D312 ANATOMY AND PHYSIOLOGY I - Set 5 - Part 2

Correct Answer: Vallate papillae

Option d is correct because vallate papillae are the largest type, arranged in a V-shape at the back of the tongue, and receive innervation from the glossopharyngeal nerve for taste sensation. Option a is incorrect because fungiform papillae are mushroom-shaped and scattered across the anterior two-thirds of the tongue surface, not arranged in a V-shape at the posterior region of the tongue. Option b is incorrect because filiform papillae are the smallest and most numerous papillae covering the tongue surface, but they do not contain taste buds and serve only a tactile sensory function. Option c is incorrect because foliate papillae are located on the lateral posterior edges of the tongue rather than in a V-shaped arrangement at the back, and they are not the largest papillae type.

Correct Answer: Taste pore

Option c is correct because the taste pore is a small opening in the tongue epithelium through which dissolved food molecules access the gustatory receptor cells housed within the taste bud. Option a is incorrect because lingual follicle is not a recognized anatomical structure of the taste bud and does not describe the opening through which tastants reach the receptor cells on the tongue. Option b is incorrect because the gustatory nucleus is a brainstem structure that receives taste signals relayed from cranial nerves, not an opening on the tongue surface for dissolved food molecules. Option d is incorrect because the olfactory cleft is a region in the nasal cavity related to the sense of smell, not a structure on the tongue involved in allowing tastants to access taste receptors.

Correct Answer: Glossopharyngeal nerve

Option b is correct because the glossopharyngeal nerve, cranial nerve nine, receives synaptic input from gustatory receptor cells specifically in the vallate and foliate papillae of the tongue. Option a is incorrect because the facial nerve, cranial nerve seven, innervates taste buds in the epiglottis and throat region rather than the vallate and foliate papillae located on the tongue itself. Option c is incorrect because the vagus nerve, cranial nerve ten, receives synaptic input from gustatory receptor cells in the fungiform papillae, not from the vallate and foliate papillae of the tongue. Option d is incorrect because the hypoglossal nerve, cranial nerve twelve, controls the motor movements of the tongue muscles and does not carry any taste sensory information from papillae to the brain.

Correct Answer: Cribriform plate

Option a is correct because olfactory nerve fibers pass through the cribriform plate, a sieve-like bone between the anterior cranial fossa and nasal cavity, to reach the olfactory bulb in the brain. Option b is incorrect because the foramen magnum is the large opening at the base of the skull where the spinal cord enters and exits, not a passage for olfactory nerve fibers from the nasal cavity. Option c is incorrect because the optic canal is the passageway through which the optic nerve and ophthalmic artery travel from the eye to the brain, unrelated to the transmission of smell signals. Option d is incorrect because the sella turcica is a saddle-shaped depression in the sphenoid bone that houses the pituitary gland and is not a sieve-like structure for olfactory nerve fiber passage.

Correct Answer: Olfactory transduction

Option d is correct because olfactory transduction is the process by which olfactory receptor cell cilia convert chemical odorant molecules in the air into neural impulses through local depolarization of the receptor cell. Option a is incorrect because gustatory transduction refers to the process of converting dissolved tastant molecules into neural signals on the tongue and is specific to the sense of taste, not smell. Option b is incorrect because photoreception refers to the conversion of light energy into neural signals by photoreceptor cells in the retina and is entirely unrelated to the detection of odor molecules. Option c is incorrect because adaptation refers to the reduced perception of a constant odor over time, which is the result of olfactory transduction, not the initial conversion process itself.

Correct Answer: Lacrimal gland

Option b is correct because the lacrimal gland is the specific structure within the lacrimal apparatus that produces tears, which are then carried by ducts in the upper eyelid to the conjunctiva. Option a is incorrect because the ciliary body is a vascular tunica structure behind the iris that adjusts lens curvature and secretes aqueous humor, not the tear-producing gland of the eye. Option c is incorrect because the choroid plexus is a brain structure that produces cerebrospinal fluid within the ventricles and has no connection to tear production or eye surface moisture. Option d is incorrect because the nasolacrimal duct is the drainage channel that carries used tears from the lacrimal sac down into the inferior meatus of the nasal cavity, not the tear producer.

