Upper and lower GI Flashcards
Outer cutaneous layer of the lip
typical thin skin consisting of: epidermis, dermis, hair follicles, underlying sebaceous glands and sweat glands
Skeletal muscle at the core of the lip (orbicularis oris), closes the mouth & puckers the lips
Green: epithelium
Blue: hair follicle
Yellow: sebaceous gland
Khaki: sweat glands
Inner oral mucosa
Thick nonkeratinized stratified squamous epithelium
underlying lamina propria (blue)
Deep to the lamina propria: small salivary glands (labial) - secretions drain into the surface of the oral cavity, provide moisture and lubrication
Vermillion (red) border of the lip
Tougher, dryer
lacks glands
Stratified squamous epithelium (+/- lightly keratinized)
Lacks hair follicles
Tall CT papillae underneath
Red because epithelium is translucent with a rich capillary blood supply in the papillae underneath
Hard palate (dont have to recognize image)
Anterior roof of the mouth
Epithelium: stratified sq (+/- keratin) (green)
Epi + lamina propria (red) = masticatory mucosa - a surface for the tongue to press up against during chewing, swallowing, phonation
Mucus-secreting palatine glands in the submucosa (box) - minor salivary gland, contributes to swallowing and lingual movements/facilitating speech by lubricating the oral mucosa
Anterior tongue
Filiform papillae
- the most numerous
- no taste buds
- mechanical in function - abrasive coating on the tongue, give the tongue a cleaning function
- pointed ends with keratin covering
- lamina propria underneath projects secondary CT papillae to the base
Anterior tongue
Fungiform papillae
“mushroom-shaped”
taste buds on upper surface - five tastes
Parakeratinized epithelium (keratinocytes retain their nuclei) - key feature
Small secondary CT papillae project into it from underlying lamina propria
Sulcus terminalis
V-shaped border between the anterior (2/3) and posterior (1/3) tongue
Circumvillate papillae
Just anterior to sulcus terminalis
large, cone-shaped
covered by stratified sq epi
contain numerous, visible taste buds
Salivary glands empty serous secretions into the space at the base of the papillae - green, to flush materials from there to refresh taste buds
Parotid salivary glands
purely serous
Separated into lobes and lobules by septa arising from CT capsule
largest, ~30% of saliva
stars - ducts
Sublingual/submaxillary
Mixed seromucous glands
Septa divide gland into lobes and lobules
Blue: mucus acini
Yellow: serous
Green: mucoserous, crescent-shaped serous demilune
Esophagus
Mucosa
Blue: non-K stratified sq epi
black: lamina propria
green: muscularis mucosa (SMC)
Esophagus
Pink- submucosa
green: epi
red: lamina propria
yellow: muscularis mucosae
black circle: glands that produce acidic mucin, drain into esophagus
Esophagus
Muscularis externa
Blue: inner circular
Yellow: outer longitudinal
Upper 1/3: involuntary skeletal
Middle 1/3: inner smooth and outer skeletal
distal 1/3 both smooth
Adventitia of the esophagus
loose CT, adipose tissues, nerves, blood vessels
anchors esophagus to neighbouring structures
majority of esophagus covered by adventitia - may account for the rapid spread of metastatic cells from esophageal tumours
Mucosa of the stomach
see rugae - flatten out as stomach stretches
Mucosa of the stomach
Mucous cells line the surface - simple columnar (mucin granules: pale, washed-out)
Gastric pits in between - tall simple columnar (green)
Dip further down into gastric glands (yellow) - secrete mucus, acid, enzymes
Mucosa of the stomach
blue: parietal cells - most numerous in the body of the gastric gland, but also found in the neck/base
- large, round, pale-staining, eosinophilic, secrete HCl and IF
Green: chief cells - mostly at the base
- round, basally located nucleus, apical part of the cell is granular
- appear more basophilic
- produce pepsinogen I, II, inactive proenzymes
Muscularis mucosa
Directly underneath gastric glands (no lamina propria)
Stomach
Pink : submucosa- highly vascularized and innervated CT
Blue: muscularis externa - 3 layers (random arrangement)
Green: serosa - moist, slippery surface
- mesothelial cells, produce a thin film of serous fluid
Duodenal mucosa
epi, lamina propria, muscularis mucosa
Epi - simple columnar enterocytes + goblet cells (brown arrows)
Duodenal epithelium
Crypts of Lieberkuhn - tube-like invaginations, aka intestinal glands, extend down into the muscularis mucosae
Submucosa of the duodenum
Mucus-secreting glands of Brunner - unique to duodenal submucosa
Secrete alkaline glycoprotein to buffer acid
Jejunum
Blue - tall vili, finger-like projections
Enterocyte covering - simple columnar
goblet cells
Jejunum
Core of each villus contains lamina propria that is vascularized and cellular
Each villus also contains one lymphatic lacteal - absorb fat
When fat + lymph in lacteal = chyle
–> thoracic duct, L subclavian vein
Ileum
Villi are stubb and club-shaped
Enterocyte covering - simple columnar + goblet cells
each has a lacteal
Ileum
White: Paneth cells - deeply eosinophilic
at the base of crypts
key feature of ileum (most numerous)
secrete antimicrobial agents (lysozymes) into crypts
Ileum
Peyer’s patches (aggregates of lymphoid tissue) in yellow
Colon mucosa
No villi!!!
Simple columnar + goblet cells
Much longer intestinal glands/crypts
Many more goblet cells
Colon
Purple - muscularis mucosae
Red - Submucosa - more adipose tissue
blue - muscularis externa - inner circular, outer incomplete longitudinal
Lamina propria contains GALT and many defined lymphoid follicles
Inner surface of muscularis externa: Meissner’s plexus
Between two layers of muscularis externa: Auerbach’s plexus
Appendix!!
Large number of lymphoid follicles in the lamina propria
Esophagogastric jxn
Change from nonk stratified sq epi (blue) –> simple columnar
Serrated border = Z line
Gastroduodenal jxn
More gradual change
Blue:Finger-like projections of gastric epi extend into duodenal epithelium (green)
Anorectal jxn aka pectinate line
simple columnar epi –> transitional zone of stratified columnar –> nonkeratinized, stratified squamous
Common site for neoplastic changes
