Flashcards in Special sences CH 15 Deck (66)
Unequal curvatures in different parts of the eye that lead to blurty images.
Process by which light energy is turned into graded receptor potrntial
Deap purple pigment of the rods
Changes to opsin in dark
Photoreceptors active in dark
High rate of action potential
Primary visual cortex.
Visual association areas
Three denominational vision provided my the slightly different images delivered by the two eyes.
The receptors for smell and taste, they respond to chemicals in aqueous solution.
The yellow-tinged patch of pseudostratified epithelium that is the organ of smell
Olfactory sensory neurons
Bowling pin shaped receptors in the olfactory epithelium,
Surrounded by supporting cells that contain yellow brown pigment
Olfactory stem cells
Line the base of the epithelium.
Located at the end of each dendrite, increase receptors surface area and are covered by a thin layer of mucus
1. Odorant binds to receptor
2. Receptor activates G protein
3. G protein activated adenylate cyclase
4. Adenylate cyclase converts ATP to cAMP
5. cAMP opens a cation channel, allowing Na+ and Ca+ influx causing depolarization.
Axons of olfactory sensory neurons form>
Olfactory nerve, with synapse in>
Olfactory bulbs which are the distal end of the>
Olfactory tract, where>
Mitral cells (second-order sensory neurons) synapse in>
Peg like projections of the tongue mucosa that make the tongue slightly abrasive.
Mushroom shaped papillae scattered over the tongue. Taste buds are located mainly on the tops and in the side walls of the foliate papillae
Largest and least numerous papillae
7-12 of them form an inverted V at the back of the tongue.
Each flask shaped bud consists of 50- 100 epithelial cells of 2 types:
Gustatory epithelial cells
The taste cells, contain gustatory hairs
long microvilli called gustatory hairs that extend through a taste poor to the surface of the epithelium where they are bathed in saliva.
Stem cells that divide into new gustatory cells
5 tastes sensationss
Activation of taste receptors
Salty: Na+ influx directly depolarizes
Sour: H+ opens cation channels
Sweet, Salty and Umami: common mechanisms in different cells. Couples with G protein gustducin
Gustatory pathway (Cranial nerves)
Facial nerve: from anterior tho thirds of the tongue
Glossopharyngeal: serves posterior tongue and pharynx.
Vagus nerve: epiglottis and lower pharynx
Influence on other sences
80% of taste is smell. Temperature and texture of food enhances taste as well.
3 major ear regions
External ear structures
Auricle: funnels sound waves into the ear
Auditory canal: short curved tube that extends from the auricle to the eardrum
Tympanic memrane: flattened translucent cone that separates outer and middle ear.
sound waves make eardrum vibrate
Middle ear structures
or tympanic cavity: flanked laterally by the tympanic membrane and medially by a bony wall with the oval and round windows. Houses auditory ossicles
Malleus : hammer
Incus : anvil
Inner ear structures