Transcript The Nervous System

THE PROGRAMMING IN GENES
From what thing did He create him?
From a drop of sperm He created him
and proportioned him. Then He eases
the way for him. (Qur'an, 80:18-20)
Allah knows what every female bears
and every shrinking of the womb and
every swelling. Everything has its
measure with Him. (Qur'an, 13:8)
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35–1 Human Body Systems
The levels of organization in a
multicellular organism include:
•cells
•tissues
•organs
•organ systems
Every cell in the human body is both an
independent unit and an interdependent
part of a larger community—the entire
organism.
Cells
A cell is the basic unit of structure and
function in living things.
Individual cells in multicellular organisms
are specialized.
Specialized cells are suited to perform a
particular function.
Tissues
A group of cells that perform a
single function is called a tissue.
There are four basic types of
tissue in the human body:
epithelial, connective, nervous,
and muscle.
Organization of the
Body
Epithelial tissue includes glands and tissues that
cover interior and exterior body surfaces.
Connective tissue supports the body and
connects its parts.
Nervous tissue transmits nerve impulses through
the body.
Muscle tissue, along with bones, enables the
body to move.
Organs and Organ Systems
A group of different types of tissues that
work together to perform a single
function is called an organ.
A group of organs that perform closely
related functions is an organ system.
There are eleven organ systems in the
body.
Nervous System
Structures: Brain,
spinal cord, peripheral
nerves
Function: Recognizes
and coordinates the
body’s response to
changes in its internal
and external
environments
Integumentary System
Structures: Skin, hair,
nails, sweat and oil
glands
Function: Serves as a
barrier against infection
and injury; helps to
regulate body
temperature; provides
protection against
ultraviolet radiation from
the sun
Skeletal System
Structures: Bones,
cartilage, ligaments,
tendons
Function: Supports the
body; protects internal
organs; allows
movement; stores
mineral reserves;
provides a site for
blood cell formation
Muscular System
Structures: Skeletal
muscle, smooth muscle,
cardiac muscle
Function: Works with
skeletal system to
produce voluntary
movement; helps to
circulate blood and move
food through the digestive
system
Circulatory System
Structures: Heart, blood
vessels, blood
Function: Brings
oxygen, nutrients, and
hormones to cells;
fights infection;
removes cell wastes;
helps to regulate body
temperature
Respiratory System
Structures: Nose,
pharynx, larynx,
trachea, bronchi,
bronchioles, lungs
Function: Provides
oxygen needed for
cellular respiration and
removes excess carbon
dioxide from the body
Digestive System
Structures: Mouth,
pharynx, esophagus,
stomach, small and
large intestines, rectum
Function: Converts
food into simpler
molecules that can be
used by the cells of the
body; absorbs food;
eliminates wastes
Excretory System
Structures: Skin, lungs,
kidneys, ureters,
urinary bladder, urethra
Function: Eliminates
waste products from
the body in ways that
maintain homeostasis
Endocrine System
Structures: Hypothalamus,
pituitary, thyroid, parathyroid,
adrenals, pancreas, ovaries (in
females), testes (in males)
Function: Controls
growth,
development and
metabolism; maintains
homeostasis
Reproductive System
Structures: Testes,
epididymis, vas
deferens, urethra, and
penis (in males),
ovaries, Fallopian tubes,
uterus, vagina (in
females)
Function: Produces
reproductive cells; in
females, nurtures and
protects developing
embryo
Lymphatic/Immune
Systems
Structures: White blood
cells, thymus, spleen,
lymph nodes, lymph
vessels
Function: Helps protect the
body from disease; collects
fluid lost from blood
vessels and returns the
fluid to the circulatory
system
Homeostasis is the process by
which organisms keep internal
conditions relatively constant
despite changes in external
environments.
Homeostasis in the body is
maintained by feedback inhibition.
Feedback inhibition, or negative feedback, is the
process in which a stimulus produces a response
that opposes the original stimulus.
Systems controlled by feedback inhibition are
fully automated and very stable.
An Example of Feedback Inhibition
Thermostat senses
temperature change
and switches off
heating system
Room temperature
increases
Room temperature
decreases
Thermostat senses
temperature change
and switches on
heating system
Homeostasis In the Body
Maintenance of homeostasis requires the
integration of all organ systems at all
times.
One example is the maintenance of a
stable body temperature.
The hypothalamus monitors the temperature of
the skin and the temperature of organs.
If core body temperature drops, the
hypothalamus:
• causes blood vessels in the skin to
constrict reducing heat loss from skin.
