General Sensory Mechanisms-4

Question 1

Merkels’s discs are best characterized as what type of receptor?

Answer 1

• mechanoreceptors with expanded tip endings (free endings)

Question 2

The Meissner’s and Kraus’ corpuscle are best described as what type of mechanoreceptors?

Answer 2

• encapsulated endings. Still receives skin tactile senses

Question 3

What are the free and encapsulated endings that are located within deep tissue, mechanoreceptors?

Answer 3

• Ruffini’s corpuscle are free expanded tip

- pacinian corpuscles are encapsulated

Question 4

What roles can mechanoreceptors play in sensations?

Answer 4

• hearing
• equilibrium
• arterial pressure

Question 5

Nocireceptors respond to what type of stimulus?

Answer 5

• free nerve ending that respond to pain

Question 6

What is unique to the receptors in general?

Answer 6

• specific sensitivity: high sensitivity to one stimulus and nonresponsive to others.
• modality (refer to principal type of sensation)
• labeled line principle: specificity of nerve fiber for transmitting only one modality of sensation

Question 7

What is the adaptation of receptors refer to?

Answer 7

• adaptation of receptors to a constant stimulus after a period of time.

Question 8

What is a tonic receptors and how does it work?

Answer 8

• slow adapting receptor
• relay continuous stimulus strength
• transmit impulse while stimulus is present

Question 9

What is a phasic receptor and how does it operate?

Answer 9

• rapid adaptation
• no continuous signal transmitted
• only stimulated when the strength of the stimulus changes

Question 10

How many type A nerve fiber types are there?

Answer 10

• alpha
• beta
• gamma
• delta
• these are large to medium sized myelinated fibers

Question 11

What are type C nerve fibers?

Answer 11

• small unmyelinated

- more than half the sensory fibers in the peripheral nerves and postganglionic autonomic fibers

Question 12

What are type A alpha fibers? (Group 1a)

Answer 12

-fibers from annulospiral ending of muscle spindle

Question 13

The type A alpha (Group 1b) fibers are where?

Answer 13

• fibers that are from golgi tendons

Question 14

What are type Abeta, gamma fibers (Group II)?

Answer 14

Conduct from cutaneous tactile receptors and flower-spray

Question 15

What information do type Agamma fibers (Group III) generally conduct?

Answer 15

-temperature, crude touch, and pricking pain.

Question 16

What sensations do group IV (Type C) fibers carry?

Answer 16

• pain, itch, temperature, and crude touch.

Question 17

What is the best way to describe spatial summation?

Answer 17

-increase the signal strength being transmitted by progressively increasing the number of fibers.

Question 18

What is a common type of sensation that uses spatial summation and how does it work?

Answer 18

• pain fibers
• Large number of endings in the center of field, and dissipates as we move away from the center. Generates overlap of one pain fiber over others.

Question 19

How does temporal summation work?

Answer 19

• relies on the increasing frequency of a nerve impulse to increase the signals strength

Question 20

Where is the stimulatory field of a neuronal pool located?

Answer 20

• located in the area within the pool that is stimulated by each incoming nerve fiber.

Question 21

What is the difference of discharge and facilitated zones within a neuronal pool?

Answer 21

• the discharge zone is the area of neuron firing.
• the facilitated zone receives stimulus, but not strong enough to generate action potential, these zones can be either excitatory or inhibitory

Question 22

What are the five basic types of sensory receptors?

Answer 22

• mechanoreceptors
• thermoreceptors
• nociceptors
• electromagnetic receptors
• chemoreceptors