Chapter 47: Sensory Receptors, Neuronal Circuits for Processing Information

Question 1

These are receptors found in the hypothalamus that detect minute changes in osmolality of the body fluids

Answer 1

osmoreceptors

Question 2

This means that 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 sensitivities

Question 3

This principle pertains to the specificity of nerve fibers for transmitting only one modality of sensation

Answer 3

labeled line principle

Question 4

This is the changes in the membrane electrical potential of the receptor upon excitation by a stimulus

Answer 4

receptor potential

Question 5

Which part of the brainstem contains receptors for blood CO2

Answer 5

medulla

Question 6

Which part of the lower brain contains receptors for blood glucose, fatty acids and amino acids?

Answer 6

hypothalamus

Question 7

This process probably results from progressive “inactivation” of the sodium channels in the nerve fiber membrane, which means that sodium current flow through the channels causes them to close gradually, resulting to the much slower mechanism of adaptation of the Pacinian corpuscle.

Answer 7

accommodation

Question 8

2 ways by which a Pacinian corpuscle adapts:

Answer 8

1. redistribution of fluid within the corpuscle

2. accommodation = progressive “inactivation” of the sodium channels in the nerve fiber membrane

Question 9

These receptors detect Continuous stimulus strength; hence, they are called the “Tonic” Receptors

Answer 9

slow adapting receptors

Question 10

Give 4 slow adapting receptors

Answer 10

receptors of the macula
pain receptors
baroreceptors
chemoreceptors

Question 11

These receptors detect change in Stimulus Strength; hence, they are called the “Rate Receptors,” “Movement Receptors,” or “Phasic Receptors.”

Answer 11

rapidly adapting receptors

Question 12

Which muscle spindle ending gives information to Group II fibers?

Answer 12

flower-spray endings

Question 13

Mechanism whereby increasing signal strength is transmitted by using progressively greater numbers of fibers.

Answer 13

Spatial summation

Question 14

The entire cluster of fibers from one pain fiber frequently covers an area of skin as large as 5 centimeters in diameter. This area is called the ________ of that fiber.

Answer 14

receptor field

Question 15

A phenomenon by which the stronger signals spread to more and more fibers

Answer 15

spatial summation

Question 16

A means for transmitting signals of increasing strength is by increasing the frequency of nerve impulses in each fiber, this is called

Answer 16

frequency summation

Question 17

Which part of the spinal cord could be considered one long pool of neurons?

Answer 17

dorsal column of the spinal cord

Question 18

The neuronal area stimulated by each incoming nerve fiber is called

Answer 18

stimulatory field

Question 19

Excitatory stimulus is also called

Answer 19

Suprathreshold stimulus

Question 20

Zone wherein all the neurons are stimulated by the incoming fiber

Answer 20

discharge zone, excited or liminal zone

Question 21

Zone wherein the neurons are facilitated but not excited

Answer 21

facilitated, subthreshold or subliminal zone

Question 22

Phenomenon in which weak signals entering a neuronal pool excite far greater numbers of nerve fibers leaving the pool

Answer 22

divergence

Question 23

This means simply that an input signal spreads to an increasing number of neurons as it passes through successive orders of neurons in its path. This type of divergence is characteristic of the corticospinal pathway in its control of skeletal muscles, with a single large pyramidal cell in the motor cortex capable, under highly facilitated conditions, of exciting as many as 10,000 muscle fibers.

Answer 23

Amplifying divergence

Question 24

In this case of divergence signal, the signal is transmitted in two directions from the neuronal pool

Answer 24

Divergence into multiple tracts

Question 25

This means signals from multiple inputs uniting to excite a single neuron

Answer 25

Convergence

Question 26

This is one of the important means whereby the central nervous system correlates, summates, and sorts different types of information.

Answer 26

convergence

Question 27

The type of circuit is characteristic for controlling all antagonistic pairs of muscles

Answer 27

reciprocal inhibition circuit

Question 28

In many cases, a signal entering a pool causes a prolonged output discharge, called

Answer 28

afterdischarge

Question 29

As a result of this mechanism alone, it is possible for a single instantaneous input signal to cause a sustained signal output (a series of repetitive discharges) lasting for many milliseconds.

Answer 29

synaptic afterdischarge

Question 30

These circuits are caused by positive feedback within the neuronal circuit that feeds back to re-excite the input of the same circuit.

Answer 30

reverberatory or oscillatory circuits

Question 31

This type of information transmission is used by the autonomic nervous system to control such functions as vascular tone, gut tone, degree of constriction of the iris in the eye, and heart rate.

Answer 31

carrier wave

Question 32

2 MECHANISMS FOR STABILIZING NERVOUS SYSTEM FUNCTION

Answer 32

Inhibitory circuits and Fatigue of synapses

Question 33

This means simply that synaptic transmission becomes progressively weaker the more prolonged and more intense the period of excitation

Answer 33

Synaptic fatigue

Question 34

Mechanism for the Automatic Short-Term Adjustment of Neuronal Pathway Sensitivity

Answer 34

Fatigue mechanism

Question 35

Main cause of Long-Term Changes in Synaptic Sensitivity

Answer 35

Automatic upregulation or downregulation of synaptic receptors