Exam 4 Review:  Chapter 13:  Sensory Information Terminology

sensory modality - Any of the various types of sensation, such as cutaneous senses, taste, smell, vision, hearing, equilibrium, proprioception, and visceral sensations.

somatic sensations - The perceptions associated with stimulation of exteroreceptors to changes in the external physical environment and routed to the somatosensory cortex for interpretation; modalities include cutaneous senses (touch, pressure, vibration, pain, temperature), taste, smell, vision, hearing, and equilibrium; proprioception is also considered a somatic sensation.

visceral sensations - The perceptions associated with stimulation of interoreceptors to changes in the internal physical environment and routed to the hypothalamus and brain stem for interpretation; modalities include chemoreceptors responding to changes in concentration of various molecules, e.g., glucose, O₂, electrolytes, etc., mechanoreceptors responding to changes in the dimensions of internal organs, e.g., expansion of a portion of the G.I. tract, urinary bladder, etc., thermoreceptors responding to body temperature, and nociceptors responding to visceral pain.

proprioception - The unconscious perception of movement, position, location and spatial orientation of the body and its parts arising from stimuli within the body itself; the sensory modality in which mechanoreceptors respond to stretching of a muscle, tendon, or ligament or responding to the movement of special structures in the inner ear; the mechanism involved in the self-regulation of posture and movement.

adaptation (by sensory receptor) - The responsive adjustment of a sense organ, such as the eye, to varying conditions, such as light intensity; the decline in frequency of impulse transmissions of a sensory receptor or sensory neuron under conditions of constant stimulation.

mechanoreceptor - A specialized sensory end organ or sensory neuron which responds to mechanical stimuli such as tension (stretching), pressure, or displacement/distortion (bending); they tranduce mechanical energy into nerve impulses (graded potentials).

nociceptor - A sensory receptor or sensory neuron which responds to injurious or painful stimuli; they tranduce a variety of forms of energy into nerve impulses (graded potentials).

photoreceptor - A nerve ending, cell, or group of cells specialized to respond to electromagnetic radiation, typically wavelengths of visible light, but in some organisms to infrared or ultraviolet wavelengths as well; they tranduce light energy into nerve impulses (graded potentials); in humans (and most vertebrates), these are the rods and cones within the deepest layer of the retina of the eye.

chemoreceptor - A sensory nerve cell or sense organ which responds to chemical stimuli; they tranduce chemical bond energy into nerve impulses (graded potentials); includes exteroreceptors for smell and taste and enteroreceptors sensitive to concentration changes of a variety of molecules in the blood or other body fluids.

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