digestive system I and II Flashcards

1
Q

what does digestive system consist of

A

digestivetract (oral cavity, pharinge, esophagus, stomach, small and large intestines & Rectum-terminal partof LI)
associated glands (salivary glands, liver and pancreas)

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2
Q

what is function of digestive system

A

obtain from ingested food the metabolites for growth & energy requirements before being stored (in fat) or used as energy, the food must be digested and transformed into small (mini) molecules that can be easily absorbed through lining of digestive tract

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3
Q

which enzymes are in stomach and small intestines

A

both digest food
stomach - stomach enzymes
small intestine - pancreatic enzymes

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4
Q

describe first step of digestion

A

occurs in mouth
where food is moistened by saliva and ground by teeth into smaller pieces
saliva also initiates digestion of carbohydrates - sugars - not much since food isnt in mouth for long

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5
Q

what is oral cavity lined with

A

non keratinized stratified squamous epithelium and lamina propria of loose ct = oral mucosa

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6
Q

describe lp of oral cavity

A

transitions to keratinized at level of lip
lp is coontinous with submucosa of denser ct with diffuse small salivary glands - serous or mucous

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7
Q

describe gingiva

A

parakeratinized
skin on external aspect of lip is orthokeratinized - rest of oral mucosa = nonkeratinized

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8
Q

where does oral mucosa start

A

starts in inner aspect of lip = covers all internal parts - reflected at level of tongue and bones

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9
Q

describe area of gingiva

A

gingival suculus
mucosa very folded interdigitating with lamina propria
small area covers part of tip and crown

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10
Q

describe oral mucosa

A

non keratinized stratified squamous
superficial layer - ct of flat cells - squamous
no stratum granulosum or cornuem
mid layer = polygonal or multisided cells
stratum basal = basal layer, cuboidal or columnar

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11
Q

describe tongue

A

mass of striated muscle covered by layer of oral mucosa
muscle fibers are usually cut in the 3 planes of section
mucosa = nonkeratinized stratified squamous epithelium and a lamina propria strongly attached to muscles
dorsal surface is irregular due to presence of small eminences called papillae

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12
Q

name the 2 tonsils

A

palatine tonsil
lingual tonsil
both lymphoid tissue

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13
Q

name the 3 kinds of papilla

A

fungiform
filiform
Circumvallate

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14
Q

describe fungiform papilla

A

smaller mushroom like at base of protrusions
narrow stalk
covered by oral mucosa

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15
Q

describe circumvallate papilla

A

at base of tongue, inverted v shape, 10-18, most important
lp of loose ct
plunge in mucosa = creates groove spaces = where taste buds are
sruface covered by oral mucosa- base of peithelium very folded
von ebners glands

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16
Q

describe von ebner’s glands

A

collection of serous acinus
secretion of lipase
activate in stomach
duct opens at base of circumvallate papilla

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17
Q

describe filiform papilla

A

tongue not smooth due to these
lp = loose ct
pointy, 1-2 tips
covered by oral mucosa
submucosa = dense irregular ct, glands, striated skeletal muscle
sometimes keratin found at tip

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18
Q

name parts of taste bud

A

sensory pale cells - type 2
supporting cells - type 1
afferent fibers and schwann cell
basal cells - type 4
type 3 - intermediate cells

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19
Q

describe sensory pale cells - type 2 of taste bud

A

most are these cells
Synapse with nerve afferent fibers
columnar - start at bm and end at level of pore = small opening, allows food to come into contact with digestive contents, allows food and chemicals to contact
has microvilli on top

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20
Q

describe supporting cells - type 1 of taste bud

A

dark cells

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21
Q

describe afferent fibers and schwann cell of taste bud

A

sensory cells synapse with afferent fibers - not axons or dendrites
when pieces of food - chemical of food like glutamate - causes action potential that is transmitted to nerve afferents, which are covered by schwann cells but do not form myelin
nerve transmits action potential to brain via facial nerve, glossopharyngeal nerve and vagus nerve, takes info to brain and back to mouth

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22
Q

describe basal cells - type 4
of taste bud

A

short cells
stem cell precursors

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23
Q

describe of taste bud type 3 - intermediate cells

A

4th type of cell
not shown

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24
Q

name and describe taste bud mutations

A

familial dysautomia = lack of taste sensation & dsgeusia not life threatening but causes nutrition issues, especially in babies (since will not like food)
how to know if have it? =
phenylthiocarbamide (ptc) -bitter substance =puts drop of it in babies mouth & if baby has normal taste sensation they will frown

