Senses lab quiz

Question 1

What are the 3 components of a reflex mechanism?

Answer 1

1. Receptor organ
2. Communications network (connects the receptor and effector organs)
3. Effector organ

Question 2

Reflexes are initiated by

Answer 2

An input stimulus

Question 3

Reflexes result in

Answer 3

An output response. For some reflexes, the appropriate response to the stimulus has been programmed into the nervous system

Question 4

Spinal reflex

Answer 4

When an individual experiences a painful stimulus (burning their hand), the spinal reflex causes rapid withdrawal of the hand from the painful stimulus. The spinal reflex requires transmission from the periphery to the spinal cord and back to the effector organ- no action is required by the brain.

Question 5

Which reflexes involve centers of the brain?

Answer 5

Eye reflexes and labyrinth reflexes. The response is determined after multiple different inputs are evaluated.

Question 6

Jendrassik’s Maneuver

Answer 6

The Jendrassik maneuver is a medical maneuver wherein the patient interlocks their fingers together. The tendon below the patient’s knee is then hit with a reflex hammer to elicit the patellar reflex.

Question 7

Palpate

Answer 7

To examine by touch

Question 8

Ipsilateral

Answer 8

Same side

Question 9

Which division of the nervous system controls the ciliospinal reflex?

Answer 9

The sympathetic nervous system, occurs in response to a painful stimulus

Question 10

Ciliospinal reflex

Answer 10

If the skin on the nape of the neck is pinched, the pupil of the eye on the same side will dilate

Question 11

Plantar reflex

Answer 11

When the sole of the foot is scratched or stroked on the inner side, the toes flex downward. This is a normal adult reflex.

Question 12

Babinski reflex

Answer 12

When the sole of the foot is scratched or stroked on the inner side, the toes fan out and the big toe flexes dorsally (upward). This is normal reflex in children under one year of age because their nerves are still undergoing myelination.

Question 13

When the Babinski reflex occurs in adults, what does this indicate?

Answer 13

It is often associated with damage to the pyramidal tract fibers (efferent nerve fibers that carry signals from the cerebral cortex to the brainstem or spinal cord).

Question 14

What is a function of the semicircular canal mechanism?

Answer 14

To aid visual fixation on moving targets

Question 15

Nystagmus

Answer 15

If the semicircular canals are stimulated under experimental conditions, reflex response results in a movement
of the eyes

Question 16

What are the 2 components of nystagmus?

Answer 16

Fast and slow phases. The direction of nystagmus is designated as that of the fast phase (nystagmus will change direction after a certain amount of time).

Question 17

Rotary nystagmus

Answer 17

If a person is angularly accelerated in one direction, their eyes will move very slowly in one direction as though to maintain fixation on a moving target, then very rapidly swing back in the other direction. The initial direction is opposite the direction of rotation, then the eye jerks back toward the direction of rotation

Question 18

What causes rotary nystagmus

Answer 18

The acceleration of fluid in the semicircular canals which stimulates the cristae in the ampullae and produces the sensation of turning

Question 19

Post rotary nystagmus

Answer 19

The same phenomenon as rotary nystagmus, occurs after suddenly stopping a spinning person- eyes will move very slowly in one direction as though to maintain fixation on a moving target, then very rapidly swing back in the other direction

Question 20

Knowledge of changes in our environment depends on

Answer 20

The sensory nervous system and its receptors

Question 21

5 senses

Answer 21

1. Sight
2. Hearing
3. Touch
4. Taste
5. Smell

Question 22

Exteroreceptors

Answer 22

Receptors which receive stimuli from outside the body- usually located on the surface of the body.

Question 23

Interoceptors

Answer 23

Detect changes within the body, located deep within tissues like muscles and tendons.

Question 24

Which areas of the body have a greater sense of tactile discrimination (feel)

Answer 24

Areas of the body that have many touch receptors, such as the fingers

Question 25

The number of sensory impulses transmitted by sensory receptors change with

Answer 25

Intensity of the stimulus and the length of time the stimulus is applied

Question 26

Adaptation

Answer 26

If a stimulus is applied for a prolonged
period of time without movement, the rate of receptor discharge will slow and conscious awareness of the stimulus will decline or will be lost (until some stimulus change occurs)

Question 27

Nerve deafness

Answer 27

A defect in the auditory nerve or cochlear apparatus.

Question 28

Weber test

Answer 28

The subject holds the vibrating fork against the bridge of their nose. A person with normal hearing will localize the sound as coming from the midline position. A person with conduction deafness will hear the sound better in that ear

Question 29

Conduction deafness

Answer 29

Defective middle ear function

Question 30

Why can a person with conduction deafness hear a vibrating fork better in the deaf ear with the weber test?

Answer 30

In a normal ear, the sound of the fork is partially masked by environmental noise that the deaf ear is less sensitive to. Also, in the normal ear the sound is dampened by the tensor tympani and stapedius muscles that prevents the full amplitude of vibration of the auditory ossicles. This reflex is less effective or absent with conduction deafness.

Question 31

During the weber test, what would cause a person to better hear the vibrating fork with the normal ear?

Answer 31

A defect in the auditory nerve or cochlear apparatus- this is because neural activity is essential for hearing

Question 32

Rinne test

Answer 32

A tuning fork is placed on the subject’s mastoid process at the level of the upper portion of the ear canal. When the sound is no longer audible, the tuning fork is placed in front of the auditory canal.

