Lecture 9- Digestion Flashcards
4 functions of monogastrics mouths
Prehension (bring food in, lips, teeth, tongue, hands)
Ensalivation (mix w/ saliva)
Mastication (grinding/ pulverizing)
Bonus formation (rolling food into ball and push to back)
Define esophagus
Muscular structure connecting pharynx to stomach (tighter when no food going down)
What is the pH of the monogastric stomach?
2 or 3 b/c of hydrochloric acid
4 functions of monogastrics stomach
Store material
Secrete substances
Mixing
Move chyme from stomach to rest of digestive system
Interior listing zones of monogastric stomach
Esophageal
Cardiac (mucous)
Fundic (HCl)
Pyloric
5 parts of gastric fluid in monogastrics
Mucous
HCl
Lipase (small amt)
Rennin
Pepsinogen (a zymogen)
What is a zymogen
Inactive form of an enzyme
How does pepsinogen work?
Reacts with HCl to become pepsin and breakdown long protein chains
Gastrin (secretion, target, function) in monogastrics
Produced by pyloric region, targets stomach, signals to produce more secretions
Endocrine b/c must go through bloodstream
3 phases of gastric fluid flow regulation in monogastrics
Cephalic- nerve impulse
Gastric- nerves and hormones (longest)
Intestinal- hormonal response
3 requirements for emptying the monogastric stomach
Fluidity and acidity of chyme
Receptivity of duodenum (can’t be full already)
Pyloric pump (stomach contractions push food through pyloric sphincter)
2 ways gastric flow rate is reduced in monogastrics
Enterogastric reflex (nerve reflex reducing pumping)
Enterogastrone
Enterogastrone (secretion, target, function)
Produced by small intestine
Slows gastric fluid production and flow rate
Targets stomach
Functions of monogastric small intestines
Chemical degradation
Absorption
Sections of monogastric small intestine
Duodenum
Jejunum
Ileum
2 entrances to monogastric small intestine in anterior are from
Liver and pancreas
3 types of digestive fluids in monogastrics
Pancreatic fluid
Hepatic fluid (Bile)
Intestinal Fluid
All are alkaline to neutralize stomach pH
2 Functions of Hepatic Fluid (Bile) in monogastrics
Emulsifying agent breaks of fats into smaller droplets to increase surface area
Neutralize acids
Aid in absorption of fats
Monogastric Hepatic Fluid (Bile) - (produced, stored, and contents)
Produced in liver
Stored in gall bladder
Contains waster products of liver metabolism
Dark green- colors feces
Monogastric pancreatic fluid (produced, contains)
Produced in pancreas
Contains enzymes, carbonate, and bicarbonate= buffers
Hormonal control of pancreatic fluid in monogastrics
Secretin
Cholecystokinin (CCK) (Pancreozymin)
Cholecystokinin (CCK) (Pancreozymin) - produced, targets, function
Produced in duodenum, increases enzyme output by pancreas and release of hepatic fluid from gall bladder
3 enzymes in monogastric pancreatic fluid
- Proteolytic (proteases)
Trypsinogen —(enterokinase)—> Trypsin
Chymotrypsin
Both result from zymogen action + break down peptides into amino acids - Amylase and carbohydrates
Breakdown amylose + amylopectin
Each carbohydrate has its own: lactase, maltase - Lipase
Breakdown fats, inactive in low stomach pH
2 functions of large intestines in monogastrics
Store left over residue
Lubricate residue to exit through the anus,
3 sections of monogastric large intestine
Cecum (appendix)- gas production (some fermentation)
Colon- absorbs water
Rectum
Define absorption
Movement of materials from the digestive tract into the bloodstream
3 mechanisms of absorption
- Diffusion (passive) ex. Minerals through cell membrane
- Osmosis (passive)- water
- Active transport (NEEDS ENERGY) ex. Amino acids, fatty acids
Portal vein function in monogastrics
Carries nutrient rich blood from gastrointestinal tract to liver
Liver function in monogastrics
Liver metabolizes and detoxifies substances before they circulate to the rest of the body
Gastric vs. intestinal digestion in monogastrics
Gastric= breakdown in acidic conditions
Intestinal= breakdown in alkaline conditions
Where is starch broken down in monogastrics?
