Interest Grabber
Section 35-1
An Important Process
While walking along a dusty path, you begin to cough. As you continue
your walk, a small insect comes flying toward you. You blink and then duck
so that it misses you. These actions are just a few examples of
homeostasis. Homeostasis is the process by which organisms keep
internal conditions relatively constant despite changes in their external
environments.
1. List three other examples of homeostasis that occur in organisms.
2. Why is homeostasis important to an organism?
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Section:
Section Outline
Section 35-1
35–1
Human Body Systems
A. Organization of the Body
1. Cells
2. Tissues
3. Organs
4. Organ Systems
B. Maintaining Homeostasis
1. A Nonliving Example
2. In the Body
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Section:
Examples of Feedback Inhibition
Section 35-1
Thermostat senses temperature
change and switches off heating
system
Room temperature increases
Room temperature decreases
Thermostat senses temperature
change and switches on heating
system
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Section:
Figure 35-2 Human Organ Systems Part I
Section 35-1
Nervous System
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Section:
Integumentary System
Skeletal System
Muscular System
Circulatory System
Figure 35-2 Human Organ Systems Part I
Section 35-1
Nervous System
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Section:
Integumentary System
Skeletal System
Muscular System
Circulatory System
Figure 35-2 Human Organ Systems Part I
Section 35-1
Nervous System
Go to
Section:
Integumentary System
Skeletal System
Muscular System
Circulatory System
Figure 35-2 Human Organ Systems Part I
Section 35-1
Nervous System
Go to
Section:
Integumentary System
Skeletal System
Muscular System
Circulatory System
Figure 35-2 Human Organ Systems Part I
Section 35-1
Nervous System
Go to
Section:
Integumentary System
Skeletal System
Muscular System
Circulatory System
Figure 35-2 Human Organ Systems Part 2
Section 35-1
Respiratory System
Endocrine System
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Section:
Digestive System
Reproductive System
Excretory System
Lymphatic/Immune Systems
Interest Grabber
Section 35-2
You’ve Got a Lot of Nerve!
The nervous system controls and coordinates functions throughout the
body. The nervous system is one of the body’s communication systems.
Without communication, parts of the body could not work together
smoothly.
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Section:
Interest Grabber continued
Section 35-2
1. Think about tying the shoelace of a sneaker. Construct a flowchart that
shows what happens between your eyes and your brain, and between
your brain and your hands, when you tie a bow in the shoelace.
2. How would the communications be different if you tried to tie the
shoelace with your eyes closed?
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Section:
Section Outline
Section 35-2
35–2
The Nervous System
A. Neurons
B. The Nerve Impulse
1. The Resting Neuron
2. The Moving Impulse
3. Threshold
C. The Synapse
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Section:
A Neuron
Section 35-2
Nucleus
Axon terminals
Cell body
Myelin sheath
Nodes
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Section:
Axon
Dendrites
Figure 35-6 Resting Potential
Section 35-2
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Section:
Figure 35-7 An Impulse
Section 35-2
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Section:
Figure 35-7 An Impulse
Section 35-2
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Section:
Figure 35-7 An Impulse
Section 35-2
Go to
Section:
Figure 35-7 An Impulse
Section 35-2
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Section:
Figure 35-8 The Synapse
Section 35-2
Direction of Impulse
Dendrite of
adjacent neuron
Axon
Vesicle
Receptor
Axon
terminal
Synaptic cleft
Neurotransmitter
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Section:
Interest Grabber
Section 35-3
Brainiac
Imagine that you are a computer systems engineer and your job is to
design a computer that can perform all the functions of a human brain.
1. Which brainlike functions can already be performed by computers?
2. Which brainlike functions cannot be performed by computers?
3. How successful do you think you (or anyone) could be in designing a
computer that can perform all the functions of the human brain? Explain
your answer.
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Section:
Section Outline
Section 35-3
35–3
Divisions of the Nervous System
A. The Central Nervous System
B. The Brain
1. The Cerebrum
2. The Cerebellum
3. The Brain Stem
4. The Thalamus and Hypothalamus
C. The Spinal Cord
D. The Peripheral Nervous System
1. The Somatic Nervous System
2. The Autonomic Nervous System
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Section:
Concept Map
Section 35-3
The Nervous
System
is divided into
Central nervous
system
Peripheral
nervous system
Motor
nerves
which consists of
that make up
Somatic nervous
system
Autonomic
nervous system
which is divided into
Sympathetic
nervous system
Go to
Section:
Parasympathetic
nervous system
Sensory
nerves
Figure 35-9 The Brain
Section 35-3
Cerebrum
Thalamus
Pineal
gland
Hypothalamus
Cerebellum
Pituitary gland
Pons
Medulla oblongata
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Section:
Spinal cord
Cross Section of the Spinal Cord
Section 35-3
Gray matter
Spinal nerve
Central canal
White matter
Meninges
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Section:
Interest Grabber
Section 35-4
Taking It All In
Your senses—sight, hearing, smell, touch, taste—are constantly receiving
information about your environment. Even if you are not thinking about it,
your body is sensing and responding to conditions around you, such as the
temperature of the room.
1. List ten things you observe about the room you are in.
2. Next to each observation, write the sense that you used to make
that observation.
