Question

equilibrium
the equilibrium sense is not easy to describe because it does not “see,” “hear,” or “feel.” what it does is respond (frequently without our awareness) to various head (1). the equilibrium receptors of the inner ear, collectively called the vestibular apparatus, can be divided into two branches— one branch is responsible for monitoring static equilibrium, and the other monitors dynamic equilibrium.
static equilibrium
within the membrane sacs of the vestibule are (2) called maculae (mak’u-le; “spots”) that are essential to our sense of static equilibrium (figure 8.12). the maculae report on changes in the position of the head in space with respect to the pull of gravity when the body is not moving (static = at rest). because they provide information on which way is up or down, they help us keep our head erect. the (3) are extremely important to divers swimming in the dark depths (where most other orienting cues are absent), enabling them to tell which way is up (to the surface). each macula is a patch of receptor (hair) cells with their “hairs” embedded in the otolithic membrane, a gelatinous mass studded with otoliths (o’tô-liths), tiny stones made of calcium salts. as the head moves, the (4) roll in response to changes in the pull of gravity. this movement creates a pull on the gel, which in turn bends the hairs of the hair cells. bending activates the hair cells, which send impulses along the vestibular nerve (a division of cranial nerve viii) to the (5) of the brain, informing it of the position of the head in space.

1. cerebellum 2. movements 3. receptors 4. maculae 5. otoliths
2. movements 2. receptors 3. maculae 4. otoliths 5. cerebellum
3. receptors 2. maculae 3. otoliths 4. cerebellum 5. movements
4. otoliths 2. cerebellum 3. movements 4. receptors 5. maculae
5. maculae 2. otoliths 3. cerebellum 4. movements 5. receptors

Explanation:

• For the first blank, the equilibrium sense responds to head "movements" as it's about how the head changes position.
• The membrane sacs of the vestibule have "receptors" (maculae are a type of receptor).
• The maculae (receptors) are important for divers, so the third blank is "maculae".
• As the head moves, the "otoliths" (tiny calcium - salt stones) roll.
• Impulses are sent to the "cerebellum" (a part of the brain involved in balance - related processing).

Answer:

1. movements 2. receptors 3. maculae 4. otoliths 5. cerebellum