A&P Chapter 15

Question 1

Olfaction

Answer 1

• sense of smell
• olfactory region
  
  1. superior region of the nasal cavity
  2. lined with olfactory epithelium
• olfactory epithelium is constantly replaced
• olfactory neurons are replaced every 2 months

Question 2

Olfactory epithelium and bulb

Answer 2

• contains 10 million olfactory neurons
• olfactory neurons are bipolar
  
  1. axons project to olfactory bulb and synapse with 2nd neuron
  2. olfactory tracts project to cerebral cortex
  3. dendrites extend to olfactory vesicles

Question 3

Neuronal pathways for olfaction

Answer 3

• olfactory relayed to cerebral cortex without thalamus
• axons enter olfactory bulbs and synapse with mitral cells or tufted cells
• olfactory tracts: terminate in olfactory cortex or secondary olfactory areas

Question 4

Olfactory cortex

Answer 4

• temporal lobe

- conscious perception of smell

Question 5

Secondary olfactory

Answer 5

• frontal lobe
• medial olfactory area:visceral and emotional
• intermediate olfactory area: inhibitory to facilitate rapid adaption

Question 6

Taste(gustatory)

Answer 6

• taste buds: receptors; located in papillae
• filiform papillae
• vallate papillae
• foliate papillae
• fungiform papillae

Question 7

Histology of taste buds

Answer 7

• oval in shape
• embedded in tongue and mouth epithelium
• 3 types of epitheleal cells: taste cells, basal cells, supporting cells.
• taste cells: replaced constantly, microvilli called taste hairs, opening called taste pore.

Question 8

Function of taste

Answer 8

• substances dissolve in saliva
• enter the taste pores
• taste cells depolarize
• taste cells release neurotransmitters
• action potential stimulated in sensory neurons

Question 9

Five major tastants

Answer 9

1. Salt: sodium channels
2. sour: hydrogen gated channels
3. Sweet: potassium channels
4. Bitter: calcium release
5. Unami (glutamate or savory): calcium channel

Question 10

Factors affecting taste perceptions

Answer 10

• temperature: warmth enhances sense of taste; cold inhibits

- structure: specificity not perfect; artificial sweeteners have a higher affinity for receptor binding sites.

Question 11

neuronal pathways for taste

Answer 11

• 3 cranial nerves involved
• extend from taste buds to medulla oblongata
• facial nerve(VII): anterior 2/3 of the tongue
• glossopharyngeal nerve(IX): posterior 1/3 of tongue
• vagus nerve(X): epiglottis

Question 12

Visual system

Answer 12

• can detect most distant stimuli of all sense
• eye: eyeball and lens; responds to light
• accessory structures
• optic nerve (II)

Question 13

Accessory structures

Answer 13

• eyebrows, eyelids(palpebrae), conjunctiva (thin transparent mucous membrane), lacrimal apparatus( tear production)

Question 14

Lacrimal gland

Answer 14

produces tears to moisten, lubricate, and wash. Pass through ducts then to eye

Question 15

Lacrimal canaliculi

Answer 15

collect excess tears through openings called puncta

Question 16

Lacrimal sac leads to nasolacrimal duct

Answer 16

opens into nasal cavity beneath the inferior nasal conchae

Question 17

nasolacrimal duct

Answer 17

opens into nasal cavity

Question 18

extrinsic eye muscles

Answer 18

• responsible for eyeball movement
  
  1. superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique, inferior oblique
• innervated by trochlear(IV), Abducens(VI) and oculomotor(III)

Question 19

Tunics of the eye

Answer 19

• fibrous tunic(sclera)
  
  1. white layer, gives shape and muscle attachment
  2. light and oxygen enter via cornea
• vascular tunic(choroid)
  
  1. middle colored layer
  2. iris regulates amount of light
• nervous tunic (retina)
  
  1. neural layer responds to light
  2. contains rods and cones

Question 20

Aqueous humor

Answer 20

• front of eye
• fills anterior portion
• maintain occular pressure and eyeball shape
• provides nutrition

