Unit 3 Anatomy and Physiology of the Nervous System: Sensory Organs

Which role does the auditory nerve play in the auditory pathway?

Acts as the link between the cochlea and the brain The auditory nerve takes the signal from the cochlea and sends it to the part of the brain that is responsible for interpreting sound.

Which structure is responsible for refracting light when it enters the eye?

Cornea The cornea is a transparent bulging portion that refracts light rays that enter the eye.

Which anatomical structures are parts of the outer layer of the eye?

Sclera The sclera is the tough, white, exterior layer of the eye. Cornea The cornea is a transparent bulge that refracts and allows light rays to pass through, and is found in the outer layer.

Which statement describes the posterior cavity of the eye?

Space between the lens and the retina The posterior cavity of the eye is the space between the lens and the retina. It contains a jellylike substance called the vitreous humor.

Match the structure of the ear to the correct description.

This equalizes pressure between the middle and outer ear. -Eustachian tube This is where cilia stimulate the sensory neurons. -Cochlea This is a visible flap on the outside of the ear. -Pinna This is a hollow area in the ear that has three tiny bones. -Tympanic cavity

Which is the function of the rods and cones within the visual pathway?

To convert light into an electrical signal Rods and cones in the retina convert light into an electrical signal once they are stimulated.

Which function does the tympanic membrane perform in response to sound waves?

Vibrates against the malleus The tympanic membrane, or eardrum, vibrates in response to sound waves once they enter the auditory canal.

Which statement is included while describing the anatomy of the eye?

"The anterior chamber of your anterior cavity extends from the cornea to your iris." The eye is divided into cavities, and the anterior cavity is further divided into chambers. The anterior chamber extends from the cornea to the iris, and the posterior chamber extends from the iris and the lens.

Which statement is included while describing the physiology of hearing?

"The release of certain fluids in your ear cause tiny hair cells called cilia to move." The motion causes "water waves" that stimulate the movement of the membranes and hair cells in the organ of Corti, which converts the stimulus into a nerve impulse.

While describing the visual pathway to an individual, which statement can be made about the retina?

"The retina contains the photoreceptors needed for vision." The retina contains the photoreceptors needed for vision. Those photoreceptors are called the rods and cones. Rods are responsible for low light levels, and cones are responsible for high light levels and color.

Which statement is included when teaching students about the anatomy of the ear?

"The tympanic cavity is a hollow area that contains the malleus, incus, and stapes." The tympanic cavity is a hollow area in the ear contains three tiny bones: the malleus, incus, and stapes. These bones work together to conduct sound energy that goes from the eardrum to the cochlea.

Put the steps in order for how hearing works.

-Sound waves enter the external ear canal -Tympanic membrane vibrates -Malleus, incus, and stapes vibrate -Movement against the oval window starts the flow of perilymph and endolymph -Fluid movement stimulates motion of specialized hair cells in organ of Corti -Motion of hair cells is converted to nerve impulse, which travels from cochlear nerve to the brain The process of hearing begins as sound waves enter the external ear canal. The sound waves cause the tympanic membrane to vibrate. This makes the malleus, incus, and stapes vibrate. Then, the movement against the oval window starts the flow of perilymph and endolymph. The fluid movement stimulates motion of cilia in the organ of Corti. Then, the motion of cilia is converted to nerve impulse. Nerve impulse travels from the cochlear nerve to the auditory nerve to the brain and is interpreted as sound or hearing.

Which cranial nerve is responsible for conducting impulses to the temporal lobe to receive and interpret sound?

Cranial nerve VIII

What happens to the optic nerve at the optic chasm?

It crosses over to the other side of the visual pathway. The optic chasm is where some of the optic nerves cross over to the opposite side. This happens so that the nerve impulse transmits to the other side where it is eventually received and interpreted by the brain.

Which is the function of the aqueous humor?

Keeps the intraocular pressure of the eye in balance The aqueous humor is a fluid that maintains the intraocular pressure. It fills both chambers of the eye.

Which structure protects the eye by forming tears?

Lacrimal gland The lacrimal gland is where tears are formed. Tears help protect the eye by keeping it moist and keeping out foreign materials.

Which anatomical structure is responsible for providing comprehensive vision by coordinating movement for the eye?

Oculomotor nerve

Which anatomical structure is located in the outer ear?

Pinna The pinna is the external portion made of tissue and cartilage and makes up the outer ear.

Which is the function of the vitreous humor?

Pushes the retina up against the choroid to keep it in place The vitreous humor is a clear gel that fills the space between the lens and the retina. It presses against the retina to keep it in place by pushing it against the choroid.

A person is told that the rods in his retina are not functioning properly. Which conclusion can be drawn about the person?

The person will have a difficult time seeing in dim or dark environments. The rods are responsible for vision during dim or dark environments. The cones are responsible for vision during highly lit environments. Both are photoreceptors that are located in the retina.