Flashcards

Digestive Anatomy Powerpoint

J Wellington English 44 cards

Cards in this deck (44)

1Mono gastric digestive systemHeadgut: For seeking and ingesting feed
Foregut: For preparing feed for subsequent digestion and absorption.
Midgut: the “workhorse” of digestion and absorption.
Pancreas and Biliary System: Elaborate, source of most secretions used for digestion.
Hindgut: The End! Completes digestion and absorption, then voids undigested and unabsorbed components.
2hog digestion
3poultry digestion
4HeadgutHeadgut:
-Poultry use their eyes for seeking
- Pigs use their nose
-Prehension (poultry): use their beak and tongue for capture
-Prehension (pigs): Have lips and a tongue for capture, teeth are for mastication
5Foregut-Esophagus
-stomach
6esophagusPassage of food from the mouth to the stomach via the esophagus. This is done by “Peristaltic action” (wave of contractions).
Similar to the pig but most birds have the “crop”. Ducks have a “pseudocrop” which is very small.
7stomachMain functions are…
Mixing and storage of the ingested food
Initiation of protein and fat digestion (acidic pH)
Controlled release of contents into the duodenum
8Foregut- stomach continuedThe stomach of poultry consist of a Proventriculus and a gizzard.
Proventriculus is made of Oxynticopeptic cells (intermedidiate between chief an oxyntic cells) and are responsible for the secretion of pepsinogen and HCl.
The gizzard combines the activity of grinding and proteolysis (digestion of proteins).
The stomach of pigs consist of four regions:
Esophageal- Glandless area, thus no secretion and subject to ulceration
Cardiac- Consists of cardiac cells which secrete mucus and protects the stomach linings from HCl.
Gastric- Major secretory portion of the stomach with three cell types: Neck cells secreting mucus, parietal (oxyntic) cells secreting HCl , and chief cells secreting enzymes (pepsinogen), electrolytes and water.
Pyloric- Also has cardiac cells secreting mucus
9foregut
10MidgutMost of digestion and absorption of nutrients take place in the small intestine.
Includes:
Duodenum- Serves as a site for mixing of gastric digesta and pancreatic and biliary secretions. Purpose is to increase the pH of content from the stomach.
Jejunum- Majority of digestion and absorption takes place here.
Ileum- Some digestion and absorption. Forms a junction with the hindgut.
Poultry are very similar to pigs.
11Midgut
12midgut
13Pancreas and Biliary System-Liver
-pancreas
14liverImportant for the production of bile, which is stored in the gallbladder between meals.
Functions of Bile:
Emulsification (breakdown) of dietary fat .
Neutralization of acid
Formation of micelles
15pancreasExocrine function- secretion of pancreatic juice which supplies enzymes for digestion from “acinar cells”. Also responsible for the secretion of water, and electrolytes.
Endocrine function- secretion of hormones glucoagon, insulin and somatostatin from the “ islet cells”.
16hindgut-poultry
-pigs
17poultry- hindgutConsists of two caeca, colon and ,different from pigs, cloaca- The main function is the absorption of water. Some VFAs are produced.
18pigs- hindgutConsists of the cecum and colon- The main function is the absorption of water. No enzymatic digestion occurs, however, some VFAs are formed and readily absorbed.
19Ruminants- functions of the digestive tractIngestion
Chewing
Swallowing
Digestion of nutrients
Absorption of nutrients
Elimination of solid wastes
20Digestive System (ruminants)Mouth
Esophagus
Reticulum
Rumen
Omasum
Abomasum (true stomach)
Small and large intestines
Accessory glands
(Salivary glands, liver, pancreas)
21MouthLips:
-cattle- wide and immobile
-sheep and goats- thin and motile
22MouthTongue Taste buds:
More numerous than monogastrics
More numerous in nonselective grazers (cattle)
Mainly used for food avoidance
Cattle eat with their tongues!
23Esophagus (ruminants)Sphincters:
-Pharyngeo-esophageal
-Cardial
Contractions move both ways:
-Circular and longitudinal muscles aid in this movement
Esophageal groove:
-Channel between esophageal opening and reticulo-omasal orifice
-Closure results in rumen bypass of milk
-Stimuli?
24Ruminant
25Esophageal groove reflex
26Cattle digestion
27cattle digestion
28reticulto-rumen-Reticulum and rumen are separated by the rumino-reticular fold
Although structurally they appear as a continuous compartment, functionally they are different!
-Digesta flows freely between compartments
Reticulum acts as a trap for heavy objects
Hardware disease?
29reticulo-rumen
30reticulum-honeycomb lining:
no secretions
-Contractions:
move out large particles for re-mastication
31reticulum- Honeycomb lining
32reticulum- honeycomb lining
33contractions
34rumen-digestion and fermentation vat: 40-50 gallons and no secretions
-contains anaerobic microbes (25-50 billion bacteria/ml fluid)
-papillae lining: increase surface area
-absorption of VFA: passive diffusion
35rumen structures
36rumen
37rumen
38rumen papillae-Finger-like structures on rumen wall
-Covered with non-secretory stratified epithelial tissue
-Well-developed in ventral portion of rumen
Function?
39Omasum-Reticulo-Omasal orifice:
Contents move from the rumen into the omasum
-Wall is highly folded allowing for a large surface area:
Efficient absorption of water and salts
40omasum
41abomasum“True Stomach”
Secretory stomach similar to monogastrics
Hydrolysis of microbial and dietary protein by enzymatic and HCL production.
42Abomasumsmall intestine/large intestine
43small intestine-duodenum
-jejunum
-ileum
44large intestine-cecum
-colon
-rectum