THE SENSORY NERVOUS SYSTEM

Question 1

five basic types of sensory receptors

Answer 1

1. mechanoreceptors.
2. thermoreceptors.
3. nociceptors. ( pain receptors )
4. electromagnetic receptors. ( like photoreceptors )
5. chemoreceptors

Question 2

each type of receptor is highly sensitive to one type of stimulus for which it is designed and
yet is almost nonresponsive to other types of sensory stimuli.

Answer 2

DIFFERENTIAL SENSITIVITY OF RECEPTORS

Question 3

Each of the principal types of sensation that we can experience—pain, touch, sight, sound, and so forth—is called …………………………

Answer 3

modality of sensation.

Question 4

This specificity ( characteristics ) of nerve fibers for transmitting only one modality of sensation is called ……………………

Answer 4

the labeled line principle.

Question 5

when a continuous sensory stimulus is applied, the receptor responds at a high impulse rate at first and then at a progressively slower rate until finally, the rate of action potentials decreases to very few or often to none at all. is …………………………..

Answer 5

ADAPTATION OF RECEPTORS

Question 6

Adaptation is rapid for ……………………………………… and ……………………………………..

Answer 6

pacinian corpuscules and hair receptors

Question 7

which receptors that dont not adopt completely?

Answer 7

Chemoreceptors and pain receptors

Question 8

sensory systems code for four elementary attributes of a stimulus

Answer 8

1. modality: is the type of energy mainly transmitted by the stimulus.
2. location: is the site on the body or space where the stimulus originated.
3. intensity: is signaled by the response amplitude or frequency of action potential generation.
4. duration: refers to the time from start to end of a response in the receptor.

Question 9

The particular form of energy to which a receptor is most sensitive is ………………………………

Answer 9

adequate stimulus

Question 10

Do receptors respond to forms of energy other than their adequate stimuli?

Answer 10

yes

Question 11

Law of specific nerve energies

Answer 11

Johannes Müller’s law of specific nerve energies (LOSNE) of 1835, states that “the nature of perception is defined by the pathway over which the sensory information is carried. Hence, the origin of the sensation is not important.”

Therefore, the difference in perception of seeing, hearing, and touch are not caused by differences in the stimuli themselves but by the different nervous structures that these stimuli excite. For example, pressing on the eye elicits sensations of flashes of light because the neurons in the retina send a signal to the occipital lobe. Despite the sensory input being mechanical, the experience is visual.

Question 12

Law of projection

Answer 12

It states that “no matter where a particular sensory pathway is stimulated along its course to the cortex, the conscious sensation produced is referred to as the location of the receptor.”

For example, when the cortical receiving area for impulses from the left hand is stimulated, the patient reports sensation in the left hand, not in the head.

Question 13

Recruitments of sensory units

Answer 13

As the strength of a stimulus is increased, it tends to spread over a large area and generally not only activates the sense organs immediately in contact with it but also recruits those in the surrounding area.