ch 16 special senses

vision disorders

*Myopia: -Nearsighted -can't see far. *Amblyopia: -lazy eye -patch the unaffected eye *Presbyopia: -farsighted due to loss of elasticity from middle to old age -can't see close.

Three events occur to bring the image into focus on the retina: accommodation, pupil constriction, and convergence. Test your knowledge about these events by answering these questions 1. Accommodation is a result of parasympathetic stimulation from the optic nerve (I). 2. In accommodation, the lens becomes more spherical in shape. 3. When we look at a close-up object, the pupil diameter decreases. 4. The smaller the pupil diameter, the more light enters the eye and is directed toward the retina. 5. Both pupils can pick up the light rays when the eyes are looking forward. 6. Convergence states that eyes are rotated medially as an object moves closer. 7. In convergence, rotation of the eyes is accomplished by the medial oblique muscles.

1. F 2. T 3. T 4. T 5. T 6. T 7. F

Decide if these retinal events occur in the dark or in the light .1. Rods continuously release the neurotransmitter glutamate. 2. Glutamate inhibits the bipolar cells that synapse with the rods. 3. The bipolar cells do not stimulate the ganglion cells. 4. Activated rhodopsin inhibits the production of glutamate by rods. 5. The bipolar cells stimulate the ganglion cells. 6. Action potentials are transmitted out of the optic nerve.

1. dark 2. dark 3. dark 4. light 5. light 6. light

Match each taste receptor location to the cranial nerve that serves that area, and then choose the corresponding cranial nerve number. Some choices may be used more than once or not at all. 1. Anterior two-thirds of the tongue Facial nerve CorrectVII Correct 2. Posterior one-third of the tongue and the superior pharynx Glossopharyngeal nerve CorrectIX Correct 3. Epiglottis Vagus nerve CorrectX

1. facial VII 2.glossoph IX 3. vagus X

Decide if each of these steps for the visual pathway is true or false. 1. Each visual field is divided into three parts: central, temporal, and nasal. 2. Light from each part of a visual field projects to the same side of the retina except for the central part which projects to both. 3. An optic nerve consists of axons extending from the retina to the optic chiasm. 4. In the optic chiasm, axons from the nasal part of the retina cross while axons from the temporal part do not. 5. An optic tract consists of axons that have passed through the optic chiasm with or without crossing to the thalamus. 6. The axons synapse in hypothalamic nuclei. 7. An optic radiation consists of axons from hypothalamic neurons that project to the visual area of the prefrontal cortex. 8. The right part of each visual field projects to the left side of the brain, and the left part of each visual field projects to the right side of the brain.

1. false 2. false 3. true 4. true 5. true 6. false 7. false 8.true

Match the taste sensation to the chemical trigger. Some choices may be used more than once or not at all. 1. Na+ 2. Acidic compounds 3. Sugars, some other carbohydrates, and some proteins 4. Alkaloids/base compounds 5. Amino acid glutamate and related compounds Umami 6. Artificial sweeteners Sweet 7. Beef Umami

1. salty 2. sour 3. sweet 4. bitter 5. umami 6. sweet 7. umami

Macular degeneration is a degenerative disease of the retina with genetic and environmental causes. Answer these questions about this disease. 1. Macular degeneration is the leading cause of blindness in developed countries. 2. The amsler grid is used to test for macular degeneration. 3. The majority of macular degeneration cases are found in adolescents. 4. There is currently no cure for macular degeration.

1. true 2. true 3. false 4. true

Which is a type of tonic receptor that detects both continuous deep pressure and distortion of the skin?

Bulbous corpuscles

vision disorder: Clouding of the lens resulting from a buildup of proteins

Cataract

vision disorder: Excessive pressure buildup in the aqueous humor

Glaucoma

How does light affect rhodopsin?

It dissociates rhodopsin and changes 11-cis-retinal to all-trans-retinal.

What ion is responsible for depolarization of hair cells of the spiral organ?

