Chapter 17: Special Senses (Smell)

Question 1

Sense of Smell

Answer 1

OLFACTION

Question 2

The receptors for the sense of smell
o located in the olfactory epithelium of the nose.
With a total area of 5 cm2 (a little less than 1
in.2

Answer 2

 Olfaction

Question 3

occupies the superior part of the nasal cavity,
covering the inferior surface of the cribriform
plate and extending along the superior nasal
concha

Answer 3

Olfactory epithelium

Question 4

The olfactory epithelium consists of three kinds
of cells

Answer 4

olfactory receptor cells, supporting
cells, and basal cells

Question 5

the first-order neurons of the olfactory
pathway.
o Each olfactory receptor cell is a bipolar neuron
with an exposed, knob-shaped dendrite and an
axon projecting through the cribriform plate
that ends in the olfactory bulb.

Answer 5

 Olfactory Receptor cells

Question 6

o Extending from the dendrite of an olfactory
receptor cell are several nonmotile

Answer 6

olfactory
cilia,

Question 7

the conversion of
stimulus energy into a
graded potential in a
sensory receptor

Answer 7

 Transduction

Question 8

Within the plasma membranes of the olfactory
cilia are _________ proteins that
detect inhaled chemicals.

Answer 8

Olfactory receptor

Question 9

Chemicals that bind to and stimulate the
olfactory receptors in the olfactory cilia are
called

Answer 9

odorants

Question 10

Olfactory receptor cells respond to the
chemical stimulation of an odorant molecule
by producing a receptor potential, thus
initiating the

Answer 10

olfactory response.

Question 11

are columnar epithelial cells of the mucous
membrane lining the nose.
o They provide physical support, nourishment,
and electrical insulation for the olfactory
receptor cells and help detoxify chemicals that
come in contact with the olfactory epithelium.

Answer 11

Supporting Cells

Question 12

are stem cells located between the bases of
the supporting cells.
o They continually undergo cell division to
produce new olfactory receptor cells, which
live for only about two months before being
replaced. This process is remarkable
considering that olfactory receptor cells are
neurons, and as you have already learned,
mature neurons are generally not replaced.

Answer 12

Basal Cells

Question 13

Within the connective tissue that supports the
olfactory epithelium are _______ or
Bowman’s glands
o produce mucus that is carried to the surface of
the epithelium by ducts.

Answer 13

olfactory glands

Question 14

a flammable colorless gas with unpleasant
odor described as rotten cabbage
o used as a gas odorant

Answer 14

Methyl Mercaptan

Question 15

On each side of the nose, some 40 or so
bundles of axons of olfactory receptor cells
form the right and left ______
o The __________ pass through the
olfactory foramina of the cribriform plate of the
ethmoid bone and extend to parts of the brain
known as the olfactory bulbs

Answer 15

olfactory (I) nerves

Question 16

contain ball-like arrangements called
glomeruli (= little balls; singular is glomerulus)
o Within each glomerulus, axons of olfactory
receptor cells converge onto mitral cells

Answer 16

Olfactory Bulbs

Question 17

the second order neurons of the olfactory
pathway.
o Each glomerulus receives input from only one
type of olfactory receptor. This allows the
mitral cells of a particular glomerulus to convey
information about a select group of odorants to
the remaining parts of the olfactory pathway

Answer 17

Mitral cells

Question 18

The axons of the mitral cells form the olfactory
tract

Answer 18

Olfactory tract

Question 19

Some of the axons of the olfactory tract project
to the ___________ in the temporal
lobe of the cerebral cortex, where conscious
awareness of smell occurs

Answer 19

primary olfactory area

Question 20

a pathway extends via the thalamus

Answer 20

Olfactory cortex

Question 21

Frontal lobe, where odor identification and
discrimination occur.

Answer 21

Orbital cortex