• causes the skeletal muscles to contract
involuntarily—to “shiver.”
This causes the body temperature to
increase.
If the core body temperature increases, the
hypothalamus:
• causes blood vessels in the skin to
dilate so heat can escape from the skin.
• the body produces sweat, which cools
the body by evaporation.
This causes the body temperature to
decrease.
35–1 Human Body Systems
THE SEQUENCE IN DEVELOPMENT OF HUMAN ORGANS
It is He Who has created hearing, sight and minds for
you. What little thanks you show! (Qur'an, 23:78)
Allah brought you out of your mothers' wombs
knowing nothing at all, and gave you hearing, sight
and minds so that perhaps you would show thanks.
(Qur'an, 16:78)
Say: "What do you think? If Allah took away your
hearing and your sight and sealed up your hearts,
what god is there, other than Allah, who could give
them back to you?"… (Qur'an, 6:46)
We created man from a mingled drop to test him, and
We made him hearing and seeing. (Qur'an, 76:2)
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35–1 Human Body Systems
The Nervous System
"But if anyone turns away from My reminder, his
life will be a dark and narrow one..." (Qur'an,
20:124)
“When Allah desires to guide someone, He
expands his breast to Islam. When He desires to
misguide someone, He makes his breast narrow
and constricted as if he were climbing up into the
sky. That is how Allah defiles those who have no
faith. “(Qur'an, 6:125)
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35-2 The Nervous System
The nervous system controls and
coordinates functions throughout the body
and responds to internal and external
stimuli.
Neurons
• The messages carried by the nervous
system are electrical signals called
impulses.
• The cells that transmit
impulses (electrical signals) are
called neurons.
Neurons are classified according to
the direction in which an impulse
travels.
• Sensory neurons carry impulses from the
sense organs to the spinal cord and brain.
• Motor neurons carry impulses from the
brain and spinal cord to muscles and
glands.
• Interneurons connect sensory and motor
neurons and carry impulses between
them.
Structures of a Neuron
Nucleus
Dendrites
Axon
terminals
Cell body
Myelin sheath
Nodes
Axon
Neurons
The largest part of a typical neuron is the cell
body.
It contains the nucleus and much of the
cytoplasm.
Cell body
Neurons
Dendrites extend from the cell body and carry
impulses from the environment toward the cell
body.
Dendrites
Neurons
The axon is the long fiber that carries impulses
away from the cell body.
Axon
terminals
Axon
Neurons
The axon ends in axon terminals.
Axon
terminals
Axon
Neurons
The axon is sometimes surrounded by an
insulating membrane called the myelin sheath.
There are gaps in the myelin sheath, called
nodes, where the membrane is exposed.
Impulses jump from one node to the next.
Myelin sheath
Nodes
The Nerve Impulse
The Resting Neuron
• When resting, the outside of the neuron
has a net positive charge.
• The inside of the neuron has a net
negative charge.
• The cell membrane is electrically
charged because there is a difference
in electrical charge between its outer
and inner surfaces.
The Nerve Impulse
The sodium-potassium pump in the nerve cell
membrane pumps sodium (Na+) ions out of the
cell and potassium (K+) ions into the cell by
means of active transport.
As a result, the inside of the cell contains more
K+ ions and fewer Na+ ions than the outside.
The Nerve Impulse
• Sodium-Potassium Pump
The Nerve Impulse
More K+ ions leak across the membrane than Na+
ions. This produces a negative charge on the
inside and a positive charge on the outside.
The electrical charge across the cell membrane of
a neuron at rest is known as the resting potential.
The Nerve Impulse
The Moving Impulse
An impulse begins when a neuron
is stimulated by another neuron
or by the environment.
Khan Academy Video
The Nerve Impulse
At the leading edge of the impulse, gates in the
sodium channels open allowing positively
charged Na+ ions to flow inside the cell
membrane.
The Nerve Impulse
The inside of the membrane temporarily becomes
more positive than the outside, reversing the
resting potential.
The Nerve Impulse
This reversal of charges is called a nerve
impulse, or an action potential.
The Nerve Impulse
As the action potential passes, gates in the
potassium channels open, allowing K+ ions to
flow out restoring the negative potential inside
the axon.
The Nerve Impulse
The impulse continues to move along the axon.
An impulse at any point of the membrane causes
an impulse at the next point along the membrane.
The Nerve Impulse
Threshold
• A stimulus must be of adequate
strength to cause a neuron to transmit
an impulse.
