Chapter 16 Flashcards
Sensation
Is the conscious or subconscious awareness of changes in the external or internal environment.
Perception
Is the conscious interpretation of sensations and is primarily a function of the cerebral cortex. If sensory information doesn’t reach the cerebral cortex, we have no perception of it.
Sensory modality
Each unique type of sensation – such as touch, pain, vision, or hearing. A given sensory neuron carries information for only one sensory modality.
What two classes can sensory modality be grouped into?
- General senses
- Special senses
General senses
Refer to both somatic senses and visceral senses.
Somatic senses
Include tactile sensations (touch, pressure, vibration, itch, and tickle), thermal sensations (warm and cold), pain sensations, and proprioceptive sensations. Proprioceptive sensations allow perception of both the static (nonmoving) positions of limbs and body parts (joint and muscle position sense) and movements of the limbs and head.
Visceral senses
Provide information about conditions within internal organs (Eg. Pressure, stretch, chemicals, nausea, hunger, and temperature).
Special senses
Include the sensory modalities of smell, taste, vision, hearing, and equilibrium or balance.
Sensory receptor
What the process of sensation begins at. Can either be a specialized cell or the dendrites of a sensory neuron. Responds to a particular kind of stimulus.
Stimulus
A change in the environment that can activate certain sensory receptors.
What four events take place for a sensation to arise?
- Stimulation of the sensory receptor
- Transduction of the stimulus (sensory receptor converting the energy in the stimulus into a graded potential)
- Generation of nerve impulses
- Integration of sensory input
What are the three classifications for a sensory receptors microscopic structure?
- Free nerve endings (nonencapsulated)
- Encapsulated nerve endings
- Seperate cells
Free nerve endings (nonencapsulated)
Bare dendrites associated with pain, thermal, tickle, itch, and some touch sensations.
Encapsulated nerve endings
Dendrites enclosed in connective tissue capsule for pressure, vibration, and some touch sensations.
Separate cells
Receptor cells that synapse with first-order sensory neurons; located in retina of eye (photoreceptors), inner ear (hair cells), and taste buds of tongue (gustatory receptor cells).
Receptor potential
A graded potential generated by a sensory receptor.
What are the three classifications for a sensory receptors location and activating stimuli?
- Exteroceptors
- Interoceptors
- Proprioceptors
Exteroceptors
Located at or near body surface; sensitive to stimuli originating outside body; provide information about external environment; convey visual, smell, taste, touch, pressure, vibration, thermal, and pain sensations.
Interoceptors
Located in blood vessels, visceral organs, and nervous system; provide information about internal environment; impulses usually are not consciously perceived but occasionally may be felt as pain or pressure.
Proprioceptors
Located in muscles, tendons, joints, and inner ear; provide information about body position, muscle length and tension, position and motion of joints, and equilibrium (balance).
What are the six classifications for a sensory receptors type of stimulus detected?
- Mechanoreceptors
- Thermoreceptors
- Nociceptors
- Photoreceptors
- Chemoreceptors
- Osmoreceptors
Mechanoreceptors
Detect mechanical stimuli; provide sensations of touch, pressure, vibration, proprioception, and hearing and equilibrium; also monitor stretching of blood vessels and internal organs.
Thermoreceptors
Detect changes in temperature.
Nociceptors
Respond to painful stimuli resulting from physical or chemical damage to tissue.