Download Brain, Body, and Behavior

Chapter 3
BRAIN, BODY, AND BEHAVIOR
Examining the Brain
 Study the brain in detail because it is the
part of us that controls every thought,
action, and feeling
 The Brain uses 20% of all our oxygen, eats up
most sugar we take in, and is made up of
about 100 billion nerve cells
The Cerebral Cortex
 Outermost layer of the brain
 High level of thinking occurs in this area
 If the cortex were untwisted and spread out it
is about the size of a large bath towel
The Hemispheres
 Halves
 The brain is divided into two halves
 A fissure is what separates the two halves
 Each hemisphere controls the opposite side
of the body
 The corpus callosum helps each half of the
brain communicate with the other half
The Lobes
 The Cerebral Cortex is divided into four
major sections called Lobes
 Frontal Lobe
 Parietal Lobe
 Occipital Lobe
 Temporal Lobe
The Lobes
 Frontal Lobe
 Foremost area
 The motor strip is located in the frontal lobe
 This allows movement of the body
 Parietal Lobe
 Located behind the Frontal Lobe
 Sensory strip is located here
 Allows a person to feel sensations
The Lobes
 Occipital Lobe
 Very back of the brain
 Devoted to making sense out of what we see
 The brain sits in a fluid that acts like a shock
absorber so the brain can move back and forth
 Temporal Lobe
 Bottom of the brain
 Major centers for hearing
The Frontal Lobe
 Prefrontal Area
 Located behind your forehead
 Allows us to re-experience past events
 Frontal Association Area
 Heavily packed with nerve cells
 Phineas Gage
 Railroad worker
 Experienced damage to his frontal association area
and changed drastically
Hemispheres and Handedness
 When dealing with small, fine movements,
such as writing one hemisphere will have
dominance
 The intelligence of right versus left handed
people is about the same
 Myths: If a left handed child is forced to use
their right hand they may become insane
 Parents would sometimes make their children
switch to using their right hands
Tasks of the Cerebral
Hemispheres
 Left Hemisphere handles verbal or speech
material
 The right hemisphere deals with objects in
space, art, music, and some mathematical
reasoning
 Both hemispheres work together in virtually
everything we do
The Lower Brain
 The lower brain is located deep inside the
skull with the cerebral cortex fitting over
and around it
 Cortex means “bark” as on a tree
 Bark protects a tree just like the cortex protects
our lower brain
The Thalamus
 Oval mass of nerve cells
 Relay station to send incoming and outgoing
messages to and from various parts of the
brain
Hypothalamus
 Located below the thalamus (hypo means
“below”)
 Size of a large pea
 Controls rage, pleasure, hunger, thirst, and
sexual desire
The Limbic System
 Contains structures involved in basic
emotions and to some extent memory
 2 Structures are important in the limbic
system
 Amygdala – responsible for emotional responses
especially aggression
 Hippocampus – allows us to form memories
 Memories are not stored in the hippocampus
 If the hippocampus is damaged new memories
cannot be formed
The Cerebellum
 Looks like a ball of yarn a little larger than a
golf ball
 Complex
 Balance, coordination, gets you where you need
to go
 First day of school you followed your
schedule but within a week you no longer had
to “pay attention” - you magically arrived
The Reticular Activating
System (RAS)
 Sits at the base of the brain inside of the
spinal cord
 Reticular means “net” and the RAS catches
nerve impulses
 Regulates alertness and sleepiness
 Sensitive to steady sounds
 Major blow to the head may cause the RAS to
shut down
 Change in rhythm can stir up the RAS
Brain Communication
 All parts of our brain has to communicate
with one another as well as our body
 We need nerve cells that are separate but
able to alternate signals from one circuit to
another
The Neuron
 Each nerve cell is separate from the others
 The body of the neuron has fibers sticking out
from it
 Short fibers are called dendrites
 Look like branches
 Axons carry the message from the cell to other
neurons
 Thousands of terminals that sit opposite a receptor for
another neuron
 Message comes to a receptor on a dendrite, goes
through the cell and then goes out the cell’s axon to
another neuron
The Synapse
 Junction point
 Space is located between the endings of the axon
and the waiting dendrites
 Electricity will not go over spaces
 So what tells our body we are in pain?
Neurotransmitters
 Chemical “messengers” deliver messages to
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across the synapse
Different molecules have different shapes
and make-ups
Acetylcholine regulates your body’s
movement and memory
Dopamine – shortage of this is a main role in
Parkinson’s Disease
Endorphins – made by the body and is a
natural form of morphine
The Central and Peripheral
Nervous Systems
 Central Nervous System
 Brain and Spinal Cord
 All nerve impulses must enter and exit by the
spinal cord
 In an emergency the spinal cord reacts before the
brain does
 The spinal cord has very few synapses to slow
down messages
The Peripheral Nervous
System
 Everything minus the brain and spinal cord
 Somatic Nervous System
 Composed of sensory and motor nerves
 The Autonomic System
 Controls the things we do automatically
 Breathe, digest food, pupil dilating, heart
 Can be overridden by the brain
The Endocrine System
 The Pituitary Gland
 Master gland of the body – bean shaped unit that
is attached and controlled by the hypothalamus
 2 jobs
 Send messages that will start other glands going
 Determine how tall or short we will be
 When things are not working properly incredible
growth can occur
 Poor nutrition can also affect your growth
The Endocrine System
 The Thyroid Gland
 Sits inside the neck
 Controls metabolism
 Overactive Thyroid
 Can result in restlessness, nervousness, and anxiety
 Underactive Thyroid
 Can result in a sad mood, or even depression
The Endocrine System
 Adrenal Glands
 Pump adrenaline into the bloodstream
 Adrenaline prepares us for emergencies
 Even sends out a chemical that will help the blood
clot faster incase we are cut
 Do not have to be in an emergency for the
adrenal glands to start working
 Important tests, talking to a judging audience
Right Brain vs Left Brain
 Which are you the most?
 Do you agree or disagree with the
description?
 Why or why not? Use two examples that
prove or disprove the summaries?