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25
describe qualities of taste perceptions and aspects of taste
saltiness sweetness sourness bitterness umami taste map is wrong- taste is equally distributed everywhere taste buds are in palate, circumvallate papillae and a few in fungiform papillae - in animals = no tastes buds in fungiform
26
describe function of salivary gland
wet and lubricate oral cavity and its contents initiate digestion of carbs - not much since short time secrete amylase - destroys glycogen lysozyme - destroy bacterial wall IgA - control germs in mouth lactoferrin - sequester iron needed for protein synthesis so germs will not multiply flora regulation
27
name the salivary glands
parotid - mainly serous submandibular - serous and serous mucous sublingual gland -mainly mucous - sometimes serous too
28
what are the salivary glands
compound acinar branches, and mainly acini, could be tubular
29
describe division of salivary glands
capsule = ct, subdivides into lobes interlobar ct and ducts = between loves thin subdivisions of lobe into smaller compartments = lobules interlobular ct and duct = ct, smaller, between lobules
30
describe parotid gland
well stained acinus no mucous bit basophilic
31
describe submandibular gland
mixed acini serous demilunes no myoepithelial cells for mucous cells for mucous = bigger, more pyramidal, nuclei compressed against base of cell, does not stain well since has many glycoproteins
32
describe sublingual gland
mucous acini not well stained, due to cytoplasm nuclei pushed up against base not much ct striated intralobular duct = continuous as read end = intercalated duct in longitudinal section, very tiny, cells become cuboidal
33
what are intercalated and striated ducts
intralobular ducts
34
describe serous cell
thinner proteinaceous secretion = watery zymogenic granules - secretory granules, pyramidal, round nucleus much ER at base, prominent golgi
35
describe mucous cell
columnar shape active when stressed during exam viscous carbohydrate rich, produce mucin, much thicker glycoprotein
36
describe teeth of humans
2 sets of teeth= diphyodonty baby or deciduous = 20 teeth permanent dentition = 32 teeth upper maxillary and lower mandibular teeth form 2 dental arches each arch symmetrically divided into 2 quadrants
37
how many of each tooth does baby and adult have
center incisors = 1, 1 lateral incisors = 1, 1 canines = 1,1 premolars = 0,2 molars = 2,3 x4 because 4 quadrants
38
describe mucogingival junction
epithelium attaches to enamel, plaque formed here Attachment of gingiva to enamel, if bacteria get in = can compromise periodontal ligament = can lose tooth
39
how is tooth suspended
in pocket of alveolar bone root of tooth suspended by periodontal ligament - goes from cementum to alveolar bone
40
describe enamel
very hard tissue
41
describe clinical crown
visual crown very acidophilic
42
describe anatomical crown
real crown from start of enamel
43
describe pulp
middle of root loose ct many blood vessels and nerve terminals - provide vitality to tooth
44
describe odontoblasts
linning inner aspect of root Synthesizes dentin
45
describe cementum
contains cementocytes - hard tissue, trapped in lacunae synthesizes cementin
46
describe epithelium of tooth
from stratified squamous non keratinized to parakeratinized as approaching gingiva - transitions
47
describe enamel - tooth composition
99% inorganic matrix - practically mineral hardest tissue Hydroxyapatite 1% proteins, enamelins, amelogenins, water
48
describe dentin - tooth composition
70% inorganic matrix, 30% organic matrix proteins, proteoglycans - collagen type 1 Similar to bone in mineral composition
49
describe decalcification
for sectionning and staining 5% nitric acid - dangerous so now use 250nM EDTA = calcium trapper, looks like rubber after enamel is gone now
50
what are sharpeys fibers
collagen type 1 fibers from periodontal ligament penetrating periosteum and cementum
51
what do odontoblasts do
odontoblasts synthesized dentin, line layer of dentin withdraw to center of pulp and space becomes smaller and smaller as get older
52
Describe predentin
not calcified and paler more acidophilic = if calcified, becomes dentin
53
describe processes of odontoblasts
long processes of cells that go all the way either to cementum at level of root or enamel at level of crown, looks columnar but not synthesized in ecm = processes of odontoblasts, become canaliculi of odontoblasts, technically modified sensory cells since odontoblasts derived from nerve cells = why temp produces pain for teeth, canaliculi contain processes of odontoblasts