Correct Answer: Nasolacrimal duct

Option c is correct because the nasolacrimal duct drains tears from the lacrimal sac into the inferior meatus of the nasal cavity, which explains why the nose runs during heavy crying. Option a is incorrect because the lacrimal punctum is the small hole on each eyelid where tears initially collect before entering the lacrimal canals, not the final drainage channel into the nose. Option b is incorrect because the auditory tube connects the middle ear to the nasopharynx for pressure equalization and is not part of the tear drainage system connecting eyes to the nasal cavity. Option d is incorrect because the cribriform plate is a sieve-like bone in the skull through which olfactory nerve fibers pass and is not involved in the drainage of tears to the nasal cavity.

Correct Answer: Conjunctiva

Option a is correct because the conjunctiva is a transparent film that covers the inside of the eyelids and sits in front of the cornea, but it is classified as an accessory structure, not part of the eye proper. Option b is incorrect because the sclera is the white outer layer of the fibrous tunica that maintains eye shape and is an integral structural component of the eye wall itself. Option c is incorrect because the cornea is the avascular transparent dome at the front of the eye that refracts light and is a core component of the fibrous tunica, not an accessory structure. Option d is incorrect because the iris is a pigmented smooth muscle ring within the vascular tunica that controls pupil diameter and is an internal eye structure, not an external covering film.

Correct Answer: Lacrimal puncta

Option d is correct because the lacrimal puncta are the small holes located on each eyelid where tears collect after washing across the conjunctiva before entering the lacrimal canals for further drainage. Option a is incorrect because the lacrimal canals are channels that carry tears from the puncta toward the lacrimal sac, representing the next step in the drainage pathway after initial tear collection. Option b is incorrect because the nasolacrimal ducts are the final drainage channels carrying tears from the lacrimal sac into the nasal cavity, located much further downstream in the tear pathway. Option c is incorrect because the scleral venous sinuses are structures at the cornea-sclera junction that drain aqueous humor from within the eye and are completely unrelated to tear drainage.

Correct Answer: Eyelashes

Option c is correct because eyelashes specifically protect the eyes from airborne particles such as dust and debris by trapping them before they can reach the eye surface and cause irritation. Option a is incorrect because eyebrows serve a different protective function by directing perspiration and sunlight away from the eyes rather than filtering airborne particles near the eye surface. Option b is incorrect because eyelids provide protection from physical injury by covering the eye as a barrier but are not the structure specifically designed to filter airborne particles approaching the eye. Option d is incorrect because the conjunctiva is a transparent film lining the inner eyelids that helps maintain moisture on the eye surface, not a structure that blocks airborne particles from entering.

Correct Answer: Optic chiasm

Option a is correct because the optic chiasm is where optic nerve fibers partially cross, allowing binocular vision processing, and damage here commonly causes characteristic visual field losses in peripheral vision. Option b is incorrect because the optic disc is the point where ganglion cell axons leave the eye to form the optic nerve and contains no photoreceptors, making it the blind spot rather than a crossing point. Option c is incorrect because the fovea centralis is the pinpoint depression in the retina where vision is sharpest and is a light-detection structure, not a nerve fiber crossing in the brain. Option d is incorrect because the ora serrata is the serrated anterior border of the retina marking where light-sensitive tissue ends and is not involved in the crossing of optic nerve fibers.

Correct Answer: Macula lutea

Option d is correct because the macula lutea is the retinal region that provides the clearest vision and contains only cone photoreceptors, with the fovea centralis at its center for sharpest acuity. Option a is incorrect because the optic disc is the exit point for ganglion cell axons forming the optic nerve and contains no photoreceptors at all, making it the blind spot of the eye. Option b is incorrect because the ora serrata is the serrated boundary marking the anterior edge of the retina and is not a specialized region concentrated with cone photoreceptors for clear vision. Option c is incorrect because the retinal pigment epithelium is a supporting layer behind the photoreceptors that absorbs stray light and recycles visual pigments but does not itself detect images.

Correct Answer: Optic nerve

Option b is correct because the optic nerve, cranial nerve two, carries visual impulses from the retina to the brain and exits the eye at the optic disc, the location that contains no photoreceptors. Option a is incorrect because the vestibulocochlear nerve is cranial nerve eight, which carries hearing and balance sensory impulses from the inner ear to the brain, not visual information from the eye. Option c is incorrect because the trigeminal nerve is cranial nerve five, which provides facial sensation and controls muscles of mastication, with no involvement in transmitting visual signals from the retina. Option d is incorrect because the olfactory nerve is cranial nerve one, which carries smell sensory impulses from the olfactory epithelium in the nasal cavity to the brain, not visual impulses from the eye.

