Lecture 4: General Sensory Mechanisms I

Question 1

Mechanoreceptors

Answer 1

Free and encapsulated endings receiving skin tactile or deep tissue sensibilities; also includes receptors for hearing, equilibrium, arterial pressure

Question 2

Thermoreceptors

Answer 2

Cold/warm receptors

Question 3

Nociceptors

Answer 3

Free nerve endings responding to pain

Question 4

Electromagnetic receptors

Answer 4

Rods/cones of the eye for vision, etc.

Question 5

Chemoreceptors

Answer 5

For taste, smell, arterial O2, osmolarity, blood CO2, etc.

Question 6

Differential sensitivity

Answer 6

Receptors are highly sensitive to one type of stimulus while being almost nonresponsive to other types

Question 7

Modality

Answer 7

Principal types of sensation (i.e. somatic motor)

Question 8

Labeled line principal

Answer 8

Specificity of nerve fibers for transmitting only one modality of sensation

Question 9

Tonic receptors

Answer 9

Slow adapting, detect continuous stimulus strength, transmits impulses as long as stimulus is present

Question 10

Phasic receptors

Answer 10

Rapidly adapting, do not transmit continuous signal, stimulated only when stimulus strength changes; transmits information regarding rate of change

Question 11

Type A nerve fibers

Answer 11

Large and medium sized myelinated fibers of spinal nerves (faster conduction)

Question 12

Type C nerve fibers

Answer 12

Small, unmyelinated fibers; conduct signals at low velocity

Question 13

Group Ia fibers

Answer 13

From annulospiral endings of muscle spindles

Question 14

Group Ib fibers

Answer 14

From Golgi tendon organs

Question 15

Group II fibers

Answer 15

From cutaneous tactile receptors and flower-spray

Question 16

Group III fibers

Answer 16

Cary temperature, crude touch, and pricking pain

Question 17

Group IV fibers

Answer 17

Carry pain, itch, temperature, and crude touch

Question 18

Spatial summation

Answer 18

Increasing signal strength is transmitted by using progressively greater number of fibers

Question 19

Temporal summation

Answer 19

Increase signal strength by increasing frequency of nerve impulses in each fiber

Question 20

Stimulatory field of neuronal pool

Answer 20

Neuronal area within pool stimulated by each incoming nerve fiber

Question 21

Discharge zone of neuronal pool

Answer 21

Includes all output fibers stimulated by incoming fiber

Question 22

Facilitated/inhibition zones

Answer 22

Neurons further from discharge zones are facilitated, but not excited; may be inhibitory or excitatory depending on input fiber

Question 23

Diverging neuronal pathways

Answer 23

May result in amplification of initial signal or may allow transmission of original signal to separate areas

Question 24

Converging neuronal pathways

Answer 24

Multiple input fibers converge onto a single output neuron

Question 25

Reverberatory circuits

Answer 25

Caused by positive feedback within neuronal circuit; once stimulated may repetitively discharge for a long time

Question 26

What term is described by increasing signal strength transmitted by using progressively greater number of fibers? A. Temporal summation B. Spatial summation C. Clustered summation D. Neuronal pool

Answer 26

B. Spatial summation