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
