Test your knowledge of some of the terms of the sensory system by completing the following crossword puzzle.
ACROSS
1. Protrusions of the tongue on which taste buds are located
5. Pain receptors
8. Pain originating in a deep organ that’s sensed on the body’s surface
9. Receptors that respond to stretch
11. Specialized nerve cells that detect physical or chemical events outside the cell membrane 12. Receptor that allows you to orient your body in
space
13. Drug used to relieve pain
DOWN
2. Receptors found only in the eyes
3. Type of pain fiber that produces sharp, localized 4. painReceptors activated by a change in temperature 6. When a stimulus is continuous, the firing
frequency of the nerve begins to slow, causing the sensation to diminish; this is known as 7. Receptors that react to odors.
10. Type of pain fiber found on deep body organs
Drawing Conclusions:
Pain Pathway
Review each step in the body’s main pain pathway by filling in the blanks in the following sentences. As you go along, insert arrows in the figure to identify the pathway. Then color the key structures in the figure as desired.
1. Injured tissues release several chemicals that stimulate the and trigger pain.
2. A neuron conducts a pain signal to the horn of the spinal cord and
then up the tract to the .
3. At the same time, the tract carries pain signals to the reticular
formation of the .
4. The thalamus relays the signal from the tract to the
of the . At that point, the person becomes aware of the pain.
5. The impulse from the spinoreticular tract bypasses the and travels to
the and system. These areas trigger
and responses to pain, such as
fear and nausea.
Thalamus
Spinal cord Brainstem
Spinothalamic tract
Dorsal ganglion Reticular
formation
Spinal cord
2 4 3
5
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Fill in the Gaps:
Sense of Smell
Fill in the blanks to describe how the sense of smell occurs. Choose from the words listed in the Word Bank. (Hint: Not all the words will be used.)
CILIA CRANIAL ETHMOID
NASAL OLFACTORY OLFACTORY BULBS
PAPILLAE PRIMARY OLFACTORY
SPHENOID
1. Receptors for the sense of smell, called receptors, are buried in the roof of the cavity.
2. Incoming odor molecules bind to projecting from the ends of the receptor cells.
3. This triggers a nerve impulse along nerve fibers leaving the nasal cavity through pores in the bone.
4. The fibers synapse with other neurons in , a pair of
structures underneath the brain’s frontal lobe.
5. After being partially processed here, the signals continue to the cortex in the brain.
Just the Highlights:
Sections of the Ear
The ear has three sections: the outer ear, the middle ear, and the inner ear. In the following list, highlight the structures of the outer ear pink, the middle ear blue, and the inner ear yellow.
1. Eustachian tube 2. Bony labyrinth 3. Auricle 4. Vestibule 5. Auditory canal
6. Cochlea
7. Auditory ossicles 8. Tympanic membrane 9. Semicircular canals
140 Chapter 11 Sense Organs
1. The is the visible part of the ear. Its main function is to funnel
into the ear. (Color this part of the ear tan.)
2. The leads through the temporal bone to the
eardrum. Glands in this part of the ear secrete . (Outline this structure in red.)
3. The malleus, incus, and stapes are called the ; they connect the
to the ear. (Color the malleus pink, the incus blue, and the stapes green.) 4. The stapes fits in the window of the . (Outline this window in dark blue.)
5. The separates the outer ear from the middle ear. It vibrates
in response to . (Color this structure orange.)
6. The tube is a passageway from the middle ear to the nasopharynx. Its purpose is to equalize on both sides of the tympanic membrane. (Color this structure purple.)
7. The lie at right angles to each other and are crucial
for the maintenance of balance. (Color this structure green.)
8. The marks the entrance to the labyrinths and contains organs necessary for the sense of balance. (Color this structure light blue.)
9. The is a snail-like structure that contains the organ of Corti. (Color this structure brown.) 10. The two nerves leading from the ear are the nerve, which is linked to the vestibule, and the
nerve, which leaves from the cochlea. (Color these two nerves pink and yellow, respectively.) Drawing Conclusions:
The Ear
Improve your understanding of ear structures and functions by filling in the blanks in the following sentences.
Color the structures as described in the figure below.
Outer ear Middle ear Inner ear
Drawing Conclusions:
How Hearing Occurs
The structures of the inner ear are essential for hearing. Test your knowledge of these structures by coloring them as described in the figure.
● Cochlear duct: Green
● Tectorial membrane: Orange
● Basilar membrane: Purple
1. Sound waves enter the ear and travel down the .
The waves strike the , causing it to vibrate.
● Hair cells on the organ of Corti: Yellow
● Cochlear nerve: Tan
Next, describe the process of hearing by completing the following sentences. Insert arrows into the figure to show the progression of sound waves.
142 Chapter 11 Sense Organs