Flashcards in Chapter 13 Deck (49)
What type of adapting receptors respond to stimuli with constant action potentials that don't diminish over time.
slowly adapting receptors
Sensory receptors exist in many forms; some called ........... nerve endings are surrounded by specialized supportive cells while others, called ............. nerve endings, lack supportive cells.
where are exteroceptors located, and what do they detect?
close to surface of body, and detect stimuli originating from outside of body like texture, temp, color, smell, level of light
where are interoceptors located, and what do they detect?
body's interior, and detect, stimuli originating from within the body like blood pressure, body temp, stretch of organs, and concentration of chemicals
................ are encapsulated interoceptors or exteroceptors found in the musculoskeletal system, skin, and in many other organs. What causes them to depolarize?
mechanoreceptors, in response to anything that mechanically deforms the cell
.......... are exteroceptors, most of which are slowly adapting receptors. What causes them to depolarize?
thermoceptors, temperature changes
................. can be either interoceptors or exteroceptors that are capable of binding to specific chemicals that, once bound, generate a receptor potential as sodium ion channels open. What causes them to depolarize?
chemoreceptors, chemicals binding to their specific receptors
............... are special sensory exteroceptors found only in the eye. What causes them to depolarize?
............ are usually slowly adapting exteroceptors that detect noxious stimuli translated to pain. What causes nociceptors to depolarize?
Nociceptors, noxious stimuli
What are the six classes of mechanoreceptors?
1. Merkel Cells: (fingertips) discriminitive touch
2. Tactile corpuscles: (very numerous) discriminative touch, but less refined
3. Ruffini Endings: (ligaments) stretch/movement
4. Lamellated corpuscles: (onion shape) vibrations
5. Hair follicle receptors: stimuli that makes hair bend
6. Proprioceptors: sense position in space
Structure of sensory neurons: Somatic sensory neurons are pseudounipolar neurons with the following three main components:
a. The ................... is located in the posterior root (or dorsal root) ganglion, just lateral to the spinal cord.
b. The peripheral process of the neuron is a long ............... that transmits action potentials from the source of the stimulus (a receptor) to the neuron's central process.
c. The central process exits the cell body and travels through the posterior root to enter the spinal cord at the posterior horn (or the brainstem for cranial nerves) where they deliver their action potentials.
cell body, axon
Large diameter axons with thick myelin sheaths conduct the ............... impulses. What types of axons fall into this category?
Fastest. Proprioceptive, discriminate and nondiscriminate touch
Small diameter axons with little myelin transmit action potentials the .............. What types of axons fall into this category?
Slowest. axons that transmit pain and temperature stimuli
What is a Receptive field?
The area served by a neuron. The more branches a neuron possesses the larger that neuron's receptive field
Body regions whose primary function is sensing the environment contain many neurons with smaller receptive fields. Provide an example of a body region with a small receptive field:
Body regions that are not as involved in sensing the environment have fewer neurons with larger receptive fields. Provide an example of a body region with a large receptive field:
forearm or back
.............. is a method for measuring the relative size of receptive fields
two point discrimination threshold
What is a dermatome, and Why are dermatome maps used clinically?
Area of skin that is determined by the spinal nerve that serves it. To test the integrity of sensory pathways to different parts of the body.