• The minimum level of a stimulus that is
required to activate a neuron is called
the threshold.
The Nerve Impulse
• A stimulus that is stronger than the
threshold produces an impulse.
• A stimulus that is weaker than the
threshold produces no impulse.
The Synapse
The Synapse
• At the end of the neuron, the impulse
reaches an axon terminal. Usually the
neuron makes contact with another cell
at this site.
• The neuron may pass the impulse
along to the second cell.
• The location at which a neuron can
transfer an impulse to another cell is
called a synapse.
The Synapse
• A Synapse
movie
The Synapse
The synaptic cleft
separates the axon
terminal from the
dendrites of the
adjacent cell.
Synaptic cleft
Terminals contain
vesicles filled with
neurotransmitters.
Neurotransmitters
are chemicals
used by a neuron
to transmit an
impulse across a
synapse to
another cell.
The Synapse
Vesicle
Neurotransmitter
• As an impulse
reaches a
terminal, vesicles
send
neurotransmitters
into the synaptic
cleft.
• These diffuse
across the cleft
and attach to
membrane
receptors on the
next cell.
The Synapse
Receptor
The Synapse
Sodium ions then rush across the membrane,
stimulating the next cell.
If the stimulation exceeds the cell’s threshold, a
new impulse begins.
The Synapse
Moments after binding to receptors,
neurotransmitters are released from the cell
surface.
The neurotransmitters may then be broken down
by enzymes, or taken up and recycled by the
axon terminal.
35-3 Divisions of the Nervous System
The human nervous system has
two major divisions:
a. central nervous system
b. peripheral nervous system
The central nervous system
relays messages, processes
information, and analyzes
information.
a.The central nervous system
consists of the brain and the
spinal cord.
b. Both the brain and spinal cord are
wrapped in three layers of
connective tissue known as
meninges.
Between the meninges and the central
nervous system tissue is a space filled
with cerebrospinal fluid.
Cerebrospinal fluid acts as a shock
absorber that protects the central nervous
system.
Cerebrospinal fluid also permits exchange
of nutrients and waste products between
blood and nervous tissue.
The Brain
a. The brain is the place to which
impulses flow and from which
impulses originate.
Parts of The Human Brain FIGURE 35-9
Cerebrum
Thalamus
Pineal gland
Hypothalamus
Pituitary gland
Cerebellum
Pons
Brain stem
Medulla
oblongata
Spinal cord
The Cerebrum
a. The largest and most prominent
region of the human brain is the
cerebrum.
b. It controls
the voluntary, or
conscious, activities of the
body.
c. It is the site of intelligence, learning,
and judgment.
A deep groove divides the cerebrum into
hemispheres, which are connected by a
band of tissue called the corpus callosum.
Each hemisphere is divided into regions
called lobes.
Lobes of the Cerebrum
Each half of the cerebrum deals with the
opposite side of the body:
a. The left half of the cerebrum
controls the right side of the body.
b. The right half of the cerebrum
controls the left side of the body.
The outer layer of the cerebrum is called
the cerebral cortex and consists of gray
matter.
The inner layer of the cerebrum consists of
white matter, which is made up of bundles
of axons with myelin sheaths.
The Cerebellum
a. The second largest region of the
brain is the cerebellum.
b.It coordinates and balances
the actions of the muscles so
that the body can move gracefully
and efficiently.
Cerebellum
The Brain Stem
a. The brain stem connects the brain and
spinal cord.
b. It has two regions: the
pons and the
medulla oblongata regulate
information flow between the
brain and the rest of the body.
c.Blood pressure, heart rate,
breathing, and swallowing are
controlled in the brain stem.
Pons
Brain stem
Medulla oblongata
The Thalamus and Hypothalamus
a. The thalamus receives messages
from all sensory receptors
throughout the body and relays the
information to the proper region of
the cerebrum for further processing.
a.The hypothalamus controls
recognition and analysis of
hunger, thirst, fatigue, anger,
and body temperature.
b. It controls coordination of the
nervous and endocrine systems.
Thalamus
Hypothalamus
The Spinal Cord
a. The spinal cord is the main
communications link between the
brain and the rest of the body.
b. Certain information, including
some kinds of reflexes, are
processed directly in the
spinal cord.
c. A reflex is a quick, automatic
response to a stimulus.
The Peripheral Nervous System
a.The peripheral nervous system is
all of the nerves and associated
cells that are not part of the brain
and the spinal cord.
b. The peripheral nervous system includes
cranial nerves, spinal nerves, and ganglia.
c. Ganglia are collections of nerve cell
bodies.
