Lecture 10 Flashcards
(67 cards)
Chemoreceptors
Sense chemicals in the environment or blood (think taste, smell)
Photoreceptors
Sense light
Thermoreceptors
Respond to heat and cold
Mechanoreceptors
Stimulated by mechanical deformation of the receptor (includes touch and hearing)
Nocioreceptors
Pain receptors, depolarize in response to stimuli from tissue damage
Proprioreceptors
Provide sense of body position and allow fine control of skeletal muscles, tendons, and joints
Cutaneous receptors
Skin receptors, include touch/pressure, heat and cold, and pain receptors
Special senses
Receptors that mediate vision, hearing, taste, smell, equilibrium
Exteroceptors
Respond to stimuli from outside the body including cutaneous receptors and special senses
Interoceptors
Respond to internal stimuli, they monitor blood pressure, pH, oxygen, found in organs
Phasic receptors
Respond with a burst of activity when stimulus is first applied but quickly adapt to stimulus and reduce response
May have another burst when stimulus removed to provide on/off info, allow for sensory adaptation and alert us to changes in environment
Tonic receptors
Maintain a high firing rate as long as the stimulus is applied, example is pain, slow adapting
Four types of stimulus energy transduced by sensory receptors
Chemical, light, thermal, mechanical
Receptor/generator potentials
Sensory stimuli produce this type of depolarization, similar to EPSPs
Pressure on pacinian corpuscle
Touch on pacinian corpuscle produces generator potential, if pressure is increased the magnitude of the generator potential increases until threshold is met and an action potential occurs
Generator potential for phasic receptors
This includes pacinian corpuscles, if pressure is maintained the generator potential will diminish
Generator potential for tonic receptors
Increased intensity leads to increased frequency of action potentials after threshold is reached
Pruritis
Itch sensation
Receptive field
Area of skin that changes the firing rate of a neuron when stimulated
More receptors = smaller receptive field = greater acuity (example: finger tips)
Less receptors = larger receptive field = less acuity (example: backs of legs)
Lateral inhibition (touch)
Allows us to feel a single touch with well defined borders when a blunt object touches the skin
Receptors where touch is strongest are stimulated most and they inhibit those around them
*CNS
Five categories of taste
Sweet, salty, umami, bitter, sour
Salty taste receptor
Na+ enters the taste cell and depolarizes it
Sour taste receptor
H+ enters cell and depolarizes it
Sweet and umami taste receptors
Sugar or glutamate binds receptor activating G- proteins/second messengers to close K+ channels