Transcript CH.3_Biology_Behavior_Psychx

Unit 2: Body & Mind
Ch.3: Biology and Behavior
I. The Nervous System
• The human nervous system is involved in
thinking, dreaming feeling moving, and more.
The nervous system regulates our internal
functions. It is also involved on how we react to
the external world. Learning and memory are
made possible by the nervous system. The
nervous system has 2 parts: the central
nervous system and the peripheral nervous
system. The central nervous system is made
up of the brain and spinal cord. The peripheral
nervous system is made up of nerve cells that
send messages between the central nervous
system and all the parts of the body.
A. Neurons
• Nerve cells, neurons, run through our bodies &
communicate with each other. Neurons send & receive
messages from the other structures in the body such as
muscles & glands.
– 1. Components of a Neuron: Every neuron consist of a
cell body, dendrites, & axon.
– 2.The Cell Body: Produced energy that fuels the
activity of the cell.
– 3. The Dendrite: Branches out from the cell body and
receives information from other neurons & passes the
message through the cell body.
– 4. The Axon: Carries messages away from the cell
body.
– 5.Myelin & Axon Terminals: Myelin (white/ fatty
substance) insulates/ protects the axon. Axon
terminals are located at the end of the axon and are
smaller fibers that branch out.
B. The Communication Process
• Messages are sent from the axon
terminals of one neuron to the
dendrites of the other neurons. In order
for a message to be sent from one
neuron to another, it must cross the
synapse. The synapse is a junction
between the axon terminals of one
neuron and the dendrites of another
neuron. Messages travel in only one
direction. Messages are received by the
dendrites & travel through the cell body
and the axon to the axon terminals.
C. Neurotransmitters: Chemical
Messengers
• Neurons send messages across
synapses through the release of
neurotransmitters. Neurotransmitters
are chemicals that are stored in sacs in
the axon terminals. Dopamine is
another neurotransmitter . It is involved
primarily in motor behavior. A
deficiency in dopamine levels plays a
role in Parkinson's Disease. An excess
of dopamine may contribute to the
psychological disorder schizophrenia.
D. The Central Nervous System
• The Central Nervous System consists of
the neurons of the spinal cord and the
brain. The spinal cord extends from the
brain down the back. It is a column of
nerves about as thick a thumb and is
protected by the bones of the spine. It
transmits messages between the brain
and the muscles/ glands throughout the
body. The spinal cord is also involved in
spinal reflexes. A spinal reflex is a simple,
automatic response to something. Many of
our simple actions are reflexive.
E. The Peripheral Nervous System
• The Peripheral Nervous System lies
outside the central nervous system and
is responsible for transmitting
messages between the central nervous
system and all other parts of the body.
The two main divisions of the
peripheral nervous system are the
somatic nervous system and the
autonatic nervous system.
F. The Somatic Nervous System
• The Somatic Nervous System transmits
sensory messages to the central nervous
system. It is activated by touch, pain,
changes in temperature, and changes in
body position. The somatic nervous
system enables us to experience
sensations of hot & cold & to feel pain &
pressure. The SNS also alerts us that parts
of the body have moved or changed
positions. It sends messages to the
muscles/ glans to help us maintain posture
G. The Autonomic Nervous System
• The word automatic means “occurring
involuntarily” or automatically. The Autonomic
Nervous System regulates the body’s vital
functions, such as heartbeat, breathing,
digestion, & blood pressure. Generally, we do
not have to think about these activities, they
occur automatically & are essential to
keeping us alive. Psychologists are interested
in the ANS because of its involvement in the
experience of emotion. The response of the
ANS is particularly important when a person
experiences something stressful.
G. The Autonomic Nervous System. . . Continued!
• The ANS has two divisions, the sympathetic &
parasympathetic nervous systems. These
systems generally have opposing functions. The
sympathetic nervous system is activated when a
person is going into action, “fight or flight”. The
SNS prepares the body by suppressing
digestion, increasing the heart & respiration
rates, & elevating blood pressure. The
parasympathetic nervous system restores the
body’s reserves of energy after an action had
occurred. Heart rate & blood pressure
normalize, breathing is slowed, & digestion
returns to normal.
II. The Brain: Our Control Center
• Every person is unique in part because of the
capacities for learning and thought made
possible by the human brain.
• The accident Egyptians believed that a little
person lived inside the skull & regulated
behavior. Aristotle believed that the soul lived in
the heart. B.F. Skinner believed the the English
language still reflects the belief in the heart as
the seat of good will.
• Today we recognize that the mind, or
consciousness, dwells in the brain.
A. Parts of the Brain
• The human brain is composed of many parts that work together
to organize our movements, create our thoughts, form our
emotions, & produce our behaviors. Scientist have identified the
localized functions of different parts of the brain.
• The brain is divided into 3 sections: the hindbrain, the midbrain,
& the forebrain.
• The hindbrain is the lower portion of the brain and is involved in
many vital function such as heart rate, respiration, & balance.
• The midbrain includes areas that are involved in vision &
breathing.
• The forebrain, in the front area of the brain, is involved in
complex functions such as thought & emotion.
1. The Hindbrain
• The medulla, the pons, & the cerebellum are
important structures of the hindbrain.
• The medulla: helps regulate/ maintain vital
functions such as heart rate, blood pressure, &
breathing.
• The pons: located in front of the medulla,
regulates bodily movement, attention, sleep, &
alertness.
