Chapter 3 Notes
The Endocrine System
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The Endocrine system sends chemical
messages called hormones to the brain.
The Endocrine System consists of glands that
secrete substances, called hormones, into the
blood stream.
These hormones stimulate growth and many
kinds of reactions, such as changes in activity
levels and moods.
The Hypothalamus
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This is in your brain and it directs the pituitary
gland, which is the “master gland”
The pituitary gland secretes a large number of
hormones which carry messages through the
blood stream
These hormone messages carry information to
the organs that regulate storing of nutrients,
growth and reproduction.
The Thyroid Gland
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Produces the hormone thyroxine. Too little
thyroxine makes people feel lazy and lethargic
which is a condition called hypothyroidism.
Too much thyroxine causes people to lose
weight and become overactive. This is known
as hyperthyroidism.
Adrenal Glands
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Become active when you are frightened or
angry. They secrete adrenaline. This prepares
your body to handle emergencies.
Heredity Debate
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Heredity is the transmission of genes from
parent to child. Nature vs. Nurture asks the
question “ Do people learn to be good athletes,
or are they born that way?” and “Do people
learn to do well in school, or are they born
good at it?”
In the past, one way to study genes and
heredity was by studying twins. This is still
used today to conduct research.
Look on page 73.
Twin studies
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Identical twins develop from a single fertilized
egg and share the same genes.
Fraternal twins develop from two separate
eggs and their genes are not more similar than
those of brothers or sisters.
Read the page 72 and 73 to learn more about
several studies that have been conducted with
twins
Central Nervous System
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Includes are brain and spinal cord
Our nervous system helps control our body
movements, behavior, thinking, and emotions
Peripheral Nervous System
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Consists of smaller branches of nerves that
extend throughout your body. These nerves
carry messages to and from the CNS.
Messages travel to and from the brain through
neurons or strings of long thins cells
How messages travel throughout
the body continued
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Space between the cells is called a synapse
Page 54
Impulses travel from neuron to neuron via a
chemical called neurotransmitters
Sometimes having too many or not enough of
these chemicals can cause disease
Too much dopamine is linked to schizophrenia
whereas an undersupply is linked to
Parkinson’s disease.
Depression
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Depression is caused by an undersupply of
norepinephrine or serotonin.
Somatic Nervous System
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Refers to the part of the peripheral nervous
system that controls voluntary body
movements
Autonomic Nervous System
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Controls involuntary actions like heart beat or
pupil dilation.
THE BRAIN!!
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Left hemisphere controls the right side of the
body
Right hemisphere controls the left side of the
brain
Composed of three main part
Hind brain
Midbrain
Forebrain
Hindbrain
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Controls our most basic processes like posture,
balance and breathing
Midbrain
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Intergrates and relays information
Forebrain
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Controls higher thinking processes
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Each hemisphere of the brain has 4 lobes and
two hemispheres that are mirror images of
each other