is organized
into two halves called
hemispheres, the right and the
left.
• A structure called the corpus
callosum bridges the right and
left hemispheres (250 million
nerve fibers)
Corpus Callosum
Right vs. Left
Hemisphere
• Voluntary muscles on one
side of the body are
controlled by nerves in the
opposite hemisphere of the
brain.
• The same generally holds
true for sensory information.
For example things seen in the
left eye are processed on the
right side of the brain.
Hemispheric
Dominance
• Close to 90% of the
population is right handed.
• Most of us also show
dominance with respect to
our legs, eyes, and ears.
• Each hemisphere of the brain
is also dominant for other
behaviors :
Left Hemisphere
• Language
• Math
• Logic
Right Hemipshere
• Spatial abilities
• Face Recognition
• Visual imagery
• Music
• These are merely
generalizations as both sides
of the brain work together to
perform most functions
Lobes of the Cerebral
Cortex
• The cortex of the Cerebrum is
divided into Four Lobes:
1. Frontal Lobe
2. Parietal Lobe
3. Temporal Lobe
4. Occipital Lobe
Frontal Lobe
• Control of voluntary muscles
• Reasoning
• Critically thinking
Parietal Lobe
• Receives sensory information
from from skin and skeletal
muscles
• Associated with sense of
taste
Temporal Lobe
• Perception and recognition of
auditory stimuli
• Memory
Occipital Lobe
• Concerned with many
aspects of vision.