K

Which of the following structures is deepest in the inner ear?

Membranous labyrinth

true or false: The sense of taste is heavily influenced by the olfactory sense as well.

The brain uses gustatory and olfactory stimuli to perceive and evaluate a particular taste.

Why is visceral pain sometimes localized incorrectly?

Visceral sensory neurons travel along the same pathway as many somatic sensory neurons.

vision disorder: Destruction or atrophy of retinal pigment epithelium

age-related macular degeneration

vision disorders: Cornea or lens not uniformly curved and image is not sharply focused

astigmatism

Perilymph is located between the

bony and membranous labyrinths

Outer hair cells, near the center of the basilar membrane, will

both magnify vibrations of soft sounds and sharpen pitch perception.

Which of these is most vulnerable to irreversible damage caused by a very loud noise?

cochlear hair cells

Free nerve endings are terminal branches of

dendrites

true or false High-pitched sounds produce a peak displacement of the basilar membrane near the apex of the cochlea.

false

true or false: High-pitched sounds produce a peak displacement of the basilar membrane near the apex of the cochlea.

false Explanation High-pitched sounds produce a peak displacement of the basilar membrane near the base of the cochlea.

true or false :Rods and cones face the light coming into the eye.

false Rods and cones actually face away from the incoming light. They face the back of the retina toward the pigmented layer and choroid. Light travels through the ganglion cells, and bipolar cells, before reaching the photoreceptors.

true or false The ability to not notice the smell of fish from the previous day is due to tonic receptors.

false Sensory adaptation is due to phasic receptors that give a burst of firing when the stimulus starts and then again when it ends.

true or false: Encapsulated tactile receptors are found in the skin and consist of dendrites with no protective coat.

false Tactile receptors contain nerve fibers surrounded by flattened Schwann cells.

The papillae on the tongue that do not contain any taste buds are the ________ papillae.

filiform

As the number of cycles per second increases, the sound we perceive

gets higher

What neurotransmitter is released from depolarized hair cells to stimulate fibers of the vestibulocochlear nerve?

glutamate

When you travel in an elevator (which moves linearly in space), the ___________ detect when the elevator is accelerating or decelerating.

hair cells covered by an otolithic membrane

A part of the auditory pathway responsible for auditory reflexes is the

inferior colliculus.

Tactile receptors are a type of

mechanoreceptor

Which disorder of refraction is corrected with a concave lens?

myopia

After the thalamus, auditory nerve signals reach the

primary auditory cortex

Root hair plexuses are usually found in the

reticular layer of the dermis.

What may be the cause of hyperopia?

short eyeball

If a receptor's receptive field is ___________, it allows for greater specificity of localization.

small

What structure is attached to the oval window and transfers vibration of the tympanic membrane to the inner ear?

stapes

Photoreceptors in the retina of the eye detect changes in light intensity and wavelength. In other words, they are detecting

stimuli

What is the most numerous type of receptor?

tactile

After turning on a bright light in a previously dark room, it is difficult to see for a brief time. This is because

the photoreceptors are photobleached.

true or false : Otitis media is an infection of the middle ear.

true

true or false : When a receptor potential reaches threshold, an action potential will be produced.

true An action potential will be produced once the receptor potential has reached threshold.

true or false: Walking into a room and recognizing the smell of a favorite dish is an example of a sensation.

true Explanation A sensation is the conscious awareness of incoming sensory information, as in recognition of a face.

true or false : The sense of taste is heavily influenced by the olfactory sense as well.

true Explanation The brain uses gustatory and olfactory stimuli to perceive and evaluate a particular taste.

True or False: The greater the receptor density, the greater the sensory acuity.

true Explanation The more receptors present in a particular area, the better the sharpness (acuity) of the sensation. The fingertips have many more touch receptors than the upper arm, so more detailed touch information will be transmitted from the fingertips than from the upper arm.

The papillae that are fewest in number, but contain the most taste buds, are the _________ papillae.

vallate