Sensory Receptors
Matching. Select the best option for the following statements:
1. ___ Detect chemicals in aqueous solution
2. ___ Detect light
5. ___ Detects pain, a type of chemoreceptor
3. ___ Detect temperature change
4. ___ Detect physical changes (pressure, gravity, etc.)
6. ___ Detects body position, a type of mechanoreceptor a. Photoreceptor b. Proprioreceptor c. Thermoreceptor d. Nocireceptor e. Mechanoreceptor
f. Chemoreceptor
Sensory Adaptation
1. ___________ receptors fire quickly when first stimulated but then slow their firing. They (adapt, do not adapt) to the stimulus. An example of this is adjusting to a smell, temperature, etc.
2. ___________ receptors fire at a constant rate when the stimulus is present and stop when the stimulus is removed. They (adapt, do not adapt) to the stimulus. An example of this is a splinter in your foot.
Neural Pathways of Somatesthetic Sensations

All sensory neurons flow towards the (CNS,
PNS) through (afferent, efferent) fibers.
Two Pathways:
1. Dorsal Column Medial Lemniscal Pathway a. Is there crossover in the medulla? i. First Order: _______________ detecting neurons ascend spinal cord to the ____________ ii. Second Order: Cross over into the contralateral (opposite) side in ____________ bringing stimulus to the _____________ iii. Third Order: Neurons bring stimulus to the cerebral cortex
2. Spinothalamic Tract a. Is there crossover in the medulla? i. First Order: ________________ and ________________ detecting neurons synapse with second order neurons in the _____________ (two words) ii. Second Order: Fibers cross to contralateral side and ascend the
_________________ (two words) into the medulla bringing stimulus to the
_____________ iii. Third Order: Neurons bring stimulus to the cerebral cortex
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
294-6624
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Taste
How do you “taste” molecules?

When there is an increase of ______ , the taste receptors secrete ____________________ , sending an action potential down an afferent pathway towards the CNS

The mechanism varies with the type of taste!
Taste Molecules Detected by Taste Physiology of the Taste
Sweet
Salt
Sour a. b. c. d. a. _________ to receptor molecule binds b. Activates ______________ which activates intracellular proteins and enzymes
(cAMP, protein kinase) c. Closes ______and causes increase in ________  depolarization
______ goes inside cell, causing depolarization
______ blocks ______ channel
(making inside more positive), causing depolarization
Bitter ________ molecules close
______ channels causing depolarization
Umami
Smell
How do you smell odors?

____________ receptors respond to several different odorant chemicals

The odorant molecule binds to a receptor, activating an intracellular ____________ which in turn activates ______ as a secondary messenger

cAMP opens _____ and _______ channels, causing depolarization of receptor membrane triggering an
_______________________
Olfactory Pathway
1. Olfactory receptor cells synapse with __________ cells (cells within olfactory bulb)
2. ___________ cells send impulses to: a. c. b. d.
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