All flashcards
Flashcard 1: What is the primary somatosensory cortex, and where is it located?
Answer: Postcentral gyrus of parietal lobe; processes somatic sensory input. Located behind central sulcus; receives touch/pressure signals.
Flashcard 2: Which sensory system uniquely bypasses the thalamus before reaching cortex?
Answer: Olfaction (smell). Projects directly to piriform cortex and limbic structures.
Flashcard 3: What is the first brain structure that receives input from olfactory receptor neurons?
Answer: Olfactory bulb (via glomeruli). Synapses occur in spherical structures called glomeruli.
Flashcard 4: What is olfaction, and what type of receptor detects odorants?
Answer: Smell; GPCR olfactory receptors on olfactory sensory neurons. Each receptor responds to specific odorant molecules.
Flashcard 5: What are the five basic taste qualities commonly tested on the MCAT?
Answer: Sweet, sour, salty, bitter, umami. Each uses different receptors and transduction mechanisms.
Flashcard 6: Which receptors detect sustained pressure and fine spatial detail (edges, texture)?
Answer: Merkel (tactile) discs. Slowly adapting receptors crucial for reading Braille.
Flashcard 7: Which afferent fibers conduct fast, sharp pain?
Answer: A-delta fibers. Myelinated fibers for immediate, localized pain signals.
Flashcard 8: Which afferent fibers conduct slow, dull, aching pain?
Answer: C fibers. Unmyelinated fibers for persistent, diffuse pain signals.
Flashcard 9: What is proprioception?
Answer: Sense of body position and movement from muscles, tendons, and joints. Unconscious awareness crucial for coordinated movement.
Flashcard 10: What is taste transduction for sour stimuli primarily mediated by?
Answer: H+ (acid) effects on ion channels causing depolarization. Protons block K+ channels and activate other channels.
Flashcard 11: What does the somatotopic map (sensory homunculus) represent?
Answer: Body regions mapped to adjacent cortical areas by input location. Larger cortical areas for more sensitive body parts (lips, hands).
Flashcard 12: Which receptors detect light touch and low-frequency vibration in glabrous skin?
Answer: Meissner corpuscles. Rapidly adapting receptors in hairless skin areas.
Flashcard 13: Which receptors detect deep pressure and high-frequency vibration?
Answer: Pacinian corpuscles. Deep, onion-shaped receptors that rapidly adapt to pressure changes.
Flashcard 14: What is taste transduction for salty stimuli primarily mediated by?
Answer: Na+ influx through ion channels (depolarization). ENaC channels allow sodium entry, triggering depolarization.
Flashcard 15: What is the function of Golgi tendon organs in proprioception?
Answer: Detect muscle tension (force) in tendons. Prevent muscle damage by signaling excessive force.
Flashcard 16: What is the function of muscle spindles in proprioception?
Answer: Detect muscle length and rate of stretch. Intrafusal fibers signal changes in muscle length.
Flashcard 17: Which cutaneous receptors are most associated with skin stretch and hand shape?
Answer: Ruffini endings. Slowly adapting receptors that signal joint position.
Flashcard 18: What are nociceptors?
Answer: Pain receptors that respond to tissue damage or potentially damaging stimuli. Free nerve endings that signal actual or potential tissue harm.
Flashcard 19: Which pathway primarily carries fine touch, vibration, and proprioception?
Answer: Dorsal column–medial lemniscus pathway. Ascends ipsilaterally, crosses at medulla.
Flashcard 20: What are the five basic taste modalities tested on the MCAT?
Answer: Sweet, salty, sour, bitter, umami. Each detected by specific receptor types on taste buds.
Flashcard 21: Which cranial nerves carry taste from the anterior 32 of the tongue?
Answer: CN VII (facial nerve; chorda tympani). Chorda tympani branch innervates fungiform papillae.
Flashcard 22: Which cranial nerve carries taste from the posterior 31 of the tongue?
Answer: CN IX (glossopharyngeal nerve). Innervates circumvallate and foliate papillae.
Flashcard 23: Which cranial nerve carries olfactory information from the nasal cavity?
Answer: Cranial nerve I (olfactory nerve). Synapses directly in olfactory bulb before cortical processing.
Flashcard 24: What is the olfactory receptor neuron type and where is it located?
Answer: Bipolar neurons in the olfactory epithelium. Only neurons that directly contact external environment.
Flashcard 25: Which spinal tract primarily carries pain and temperature to the brain?
Answer: Spinothalamic tract (anterolateral system). Crosses at spinal level and ascends contralaterally.
Flashcard 26: What is somatosensation?
Answer: Body senses: touch, pressure, pain, temperature, proprioception. Encompasses all sensory modalities from skin, muscles, and joints.
Flashcard 27: What is the primary somatosensory cortex (S1) location?
Answer: Postcentral gyrus of the parietal lobe. Located behind the central sulcus, receives sensory input from the body.
Flashcard 28: What does the somatosensory homunculus represent in S1?
Answer: Cortical area proportional to sensory receptor density. Body parts with more receptors get larger cortical representation.
Flashcard 29: Which mechanoreceptor detects light touch and low-frequency vibration?
Answer: Meissner corpuscle. Superficial, rapidly adapting receptor in glabrous skin.
Flashcard 30: Which mechanoreceptor detects deep pressure and high-frequency vibration?
Answer: Pacinian corpuscle. Deep, rapidly adapting receptor sensitive to vibration.