Download Sensory System #3

Biology 30 Reading Notes
Section 12.3
Pages 419-429
Name:______________________
Mechanoreception and Chemoreception

Human senses go beyond vision. They include the senses of
__________, __________, __________, and __________, as well as
internal senses, such as the sense of __________.
Hearing and Balance

When we communicate, ___________ is often our most important sense.

Sense receptors in the muscles and ears provide constant information
about the body’s _______________ in __________. This sensory input
gives us our sixth sense of _______________.

The specialized sensory receptor cells for both hearing and balance are
_______________.

The _______________ system detects tiny movements of particles as
fluctuations in air pressure, and they are called __________ __________.

___________________ in the inner ear convert the energy of sound
waves into the ______________________energy that the brain perceives
as ____________.

There are three major divisions of the ear- the _________ ______,
_________ ______, and __________ _____.

The outer ear consists of the _________ and _________ ______.
o The ________ is the outside flap of the ear and is made of ______
and _______________. It is shaped in a way that
_______________ sound vibrations and _______________ them
into the ear.
o The _________ ______is a tube (2.5 cm long) that leads to the
_______________ in the middle ear. It _______________ sound
waves. ________ and ____________ protect the ear from foreign
materials going deeper into the ear.

The middle ear is an air filled space that is bordered on one side by the
_______________ (________________ ______________).
o The _______________ is a round, elastic structure that
_______________ in response to sound waves. These vibrations
are then passed on and _______________ by the neighbouring
_______________.
o Ossicles are three tiny, _______________ bones in the middle ear,
they are the _______________ bones in the body. Each bone acts
as a ____________ for the next, so that a small movement in one
results in a ___________ movement in the next. The strength of
the vibrations is _______________ as they pass from the
_______________ (hammer) to the __________ (anvil) and finally
to the __________ (stirrup). The stapes concentrates vibrations
into the membrane-covered opening in the wall of the inner ear,
called the ________ _______.
o The middle is connected to the throat by the thin ______________
__________. This tube allows air pressure to equalize when there
is a _______________ in air pressure.

The inner ear consists of three interconnecting structures: the
_____________ __________, the _______________, and the
_______________.
o The semicircular canals and vestibule contain sensors for
_______________.
o The _______________ is used for hearing. It is within the
structures of the cochlea that the _______________ energy of
sound is converted into the _______________ impulses that are
transmitted to the __________. Because the inner ear is fluid-filled,
vibrations in the oval window must be _______________ to
pressure waves in the fluid.
o Parts of the cochlea: the middle chamber contains the _______
___ ______________, which is the organ of hearing. Along the
base of the organ of Corti is the _______________ _________, to
which sensory mechanoreceptors known as hair cells are attached.
The hair cells have thin _______________ called
_______________, which stick out at the top of the cells. The far
ends of the stereocilia are embedded within the _______________
membrane.

How we hear:
o When the _______________ strikes the _______ ________, this
vibrates the window and creates pressure waves in the fluid of the
_______________. The pressure waves make the ____________
membrane to move up and down, which causes the
_______________ of the hair cells to bend against the
_______________ membrane. The hair cells, which ___________
the nerve fibres of the auditory nerve, sense the bending of the
stereocilia and relay this message to the _______________. The
nerves then send an impulse to the _______________.
Frequencies of Sound

Different areas of the organ of Corti are sensitive to different
_______________. High frequencies stimulate the hair cells __________
to the oval window. Low frequencies stimulate the hair cells ___________
from the oval window.
Hearing Loss

Hearing loss generally results from _____________ __________or
damage to the sound _______________ system of the outer or middle
ear. Birth defects, _____ __________, noise and aging are common
causes of hearing loss.
The Perception of Sound

Sensory neurons in the ear send information through the _____________
nerve to the brain stem, _______________, and ultimately the
_______________lobes of the cerebrum for processing.
Balance and coordination

Three major structures in the inner ear help us ________ _______and
move without losing our _______________.
o _______________ canals contain mechanoreceptors that detect
head and body _______________ (rotational equilibrium). The
semicircular canals are ________ fluid-filled loops, arrange in three
different ___________.
o The balance required while moving the head forward and backward
is called _______________ equilibrium, and depends on the
________ and the ____________. Together they make up the
fluid-filled _______________ of the inner ear. Both of these
structures contain _______________ _______________ granules
called _______________. When the head dips forward or back,
_______________ pulls on the _______________. This puts
pressure on some of the hair cells, causing them to send a
__________ _______________ to the brain, indicating the position
of the head.

_______________ are another type of mechanoreceptor involved in
coordination. They are found in _______________, tendons, and joints
throughout the body, and they send information about body
_______________ to the brain.
Taste

The tongue contains _______________ that allow us to taste substances
entering the mouth.

Most scientists recognize four basic tastes: _______, ________, ______
and _________. Specific molecules dissolved in the saliva are detected
by the taste buds: the sensory receptors in the bumps
(_______________) on the tongue.

Impulses from the ________ _______travel to areas of the brain stem, to
the _______________, and then to the _______________ centre of the
_______________ lobe.
Smell

Scientists think that each odour is produced from particles that fit, much
like a lock and key, into specific _______________, called
_______________ cells, lining the upper nasal cavity. When they bind to
the _______________cells, ______ _________in the cell membrane
open. This generates an ______________ ________________in the
_______________ cells, which are directly linked to the olfactory bulb of
the brain. It ends up at the _______________ lobe, where the perception
of odour occurs.

The sense of smell is closely linked to the sense of _______________.
As much as _______________percent of what we perceive as taste is
actually due to the sense of smell.

Many animals release substances called _______________ that aid in the
recognition and attraction of a mate.
Touch

The _______________ associated with the sense of touch are located all
over the body, but they are not _______________ distributed.

Pain is a _______________sense that occurs when specialized sensors
or nerve endings in the skin are activated by _______________ pressure
or _______________ signals.
Sensation and Homeostasis

The _______________ relay information to the _______________
_______________that allows the body to maintain _______________.