Until class 9/7

Question 1

Whats the animal composition in a fat free basis?

Answer 1

75 water, 20 protein and 5 ash

Question 2

Whats the animal composition in a dry fat free basis?

Answer 2

80 protein adn 20 ash

Question 3

How can the GIT be divided?

Answer 3

Headgut, foregut, pancreas and biliary system, midgut and hindgut

Question 4

What constitutes the foregut?

Answer 4

esophagus and stomach, or in poultry crop, proventriculus and gizzard

Question 5

What are the main differences between swine and poultry GIT?

Answer 5

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

Question 6

What type of cell line the esophagus?

Answer 6

stratified squamiys epithelium that secret mucus by goblet cells

Question 7

What are the 4 regions of the stomach of swine?

Answer 7

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)

Question 8

What type of cell secretes HCl and pepsinogen in swine? and in poultry?

Answer 8

parietal and chief in swine, and oxyntico peptic cell in poultry

Question 9

What is the gizzard lined with?

Answer 9

Glycoprotein KOILIN

Question 10

Where does pepsin work?

Answer 10

Carboxyl end of aromatic (Phe, Trp and Tyr) and acidic AA (glutamate and aspartate)

Question 11

Where does the duodenum end in poultrY?

Answer 11

where bile and pancreatic ducts form a common papillae, duodenal loop

Question 12

Where does the jejunum end in poultry?

Answer 12

at meckels diverticulum (remnant of yolk stalk (where yolk sac was attached)) it marks start of ileum

Question 13

What are the 4 layers of the midgut?

Answer 13

Serosa, muscle, submucosa and mucosa

Question 14

Whats the function of the serosa layer?

Answer 14

is the outermost has connective tissue to support git, large blood vessels and nerves

Question 15

Whats the function of the muscle layer?

Answer 15

responsible for the motility of git (2 muscle fiber arrangements: outer longitudinal and inner circular)

Question 16

Whats the function of the submucosa layer?

Answer 16

(fluid glands and blood vessels) has large blood vessels

Question 17

What are the 3 sublayers of the mucosa?

Answer 17

muscularis, lamina propia and epithelium

Question 18

How are epithelial cells renewed?

Answer 18

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

Question 19

How is the absorptive are in the GIT expanded?

Answer 19

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

Question 20

What are the 6 different cell types are produced by stem cells in the base of the crypt?

Answer 20

Enterocytes, goblet cells, enteriendocrine, paneth, microfold and tuft

Question 21

What are the functions of the 6 types of cells?

Answer 21

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

Question 22

What are the types of junctions of the intestinal cells?

Answer 22

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

Question 23

What is the glycocalyx?

Answer 23

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

Question 24

What are the types of cells in the pancreas?

Answer 24

islet cells of langerhans secrete hormones (insulin, glucagon, etc)) and acinar cells (most) secrete pancreatic juice and hormones

Question 25

What are the types of islet cells?

Answer 25

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

Question 26

What is the main enzyme for luminal digestion?

Answer 26

Pancreatic alfa amylase

Question 27

Food entry in stomach stimulate secretion of _____ and ______ into duodenum

Answer 27

secretin and CCK

Question 28

What is the function of secretin?

Answer 28

stimulates pancreas to release ions (Na, K, HCO3 etc) to neutralize digesta entering duodenum for proper enzyme action and deactivate pepsin

Question 29

What does CCK do?

Answer 29

stimulates pancreas to secrete proenzymes and enzymes, induces satiety and inhibits gastric acid release

Question 30

What is in the bile?

Answer 30

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

Question 31

How many bile ducts are in swine? and poultry?

Answer 31

In swine there is one bile duct (major papilla) and 1 pancreatic duct (minor papilla) Poultry has 2 bile ducts and 3 pancreatic ducts

Question 32

What is mucosal digestion?

Answer 32

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

Question 33

How is the lipase-colipase complex formed?

Answer 33

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

Question 34

How is a triglyceride digested?

Answer 34

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

Question 35

What are the bile salts?

Answer 35

sodium or K taurocholate, and glycocholate in swine and taurocholate only in poultry

Question 36

What are the functions of bile salts?

Answer 36

reduce surface tension, emulsify, neutralize acid, aid in excretion