• The cerebellum: rests under the large part of the
brain, & is involved in balance & coordination.
2. The Midbrain
• The midbrain is located between the
hindbrain & the forebrain.
• Areas within the midbrain are involved in
vision & hearing.
• The midbrain contains the reticular
activating system: this is important for
attention, sleep, & arousal.
3. The Forebrain
• Four key areas of the forebrain are the thalamus,
the hypothalamus, the limbic system, & the
cerebrum.
• The thalamus is a critical structure of the brain
because it serves as a relay station for sensory
stimulation.
• The thalamus transmits sensory information,
such as pain, to the areas of the brain that
interpret and respond to the information. The
thalamus also relays sensory input from the
eyes and ears to the appropriate parts of the
brain for interpretation of the input.
• Hypothalamus lies below the thalamus, it is tiny but
important because it is involved in many aspects of
behavior & physiological functions. Also vital to
regulating body temperature, storage of nutrients, &
motivation/ emotion. It is also involved in hunger, thirst,
sexual behavior, caring for off spring & aggression.
•
• The limbic system: forms a fringe along the inner edge
of the cerebrum. It is involved in learning/ memory,
emotion, hunger, sex, & aggression.
• The cerebrum: (Latin for “brain”): accounts for 70% of
the weight of the brain. The surface of the cerebrum is
wrinkled w/ ridges & valleys, this surface is the cerebral
cortex, the cortex is involved in memory, language,
emotions, complex motor functions, & perceptions
B. The Cerebral Cortex: What makes us unique
• The cerebral cortex is composed of 2 sides: a left & right
hemisphere.
• The structure that connects the 2 hemispheres is the corpus
callosum.
• Information received by one side of the body is transmitted to
the opposite hemisphere of the brain.
• The corpus callosum aids in getting information from one side
of the brain to the other.
• Each hemisphere of the cerebral cortex is divided into 4 parts,
or lobes: The frontal lobe (behind the forehead), parietal lobe
(top/ rear of the head), the temporal lobe (off to the side, behind
your ears), & the occipital lobe (back of the head).
1. Senses & Motor Behavior
• The Occipital Lobe: Contains the primary visual
area of the cerebral cortex.
• The Temporal Lobe: Contains the auditory area
of the cortex. Sounds are relayed from the ears
to the thalamus to the auditory area. When this
occurs we hear sounds.
• Frontal Lobe: Motor portion of the cortex.
• Parietal Lobe: Primary sensory area.
2. Association Areas
• Much of the cerebral cortex is composed of
areas that involve sensory and motor functions,
these areas help shape information into
something more meaningful.
• Association areas in the frontal lobe (near the
forehead) is the brain’s executive center. This is
the area of the brain we use to solve problems,
make plans and decisions.
• Association areas also provide the core of your
working memory.
2. Language Abilities
• For nearly all right- handed people,
language functions are based in the the left
hemisphere. Language functions are also
based in the left hemisphere of about 2 out
of 3 left handed people.
• Two language areas: Broca’s area (located
in the frontal lobe) & Wernicke’s area (
located un the temporal lobe, pieces
together sight & sound).
3. Left vs. Right Hemispheres
• The same hemisphere that contains most
language functions is usually more
involved in logic, problem solving, &
mathematical computation than the other
hemisphere.
• People who are said to be more logical are
said to be more “left –brained”, people who
are particularly creative are more “rightbrained”.
III. The Endocrine System
• The Endocrine System contains glands
that secrete hormones into the
bloodstream. Hormones have specific
receptor sites. Hormones are produced by
certain glands: the pituitary gland, the
thyroid gland, the adrenal gland, and the
testes and the ovaries.
A. The Pituitary Gland
• The pituitary gland, lies below the
hypothalamus, is the size of a pea=
“The Master Gland”, controls growth
and development.
• Specifically producing oxytocin,
which stimulates labor in pregnant
women.
B. The Thyroid Gland
• The thyroid gland produces thyroxin,
which effects the body’s metabolism
(the rate of converting food into
energy). Too little= hypothyroidism,
too much= hyperthyroidism.
C. The Adrenal Glad
• The Adrenal Glands, located above
the kidneys. The outer layer (the
cortex) secretes cortical steroids,
which increase resistance to stress
& promote muscle development.
Also causes the liver to release
sugar, making energy available for
emergencies. The Adrenal glad also
produces adrenaline &
noradrenaline
D. The Testes & the
Ovaries
• Testes= glands in males
• Ovaries= glands in females.
• Produce testosterone, progesterone,
& estrogen.
1. Testosterone
• Male sex hormone (similar to a steroid),
females produce small amounts of this
hormone. Produced in the testes in males.
Produced in the ovaries in females.
Testosterone, in prenatal development,
influences the sex organs. At 8 weeks
gestation, testosterone is release, resulting
in the creation of male sex organs. During
adolescence, aids growth of muscle &
growth development as well as primary
(directly involved in reproduction) &
secondary sex characteristics.
2. Estrogen & Progesterone
• Both are female sex hormones, also small amounts
found in males. The ovaries produce both
hormones in females. Estrogen is produced in small
amounts in the testes in males. Estrogen fosters the
development of primary & secondary sex
characteristics in women.
• Progesterone: stimulates the growth of female
reproductive organs, & prepares the body for
pregnancy.
• Progesterone & Estrogen= regulate the menstrual
cycle