The sensory division of the
peripheral nervous system
transmits impulses from sense
organs to the central nervous
system.
The motor division transmits
impulses from the central
nervous system to the muscles
or glands.
The motor division is divided into the
somatic nervous system and the
autonomic nervous system.
The Somatic Nervous System
a.The somatic nervous system
regulates activities that are
under conscious control, such
as the movement of skeletal
muscles.
b.Some somatic nerves are
involved with reflexes = react to
pain.
A reflex arc includes a sensory receptor,
sensory neuron, motor neuron, and
effector that are involved in a quick
response to a stimulus.
Sensory neuron
a. Reflex Arc
Motor
neuron
Interneuron
Spinal cord
Effector (responding
muscle)
Sensory
receptors
The Autonomic Nervous System
a.The autonomic nervous
system regulates involuntary
activities.
b. The autonomic nervous system is
subdivided into two parts:
sympathetic nervous system
parasympathetic nervous system
The sympathetic and
parasympathetic nervous
systems have opposite effects on
the same organ system.
These opposing effects help maintain
homeostasis.
35–4 The Senses
Neurons that react directly to stimuli from
the environment are called sensory
receptors.
Sensory receptors react to stimuli
by sending impulses to other
neurons and to the central
nervous system.
Sensory receptors are located throughout
the body but are concentrated in the sense
organs.
Sense organs include the:
a.eyes
b.ears
c.nose
d.mouth
e.skin
5 categories of sensory receptors:
a.pain receptors
b.Thermoreceptors- heat
c.Mechanoreceptors- pressure
d.Chemoreceptors- chemicals
NOSE & TASTE BUDS
e.Photoreceptors- light
EYES
Pain receptors are located throughout the
body except in the brain.
They respond to chemicals released by
damaged cells.
Pain usually indicates danger, injury, or
disease.
Thermoreceptors are located in the skin,
body core, and hypothalamus.
They detect variations in temperature.
Mechanoreceptors are found in the skin,
skeletal muscles, and inner ears.
They are sensitive to touch, pressure,
stretching of muscles, sound, and motion.
Chemoreceptors, located in the nose and
taste buds, are sensitive to chemicals in
the external environment.
Photoreceptors, found in the eyes, are
sensitive to light.
Vision
a. The sense organ that animals use to
sense light is the eye.
b. The eye has three layers:
the retina
the choroid
the sclera
The retina is the inner layer of
eye that contains
photoreceptors.
Retina
The choroid is the middle layer of eye that
is rich in blood vessels.
Choroid
The sclera is the outer layer of eye that
maintains its shape.
The sclera serves as point of attachment
for muscles that move the eye.
Sclera
ACTIVE ART
Light enters the eye through the cornea,
a tough transparent layer of cells.
Cornea
The cornea helps focus light, which
then passes through a chamber filled
with a fluid called aqueous humor.
Aqueous
humor
Cornea
At the back of the chamber is a disklike
structure called the iris, which is the
colored part of the eye.
Iris
In the middle of the iris is a small opening
called the pupil. Muscles in the iris adjust
pupil size to regulate the amount of light
that enters the eye.
Pupil
In dim light, the pupil becomes larger.
In bright light, the pupil becomes
smaller.
Just behind the iris is the lens.
Muscles attached to the lens change its
shape to adjust focus to see near or
distant objects.
Lens
Behind the lens is a large chamber filled
with a transparent, jellylike fluid called
vitreous humor.
Vitreous humor
The lens focuses light onto the
retina.
Photoreceptors are arranged in a layer in
the retina.
Retina
The photoreceptors convert light
energy into nerve impulses that
are carried to the central nervous
system.
There are two types of photoreceptors:
rods and cones.
Rods are sensitive to light, but
not color.
Cones respond to light of
different colors, producing color
vision.
Cones are concentrated in the fovea,
which is the site of sharpest vision.
Fovea
There are no photoreceptors where the
optic nerve passes through the back of the
eye, which is called the blind spot.
The impulses leave each eye by way of the
optic nerve. Optic nerves carry impulses
to the brain.
The brain interprets them as visual images
and provides information about the
external world.
Optic nerve
The Ear
a.The human ear has two
sensory functions:
hearing
balance
Hearing
a. Ears can distinguish both the pitch
and loudness of those vibrations.
The Human Ear Figure 35-14 pg908
Locate- Tympanum, hammer, anvil, stirrup,
& cochlea
Vibrations enter the ear through the
auditory canal.
