Applies to birds; sreves as a temporary storage for food. Wetting food with saliva. Will also soften food for young when regurgitated.
High in protein and fat
Extract nutrients from blood and processes/concentrates them for subsequent secretion into the lumen (holocrine=exocrine gland) and then regurgitation.
stimulates secretion of crop milk by the crop glands
hormones into the blood
secretion into the ducts
secrete via exocytosis= "puking' out "stuff"
pinching off part of cell= burst open
cell will divide via mitosis and whole cell will burst open= like killing cell itself
Birds true stomach containing mucous, HCl and pepsinogen
very muscular; used primarily to grind and break up food (seeds); may, in seed eating birds, contain grit (small stones ingested by birds to help grind food)
Digestion and fermentation of fiber; Absorptiong of VFA
excretion of feces and uric acid
1. Feed on plants- cellulose.
2. Need cellulase to digest it
3. But ruminants do not produce cellulase
4. Their digestive system are specially adapted to carry out cellulose digestion.
First and largest compartment = contains bacteria that produce cellulase for the cellulose digestion; Functions as the fermentation chamber
conversion of carbohydrates to alcohols and CO2 or organic acids using yeast, bacteria, or both under anaerobic conditions
1. Bacterial hydrolysis first breaks down the insoluble organic polymers = proteins, fats and carbohydrates, into simpler amino acids, fatty acids and sugars
2. Acidogenic bacteria: convert amino acids, fatty acids and sugars into hydrogen (H2), carbon dioxide (CO2), ammonia and organic acids = Volatile fatty acids (VFA).
3. Hydrogen-producing acetogenic bacteria convert the organic acids (VFA) to H2, CO2, and acetic acid
4.Methanogenic bacteria convert H2, CO2, and acetic acid to CH4 (methane) and CO2. Methane is exhaled.
Volatile Fattey Acids; EX. Acetic acid, Propionic acid, butyric acid
Used throughout most of the body to generate ATP; Major source of acetyl CoA for synthesis of lipids (In Krebs cycle or citric cycle)
Almost completely removed from portal blood by the liver; within the liver it serves as a major substrate for gluconeogenesis, which is absolutely critical to the ruminant because almost no glucose reaches the small intestine for absorbtion
Most of which comes out of the Rumen as the ketone beta-hydroxybutyric acid, is used in many tissues for energy production.
saliva is rich in bicarbonate, which buffers the large quantity of acid produced in the rumen and is critical for maintenance of rumen pH.
constantly flush lighter solids back into the rumen. The smaller and more dense material tends to be pushed into the reticulum.
making glucose from non-carbohydrate precursors
Cud= food that a ruminant returns from the first stomach to the mouth to chew a second time = Regurgitation occurs
1.Regurgitation is initiated with a reticular contraction
2.This contraction, in conjunction with relaxation of the distal esophageal sphincter, allows a bolus of ingesta to enter the esophagus
3.The bolus is carried into the mouth by reverse peristalsis
4.The fluid in the bolus is squeezed out with the tongue and reswallowed, and the bolus itself is remasticated, then reswallowed.
Re-swallowed cud will be sent here; Large particles are broken down by peristalsis; Absorption of water, magnesium and volatile fatty acids produced by rumen fermentation that have not been absorbed into the bloodstream
True stomach of the ruminants; contains HCl and pepsin
the first segment of the large intestine into which the ileum empties digestive matter
Rodent Digestive System
Their caecum and appendix are enlarged to store the cellulase producing bacteria;
Food passes the alimentary canal twice: first as food, then as soft feces; Soft and watery feces → Eaten again → hard and dry feces