Question 33

What do the results of the Rinne test indicate?

Answer 33

A person with normal hearing will hear the sound conducted through air a few seconds longer than sound conducted through bone.
The person with conduction deafness will hear as long or longer by bone conduction
The person with nerve deafness will
hear longer by air conduction, but usually requires a louder sound to hear at all

Question 34

Blind spot/optic disc

Answer 34

an area on the retina where the optic nerve and blood vessels enter and leave the retina and hence there are no rods or cones for visual reception.

Question 35

Visual acuity

Answer 35

The power to discriminate details

Question 36

Snellen test

Answer 36

The letter chart tested at physicals- the letters on certain lines should be able to be read easily at certain distances if a person has normal visual acuity

Question 37

What is the visual acuity formula?

Answer 37

V= d/D
d is the distance at which the patient can read the letters
D is the distance at which a normal eye can read the letters.
Someone with 10/20 vision, for example, has subnormal vision because they can only read the letters at 10 feet when they should be visible 20 feet away.

Question 38

Color blindness

Answer 38

A genetic condition linked to the X chromosome. Red green colorblindness is the most common type- the person lacks either red or green cones in the retina. A person who lacks red cones will perceive red as green- the red wavelengths will stimulate primarily red cones

Question 39

Isihara test

Answer 39

A color blindness test. Charts consist of various color dots arranged into a picture. A person with normal color vision will see one figure, a person without normal color vision will perceive a different number or figure.

Question 40

Pupillary reflex

Answer 40

When one eye is exposed to light, both pupils will constrict. The response of the pupil in the stimulated eye is the direct response, and the pupil of the contralateral pupil (which is not stimulated) is the consensual response.

Question 41

Pupillary reflex receptor and effector

Answer 41

The receptors are the photoreceptors of the retina and the effector is the smooth muscle of the iris.

Question 42

Accommodation reflex

Answer 42

This reflex is required for near vision. A few things occur:

1. Pupillary constriction (to sharpen the image on the retina)
2. Convergence of the optic axis- both eyes move medially. Keeps object focused on foveae
3. Increased convexity of the lens to increase its refractive power

Question 43

What happens within the eye when viewing near and far objects?

Answer 43

The curvature of the lens is controlled by ciliary muscles. When viewing near objects, the ciliary muscles contract. The suspensory ligaments loosen, which causes the lens to become rounder/bulge outward. This gives the lens higher refractive power. For far objects, the muscles relax and the lens is flat.

Question 44

Patellar reflex

Answer 44

Knee jerk response when the patellar tendon is tapped with a reflex hammer. This is caused by stretching of the patellar tendon and contraction of the quadriceps muscle.

Question 45

What happens to the patellar reflex when the Jendrassik maneuver is performed?

Answer 45

The patellar reflex is exaggerated. The maneuver activates the fight or flight response so everything is “primed”. That way, a lighter tap has a stronger response. Distraction of the individual will also a play a role

Question 46

Achilles reflex

Answer 46

When the Achilles tendon (between the foot and leg) is tapped with a reflex hammier, you observe the ankle jerk reflex. The contraction of the gastrocnemius muscle causes plantar flexion of the foot.

Question 47

What happens to the Achilles reflex when the subject is grasping the back of a chair?

Answer 47

The reflex should be stronger, just like the Jendrassik maneuver makes the Patellar reflex stronger. It activates the sympathetic nervous system and is related to distraction in the patient.

Question 48

Which muscles would contract if you pushed down on a table?

Answer 48

Triceps

Question 49

Which muscles would contract if you tried to lift a table?

Answer 49

Biceps

Question 50

Which semicircular canal is stimulated when the head touches the shoulder?

Answer 50

Posterior semicircular canal

Question 51

Which semicircular canal is stimulated when the head is moving up and down?

Answer 51

Superior semicircular canal

Question 52

Which semicircular canal is stimulated when moving the head from side to side?

Answer 52

Lateral semicircular canal

Question 53

How would a person’s ability to do the past pointing test be altered by spinning?

Answer 53

The person would point in the direction of the previous rotation. If the previous rotation was clockwise, they will consistently point to the right of the target.

Question 54

What is the purpose of adaptation?

Answer 54

Prevents sensory overload- we no longer consciously perceive a routine stimulus to focus on other aspects of our environment.

Question 55

Accommodation

Answer 55

Accommodation is the adjustment of the optics of the eye to keep an object in focus on the retina as its distance from the eye varies.

Question 56

Which muscles of the eye are involved in accommodation?

Answer 56

The ciliary muscles are involved in the change in lens shape. The sphincter pupillae constricts the pupil, and the medial rectus muscles contract so the eyes will converge

Question 57

Presbyopia

Answer 57

“Farsightedness”- loss of the eyes’ ability to focus on nearby objects. It is caused as the lens becomes less flexible with age and can no longer change shape to focus on nearby objects. Could potentially be corrected by convex shaped corrective lenses.

Question 58

Myopia

Answer 58

Nearsightedness- difficulty seeing things that are far away. This is caused by an elongated eyeball shape (past the focal point of the retina). Correction- concave shaped corrective lenses

Question 59

Young-Helmholtz theory of color vision

Answer 59

a theory to explain color vision in terms of components or processes sensitive to three different parts of the spectrum, corresponding to the colors red, green, and blue. According to this theory, other colors are perceived by stimulation of two of the three processes, whereas light that stimulates all three processes equally is perceived as white.