Download Chapter 6 - Trimble County Schools

Chapter 6
Body and Behavior
Section 1
The Nervous System:
The Basic Structure
How the nervous system works
Central nervous system (CNS)- the
brain and spinal cord
Spinal cord- nerves that run up and
down the length of the back and
transmit most messages between the
body and brain
Peripheral nervous system (PNS)nerves branching beyond the spinal
cord into the body
Neurons
The long, thin cells of nerve tissue
along which messages travel to and
from the brain
Transmission occurs whenever cells
are stimulated past a minimum point
and emit a signal.
Either fires or does not fire
Parts of a neuron
Dendrites- short, thin fibers that
protrude from the cell body
– Receive impulses or messages and send
them to the cell body
Axon- carries the impulses from the
cell body to the axon terminals
Axon terminals- release
neurotransmitters to stimulate
dendrites of the next neuron
Parts of a neuron
Myelin sheath- insulates and protects
the axon for some neurons
– speeds the transmission of impulses
– In cases of multiple sclerosis, the myelin
sheath is gone.
The Neuron Connection
Synapse- the gap that exists
between individual nerve cells
Neurotransmitters- the chemicals
released by neurons which determine
the rate at which other neurons fire
Examples of neurotransmitters
– Norepinephrine- is involved with
memory and learning
– Endorphine- inhibits pain
Neuron Activity
Intensity of neurons depends on how
many other neurons are acting on it
Afferent neurons- sensory neurons that
relay messages from the sense organs to
the brain (eyes, ears, nose, skin)
Efferent neurons- motor neurons that
send messages from the brain to the
glands and muscles
Interneurons- process signals, connecting
only to other neurons, not to sensors or
muscles
Voluntary and Involuntary activities
Somatic nervous system (SNS)- the
part of the peripheral nervous
system that controls voluntary
movement of skeletal muscles
Autonomic nervous system (ANS)the part of the peripheral nervous
system that controls internal
biological functions
Autonomic Nervous System
Sympathetic nervous system
– Prepares the body for dealing with
emergencies or strenuous activity
Parasympathetic
– Works to conserve energy and to
enhance the body’s ability to recover
from strenuous activity
Section 2
Studying the Brain
Three parts of the Brain
Hindbrain- a part of the brain located at
the rear base of the skull that is involved
in the basic processes of life.
Midbrain- a small part of the brain above
the pons that arouses the brain, integrates
sensory information, and relays it upward
Forebrain- a part of the brain that covers
the brain’s central core, responsible for
sensory and motor control and the
processing of thinking and language
Hindbrain
Includes the following parts:
Cerebellum
– Helps control posture, balance and
voluntary movements
Medulla
– Controls breathing, heart rate, and
reflexes
Pons
– Bridge between the spinal cord and
brain
– Produces chemicals the body needs for
Forebrain
Includes the following parts:
Thalamus
– Integrates sensory input
– “relay station” for all info that travels to
and from the cortex
Hypothalamus
– Controls functions of hunger, thirst, and
sexual behavior
– Controls the bodies reaction to
temperature
Forebrain
Includes the following parts:
Cerebral cortex
– Outer layer of the forebrain
Cerebrum
– Inner layer of the forebrain
– Gives you the ability to learn and store
complex and abstract information
Forebrain
Limbic system
– Includes various structures that regulate
our emotions and motivations
– Amygdala- controls violent emotions like
rage or fear
– Hippocampus- is important for the
formation of memories
The Lobes of the Brain
Corpus callosum- a band of fibers
that joins the two sides or
hemispheres of the cerebrum
Lobes- are the different regions into
which the cerebral cortex is divided
Lobes of the Brain
Occipital lobe- visual signals are sent
Pariental lobe- concerned with
various information from the senses
Temporal lobe- concerned with
hearing, memory, emotion, and
speaking
Frontal lobe- concerned with
organization, planning, and creative
thinking
Left and Right Hemispheres
Right and left sides of the brain
complement each other
Left hemisphere of the brain controls
the right side of the body
