Lab Practicum 3

Fungiform

Mushroom shape, contains 6 taste buds per papillae; found on apex & sides of tongue

Foliate

lined trenches on posterior side of tongue

Circumvallate

circular trenches on posterior side of tongue

Filiform

no taste receptors but most numerous, cone or v shape in middle of tongue

CNs that send taste info to brain

glossopharyngeal, vagus, corda tympani

Taste pathway

Cranial nerves → nucleus of the solitary tract (brainstem) → thalamus → insular cortex

Supertasters

Have largest density of taste receptors on anterior portion of tongue

Bitter Taste Transduction

metabotropic with g protein that couples with PDE or PLC

Salt Transduction

calcium, lithium, hydrogen, and potassium enter cell; ionotropic

Sour Transduction

acids donate H atom → K leaves cell → depolarization

Umami, Bitter, and sweet transduction

tastant molecule binds to receptor

Artificial sweeteners that activate sweet receptors

saccharine & aspatarme

properties of odorants

small mass, hydrophobic, volatile

OSNs project to

pyriform cortex , amygdala-hippocampus, entorhinal cortex and septal nuclei

OSN Synapse

Molecules bind to g-protein coupled receptors on their cilia, axons of OSNs form olfactory nerve and synapse with glomeruli (dendrites of mitral and tufted cells) Afterwards that signal goes through the lateral olfactory pathway

Orthonasal olfaction

inhale odorants through nostrils and then binds to nasal receptors.

Retronasal Olfaction

odorant enter mouth, is diffused by nasopharynx, to nasal receptors and leaves through nostrils

Cells in olfactory epithelium

OSNs, basal cells and supporting cells

Cells in olfactory bulb

mitral and tufted cells

Olfactory Nerve (CN1)

made up from axons of OSNs that travel through cribriform plate to the olfactory bulb

Turbinate bones

curly bones covered by the olfactory epithelium

regulate airflow and provide larger surface area for epithelium

cribriform plate

bone structure that separates nose from brain; axons of OSNs travel through it

glomeruli

clusters of dendrites of mitral cells in olfactory bulb

mitral cells

make up part of lateral olfactory tract which projects to pyriform cortex