Until class 9/7 Flashcards
Whats the animal composition in a fat free basis?
75 water, 20 protein and 5 ash
Whats the animal composition in a dry fat free basis?
80 protein adn 20 ash
How can the GIT be divided?
Headgut, foregut, pancreas and biliary system, midgut and hindgut
What constitutes the foregut?
esophagus and stomach, or in poultry crop, proventriculus and gizzard
What are the main differences between swine and poultry GIT?
How they seek food, mastication, storage of food (crop proventriculus and gizzard), GIT length, speed of blood divertion to liver, cecum length and passage time
What type of cell line the esophagus?
stratified squamiys epithelium that secret mucus by goblet cells
What are the 4 regions of the stomach of swine?
Esophageal (prone to ulcers), cardiac (secretes mucus to protect from pH), gastric (parietal cells secrete HCl and chief secrete pepsinogen) and pyloric (secretes mucus and has sphincter)
What type of cell secretes HCl and pepsinogen in swine? and in poultry?
parietal and chief in swine, and oxyntico peptic cell in poultry
What is the gizzard lined with?
Glycoprotein KOILIN
Where does pepsin work?
Carboxyl end of aromatic (Phe, Trp and Tyr) and acidic AA (glutamate and aspartate)
Where does the duodenum end in poultrY?
where bile and pancreatic ducts form a common papillae, duodenal loop
Where does the jejunum end in poultry?
at meckels diverticulum (remnant of yolk stalk (where yolk sac was attached)) it marks start of ileum
What are the 4 layers of the midgut?
Serosa, muscle, submucosa and mucosa
Whats the function of the serosa layer?
is the outermost has connective tissue to support git, large blood vessels and nerves
Whats the function of the muscle layer?
responsible for the motility of git (2 muscle fiber arrangements: outer longitudinal and inner circular)
Whats the function of the submucosa layer?
(fluid glands and blood vessels) has large blood vessels
What are the 3 sublayers of the mucosa?
muscularis, lamina propia and epithelium
How are epithelial cells renewed?
by a process where proliferative (stem) cells in the base of the intestinal glands produce new epithelial cells that migrate upward and out of the crypt and are eventually shed into the lumen
How is the absorptive are in the GIT expanded?
the transversal fold ensure the slow passage of the digesta that gives time for digestion and absorption, villi and mucosal glands increase the surface area 10X and microvilli increase absorptive surface 20X forming and undulated brush border
What are the 6 different cell types are produced by stem cells in the base of the crypt?
Enterocytes, goblet cells, enteriendocrine, paneth, microfold and tuft
What are the functions of the 6 types of cells?
Enterocytes: for absorption, most numerous
Goblet cells: secrete mucus layer
Enteroendocrine: secrete hormones as secretin, pancreozymin, enteroglucagon, etc
Paneth cells: produce antimicrobial peptides
Microfold cells (M cell): sample antigens from the lumen and deliver them to mucosa associated lymphoid tissue (MALT)
Tuft cells: Immune response
What are the types of junctions of the intestinal cells?
Tight junctions: claudins (lateral border) and occludins (apical border) forming a ring shaped ribbon around the cells
Adhesion/anchoring junctions: located in the membrane at contact points between the cells
Gap junctions: connect cells with channels for intercellular communication
What is the glycocalyx?
A layer that acts as a barrier to suspend particulate and filter nutrients and can form visocus gels from some feedstuff that affect permeability of unstirred water layer and cause poor nutrient utilization
What are the types of cells in the pancreas?
islet cells of langerhans secrete hormones (insulin, glucagon, etc)) and acinar cells (most) secrete pancreatic juice and hormones
What are the types of islet cells?
A (α): produce glucagon
B (β): produce insulin, is most abundant
D (δ): produce somatostatin (local regulation of insulin and glucagon secretion, inhibits HCl and pancreatic secretion, intestinal motility and splanchnic blood flow)
F or PP: produce pancreatic polypeptide (regulates GIT secretion and motility
What is the main enzyme for luminal digestion?
Pancreatic alfa amylase
Food entry in stomach stimulate secretion of _____ and ______ into duodenum
secretin and CCK
What is the function of secretin?
stimulates pancreas to release ions (Na, K, HCO3 etc) to neutralize digesta entering duodenum for proper enzyme action and deactivate pepsin
What does CCK do?
stimulates pancreas to secrete proenzymes and enzymes, induces satiety and inhibits gastric acid release
What is in the bile?
Bile contains Na and K salt of bile acid, phospholipids, bile pigments (bilirubin and biliverdin), cholesterol and mucin that is stored in gall bladder except in horse, rat or deer
How many bile ducts are in swine? and poultry?
In swine there is one bile duct (major papilla) and 1 pancreatic duct (minor papilla)
Poultry has 2 bile ducts and 3 pancreatic ducts
What is mucosal digestion?
Enterocyte in mucosal layer produces 6 carbohydrases that are transported to brush border membrane:
Maltase: involved in mucosal digestion only because its anchored in the lipid bilayer membrane of the microvilli. It Breaks maltose (2 glucose alfa 1-4) into 2 glucose
isomaltase: isomaltase into 2 glucose
Sucrase: sucrose into glucose and fructose
Trehalase: trehalose (2 glucose linked by alfa 1-1) into 2 glucose
Lactase: lactose into galactose and glucose
Alfa limit dextrinase: dextrins into glucose
How is the lipase-colipase complex formed?
Procolipase (inactive form of colipase) is secreted and trypsin activates it into colipase and it merges with prolipase to form lipase-colipase complex that is active
How is a triglyceride digested?
Na and bile salt + lipase-colipase complex act on triglyceride releasing a Na salt of fatty acid and diglyceride, then this is digested into a Na salt of FA and 2 monoacylglycerol, digested from C1 on
What are the bile salts?
sodium or K taurocholate, and glycocholate in swine and taurocholate only in poultry
What are the functions of bile salts?
reduce surface tension, emulsify, neutralize acid, aid in excretion