3. What sense did you use most?
Go to
Section:
Section Outline
Section 35-4
35–4
The Senses
A. Vision
B. Hearing and Balance
1. Hearing
2. Balance
C. Smell and Taste
D. Touch and Related Senses
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Section:
The Senses of Smell and Taste
Section 35-4
Olfactory
(smell) bulb
Taste
sensory
area
Olfactory
nerve
Thalamus
Cerebral cortex
Smell
receptor
Nasal cavity
Smell
sensory area
Taste bud
Taste
pore
Taste
receptor
Sensory
nerve fibers
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Section:
Figure 35-14 The Eye
Section 35-4
Vitreous humor
Muscle
Lens
Fovea
Aqueous humor
Cornea
Pupil
Optic nerve
Iris
Blood vessels
Ligaments
Retina
Choroid
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Section:
Sclera
Figure 35-15 The Ear
Section 35-4
Anvil Stirrup
Hammer
Oval
window
Semicircular canals
Cochlear nerve
Cochlea
Bone
Auditory canal
Tympanum
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Section:
Round window
Eustachian tube
Interest Grabber
Section 35-5
Poster Designer
Imagine that you are working with a local community group to help stop
drug abuse among teenagers. Your first assignment is to design a drug
abuse awareness poster.
1. Complete a brief sketch of your idea on a sheet of paper. What effects
of drugs does your poster depict?
2. Why do you think teenagers will pay attention to your poster?
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Section:
Section Outline
Section 35-5
35–5
Drugs and the Nervous System
A. Drugs That Affect the Synapse
1. Stimulants
2. Depressants
3. Cocaine
4. Opiates
5. Marijuana
6. Alcohol
7. Alcohol and Disease
B. Drug Abuse
Go to
Section:
Commonly Abused Drugs
Section 35-5
Drug Type
Medical Use
Examples
Effects on the body
Stimulants
Used to increase alertness,
relieve fatigue
Amphetamines
Increase heart and respiratory rates;
elevate blood pressure; dilate pupils;
decrease appetite
Depressants
Used to relieve anxiety,
irritability, tension
Barbiturates
Tranquilizers
Slow down the actions of the central
nervous system; small amounts cause
calmness and relaxation; larger
amounts cause slurred speech and
impaired judgement
Opiates
Used to relieve pain
Morphine
Codeine
Act as a depressant; cause
drowsiness, restlessness, nausea
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Section:
Videos
Click a hyperlink to choose a video.
Action Potential
Synaptic Transmission
Video 1
Action Potential
Click the image to play the video segment.
Video 2
Synaptic Transmission
Click the image to play the video segment.
Go Online
The latest discoveries in the nervous and immune systems
Interactive test
Articles on the human body
For links on the nervous system, go to www.SciLinks.org and enter the
Web Code as follows: cbn-0352.
For links on the human brain, go to www.SciLinks.org and enter the
Web Code as follows: cbn-0353.
For links on the senses, go to www.SciLinks.org and enter the
Web Code as follows: cbn-0354.
For links on drugs and drug abuse, go to www.SciLinks.org and enter
the Web Code as follows: cbn-0355.
Interest Grabber Answers
1. List three other examples of homeostasis that occur in organisms.
Accept all reasonable student examples that show an understanding of
homeostasis.
2. Why is homeostasis important to an organism?
Homeostasis allows an organism to remain in balance with its environment.
If homeostasis is not maintained, it can harm the organism or result in the
death of the organism.
Interest Grabber Answers
1. Think about tying the shoelace of a sneaker. Construct a flowchart that
shows what happens between your eyes and your brain, and between your
brain and your hands, when you tie a bow in the shoelace.
Students’ flowcharts should include: The eyes inform the brain about the
position of the hands and the shoelace; the brain signals the hands how to
move to begin to tie the bow; and so on.
2. How would the communications be different if you tried to tie the shoelace
with your eyes closed?
All information about the position of the shoelace would have to come from
the hands as they feel and manipulate the shoelace.
Interest Grabber Answers
1. Which brainlike functions can already be performed by computers?
Computation and data sorting
2. Which brainlike functions cannot be performed by computers?
Original thought and perception of emotions
3. How successful do you think you (or anyone) could be in designing a
computer that can perform all the functions of the human brain? Explain
your answer.
Students will likely say not successful, because a computer cannot be
designed to feel emotions.
Interest Grabber Answers
1. List ten things you observe about the room you are in.
Students will likely describe the shape and color of the room, what is written
on the chalkboard, whether doors or windows are open, how bright the
lighting is, the temperature, ticking of a clock, rustling of papers, and so on.
2. Next to each observation, write the sense that you used to make
that observation.
Most observations are likely to be based on sight and hearing. If students list
only visual observations, have them make some observations with their
eyes closed.
3. What sense did you use most?
Possible answer: sight
Interest Grabber Answers
1. Complete a brief sketch of your idea on a sheet of paper. What effects of
drugs does your poster depict?
Possible answer: negative effects on the brain, which may result in various
types of injuries or death.
2. Why do you think teenagers will pay attention to your poster?
Answers will depend on the design of the poster. Teenagers may respond
to concern about loss of mental or athletic ability or concern about possible
injuries.
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