Anatomy 2130 Chapter 8

What term refers to the ability to focus on close objects?

Accommodation

Which cochlear hair cells are stimulated by low frequency sounds?

Hair cells located near the apex of the basilar membrane

What is a possible cause of conduction deafness?

Inability of auditory ossicles to vibrate

Which of these provides sensory input that helps keep the head erect?

Maculae of the vestibule

The vibration of sound waves cause the tympanic membrane, or eardrum, to move against an ossicle known as ________.

Malleus or hammer

Which of these is associated with rods?

Night vision

At what point do some axons leave the optic nerve and cross to the opposite side of the brain?

Optic chiasma

Tiny stones made of calcium salts that roll in response to changes in gravitational pull are called ________.

Otoliths

The fusion of ear bones is known as ________.

Otosclerosis

After the age of 40 the elasticity of the lens decreases, making it difficult to clearly see close objects. What is this condition called?

Presbyopia

What is the function of the otoliths?

Responding to changes in the pull of gravity and in acceleration when the body moves

Which of these is part of the sensory layer of the eye?

Retina

Which of these can cause sensorineural deafness?

Degeneration of the hair cells in the spiral organ of Corti

The greatest visual acuity is housed in the ________.

Fovea centralis

Dynamic equilibrium receptors that detect information about angular or rotational movements of the head are housed in the ________.

Semicircular canals

What part of the inner ear is contains receptors for dynamic equilibrium?

Semicircular canals

Which of these are oriented in the three planes of space, allowing sensation of movement in any plane?

Semicircular canals

What information does the brain use to interpret the source of a sound?

Sound reaches the two ears at slightly different times

Hair cells that function as hearing receptors are located within the _______

Spiral organ of Corti

What part of the eye is affected by cataracts?

The lens

How do organs of equilibrium help us maintain our balance?

The macula sends information on head position and the crista ampullaris sends information on rotation movements to the cerebellum for integration