Sensory receptors

Question 1

Sensory transduction

Answer 1

The process by which different types of stimuli from varying sources are received and changed into the electrochemical signals of the nervous system.

Question 2

Sensation

Answer 2

The activation of sensory receptors at the level of the stimulus.

Question 3

Perception

Answer 3

The central processing of sensory stimuli into a meaningful pattern involving awareness.

Question 4

Receptor

Answer 4

A structure/cell that detects a sensation and is changed directly by a stimulus.

Question 5

Sense organs

Answer 5

The organs that respond to external stimuli by conveying impulses to the sensory nervous system.

Question 6

Structural receptor types

Answer 6

• free nerve endings
• encapsulated nerve endings
• specialised receptor cells

Question 7

Receptor location

Answer 7

• exteroceptor; located near a stimulus in the external environment
• interoceptor; interprets stimuli from internal organs and tissues
• proprioceptor; located near a moving part of the body, such as a muscle or joint capsule, that interprets the position of the tissues as they move

Question 8

Functional receptor types

Answer 8

• chemoreceptors; detect chemical stimuli
• osmoreceptors; respond to solute concentrations of body fluids
• nociceptors; detect pain stimuli
• mechanoreceptors; detect physical stimuli
• thermoreceptors; sensitive to temperature

Question 9

Stimulus coding

Answer 9

• stimulus modality
• stimulus intensity
• stimulus location
• stimulus duration

Question 10

Adequate stimulus

Answer 10

The stimulus to which a particular receptor responds effectively and that gives rise to a characteristic sensation.

Question 11

Stimulus modality

Answer 11

The type of energy that is detected by a sensory receptor may be:

• Electromagnetic/thermal eg. light, temperature
• Mechanical eg. sound, touch, pressure, vibration
• Chemical eg. taste, odour, humidity

Question 12

Adaptation

Answer 12

The decline of the electric responses of a receptor neurone over time, and in spite of the continued presence of an appropriate stimulus of constant strength.

Question 13

Types of adaptation

Answer 13

• phasic receptors; adapt rapidly, inform about the rate of change of a stimulus
• tonic receptors; adapt slowly, inform about the presence and strength of a stimulus

Question 14

Stimulus intensity

Answer 14

• threshold; the minimum intensity of a stimulus that is required to produce a response from a sensory system
• saturation; the maximum intensity of a stimulus that produces a response from a sensory system
• dynamic range; the range of intensities that will produce a response from a receptor or sensory system

Question 15

Acuity

Answer 15

The ability to precisely localise a sensation, determined by receptor field size and receptor density.