Small intestine into glucose
Where are sugars broken down in monogastrics
Small intestine into glucose
Where are cellulose and lignin broken down in monogastrics
It’s not, left in feces
Where is protein broken down in monogastrics
Stomach into peptide chains
Small intestine into amino acids
Where are lipids broken down in monogastrics
Small intestine into fatty acid and glycerol
Where are minerals broken down in monogastrics
Small intestine into solution
Where are vitamins broken down in monogastrics
Small intestine into solution
Where is water absorbed in monogastrics
Small and mostly large intestines
6 Composites of feces
Cellulose, lignin, bacteria, mucous, water, epithelial cells
Birds are considered
Modified monogastrics
3 Functions of beak
Prehension, ensalivation, bolus formation
Order of bird digestive system
Beak—>pharynx —> esophagus —> crop (gullet)—> proventriculus( true stomach)—> ventrigulus (gizzard)—> small intestine—>large intestine—> cloaca + vent
Location and 2 functions of crop
Outpocket of esophagus
Moisten/lubricate
Storage (no chemical degradation)
Location and function of proventriculus (true stomach)
At end of esophagus
Secretarial gastric juices and HCl (acid)
Structure and 2 functions of ventriculus (gizzard)
Contains grit
Grind food
Mix with gastric fluid (gastric digestion begins here)
Why are contents of duodenum acidic in birds?
Pancreatic and liver(bile) ducts don’t enter until posterior end of duodenum.
The large intestine of birds has ____ ceca and _____ colon.
2 ceca (very little fermentation)
1 colon (absorbs water)
3 systems a part of the cloaca in birds
Digestive system
Urinary system
Reproductive system
What is the anus of birds called?
Vent
Why is bird waste so liquidy?
The digestive feces and stuff from kidneys mix before being expelled
Significant differences in horse digestions:
Large cecum (fermentates cellulose and hemicellulose into VFA’s)
- large intestine absorbs VFA’s = provide energy
No gall bladder= bile duct comes directly from liver
Significant differences in rabbit digestion:
Large cecum
Coprophagy (eating fecal pellets) “second chance” to absorb nutrients
2 differences of ruminants mouth
Dental pad instead of upper incisors
Lots of saliva (sodium bicarbonate- alkaline buffer w/ no sig. enzymes)
8 functions of ruminants mouth
Eating: Prehension, mastication, ensalivation, bolus formation
Rumination “chewing cud”: regurgitation, remastication, reensalivation, reswallowing
4 compartments of ruminant stomach
Rumen (paunch)
Reticulum (honeycomb)
Omasum (manypiles)
Abomasum (true stomach)
Appearance and function of rumen
Loaded with fluid (grass floats on top)
Millions of papillae
Absorbs VFA’s
“Gigantic fermentation vat” = produces heat and gas
Appearance and function of reticulum
Close to heart
Collects heavy feeds to regurgitate
Hardwire disease
wire/nails trapped in reticulum and irritate the lining; treat by feeding animal a magnet
Appearance and function of omasum
Conical papillae on folds of muscle
Absorbs water + secondarily reduces particle size
Appearance and function of abomasum
Small inner surface
Secrets HCl and gastric fluid
Gastric digestion begins
Compartment volumes of immature ruminant
Rumen + reticulum 30%
Omasum + abomasum 70%
Compartment volumes of mature ruminant
Rumen 65-80%
Reticulum 5%
Omasum 7%
Abomasum 8%
Proportions of digestive system in mature cattle
Stomach 71% —pre-gastric fermenters
Small I. 18%
Large I. 11%
Proportions of digestive system in mature pigs
Stomach 29%
Small I. 34%
Large I. 37%
(Closest to human)
Proportions of digestive system in horse:
Stomach 8%
Small I. 25%
Large I. 67% - post-gastric fermenters
2 factors effecting rumen development
- Dry feed
- amount
- characteristics (course grain is best, hay doesn’t do much) - Fermentation products (VFA ratios — butyric acid)
How does the esophageal groove function?