Question 21

Vitreous humor

Answer 21

• back of eye
• fills posterior portion
• maintains pressure and shape
• holds lens and retina in place

Question 22

Lens

Answer 22

• transparent and biconvex
• anterior surface is cuboidal epithelial cells
• posterior surface is columnar epithelial cells
• ligaments suspend lens between posterior and vitreous chambers( ability to stretch

Question 23

Eye functions

Answer 23

• iris allows light to enter the eye
• light reaches retina is converted to action potential
• visible light: portion of spectrum that is visible
• focal point: convergence of light rays
• eye project clear image on retina
• adjustment occurs by changing shape of lens

Question 24

Structures and function of retina

Answer 24

• consists of neural and pigmented layer
• neural layer
  
  1. photoreceptors, bipolar cells, and ganglionic cells
  2. synapses for adjacent neurons
• pigmented layer
  
  1. single kayer of malanin filled cells
  2. isolates photoreceptors and reduces light scattering

Question 25

Rods

Answer 25

- non color vision and reduced light - contains rhodopsin( consists of retinal and dopsin) - continuously release inhibitory neurotransmitter glutamate - glutamate release inhibited by hyperpolarization

Question 26

cones

Answer 26

color vision and sharpness - contains pigment iodopsin 1. retinal combined with color- sensitive opsin 2. each moiety of iodopsin is sensitive to narrow spectrum - light hits the retina - cones specific for wavelength generate action potential

Question 27

Neuronal pathways for vision

Answer 27

- light enters the retina - action potential travel optic nerve - optic nerves connect to optic chiasm - route of axons called optic tract - optic tract can terminate in 1. lateral geniculate nucleus 2. superior colliculi

Question 28

Hearing and balance

Answer 28

- divided into 3 parts - external ear: auricle and external auditory canal,part you can touch and receives sound -

Question 29

external ear

Answer 29

- auricle and external auditory canal | - part you can touch and receiver of sound

Question 30

middle ear

Answer 30

- air filled space containing 3 ossicles | - incus, malleus, stapes

Question 31

inner ear

Answer 31

houses sensory organs for hearing and balance (eardrum)

Question 32

Auricle

Answer 32

- fleshy visible portion of outer ear | - directs sound waves

Question 33

ceruminious gland

Answer 33

- produces ear wax

Question 34

Tympanic membrane

Answer 34

- thin transparent membrane | - conducts vibration

Question 35

middle ear

Answer 35

- air filled space - eustachian tube: opens into pharynx to equalize pressure - ear ossicles: malleus, incus, stapes; transmit vibrations to oval window

Question 36

bony labyrinth

Answer 36

chambers within the temporal lobe

Question 37

Inner ear contains 3 regions

Answer 37

- cochlea: hearing - vestibule: balance - semicircular canals:balance

Question 38

Inner ear

Answer 38

- membranous labyrinth: smaller tunnels within bony labyrinth - filled wit endolymph and paralymph (fluid) - spiral organs contain sensory hair cells - hair cells have tip links that open potassium channels

Question 39

external ear

Answer 39

- auricle collects sound waves | - sound waves travel auditory canal to tympanic membrane

Question 40

middle ear

Answer 40

- soundwaves strike tympanic membrane - tympanic membrane vibrates - ear ossicle vibrate

Question 41

Tensor tympani

Answer 41

inserts on malleus; innervated by cranial; nerve V

Question 42

Stapedius

Answer 42

inserts on stapes and innervated by cranial nerve VII

Question 43

Attenuation reflex

Answer 43

muscles contract during loud noises and prevent damaging vibrations

Question 44

Balance

Answer 44

- static labyrinth: position of head relative to gravity; acceleration and deceleration - dynamic labyrinth: evaluating head movement

Question 45

Dynamic labyrinth

Answer 45

- allows direction perception - 3 semicircular canals - canals expanded into ampulla - ampulla contains crista ampullaris - crista ampullaris have a gelatinous cupula - endolymph moves cupula and causes hair cells to bend