– Mathematical ability, where speech is
located
Right hemisphere of the brain
controls the left side of the body
– Controls visual and spatial relations
– Perceptual tasks
How Psychologists Study the Brain
Recording
– Electroencephalograph (EEG)- is a
machine used to record electrical
activity of large portions of the brain
– Overall electrical activity can be
measured and the rhythms of the brain
differ depending on whether a person is
awake, drowsy, or asleep
How Psychologists Study the Brain
Stimulation
– Electrodes may be used to set off the
firing of neurons as well as record it
– Has been used with terminal cancer
patients to relieve their pain
– Used to control violent emotional
behavior
Images
Computerized axial tomography (CT)
– An imaging technique used to study the
brain to pinpoint injuries and brain
deterioration
– Radiation is absorbed depending on the
density of the brain tissue
– Computers measure the amount of
radiation absorbed and then
transformed into 3-D images
Images
Positron Emission Tomography (PET)
– Is an imaging technique used to see
which brain areas are being activated
while performing tasks
– Injects radioactive solution into the
blood and measuring the amount of
radiation absorbed by the blood cells
– Show activity in different areas of the
brain when a person is thinking,
speaking, or looking at objects
Images
Magnetic Resonance Imaging (MRI)
– A measuring technique used to study
brain structure and activity
– Combines the features of CT and PET
scans
fMRI- observes both the functions of
different structures of the brain and
which structures participate in
specific functions
Section 3
The Endocrine System
The Endocrine Glands
Endocrine system- a chemical
communication system, using
hormones, by which messages are
sent through the bloodstream.
Hormones- chemical substances that
carry messages through the body in
blood
The Endocrine Glands
Hormones have effects on your
behavior
Hormones can also influence your
moods and drives
Duct glands
– Release their contents through small
holes on the surface of the body
Sweat glands, tear glands, salivary glands
Pituitary Gland
Is the center of control of the
endocrine system that secretes a
large number of hormones
Controls growth and reproduction
including ovulation and lactation
Thyroid Gland
Produces thyroxine
Stimulates certain chemical reactions
that are important for all tissues of
the body
Hyperthyroidism- too much thyroxine
which causes overactivity
Hypothyroidism- too little thyroxine
makes people feel lazy
Adrenal Glands
Become active when angry or
frightened
Release epinephrene and
norepinephrine which cause
heartbeat and breathing to increase
Secrete cortical steroids which help
muscles develop
Sex Glands
Testes
– Testosterone (male sex hormone)
Important in physical development
Helps decide sex of the fetus
Ovaries
– Produce estrogen and progesterone
Important in the development of female sex
characteristics
Vary throughout the menstrual cycle
Hormones v.s. Neurotransmitters
Both work to affect the nervous
system
When a chemical is used as a
neurotransmitter:
– It is released right beside the cell that it
is to excite or inhibit
When a chemical is used as a
hormone:
– It is released into the blood, which
defuses into the body
Section 4
Heredity and Environment
Heredity and Environment
Heredity- the genetic transmission of
characteristics from parents to their
offspring
Inherited factors and environmental
conditions always act together in
different ways
Nature versus Nurture
Nature refers to characteristics that a
person inherits
– Family, culture, education, individual
experiences
Genes are the basic units of heredity
– Can be reproduced and passed from
generation to generation
– For example, musical talent
Twin Studies
Identical twins- twins who come from
one fertilized egg; twins having the
same heredity
Genes- the basic building blocks of
heredity
Fraternal twins- twins who come
from two different eggs fertilized by
two different sperm
Twin Studies
Twins growing up in the same house
share the same environment as well
as the same genes
Twins growing up in different
environments have common
behaviors despite different social,
cultural, or economic backgrounds
Sources:
Kasschau, Richard, A.
Understanding Psychology. McGrawHill, Glencoe, New York, New York,
2008.