Special sences CH 15 Flashcards Preview

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Flashcards in Special sences CH 15 Deck (66)
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31

Astigmatisn

Unequal curvatures in different parts of the eye that lead to blurty images.

32

Phototransduction

Process by which light energy is turned into graded receptor potrntial

33

Rhodopsin

Deap purple pigment of the rods
Changes to opsin in dark
Photoreceptors active in dark
High rate of action potential

34

Striate cortex

Primary visual cortex.

35

Prestriate cortex

Visual association areas

36

Depth preception

Three denominational vision provided my the slightly different images delivered by the two eyes.

37

Chemoreceptors

The receptors for smell and taste, they respond to chemicals in aqueous solution.

38

Olfactory Epithelium

The yellow-tinged patch of pseudostratified epithelium that is the organ of smell

39

Olfactory sensory neurons

Bowling pin shaped receptors in the olfactory epithelium,
Bipolar,
Surrounded by supporting cells that contain yellow brown pigment

40

Olfactory stem cells

Line the base of the epithelium.

41

Olfactory Cilia

Located at the end of each dendrite, increase receptors surface area and are covered by a thin layer of mucus
Largely non-motile

42

Olfactory Transduction

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.

43

Olfactory pathway

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>
Glomeruli

44

Papillae

Peg like projections of the tongue mucosa that make the tongue slightly abrasive.

45

Fungiform papillae

Mushroom shaped papillae scattered over the tongue. Taste buds are located mainly on the tops and in the side walls of the foliate papillae

46

Vallate papillae

Largest and least numerous papillae
7-12 of them form an inverted V at the back of the tongue.

47

Taste bud

Each flask shaped bud consists of 50- 100 epithelial cells of 2 types:
Gustatory
Basal

48

Gustatory epithelial cells

The taste cells, contain gustatory hairs

49

Gustatory hairs

Sensitive portion.
long microvilli called gustatory hairs that extend through a taste poor to the surface of the epithelium where they are bathed in saliva.

50

Basal epithelium

Stem cells that divide into new gustatory cells

51

5 tastes sensationss

Sweet
Sour
Salty
Bitter
Umami

52

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

53

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

54

Influence on other sences

80% of taste is smell. Temperature and texture of food enhances taste as well.

55

3 major ear regions

External ear
Middle ear
Inner ear

56

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

57

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

58

Auditory ossicles

Malleus : hammer
Incus : anvil
Stapes :stirrup

59

Inner ear structures

Bony labyrinth
Membranous labyrinth
Vestibule
Semicircular canals
Cochlea

60

Bony labyrinth

Canals worming through the bone, filled with perilymph fluid