Auditory
canal
The vibrations
cause the
tympanum, or eardrum, to vibrate.
Tympanum
The vibrations are picked up by the
hammer, anvil, and stirrup.
Hammer
Anvil
Stirrup
The stirrup transmits the
vibrations to the oval window.
Stirrup
Oval window
Vibrations of the oval window
create pressure waves in the fluidfilled cochlea of the inner ear.
Cochlea
The fluid-filled cochlea is lined
with tiny hair cells that are
pushed back and forth by these
pressure waves.
In response to the waves, the
hair cells
produce nerve impulses that are
sent to the brain through the cochlear
nerve.
Balance
a. Your ears help you to maintain your
balance, or equilibrium.
Within the inner ear, just above the
cochlea are three semicircular canals.
Semicircular canals
The canals are filled with fluid and lined
with hair cells.
As the head changes position, fluid in the
canals changes position, causing the hair
on the hair cells to bend.
This sends impulses to the brain that
enable it to determine body motion and
position.
Smell
a. The sense of smell is actually an
ability to detect chemicals.
b. Chemoreceptors in the nasal
passageway respond to chemicals
and send impulses to the brain
through sensory nerves.
Taste
a. The sense of taste is also a chemical
sense.
b. The sense organs that detect taste
are the taste buds. Most taste buds
are on the tongue.
c. Tastes detected by the taste buds
are classified as salty, bitter, sweet,
and sour.
d. Sensitivity to these tastes varies on
different parts of the tongue.
Touch and Related Senses
a. The skin’s sensory receptors
respond to temperature, touch, and
pain.
b. Not all parts of the body are equally
sensitive to touch, because not all
parts have the same number of
receptors.
c. The greatest density of sensory
receptors is found on your fingers,
toes, and face.
35–5 Drugs and the Nervous
System
A drug is any substance, other than food,
that changes the structure or function of
the body.
Some drugs, such as cocaine and heroin
are illegal. Other drugs, such as penicillin
and codeine are prescribed by doctors.
Still other drugs, including cough
medicines can be purchased over the
counter.
All drugs can be harmful if used
improperly or abused.
Drugs differ in the ways in which they
affect the body.
a. Some kill bacteria and are useful in
treating disease.
b. Others affect a particular system of
the body.
c. Others cause changes to the brain
and synapses.
Stimulants
Stimulants increase heart rate, blood
pressure, and breathing rate. In addition,
stimulants increase the release of
neurotransmitters at some synapses in the
brain.
Common stimulants include amphetamines,
cocaine, nicotine, and caffeine.
Depressants
a. Depressants slow down heart
rate and breathing rate, lower
blood pressure, relax muscles,
and relieve tension.
b. Barbiturates, tranquilizers, and
alcohol are some examples of
depressants.
Cocaine
a. Cocaine causes the sudden release
in the brain of a neurotransmitter
called dopamine.
b. Cocaine also acts as a powerful
stimulant.
Opiates
a. Opiates mimic endorphins which
normally help to overcome
sensations of pain.
b. Common opiates include
morphine and codeine.
Marijuana
a. The most widely abused illegal drug
is marijuana.
b. Marijuana comes from Cannabis
sativa, a hemp plant.
c. Hashish, or hash, is a potent form of
marijuana.
d. The active ingredient in marijuana is
THC.
Long-term use of marijuana can result in:
a. loss of memory
b. inability to concentrate
c. in males, reduced levels of the
hormone testosterone in males
a. Alcohol is a depressant that slows
down the rate at which the central
nervous system functions.
b. Alcohol slows down reflexes,
disrupts coordination, and impairs
judgment.
Heavy drinking fills the blood with so
much alcohol that the central nervous
system cannot function properly.
People who drink a lot of alcohol usually
cannot walk or talk properly, and they are
not able to safely control an automobile.
Pregnant women who drink alcohol risk
having a child with FAS.
Fetal alcohol syndrome (FAS) is a group of
birth defects caused by the effects of
alcohol on the fetus.
FAS can cause minor to serious brain
damage, heart defects, malformed faces,
delayed growth, and poor motor
development.
Alcohol and Disease
a. People who have become addicted
to alcohol suffer from a disease
called alcoholism.
b. If a person cannot function properly
without satisfying the craving for
alcohol, that person has an alcoholabuse problem.
c. Long-term alcohol use destroys liver
cells.
Drug Abuse
a. Drug abuse is the intentional misuse
of any drug for nonmedical
purposes.
b. Drug abuse can cause psychological
dependence or serious physical
damage to the body.
