histology- digestive system

tubular, MSMS structure

except for glands, all digestive organs are _______(parenchymal or tubular), so all have____

keratinized stratified squamous epithelium, hair follicles, sebacious glands, sweat glands

describe the composition of the external region of the lips

cutaneous region,

red region,

oral mucosa region

what are the 3 regions of the lips/gums?

non-keratinized stratified squamous epithelium, tall papillae with blood vessels

what composes the red region of the oral cavity?

cutaneous region

which region of the mouth is keratinized- cutaneous region, red region, or oral mucosa region?

lip

what is this?

left side, because there are hair follicles

the right is internal because there are salivary glands

sample of a lip- which side is exterior, and why?

hair follicles (this is a sample of the lip)

what are these structures?

salivary glands of the lip

what are these structures?

2, because it has mucus glands

which is a sample of the sublingual gland? why?

1

which has mixed glands (both serous and mucus)?

1, because it is mixed (has both mucus and serous glands)

which belongs to the mandibular gland? why?

2

which is mucus glands?

3, because it has serous glands

which is a sample of the parotid gland? why?

3

which has serous glands?

hair follicle

what is this?

sweat glands

what are these?

sebacious glands

what are these?

large hair follicle (whisker)

what is this?

lip/oral cavity because of the presence of sebacious and sweat glands and hair follicles and keratin on exterior

what is this? why?

the dorsal side is, the ventral side is not

is the tongue keratinized?

muscle

what is the tongue mostly composed of ?

dorsal

which side of the tongue has lingual papillae?

no

does the ventral surface of the the tongue have papillae?

the tongue

what is this?

1- dorsal: papillae, keratin

2- ventral: no papillae, nonkeratinized

how can you distinguish between the ventral and dorsal surfaces of the tongue? which is which in this picture?

dense CT

the submucosa of the tongue is made of...

3 layers of skeletal muscle in 3 different directions

describe the muscularis of the tongue

filiform- conical, long

what type of lingual papillae? why?

fungiform- fungi shaped, protrusion (sticks out)

what type of lingual papillae? why?

circumvallate- flat (not a protrusion of the mucosa), serosa glands at bottom, taste buds on lateral surface

what type of lingual papillae? why?

foliate- short, vertical, taste buds in surface

what type of lingual papillae? why?

1- fungiform (protrudes from mucosa)

2- circumvallate (flat against mucosa)

which is fungiform and which is circumvallate?

A- conical, protrusions

which is filiform?

foliate

what type of lingual papillae is B?

C

which is fungiform papillae?

circumvallate

what type of papillae is D?

circumvallate

which lingual papillae has serosa glands at the base?

it is cornificated (keratinized)

what is different in the filiform papillae of cows and cats?

filiform and fungiform

which lingual papillae protrude from the mucosa?

bone with mucosa covering

what is the composition of hard palate?

oropharyx- stratified squamous

nasopharynx- pseudostratified columnar with cilia

what are the 2 types of epithelium of the pharynx?

stratified squamous

what type of epithelium is in the oropharynx?

pseudostratified columnar epithelium with cilia

what epithelium is in the nasopharynx?

no

are the tonsils keratinized?

only the nasopharynx

does the pharynx have cilia?

lymphoid follicles with B cells

interfollicular tissue with T cells

what important structures do you find in the tonsils?

a tonsil

what is this?

it is deeply folded

what is the appearance of the mucosa of the esophagus when it is relaxed?

keratinized stratified squamous epithelium (carnivores don't have keratin)

what is the epithelium of the esophagus?

yes, except for carnivores

is the esophagus keratinized?

pig

what species has lymphoid accumulation in the lamina propria of the esophagus?

close to the stomach

where is the muscularis layer of the esophagus the thickest?

usually 2

how many layers of muscle is in the muscularis of the esophagus?

ruminant and dog

which species have all striated muscle in the esophagus?