Closed by suckling action and sends milk straight to abomasum.
3 symbiotic relationships
- Bacteria A helps bacteria B which helps Bacteria C digest food
- reason must slowly change ruminant diets - Protozoa eat bacteria
- Host provides a lot
Why are no enzymes secreted within the reticulo-rumen?
Food is broken down by microbes
5 things host does for bacteria
Provides food
Fine grinding: rumination
Removes microbial waste
constant pH
constant temperature
3 most common VFA’s
Acetic Acid (2C)
Propionic Acid (3C)
Butyric Acid (4C)
Ranking relative value of proteins
- Eggs
- Milk
- Meat
- Ruminant (microbial proteins)
- Plant
What two things do microbes break proteins into or use to form amino acids out of NPN
Organic acid and Ammonia (NH3)
Define hydrolysis
Breakdown of triglycerides
What vitamins are synthesized by ruminant microbes
B complex and K
What vitamins must be acquired through ruminant diet.
A and E, sometimes D (sunlight)
What 4 gases do microbes produce
- Nitrogen
- Ammonia
- Carbon Dioxide
- Methane
Define Eructation
Getting rid of gas; burping
Define bloat
Gas build up, froth covers esophageal opening
What happens if an animal is overly bloated?
Blocks diaphragm from moving and suffocates animal
What 3 material flow from reticule-rumen to omasum
Microorganisms
Fermentation products (leftover VFAs)
Feed residues (digestible and non-digestible lignin)
What is the function of the omasum?
Absorb water
Function of abomasum
Gastric digestion- acid, mucous, rennin, pepsin
What are the 4 intestinal movements?
Peristalsis - wave from beginning to end
Segmented - couple inches of mixing
Pendular - back and forth mixing
Defacation - only voluntary
Where are VFAs absorbed in ruminants?
Rumen
What is the significance of the rumen pH?
pH of 6 allows microbes to live and then die when they enter the acidic abomasum.
How to make ruminant meat with more unsaturated fat?
Feed bypass lipids and proteins, so feeds are not digested in rumen and fats remain unsaturated.
What treatments are used to create bypass lipids and proteins
Heating, roasting, pelleting, kibble
(Microbes can’t breakdown denatured proteins)
What is the disadvantage to having very soluble food?
Too much food is incompletely digested and then wasted
4 types of storage
Bones/ teeth (minerals, Ca, + P)
Liver (fat soluble vitamins, B12, glycogen, etc.)
Body tissue (varies greatly)
Adipose (fat)
What is the main difference about how monogastric and ruminants digest lipids?
Mono- remain unsaturated
Ruminant- fatty acids get saturated
What is the main difference between how monogastric and ruminants digest nitrogen?
Mono- composition is not changed
Ruminants composition is changed
What is the main difference between how monogastric and ruminants digest vitamins?
Mono- need all vitamins in diet
Ruminants- only need A, E, sometimes D (fat soluble except K)
What is significant about monogastric and ruminant digestion of minerals?
All animals need full complement of minerals in their diet
What are 3 functions of feed stuffs
- Energy (carbs, lipids, proteins)
- Building blocks (proteins, minerals, lipids, water)
- Cofactors (minerals) + coenzymes (vitamins)
Define intermediary metabolism
Process where nutrients are converted to simple compounds for use by cells
Moles of ATP/100g of carbs, protein, and lipids
Carbs- 4
Proteins- 4
Lipids- 9 (x2.25 more b/c of lower oxygen number)
Anabolism vs catabolism
Ana- building (requires energy)
Cata- breakdown (release energy)
Genesis
To form
Lysis
To breakdown
Neogenesis
New formation