Uncontrollable dependence on a drug is
called an addiction.
Some drugs cause a strong psychological
dependence, or mental craving.
35–1
The type of tissue that holds organs in
place and binds different parts of the
body together is called
a. muscle tissue.
b. epithelial tissue.
c. connective tissue.
d. skeletal tissue.
35–
1
One major function of the
integumentary system is to
a. help regulate body temperature.
b. cause the body to move.
c. provide a surface for gas exchange.
d. control growth, development, and
metabolism.
35–
1
Which of the following is NOT an
example of feedback inhibition?
a. shivering to warm the body
b. sweating to cool the body
c. nervous tissue receiving messages
d. turning on the heating system of a
house
35–
1
The process by which an organism
keeps internal conditions relatively
constant is called
a. a feedback loop.
b. negative feedback.
c. homeostasis.
d. normal temperature.
Which of the following organ systems
transports oxygen, nutrients, and
hormones to cells?
a. circulatory system
b. muscular system
c. excretory system
d. nervous system
35-2
Neurons that carry impulses from the
brain and spinal cord to the muscles
are
a. interneurons.
b. sensory neurons.
c. resting neurons.
d. motor neurons.
35-2
The part of the neuron that carries
impulses toward the cell body is the
a. axon.
b. myelin sheath.
c. dendrite.
d. nodes.
35-2
The minimum level of a stimulus that is
required to activate a neuron is called
its
a. action potential.
b. resting potential.
c. threshold.
d. synapse.
35-2
Chemicals that are used by a neuron to
transmit impulses are called
a. neurotransmitters.
b. synapses.
c. axons.
d. inhibitors.
35-2
An action potential begins when
a. sodium ions flow into the neuron.
b. potassium ions flow into the neuron.
c. sodium and potassium ions flow
into the neuron.
d. sodium and potassium ions flow out
of the neuron.
35-3
The brain stem functions as
a. a location for memory and learning.
b. the control site responsible for heart rate,
blood pressure, and breathing.
c. the location where all sensory information is
processed and delivered to the cerebrum.
d. an area that recognizes hunger, thirst, and
body temperature.
35-3
The left half of the cerebrum largely controls
a. the left side of the body.
b. both the right and left sides of the body.
c. the right side of the body.
d. the right half of the brain.
35-3
The part of the brain that is responsible for
coordination and balance is the
a. cerebellum.
b. cerebrum.
c. brain stem.
d. thalamus.
35-3
Reflex arcs are actions that are a part of the
peripheral nervous system's
a. sensory division.
b. somatic system.
c. autonomic system.
d. motor division.
35-3
Which of the following is NOT under the control
of the autonomic nervous system?
a. heartbeat
b. digestion
c. walking
d. sweating
35–4
The sensory receptor that detects variations in
body temperature is a
a. chemoreceptor.
b. mechanoreceptor.
c. thermoreceptor.
d. photoreceptor.
35–4
The part of the eye containing tiny muscles that
adjust the size of the pupil is the
a. cornea.
b. iris.
c. lens.
d. retina.
35–4
The part of the ear that produces the nerve
impulses sent to the brain is the
a. tympanum.
b. Eustachian tube.
c. cochlea.
d. oval window.
35–4
The structures in your ears that help maintain
your sense of balance
a. is the auditory canal.
b. is the hammer.
c. is the tympanum.
d. are the semicircular canals.
35–4
Photoreceptors in the eye that are sensitive to
color are
a. rods.
b. cones.
c. rods and cones.
d. the optic nerve.
35–5
35–5
A drug that increases the heart rate and
breathing rate is a
a. depressant.
b. opiate.
c. stimulant.
d. barbiturate.
35–5
A powerful stimulant that increases blood
pressure and heart rate that can lead to a heart
attack is
a. cocaine.
b. opium.
c. marijuana.
d. caffeine.
35–5
Many drugs that affect the brain and behavior do
so because they
a. affect organ systems and those changes are
detected by the brain.
b. interfere with the normal functioning of
neurotransmitters.
c. cause the brain to release endorphins.
d. enter the cell bodies of brain neurons
causing them to behave differently.
35–5
True or False? Medically prescribed drugs
cannot cause addiction.
a. True
b. False
35–5
Alcohol acts on the brain as a
a. general stimulant of the nervous system.
b. general depressant of the nervous system.
c. pain reliever acting in the cerebrum.
d. stimulant of the brain stem and cerebellum.