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Questions and Answers
What happens to the membrane potential of photoreceptors in response to light?
What happens to the membrane potential of photoreceptors in response to light?
What is the function of phosphodiesterase (PDE) in photoreception?
What is the function of phosphodiesterase (PDE) in photoreception?
What is the name of the G-protein stimulated by the bleaching of rhodopsin in photoreception?
What is the name of the G-protein stimulated by the bleaching of rhodopsin in photoreception?
What is the function of taste buds in the sensation of taste?
What is the function of taste buds in the sensation of taste?
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What is the name of the protein that acts as a receptor with a prebound chemical agonist in photoreception?
What is the name of the protein that acts as a receptor with a prebound chemical agonist in photoreception?
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What is the name of the sensory pathway that involves the interaction of dissolved molecules with taste buds?
What is the name of the sensory pathway that involves the interaction of dissolved molecules with taste buds?
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What is the type of papilla that contains taste buds on the surface of the tongue?
What is the type of papilla that contains taste buds on the surface of the tongue?
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What is released by gustatory receptor cells when certain chemicals in ingested substances are carried to their surface in saliva?
What is released by gustatory receptor cells when certain chemicals in ingested substances are carried to their surface in saliva?
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What is the name of the fifth sub-modality of taste, also known as the savory taste or the taste of protein?
What is the name of the fifth sub-modality of taste, also known as the savory taste or the taste of protein?
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What is the result of the hyperpolarization of photoreceptors in response to light?
What is the result of the hyperpolarization of photoreceptors in response to light?
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Study Notes
Taste (Gustation)
- The glossopharyngeal nerve connects to taste buds in the posterior two-thirds of the tongue.
- The vagus nerve connects to taste buds in the extreme posterior of the tongue, which are more sensitive to noxious stimuli like bitterness.
- Axons from the three cranial nerves carrying taste information travel to the medulla.
- The primary gustatory cortex, located near the inferior margin of the post-central gyrus, is responsible for our sensations of taste.
Smell (Olfaction)
- Olfactory receptor neurons are incorporated into a limited region of the nasal epithelium in the superior nasal cavity.
- The olfactory epithelium contains bipolar sensory neurons with dendrites extending from the apical surface of the epithelium into the mucus lining the nasal cavity.
- Odorant molecules bind to proteins that keep them dissolved in the mucus and help transport them to the olfactory dendrites.
- The odorant-protein complex binds to a receptor protein on the membrane of the olfactory cell.
- Each cilia may have as many as 40 specific receptor membrane proteins for interaction with different odorant molecules.
- Rapid adaptation and removal of the odorants permit continued recognition and discrimination of new aromas.
- Action potentials generated in the axon terminals of activated neurons are propagated into the glomeruli within the olfactory bulb.
- The axons of the olfactory neurons extend into the olfactory bulb located on the ventral surface of the frontal lobe.
- Smell is the one sensory modality that does not require a synaptic connection in the thalamus before connecting to the cerebral cortex.
Divisions of the Autonomic Nervous System
- The efferent nervous system can be divided into two functional parts: the somatic nervous system and the autonomic nervous system.
- The major differences between the two systems are evident in the responses that each produces.
- The somatic nervous system causes contraction of skeletal muscles.
Vision
- Light reduces cGMP, causing the Na channels to close, and the membrane potential becomes more negative.
- The hyperpolarizing response to light is initiated by the absorption of electromagnetic radiation by the photopigment in the membrane of the stacked disks in the rod outer segments.
- Rhodopsin can be thought of as a receptor protein with a prebound chemical agonist.
- The bleaching of rhodopsin stimulates a G-protein called transducin in the disk membrane, which in turn activates the effector enzyme phosphodiesterase (PDE), which breaks down the cGMP that is normally present.
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Description
This quiz covers the connection between cranial nerves and taste buds, including the glossopharyngeal and vagus nerves. Learn about the pathway of taste information from the tongue to the brain.