horses, cats

which species have mostly striated and a little smooth muscle in esophagus?

pig

which species have equal amount of stratified and smooth muscle in the esophagus?

the mediastinal pleura

the serosa of the thoracic esophagus is continuous with...

the peritoneum

the serosa of the abdominal esophagus is continuous with...

carnivores

which species do not have keratin in the esophagus?

pig, dog

which species have a discontinuous muscularis mucosa in the esophagus?

horse, cat, ruminant

which species have a continuous muscularis mucosa in the esophagus?

discontinuous

do dogs have a complete or discontinuous muscularis mucosa in the esophagus?

horse, cat, or ruminant, because the muscularis mucosa is complete

esophagus- which species? why?

dog- discontinuous muscularis mucosa, non keratinized

esophagus- what species? why?

keratin:

yes- ruminant, horse, pig

no- dog, cat

muscularis mucosa:

continuous- horse, ruminant, cat

discontinuous- pig, dog

how can you distinguish species when looking at a sample of an esophagus?

ruminant- continuous muscularis mucosa, keratin

esophagus- what species? why?

keratinized stratified squamous epithelium

how is the epithelium of the forestomachs of a ruminant?

no muscularis mucosa

thickened folds that form grooves, called pillars of the rumen

describe the main attributes of the rumen

long and short folds

muscularis mucosa in apical parts of long folds only

describe the main attributes of the reticulum

long folds with cornified papillae

muscularis mucosa in all folds

describe the main attributes of the omasum

rumen- no muscularis mucosa

which forestomach? why?

reticulum- short and long folds, long folds with muscularis mucosa at apical part

which forestomach? why?

omasum- only long folds, all with muscularis mucosa

which forestomach? why?

lamina propria of mucosa

in which layer of the glandular stomach are there gastric glands?

3

how many layers of muscle in the muscularis of the glandular stomach?

3 layers:

inner- oblique

middle- circular

outer- longitudinal

describe the muscularis of the glandular stomach

columnar with mucous cells

what is the epithelium of the mucosa of the glandular stomach?

glandular stomach

what is this?

parietal cells and chief cells

what are the 2 types of gastric glands in the lamina propria of the glandular stomach?

looks like fried egg

lots of cytoplasm

individually distributed cells

central nucleus

eosinophilic cytoplasm

basophilic nucleus

secrete gastric acid

describe parietal cells (appearance and function)

secrete gastric acid

what do parietal cells do?

clustered together

nucleus at base

basophilic cytoplasm

what do chief cells look like?

secrete pepsin

what do chief cells do?

the mucosa of the glandular stomach

what is this?

parietal cells

what are the cells at 1?

chief cells

what are 2?

the mucosa of the glandular stomach

what is this?

the abomasum

what is this?

1. very long organ

2. mucosa and submucosa are folded in circular arrangements called plicae circulares

3. villi on mucosa surface

4. microvilli on enterocytes

what factors allow the small intestine to have large surface area?

it is only at the apical part of the enterocytes, so it allows the cells to open and close to allow molecules past into the bloodstream (for absorption)

what is the function of the gap junctions of the mucosa of the small intestine?

at the apical part of the enterocytes

where are gap junctions located in the small intestine?

columnar

what is the epithelium of the small intestine?

enterocytes, goblet cells, neuroendocrine cells, lymphocytes

what types of cells do we see in the mucosa of the small intestine?

yes

are there goblet cells in the small intestine?

enterocytes

what are the most abundant cells of the mucosa of the small intestine?

tall and columnar with a basal nucleus and microvilli on the surface

describe the appearance of enterocytes

stomach- no goblet cells, parietal and chief cells

small intestine- goblet cells, intestinal glands

what is the difference between the mucosa of the glandular stomach and the mucosa of the small intestine?

brunner's glands

what structures are unique to the duodenum?

in the submucosa of the duodenum

where are brunners glands located in the digestive system?