Question

in viewing the spinal cord cross section,
the central canal contains plasma.
white matter areas contain fiber tracts that carry ascending and descending messages.
the gray matter is shaped like a caterpillar.
spinal nerves carry both sensory and association neurons.
44 multiple choice 1 point
sound conduction follows which pathway?
external auditory meatus, malleus, incus, stapes, tympanic membrane, oval window, cochlea
external auditory meatus, tympanic membrane, malleus, incus, stapes, cochlea, oval window
external auditory meatus, tympanic membrane, stapes, incus, malleus, oval window, cochlea
external auditory meatus, tympanic membrane, malleus, incus, stapes, oval window, cochlea
45 multiple choice 1 point
what category of receptor cell is used to sense touch, vibration and pressure?
photoreceptor
mechanoreceptor
thermoreceptor
chemoreceptor

Explanation:

Question 44 (Sound Conduction Pathway)

To determine the correct sound conduction pathway, recall the anatomy of the ear: sound enters the external auditory meatus, hits the tympanic membrane (eardrum), then vibrates the ossicles (malleus, incus, stapes in order), then the stapes hits the oval window, and finally sound is transmitted to the cochlea. Let's analyze each option:

• First option: Incorrect order (tympanic membrane comes after ossicles here).
• Second option: Cochlea comes before oval window, which is wrong.
• Third option: Ossicles order is reversed (stapes, incus, malleus instead of malleus, incus, stapes).
• Fourth option: Follows the correct sequence: external auditory meatus → tympanic membrane → malleus → incus → stapes → oval window → cochlea.

• Photoreceptors: Detect light (vision), so not for touch/vibration/pressure.
• Mechanoreceptors: Respond to mechanical stimuli like touch, vibration, pressure (e.g., Pacinian corpuscles, Meissner's corpuscles).
• Thermoreceptors: Detect temperature changes.
• Chemoreceptors: Detect chemicals (e.g., taste, smell, blood chemistry).

So the receptor for touch, vibration, and pressure is a mechanoreceptor.

Answer:

D. external auditory meatus, tympanic membrane, malleus, incus, stapes, oval window, cochlea (assuming the fourth option is labeled D; if options are labeled A - D as per standard, with the fourth option being D, then the answer is D with the pathway text as above)

Question 45 (Receptor for Touch, Vibration, Pressure)