Micro - Week 7

Functions of GI system:

- prehension: ingestion -> fragmentation - mechanical and enzymatic breakdown (fermentation) of nutrients: digestion- absorption of nutrients- synthesis/secretion (hormones)- excretion of waste material

origin and tissue/organ of GI system chart

write it

stratified squamous epithelium is from .....

lip, oral cavity to non-glandular stomach (beginning and end)

simple columnar epithelium is the lining of...

glandular stomach and intestine (secretion and absorption)

the anus is lined by what type of cells?

stratified squamous

The oral mucosa is lined by what type of cells?

stratified squamous (may or may not be keratinized)

ruminants have a ________

dental pad (no upper incisors)

The tongue is covered by mucosa: ______ epithelium and is...

stratified squamous , keratinized on dorsal side

The tongue has papillae which are.... Some have...

mechanical and gustatory
taste buds

What is one of the strongest skeletal muscle in the body?

tongue

Skeletal muscle in the tongue arrangements:

- longitudinal- transverse- vertical

What influences the shape and structure of the denition?

- type of food- prehension (how to get food to mouth)- mastication (chewing)

enamel (location and hard tissue)

- above gumline - ameloblasts

cementum (location and hard tissue)

- below gumline- cementoblasts

dentin (hard tissue)

odontoblasts

pulp contains....it is associated with..

blood vessels and nerves
loose CT and nerves

periodontal ligament function? They are associated with...

hold individual teeth in place
fibroblast

Are Hypsodont tall or short? Do they grow after eruption?

tall
yes

Are brachyodont tall or short? Do they grow after eruption?

short
no

One or more roots embedded in a bony socket is called...

alveolus

What type of animals have brachydont teeth?

carnivores, humans, incisors of ruminants, pigs (except incisors)

What type of animals have hypsodont teeth?

horses, cheek teeth of ruminants, canine teeth of pigs

Why type of teeth have crowns and a neck? Where are they located?

brachydont
crown = above gingivaneck = below gingiva

Tunics of tubular digestive organs

1. mucosa2. submucosa3. muscularis 4. serosa

What is the mucosa tunic features?

- inner epithelium- middle lamina propria- thin outer muscularis mucosae

What is the muscularis tunic features?

- inner circular- outer longitudinal

What is the serosa tunic features? Examples?

called "adventitia" if abuts other structures
esophagus and part of rectum

tunics chart (jiashi)

write it

The esophagus is lined with _______ epithelium

non-keratinized/keratinized squamous

The submucosa of esophagus contains....

mucous glands

The muscularis of esophagus has what?

skeletal only or skeletal + smooth muscle

Distinct regions of the enteric nervous system

submucosal plexus (Meissner's plexus)andMyenteric plexus (Auerbach's plexus)

The adventia of esophagus is...

over most

What animals have a simple stomach?What type of mucosa?

carnivores and humans
glandular mucosa (simple columnar) ONLY

What type of animals have a compound multi-chambered stomach?What mucosa is in each chamber?

ruminants
- stratified squamous in forestomachs (rumen, reticulum, omasum)- glandular in abomasum (true stomach)

What kind of animals have a composite stomach?What type of mucosa?

pig and horse
glandular and stratified squamous

The horse has a ____________ which is a junction between what?

margo plicatus
between glandular and non-glandular stomach

The forestomach of ruminants is all lined by what type of epithelium?

keratinized stratified squamous

The rumen contains what?

- complex microbial community (fermentation)- papilla (increase SA enhancing absorption of volatile fatty acid)

The reticulum has what kind of apperance?

honey-comb

Reticulum features

- small segments of smooth muscle along ridges- cuds are formed (starts rumination)- acts as sieve- retain large items

Which compartment of ruminant stomach is the largest?

rumen

What is also called the Butcher's bible?

Omasum

Omasum features

- layered muscular organ- reduce particle size- water absorption

What is the true stomach of ruminants?

abomasum (glandular stomach)

What kind of cells line the glandular stomach?

(glandular stomach = true stomach = abomasum)simple columnar mucous cells

regions of glandular stomach

cardiacfundicpyloric

the cardiac region of the glandular stomach is mainly....It is not important in...

mucous glands
digestion

The fundic region of the glandular stomach has what glands? It is composed of what cells?

proper gastric glands
parietal cells, chief cells, endocrine G cells

What do parietal cell secrete?

