7-1 How the Nervous System Works
Jobs of the Nervous System
1. Receives ________________________________
2. Responds to ________________________________
a) ___________________________: A change or signal in the environment that can make
an organism react.
b) ___________________________: What the body does in reaction to a stimulus.
3. Maintains ____________________________________.
The Neuron – A Message Carrying Cell
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____________________________: A cell that carries information through the nervous system; a
nerve cell.
___________________________________: The message that a neuron carries.
A neuron has one ______________________ and many ________________________.
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____________________________: Carries impulses toward the cell body.
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____________________________: Carries impulses away from the cell body.
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Axons and dendrites are sometimes called ___________________________________.
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____________________________: A bundle of nerve fibers.
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____________________________: Picks up stimuli from the internal or external environment
and converts each stimulus into a nerve impulse.
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____________________________: A neuron that carries nerve impulses form one neuron to
another; usually found in the brain or spinal cord.
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____________________________: A neuron that sends an impulse to a muscle, and the muscle
contracts in response.
How a Nerve Impulse Travels
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A nerve impulse begins in the ___________________________ of a neuron, moves toward the
___________________________, then down the axon to the ___________________________.
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___________________________: The tiny space between each axon tip and the next structure,
such as a dendrite, muscle or cell of another organ.
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Axon tips release ___________________________ that enable the impulse to cross the synapse.
7-2 Divisions of the Nervous System
Central Nervous System consists of the _______________________, & ___________________________.
_________________________________ Nervous System consists of all the nerves located outside of the
Central Nervous System.
The Central Nervous System (CNS)
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The CNS is the ________________________ center of the body.
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The part of the CNS that controls most functions is the ______________________________.
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_________________________________:Thick column of nerve tissue, links the brain to most of
the nerves in the Peripheral Nervous System.
The Brain
____________________________: Largest part of the brain; interprets input from the senses.
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Cerebrum controls the movement of ___________________________
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Cerebrum carries out complex _______________________ processes such as learning,
remembering, and making judgments.
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Right half of cerebrum controls the ______________________ side of body. And vice versa.
_______________________ side of brain associated with creativity, & artistic ability.
_______________________ side of brain associated with math skills, speech, writing, & logical thinking.
_____________________________: Second largest part of the brain; coordinates the actions of your
muscles & helps keep your balance.
_____________________________: Lies between the cerebellum and spinal cord; controls the body’s
involuntary actions (breathing, heartbeat).
The Spinal Cord
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Surrounded & protected by a vertical column.
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Links _______________________________ & ________________________________.
The Peripheral Nervous System (PNS)
Somatic Nervous system controls _______________________________ actions.
Autonomic Nervous System controls ______________________________ actions.
Reflexes
__________________________: Automatic response that occurs very rapidly without conscious control.
Safety and the Nervous System
______________________________: Bruise-like injury of the brain. Occurs when soft tissue of the
cerebrum bumps against the skull.
Spinal cord injuries occur when the spinal cord is cut or crushed resulting in loss of
__________________________.
7-3 The Senses
Vision
___________________________: The clear tissue that covers the front of the eye.
___________________________: The opening through which light enters the eye.
___________________________: A circular structure that surrounds the pupil and regulates the amount
of light entering the eye; also gives the eye its color.
___________________________: A flexible structure that focuses light.
___________________________: Enable you to see black, white & shades of gray.
___________________________: Enable color vision.
Nerve impulses travel from the retina to the cerebrum through the _____________________________.
___________________________: Nearby objects can be seen clearly by distant objects look blurry.
___________________________: Distant objects can be seen clearly but nearby objects look blurry.
Hearing
Sound is produced by _________________________________.
_______________________________: Shaped like a funnel, gathers sound waves & directs them down
the ear canal.
_______________________________: Membrane that vibrates when sound waves strike it; separates
the outer ear from the middle ear.
Vibrations from the eardrum pass to the __________________________, ________________________,
and ____________________________, tiny bones in the middle ear.
__________________________________: A snail-shaped tube that is lined with receptors that respond
to sound. Vibrations pass to fluid in the cochlea.
As fluid in the cochlea vibrates, it stimulates __________________________________.
Sensory neurons send the impulse to the cerebrum, through the ______________________________,
where the sound is interpreted.
Your Sense of Balance
________________________________: Structures in the inner ear that are responsible for your balance.
Moving fluid in the semicircular canals tells the cerebellum about the body’s ______________________.
Smell and Taste
The senses of smell and taste work closely together, and both depend on _________________________.
Chemicals trigger responses in _____________________________ in the nose and mouth.
__________________________________ then travel to the brain for interpretation.
Touch
The sense of touch is found in all areas of the ______________________________.
The dermis has different kinds of receptors: _______________________, ________________________,
_______________________________, and _______________________________.
8-1 The Endocrine System
The Role of the Endocrine System
Controls many of the body’s daily ___________________________ as well as long-term changes such as
_______________________________.
____________________________________: An organ of the endocrine system which produces and
releases its chemical products directly into the bloodstream.
Hormones
____________________________: The chemical product of an endocrine gland; regulates the activities
of different organs & tissues.
In some situations, hormones are released by __________________________ impulses to the brain and
then to a specific endocrine ______________________.
A hormone interacts only with certain _____________________________, that recognize the hormone’s
chemical structure.
The Hypothalamus
__________________________________: Tiny part of the brain that links the Nervous System and the
Endocrine System.
Sends nerve messages to control ____________________, _____________________ & other conditions.
Produces __________________________ that control other endocrine glands & organs.
Plays a major role in maintaining _________________________________________.
The Pituitary Gland
__________________________________: An endocrine gland just below the hypothalamus to control
many body activities.
Responds to signals from the hypothalamus by releasing its own ___________________________, some
of which act as “on” switches for other endocrine glands.
Other pituitary hormones control body activities directly.
Negative Feedback
________________________________: A process in which a system is turned off by the condition it
produces. Ex: The regulation of temperature by a thermostat & the regulation of levels of many hormones in
blood.
Negative Feedback is an important way that the body maintains ___________________________________.