Chapter 17 - Sense Organs Flashcards
Receptors
structures that detect stimuli
Class of Receptors by Modality (type of stimuli)
- Thermoreceptors
- Photoreceptors
- Chemoreceptors
- Nociceptors
- Mechanoreceptors
Classes of Receptors by Distribution
- General senses - widely distributed
2. Special senses - involve cranial nerves, complex
Class of Receptors by Stimulus Origin
- Exteroceptros
- Interoceptors
- Proprioceptors
General senses are detected by different receptors that included both ______________ and ______________ nerve endings.
unencapsulated, encapsulated
Unencapsulated Nerve Endings
dendrites lack connective wrapping
- Free nerve endings - warm receptors, cold receptors, nociceptors
- Tactile (Merkel) discs - light touch, pressure
- Hair receptors - movement of hairs
Encapsulated Nerve Endings
dendrites wrapped by glia or connective tissue
- Tactile (Meissner) corpuscles
- End bulbs (Krause)
- Bulbous (Ruffini) corpuscles
- Lamellar (Pacinian) corpuscles
- Muscle spindles
- Tendon organs
Tactile (Meissner) Corpuscles
- oval mass in dermal papillae
- sense light touch, texture perception
End bulbs (Krause)
similar to tactile corpuscles but located in mucous membranes
Bulbous (Ruffini) Corpuscles
- flat
- sense pressure, skin stretch, and joint movement
Lamellar (Pacinian) Corpuscles
- onionlike
- sense deep pressure, stretch, tickle, and vibration
Muscle Spindles
- fusiform
- sense skeletal muscle stretch
Tendon Organs
- leaflike
- sense tendon stretch caused by muscle activity
Receptive Field
area supplied by a single neuron
Referred Pain
pain from the viscera mistakenly thought to come from more superficial areas (pain fibers from deep tissues merge with those of the skin)
Gating of Pain
pain signals from periphery never reach brain (e.g. heart attack pain in arm - stress and tension, mental factors, lack of activity)
Taste Bud Locations
- Tongue (most)
- Soft palate
- Pharynx
- Epiglottis
- Cheeks
Types of Lingual Papillae
- Filiform - numerous, tiny spikes, no buds
- Folate - ridges on tongue sides, bud in children
- Fungiform - mushroom shaped bumps, have buds
- Vallate - large bumps in a row at back of tongue, have buds
Taste Cells
- banana-shaped
- live 7-10 days
- taste hairs (receptor for taste module)
- synapse with sensory nerve