Introductory Information
No principle is more central to
today’s psychology than this:
“Everything Psychological is
also biological.”
Your every idea, every urge, every mood, is a
biological happening. You love, laugh, and cry
with your body. Without your body, your genes,
your brain, your appearance…you are nobody.
Although we find it convenient to talk separately
of biological and psychological influences on
behavior, we need to remember: to think, feel, or
act without a body would be like running without
legs.
Early Approaches to Understanding
the Brain
Plato correctly located the mind in the
spherical head-his idea of the perfect form.
His student Aristotle believed the mid was
in the heart, which pumps warmth and
vitality to the body. The heart remains our
symbol for love, but science has long since
overtaken philosophy on this issue. It’s your
brain, not your heart that falls in love.
Anybody Know What Phrenology
Is?
Neural Communication
BASIC TERMS
 Neuron: A nerve cell. The basic building blocks of the
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nervous system.
Motor Neuron: Neurons that carry outgoing information
from the brain and spinal cord to the muscles and glands.
Interneurons: Neurons within the brain and spinal cord
that communicate internally and intervene between the
sensory inputs and motor outputs.
Dendrite: the bushy, branching extensions of a neuron that
receive messages and conduct impulses toward the cell
body.
Axon: the extension of a neuron, ending in branching
terminal fibers, through which messages pass to other
neurons or to muscles and glands.
All my science people…
What does this statement
mean…
AXONS SPEAK…DENDRITES
LISTEN.
Also…
To remember that dendrites bring
information in and axons convey
information out, just remember…
AXONS AWAY
MORE BASIC TERMS:
 Myelin Sheath: a layer of fatty tissue segmentally
encasing the fibers of many neurons; enables vastly
greater transmission speed of neural impulses as the
impulse hops from one node to the next.
 Action Potential: a neural impulse; a brief electrical
charge that travels down an axon.
ACTION POTENTIAL
Understanding Action Potential
Threshold: The level of stimulation required to trigger
a neural impulse
Synapse: The junction between the axon tip of the
sending neuron and the dendrite or cell body of the
receiving neuron. When released by the sending
neuron, neurotransmitters travel across the synapse
and bind to receptor sites on the receiving neuron,
thereby influencing whether that neuron will generate
a neural impulse.
How Neurons Communicate
The Nervous System
Dual Functions of the Autonomic
Nervous System
Nervous System Vocabulary Words
 Nervous System: The body’s speedy electrochemical
communication network, consisting of all the nerve
cells of the CNS and PNS.
 CNS: Brain and spinal cord
 Nerves: bundled axons that form neural “cables”
connecting the CNS with muscles, glands, and sense
organs.
 Somatic Nervous System: Division of the PNS that
controls the body’s skeletal muscles.
More Vocab
 Autonomic Nervous System: the part of the PNS that
controls the glands and the muscles of the internal
organs (such as the heart). It’s sympathetic division
arouses; it’s parasympathetic system calms.
 Sympathetic Nervous System: the division of the
autonomic nervous system that arouses the body,
mobilizing it’s energy in stressful situations.
Reflexes
Reflexes are our responses to
sensory stimuli. Such as the
knee-jerk response. Relates to
our Central Nervous System.
More On Reflexes
Endocrine System
Endocrine System Vocabulary
 Endocrine System: The body’s “slow” chemical
communication system; a set of glands that secrete
hormones into the bloodstream.
 Hormones: chemical messengers that are
manufactured by the endocrine glands, travel through
the bloodstream and affect other tissues.
 Adrenal Glands: A pair of endocrine glands that sit
just above the kidneys and secrete hormones
(epinephrine and norepinephrine) that help arouse
the body in times of stress.
 Pituitary Gland: The Endocrine System’s most
influential gland. Under the influence of the
hypothalamus, the pituitary gland regulates growth
and controls other endocrine glands.
Important Endocrine Glands and
Their Functions
 Anterior Pituitary Gland: Secretes Growth Hormone.
Too little produces dwarfism. Too much results in
gigantism.
 Posterior Pituitary Gland: Secretes Vasopressin
constricting blood vessels and raising blood pressure.
 Thyroid releases thyroxine and triiodothyronine,
increasing metabolic rate, growth, and maturation.
 Parathyroids release parathyroid hormone, increasing
blood calcium and decreasing potassium
 Pancreas secretes insulin, regulating the level of sugar
in the bloodstream
 Ovaries secrete estrogen
 Testes release androgens promoting sperm production