Question

Answer parts A-D to receive full credit for number 1:

A. Which of the following is most accurate concerning the external ear?

1. The auricle is designed to sort waves by frequency before they reaching the external acoustic means

2. The external acoustic meatus direct sound waves towards the oval window

3. The external acoustic meatus lacks glands but has thick hairs that serve to protect the ear

4. The external acoustic meatus serves as a barrier to airborne particles

5. The tympanic membrane serves as the boundary between the external ear and middle ear

B. Which one is found in the inner ear:

1. Acoustic mucus

2. Eustachian tube

3. Ossicles

4. Scala vestibuli

5. Tympanic membrane

C. Which of the following do preganglionic axons of the ANNS release?

1. Acetylcholine

2. Dopamine

3. Epinephrine

4. Norepinephrine

5. Serotonin

D. The muscles that regulate the passage of light into the eye are found in _____

1. Cornea

2. Lens

3. Iris

4. Pupil

5. Retina

Answer 1

A)Option -E -The tympanic membrane serves as the boundary between the external ear and middle ear

Ear pinnae help to direct the sound waves into the external acoustic meatus.

External acoustic meatus direct sound waves int the tympanic membrane.

External acoustic meatus have ceruminous gland which secrete cerumen.it is a yellow waxy material taht protect the ear from the external particles.

External ear is seperated from the middle ear by the tympanic membrane

B) Option D -Scala vestibuli

Inner ear is composed of cochlea,semicircular canal and vestibular apparatus that is utricle and saccule.

The upper segment of the cochlea is called the scala vestibuli. it is seperated from the middle bony segment of the cochlea that is scala media by ressieners membrane.

Scala vestibui the the sound vibration coming from the oval window to the scala media .The fluid present in the scala vestibuli is perilymph and in scala media is endolymph.

Eustachian tube is otherwise called auditory tube which connect te middle ear with the pharynx.the function of eustachian tube to stabiise the pressure on the both side of the tympanic membrane.

Ear ossicles are malleus,incus,stapes and they are found in the middle ear.

C)Option A - Acetylcholine

Pregnaglionic fiber are the nerve fiber of autonomic nervous system that are coming from the CNS sympathetic division ro the ganglion.

Whether it is sympathetic or parasympathetic the preganglionic fiber releases acetylcholine neurotransmitter.

Acetylcholine bind with the acetylcholine receptor present in the postsynaptic membrane.

D)Option C -IRIS

the muscles which regulate the netry of light into theh eyes are controlled by the muscles present in the iris.

The opening of the eye through which light is entering into the lens is pupil.

The diamter of the pupil is regulated by the sphincter pupillae muscles preent in the iris.

Sphincter pupillae muscle is a radial muscle,when the sphincter dialatr contract the diameter of the pupil increases.

like wise when the spinctor constrictor contract the dameter of the pupil decreases.