54
describe a cavity
bacteria penetrate via canaliculi if reach pulp = worse, inflammation of pulp = pulpitis, not good root canal treatment = pulp must be leaned, dont want cavity to reach dentin
55
describe step 1 of tooth formation
neuroectoderm cells migrate from neural crest go from ct under arch and causes stimulation of epithelium to undergo mitosis - divide more and start invading ct
56
what is stomadeum
pocket cavity all surrounded. by ectoderm all mouth forms from this, developing tongue and including teeth
57
describe step 2 of tooth formation
neuroectoderm cells induce formation of epithelial tooth buds - 10 future baby/deciduous teeth = 20 epithelial tooth buds, since there is also 10 above at level of maxilla
58
describe neuroectoderm
cells at level of neural crest or plate - has 2 layers like tube some cells penetrate through mesoderm and reach stomadeum region stomadeum = space with ectoderm located between pericardium - around developing heart and developing brain
59
describe step 3 of tooth formation
epithelial structure - oral ectoderm - will form future enamel organ
60
describe step 4 of tooth formation
neuroectoderm cells mix with mesoderm cells and form neural crest mesoderm eventually neural ectoderm cells will differentiate into odontoblasts
61
describe step 5 of tooth formation
future enamel organ remains connected to oral ectoderm by dental lamina and orginates a second second bud for permanent tooth will undergo same steps as later on
62
describe step 6 of tooth formation
cells of enamel organ differentiate into define layers = inner and outer dental epithelium ode = connected to ectoderm by dental lamin IDE = thinner, cells become columnar, later = makes enamel some cells form stratum intermedium and some will be inbetween stratum intermedium and ODE
63
describe step 7 of tooth formation
some of neural crest mesoderm - mainly neuro crest ectoderm cells - start differentiating into odontoblasts
64
what is SR and SI
stellate reticulum = star like cells stratum intermedium = layer of cuboidal epithelial cells
65
describe ode
connected to dental lamina that is connected to ectoderm
66
describe ide
columnar synthesizes enamel
67
describe step 8 of tooth formation
in addition to ode and ide - enamel organ differentiates into si and sr
68
describe step 9 of tooth formation
ide is formed by ameloblasts (differentiates into) which synthesize enamel crown shapes at bell stage - future shape of crown
69
describe step 10 of tooth formation
cervical loop marks position of neck of tooth - crown root junction = where root will grow recruits ameloblasts- synthesize enamel and will become layer of odontoblasts = synthesizes dentin
70
describe step 11 of tooth formation
odontoblasts become aligned and primitive dental papilla - future pulp - is formed
71
describe step 12 of tooth formation
junction of ide and odontoblasts marks dentino enamel junction from this point on = odontoblasts grow inwardly ide does not form enamel in this region - involved in recruitment of odontoblasts for future root ameloblasts continuous with ide odontoblasts synthesize predentin and then dentin
72
describe step 13 of tooth formation
ode and ide eventually disappear (deteriorates and dies) and odotoblasts induce mesenchyme to form cementoblasts and cementum
73
describe step 14 of tooth formation
forming tooth is within a pocket of alveolar bone between bone and cementum the periodontal ligament is formed
74
describe step 15 of tooth formation
baby tooth functions until 5-6 years of age
75
describe step 16 of tooth formation
permanent tooth awaits further development until baby tooth is scheduled to fall out
76
describe step 17 of tooth formation
Permanent tooth develops in same way as baby tooth
77
describe step 18 of tooth formation
odontoclasts - osteoclasts erode root of baby tooth and new permanent tooth grows as root of baby tooth is eroded
78
describe dentinoenamel junction
future root- dentin joins enamel - from this point = future root becomes dentino-enamel junction = called ide not ameloblasts anymore
79
what are tomes processes.
on ameloblasts during synthesis of enamel ameloblast moves away from dentin and forms a project surrounded by developing enamel - gives ameloblasts a fence look under microscope
80
what are odontoblast processes called
tome's fibers or tomes fibrils located in dentinal tubule