Correct Answer: Retinal and opsin

Option c is correct because all photopigments, whether rhodopsin in rods or photopsin in cones, share the same two-component molecular structure consisting of retinal and opsin combined together. Option a is incorrect because rhodopsin and photopsin are the names of complete photopigments found in rods and cones respectively, not the two universal molecular building blocks that compose all photopigments. Option b is incorrect because cone cells and rod cells are the two types of photoreceptor cells themselves, not the molecular components that make up the photopigments contained within those receptor cells. Option d is incorrect because melanin is a skin and eye pigment for coloration and keratin is a structural protein in hair and nails, and neither is a component of retinal photopigments.

Correct Answer: Optic disc

Option a is correct because the optic disc is where ganglion cell axons exit the eye to form the optic nerve, and it contains no photoreceptors, which is why it is called the blind spot. Option b is incorrect because the fovea centralis is the pinpoint depression at the center of the macula where vision is most accurate, containing concentrated photoreceptors rather than being a blind spot. Option c is incorrect because the macula lutea is the retinal region surrounding the fovea that provides the clearest vision using only cone photoreceptors and is not an area lacking light detection. Option d is incorrect because the ora serrata is the serrated anterior boundary of the retina and while it marks where light-sensitive tissue ends, it is not the exit point for optic nerve fibers.

Correct Answer: Basal cells

Option d is correct because basal cells are small round stem cells located at the base of taste buds that regenerate both gustatory receptor cells and supporting cells as they wear out. Option a is incorrect because gustatory receptor cells are the main sensory cells within taste buds that detect dissolved tastants, and they are the cells being regenerated by basal cells, not the regenerators. Option b is incorrect because supporting cells are long spindle-shaped cells that provide structural support within the taste bud, and they are also regenerated by basal cells rather than regenerating others. Option c is incorrect because gustatory hairs are extensions projecting from receptor cells through the taste pore to increase surface area for tastant detection, not independent cells capable of regeneration.

Correct Answer: Thalamus

Option c is correct because the thalamus is the central relay station that receives taste signals from the gustatory nucleus in the brainstem and relays them to the primary gustatory cortex in the parietal lobe. Option a is incorrect because the hypothalamus connects taste to emotional states and memory formation through the limbic system but is not the primary relay station sending taste signals to the gustatory cortex. Option b is incorrect because the cerebellum is primarily involved in coordinating voluntary movements, balance, and motor learning, and it does not serve as a relay station for taste sensory information. Option d is incorrect because the medulla oblongata is a brainstem structure containing the gustatory nucleus where taste signals first arrive, but it is not the relay station that sends them to the cortex.

Correct Answer: Parietal lobe

Option a is correct because the primary gustatory cortex is located in the parietal lobe, where the thalamus relays taste signals for conscious processing and perception of taste sensations. Option b is incorrect because the occipital lobe is primarily responsible for processing visual information received from the optic nerves and does not contain the primary gustatory cortex for taste perception. Option c is incorrect because the frontal lobe is primarily associated with motor function, decision-making, and higher cognitive processes rather than serving as the location for primary taste processing. Option d is incorrect because the temporal lobe is primarily associated with auditory processing and olfactory processing, and while it handles smell, it does not house the primary gustatory cortex for taste.

Correct Answer: Gustatory hairs

Option d is correct because gustatory hairs are the thin projections extending from gustatory receptor cells through the taste pore, increasing the surface area exposed to dissolved tastants in the oral environment. Option a is incorrect because cilia are motile or sensory projections found on other cell types, such as olfactory receptor cells, and are not the specific term used for the taste receptor cell projections. Option b is incorrect because stereocilia are specialized projections found on hair cells in the inner ear for hearing and balance detection, not on gustatory receptor cells within taste buds on the tongue. Option c is incorrect because microvilli are general cellular projections found on absorptive cells in the intestines and other tissues, and the specific term for taste bud projections is gustatory hairs.

Correct Answer: Umami

Option b is correct because umami is the fifth basic taste sensation described as meaty or savory, recognized more recently alongside the traditional four tastes of sweet, salty, sour, and bitter. Option a is incorrect because sour is one of the four traditionally recognized taste sensations and is associated with acidic foods like citrus fruits and vinegar rather than a meaty or savory flavor. Option c is incorrect because bitter is one of the four traditional taste sensations associated with alkaloid compounds and serves as a warning for potentially toxic substances, not a savory or meaty taste. Option d is incorrect because sweet is one of the four traditionally recognized taste sensations associated with sugars and carbohydrates, producing a pleasant flavor quality distinct from meaty or savory taste.