Transcript Unit 2 PowerPoint - San Diego Unified School District

AP Psychology
Unit 2
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Biological Basis of Behavior
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It all starts with the brain. The Human brain is
an extremely complex network nerve cells,
neurons, lobes, ridges and electric pulses.
To understand behavior, we must first look at
the brain, and how it operates.
The Brain
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Neurons are individual nerve cells that carry
and process information. The brain is literally
made up of BILLIONS of neurons.
Neurons link together to form chains and carry
information throughout the brain.
Think of neurons as messengers that carry vital
information to and from different parts of the
brain.
Neurons
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A neuron is made up of four different parts
Dendrites: neuron fibers that receive incoming
messages. They look like tree roots
Soma: The soma is the main cell body of the neuron,
also receives information
Axon: Fiber that carries information away from the
cell body
Axon Terminals: Branching fibers at the end of the
axon. They link up with Dendrites of other neurons
Myelin Sheath: A fatty covering of the axon that
speeds up nerve impulses.
Parts of a Neuron
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Electronically charged molecules inside the
neurons are called Ions.
Neurons have an electrical charge of minus 70
millivolts. The electrical charge of an
INACTIVE neuron is called its Resting Potential.
When a message arrives from another neuron
and raises its charge to minus 50 millivolts the
neuron reaches its threshold and fires off. This
is called the action potential of a neuron. The
message is carried on at a speed of 200 miles
per hour!!
Ions and Nerve Impulses
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Synapse: a microscopic area between neurons.
Neurons technically do not touch each other as
they are separated by a very small synapse.
When messages cross a synapse, they are met
with a chemical which is released by the
neurons called Neurotransmitters. These
neurotransmitters alter the activity of a
neuron’s message in various
ways(inhibiting/exciting messages).
Synapses and
Neurotransmitters
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The brain must relay all of the messages that
are being spread to corresponding parts of the
body. This takes place through the nervous
system.
Central Nervous system: consisting of the brain
at the spinal cord. The CNS is of utmost
importance to the human body. The CNS
spreads messages to the Peripheral Nervous
System
Peripheral nervous system: All of the parts of the
nervous system outside of the brain and spinal
cord.
Nervous networks
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The Peripheral Nervous System is further
broken down into two major parts. The somatic
system carries messages to the sense organs and
skeletal muscles. The autonomic system
communicates with the internal organs and
glands of the body.
The Autonomic system is further subdivided
into the sympathetic(arousal) and
parasympathetic(lowers levels of arousal)
branches.
Peripheral Nervous
system
The Brain
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Researches aim to study the different areas and
functions of the brain in an array of different
ways.
Scientists can determine the different brain
functions through Ablations(surgical removal
of part of the brain), CT, PET, and MRI scans,
and by using electrode wires to stimulate the
brain and induce responses to stimulus.
The Brain
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The Cerebrum makes up the two large
hemispheres that cover the upper part of the
brain. The brain is broken up into two cerebral
hemispheres(right and left halves of the
cerebrum)
The two sides of the brain are able to
communicate by a bundle of fibers connecting
the two sides called the Corpus Callosum.
The cerebral cortex is the outer layer of the
cerebrum and contains roughly 70% of all
neuron activity in the CNS.
Parts of the Brain
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The two sides of the brain(left and right) have
different functions, and control different parts
of the body. The right side of the brain mainly
controls the actions of the left side of the body,
and the left side of the brain controls the other.
Strokes on the right side of the brain can cause
damage to the left side of the body. Can create
a curious problem called Spatial neglect.
Cerebral Hemispheres
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Spatial neglect occurs when people who have
suffered a stoke pay no attention to specific
sides of the body. Patients often do not eat food
on the left side of their plate(if the injury was o
the right side of the brain), and may not even
believe their own left arm is theirs.
Spatial Neglect
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Split brains occur in people who have had their
Corpus callosum severed.
People will literally have two different brains
telling them what to do.
Your brain could tell you to walk into two
different directions, turn on and off light
switches and talk or be silent all at the same
time.
“Split Brains”
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Each side of our brain takes on specific roles to
perform simple as well as complex tasks and
everything in between. The left side of the brain is
generally used for language(speaking, writing and
understanding. Further, the left side is controls the
ability to do math, tell time and keep rhythm.
The right side of the brain is better at picking up on
patterns, recognizing faces, drawing or figuring out
puzzles. The right side of the brain also understand
irony, sarcasm and context.
The left side understands pinpoint details whereas
the right side sees the bigger picture.
Right Brain/Left Brain
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The human brain is broken up into multiple
lobes, each with their own individual function.
Occipital Lobes: found in the back of the brain
and main function is sight
Parietal Lobes: Next to the occipital lobes.
Control touch, temperature and pressure.
Temporal Lobes: main function is controlling
hearing. On the sides of the brain
Frontal Lobes: higher mental abilities and
movement
Lobes of the Brain
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The subcortex area of the brain is found
immediately below the cerebral hemispheres.
It is divided into the forebrain, midbrain and
hindbrain
Each part of the subcortex play vital roles in
human cognition
Subcortex
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The hindbrain contains important parts of the
brain such as the Medulla and the Cerebellum.
The Medulla connects the brain with the spinal
cord and regulates vital bodily function such as
heart rate, breathing and swallowing.
The Cerebellum regulates posture, muscle tone
and muscular coordination.
Hindbrain
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Found in the Forebrain are the extremely
important parts of the brain, the Thalamus and
the Hypothalamus.
The Thalamus is the area of the brain that relays
messages to the cerebral cortex.
The Hypothalamus regulates emotional
behaviors and motives such as rage,
temperature control, eating, drinking and
waking up.
Forebrain
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Found in the Limbic system are the Amygdala
and the Hippocampus.
The Amygdala regulates emotions such as fear
The Hippocampus has the main function of
storing memories.
Limbic System
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The Endocrine system is a network of glands
that’s secrete hormones into our bodies.
A hormone affects our moods, behavior,
growth and more.
These hormones come from a variety of
different glands in our body.
The Pituitary gland is deemed the master gland.
It regulates growth, or the lack thereof. Too
much or too little of a specific hormone coming
from the Pituitary gland can cause Gigantism
or people being very small.
Endocrine System
Other glands of note:
Thyroid gland
Pineal gland
Adrenal gland
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All of these other glands have very specific jobs
including the regulation of sleep, metabolism,
stress, fear and anger.
Other glands