HCl

What do chief cells produce?

pepsinogen

What do endocrine G cells produce? Where does it enter?

GI hormone gastrin (enters blood stream)

The pyloric region of glandular stomach contains what?

mucous glands and endocrine G cells

What are the invaginations of lining epithelium that leads to glands?

gastric pits

rugae are the ________. They allow what?

folds
distention

The muscularis tunic of the glandular stomach has 3 layers of _______ muscle called....

smooth muscle
oblique, circular and longitudinal

Chief cells are eosinophilic or basophilic? What about parietal cells?

chief cells = basophilicparietal cells = eosinophilic

Do parietal cells or chief cells have a centrally located nucleus?

parietal

What kind of epithelium lines the small intestine? What kind of cells?

simple columnar
enterocytes and goblet (mucous) cells

enterocytes are _________

absorptive w/ microvilli

goblet cells make _______

mucus

does the \# of goblet cells increase or decrease as you go from SI to LI?

increase

The Small Intestine has what kind of folds? It also has what?

circular
villi and microvilli to increase SA

What are the submucosal glands in the duodenum?

Brunner's glands

What are the lymphatic nodules in distal small intestine?

Peyer's patches

What has MAST? What does it stand for?

Small intestine
mucosal associated lymphoid tissue

Villi are only located where?

small intestine

What are intestinal crypts?

- at base of villi- invaginations (continuous with epithelium NOT separate)- site of ell production/division

lamina propria

microvasculature, lymphatics and muscle in villi

What are lacteals?
What is found in them?

blind-ended lymphatic vessels in intestinal villi
chyle

What layer are peyer's patches located in? What part of the body?

lamina propria and submucosa
distal jejunum and ileum (varies with species)

What are M cells?

- specialized epithelial cells- sample antigens

Where are Brunner's glands located? What is their function?

duodenum
produce alkaline mucus to protect from acidic chyme

What gland isn't present in non-mammalian species?

Brunner's glands

What epithelium lines the large intestine?

simple columnar (mostly goblet cells)

Function of large intestine:

- absorb water- secrete mucus- fermentation and volatile FA absorption (hindgut fermenter)

Does the large intestine have villi?

No - only crypts

Pigs and horses have longitudinal flat bands called ____________ What are they composed of?

taeniae coli
smooth muscle and elastic fibers forms haustra (sacculation)

The rectum is lined by what epithelium?

simple columnar

How to distinguish parts of intestine?

SI- villi- intestinal crypts
duodenum - brunner's glands in submucosa
jejunum - no specific structures in submucosa
ileum - peyer's patches in submucosa
LI- no villi- smooth surface- only intestinal glands present

What does the rectum do?

store feces and secrete mucus

What epithelium lines the anus?

stratified squamous

Glandular regions of anus

- anal glands- anal sac glands- circumanal glands (DOGS)

Anal glands empty into....

lumen of anus

what animals have anal sac glands?

carnivores

anal sac glands empty into...

anal sacs

What kind of animals have circumanal glands?

dogs

What gland can form benign tumors?

circumanal glands

Circumanal glands info

- nonpatent ducts- unknown fxn

What epithelium are anal sacs lined by?

keratinized stratified squamous

Where are anal sacs located?

between smooth muscle of internal anal sphincterANDskeletal muscle of external anal sphincter

Glands of anal sac in dogs?In cats?

Dogs: - apocrine tubular sweat glands
Cats: - sebaceous and tubular apocrine sweat glands

What glands resemble hepatocytes?

circumanal glands (hepatoid glands)

Identify location in digestive system

make pictures

Saliva functions

- digestion - provide moisture and lubrication- local immunity- evaporative cooling

What enzymes help with digestion in saliva?

- amylase- maltase- lipase

What helps provide moisture and lubrication in saliva?

water, salts and mucin

What helps with local immunity in saliva?

IgA , lysozyme and lactoferrin

Saliva glands have what types of secretion?

serous, mucous and mixed

Major salivary glands:

parotid (serous), mandibular (mixed), sublingual (mixed)