Spinal Cord, Brainstem And Motor Fnx II (Obj. 3)

Question 1

Macula of the Utricle vs Saccule

Answer 1

Utricle
- Located on the HORIZONTAL plane

Saccule
- Located on the VERTICAL plane

Question 2

Cristina Ampullaris

Answer 2

Small CREST within each Ampulla

Question 3

Macula of the Utricle and Saccule Characteristics

Answer 3

• Covered by a GELATINOUS Layer
• Contains Ca2+ Crystals
• Contains Hair cells which project cilia into gel layer
• Weight of Statoconia bends cilia in the direction of GRAVITY

Question 4

The Vestibular Apparatus can detect what?

Answer 4

• Detect Angular acceleration of head
  (Semicircular Canals)
• Detect Linear Acceleration of head
  (Utricle and Saccule)

Question 5

Each Semicircular canal has enlargement at one end Called a ______ which contains ______.

Answer 5

• Ampulla

- Hair Cells

Question 6

The Vestibular apparatus Consist of what?

Answer 6

• 3 Semicircular canals
• Vestibule (Utricle and Saccule)
• Cochlea

Question 7

The Saccule and Utricle both contain what?

Answer 7

A Macula

- Contains HAIR cells

Question 8

Purpose of the Vestibular Apparatus?

Answer 8

• Involved in Reflex adjustments of Head, Eyes and Postural muscles
• Provides stable vision and posture

Question 9

What happens to the Semicircular canals when the head begins to rotate in ANY Direction?

Answer 9

• Inertia of the Fluid in one or more of the SCC remains STATIONARY while the canals rotate with the head
• Fluid flows from the duct through the AMPULLA and causes CUPULA to bend to one side
• Hundreds of hair cells w/in each CUPULA detect the bending and send signals to the Vestibular NERVE

Question 10

CUPULA

Answer 10

Loose mass of Gelatinous Tissue on Top of Crista

Question 11

When the head is bend forward by 30 degrees, what happens?

Answer 11

• Lateral ducts are HORIZONTAL
• ANT. Ducts are in Vertical Planes projecting FORWARD and 45 degrees Outward
• POST. Ducts are in Vertical Planes projecting BACKWARD and 45 degrees Outward.

Question 12

Ampulla of the Ear Canal

Answer 12

• Enlargement at one end of each SCC duct

- Filled with Endolymph

Question 13

Hair Cell Characteristics

Answer 13

• Has 50 to 70 cilia
  (Sterocilia)
• Has one Large Cilium off set
  (Kinocilium)
• Tips of the Stereocilia are connected together and to the Kinocilium

Question 14

The Vestibule of the Apparatus is composed of what?

Answer 14

• Utricle
• Saccule
• Deals with BALANCE*

Question 15

T/F: Hair cells are oriented such that bending the head in diff directions causes Diff groups of hair cells to depolarize.

Answer 15

True

Question 16

If Stereocilia bends TOWARDS the Kinocilium what happens?

Answer 16

• Depolarizes

- Excitation

Question 17

If Stereocilia bends AWAY the Kinocilium what happens?

Answer 17

• Hyper-polarization

- Inhibition

Question 18

Statoconia

Answer 18

• Small calcium carbonate crystals

- The weight bends the cilia in direction of Gravitational pull

Question 19

The Ducts are filled with ____ and surrounded by _____.

Answer 19

• Endolymph

- Perilymph