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Flashcards in GI/L Deck (56)
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1

LIP 1

  • mucosa = typical of mouth (stratified squamous non-keratinising epithelium - SSNKE)
  • @ margin, abrupt transer to skin (stratified squamous keratinising epithelium - SSKE)
  • connective tissue (sub-mucosa) - collage and elastin
  • deeper layers - glands and striated skeletal muscle (change shape of oral cavity)
  • small blood vessl @ sub-mucosa help keep moist

2

LIP 2: TRANSITION

SSNKE (lower) to SSKE (upper)

3

LIP 3

  • inner lip: SSNKE
  • small clumps of salivary tissue
  • sebaceous glands (Fordyce's spots) open to surface rather than hair follicles

4

HAIR FOLLICLE

  • on keratinised surface of lip

5

TONGUE 1

  • SSNKE on ventral (lower) surface
  • SSKE on dorsal (upper) surface - constant abrasion
  • coarse multi-directional skeletal muscle bundles

extrinsic fibers - skeletal muscle inserted to lower jaw

intrinsic fibers - skeletal muscle inserted to fibrous connective tissue underlying mucosa

mixed sero-mucous salivary glands (SUBLINGUAL)

lymph nodules - particularly @ posterior 1/3 of tongue (linguinal tonsisl)

6

TONGUE - UPPER SURFACE

  • SSKE
  • connective tissue
  • 2 types of salivary glands
  • large bundles of striated muscle

7

TONGUE - SEROUS GLANDS

  • more pink staining (darker than mucous)
  • small serous salivary glands
  • acini - clusters of grapes
  • nucleus on base

8

MUCOUS GLANDS

  • small salivary mucus gland

 

michael palin = mucus pale 

mucus glands stain paler than serous!

9

PAPILLAE AND TASTE BUDS

  • dorsal tongue surface - complex folds = papillae

sweet (tip) / slaty (front/side) / sour (further back) / bitter (whole back)

filiform papillae (threadlike) - most common, tall, pointed - @ whole anterior 2/3

fungiform papillae (mushroom-like) @ tip and sides 

  • @ lateral side fungiform papillae = pale-staining, spindle-shaped taste buds w/ nerves/synaptic vesicles

circumvallate papillae (V-shaped row) @ divide between anterior 2/3 and post. 1/3

this slide - 2 paler staining taste buds embedded in opposing sides of adjacent fungiform papillae

10

NERVES OF TONGUE

  • small nerves lying in sub-mucosa of tongue
  • supple close by taste buds

11

PAROTID SALIVARY GLAND (SEROUS ONLY)

  • striated duct (top left)
  • surrounded by serous acini
  • synthesise alpha-amylase
  • secreted via ducts to mouth
  • ducts can alter ionic concentrations
  1. branches of facial nerve pass through gland
  2. large lymph nodes embedded within gland

secretory cells - pyramidal, spherical nucleus, basal cytoplasm full of rER, apex contains prominent secretory granules (pink staining)

duct cells - simple cuboidal (stratified at distal end)

12

PAROTID GLAND 2

  • C (bottom) = nerve
  • D = large lymph node

inset - close up of lymph node

parotid saliva contains IgA (from plasma), combines with proteinous pieces so reaches intestine unmodified by amylase

striated duct - from invaginations, indicative of water reabsorption

13

SUBLINGUAL SALIVARY GLAND (MAINLY MUCUS)

  • pale staining secretory cells
  • darker staining duct w/ simple cuboidal epithelium
  • flattened oval nuclei to base of cells
  • branched tubular acinar glands
  • sticky mucus rich secretion

major constiuent - polysaccharide

14

PSNS (parasympathetic nervous system) GANGLION

  • PSNS ganglion
  • many nerve cell bodies
  • involved heavily in secretion regulation

this slide = sublingual

15

SUBMANDIBULAR SALIVARY GLANDS (MIXED)

  • well defined / globular
  • branched tubulo-acinar
  • interspersed with fat adipose
  • mixed secertion - part mucus, part enzyme rich

demi-lunes - serous cells form demi-lunes (half-moons) at closed ends of tubules

16

LYMPH NODULE WITHIN SUBMANDIBULAR GLAND

17

EPIGLOTTIS

  • @ posterior of tongue
  • boundary of oropharynx and laryngeal pharynx
  • mostly SSNKE
  • lower part posterior - pseudo-stratified columnar ciliated epithelium (respiratory)

contains:

  1. elastic cartilage plate
  2. lymph nodules (submucosa)
  3. salivary glands (submucosa)

Box A = buccal surface - faces mouth

18

EPIGLOTTIS 2

  • SSNKE

19

GI FORMATIVE 1

  • this is a tastebud surrounded by squamous epithelium

20

GI FORMATIVE 2

  • mucus acini
  • basally located nuclei 
  • ducts lined by cuboidal/columnar epithelium

this is a sublingual gland

21

GI FORMATIVE 3

  • serous glands @ bottom
  • mucus glands @ top
  • this is mixed

therefore this is a submandibular gland

(mixed = submandibular)

22

GI FORMATIVE 4

  • this is purely serous (granules)

this is parotid gland

therefore contains branches of facial nerve

23

GI TRACT LAYERS (x4)

  1. mucosa - innermost. epithelium (folded), connective tissue (lamina propria - w/ lymphoid tissue), smooth muscle ring (muscularis mucosa)
  2. sub-mucosa - loose connective tissue, glands and lymphoid tissue, many blood vessels, meissner's plexus (enteric nervous sytem)
  3. external muscle coat (muscularis externa) - 2 layers of smooth muscle - persistalis - auerbach's plexus (enteric nervous system)
  4. serosa - simple squamous epithelium

24

OSEOPHAGUS

mucosa:

  • SSNKE
  • thin lamina propria
  • narrow muscularis mucosa (thicker @ gastric end)

below diaphragm:

  • simple columnar epithelium (same as gastric region of stomach)
  • site of pathological change - Barrett's oesophagus!

sub-mucosa: sero-mucous glands (lubrication), large thin-walled veins (@ distal end - oesophageal variscosities)

muscularis externa:

upper 1/3 = skeletal / middle 1/3 = mixed / lower 1/3 = smooth

 

25

STOMACH

  • 4 regions: cardia/body/fundus/pyorus
  • cardia and body are histologically similar with respect to glands
  • muscosa thrown into folds (rugae)
  • simple columnar epithelium punctuated by gastric pits
  • muscularis externa is 3 layers thick - additional oblique fibers for churning

gastric mucosa scattered with pale-staining endocrine cells - serotonin, somatostatin, vasoactive intestinal peptide (VIP).

these regulate breakdown and delivery to duodenum

26

GASTRIC GLANDS

  • tubular @ mucosa
  • fill lamina propria
  • 3 main cell types
    1. parietal (HCl + intrinsic factor [B12 absorpition])
    2. chief cells (digestive enzymes - pepsinogen, zymogen for pepsin)
    3. mucus neck cells (lubricant - acid resistant mucus)
  • full glands @ body and fundus
  • no parietal / chief @ cardia and pylorus

27

STOMACH BODY - GASTRIC MUCOSA

  • simple columnar epithelium - produce acid resistant mucin
  • gastric pit invaginations (green arrows)
  • several tall, straight or brached glands to each pit
  • submucosa = loose connective tissue with abundant vessels
  • muscularis externa = 3 layers of smooth muscle

muscularis mucosa also contains elastic (black) to stop stomach collapse on empty

28

PARIETAL (OXYNIC CELLS)

  • @ gastric glands of body/fundus
  • @ upper part of gland close to pits
  • globular - bright pink with H&E
  • cell surface invaginated (intracellular canaliculi) w/ many mitochondria (dark staining- grainy appearance)
  • rich in carbonic anhydrase

pH - 2

29

CHIEF (ZYMOGENIC CELLS)

  • pyramidal @ deeper gland
  • cytoplasm - blue H&E - contains granules (pepsiogen/lipases)
  • @ body and fundus
  • close to muscularis mucosa

PEPSIN - affinity for collagen

30

PYLORIC REGION

  • cardiac and pyloric glands are shorter
  • glands are coiled
  • mainly mucus neck cells
  • scattered with cells producing gastrin