ANSC 212 - lec 4

What are the 3 sections of the small intestine?

1. Duodenum

2. Jejunum

3. Ileum

What is the duodenum responsible for?

Receives digestive juices from pancreas, gallbladder, and liver

does the gallbladder make bile?

No, it is just stored there

What does the jejunum do?

Responsible for digestion and absorption

Also the longest

What does the ileum do?

absorption

Which part of the small intestine is closest to the large intestine

Ileum

What is the function of the mesentary

Made of blood vessels and tissues responsible for holding the digestive system together

What are villi and what do they produce

Finger-like projections of tissues that increase the surface area of the intestine and produce enzymes

What are the enzymes that the villi produce

Sucrase

Maltase

Lactase

Aminopeptidases

Dipeptidase

What is sucrase responsible for

Coverts sucrose to glucose and fructose

What is maltase responsible for

Converts maltose into 2 glucose molecules

What is lactase responsible for

Hydrolysis of lactose into 1 glucose and 1 galactose

What does aminopeptidase do

Act on peptide bond adjacent to free amino group of simple peptides

What do dipeptidase do

Complete the breakdown of dipeptides to amino acids

What makes up the large intestine

cecum, colon, rectum

What is the cecum and what does it do

Large area where small and large intestine meet

Response for hind gut microbial digestion (monogastrics)

What is the role of the colon

Water reabsorption

What is the role of the rectum

Excretion of waste products

Where does microbial fermentation occur

large intestine

What parts of the avian digestive tract are different from those of other animals

Have:

Beak

Crop

Proventriculus

Gizzard

Vent

Where does chemical digestion occur in avians

Proventriculus

Where does mechanical digestion happen in avians

Gizzard

What is the role of the crop in avians

Softening and swelling (moisturization) of the feed in preparation for digestion

What are the accessory glands of the the digestive system

salivary glands, liver, pancreas

What are the functions of the liver

Detox

Store vit and carbs

Form bile

What do bile salts play an important part in

Digestion of fats as it emulsifies them

What animal does NOT store bile and why

Horses, do not possess a gallbladder

What is the pancreas?

Pale yellow or red organ

Lies in duodenal loop

Endocrine and exocrine organ

What are the functions of the pancreas

Produces pancreatic secretions

What are the pancreatic secretion

Insulin

Glucagon

Enzymes

What are the enzymes produced by the pancreas and what does they breakdown

Amylase - carbs

Lipase - fats

Proteases - proteins

Nucleases - nucleotides

What are the functions of saliva production in ruminants (7 of them)

Lubrication

Enzymatic activity (only in calves)

Source of nutrients for ruminal microorganisms

Influences nutrient removal rate from rumen

Buffering capacity

Antifoaming agent

Source of antibodies

Why is the enzymatic activity of saliva only important/relevant in calves

Calves do not yet develop a ruminant GI system and drink colostrum from their mothers. The esophageal groove carries this milk directly from esophagus to abomasum (true stomach) to prevent fermentation

What are the 4 compartments of the ruminant stomach

1. Rumen

2. Reticulum

3. Omasum

4. Abomasum

On which side of the body is the rumen located

left

What is rumination?

Regurgitating ingesta from reticulum when animal is resting

What is eructation?

Gases generated from fermentation (burps)

What are some characteristics of the rumen

Largest of the 4 compartments

Large # of papillae

Large particles in the lower middle of rumen and small particles outer edges with gas in the upper portion

Generates VFAs

What are volatile fatty acids (VFAs)

Main source of energy in ruminants

What are the 3 short chain fatty acids (SCFAs)

Acetate

Propionate

Butyrate

What absorbs the SCFA

The rumen wall

What are the main functions of the rumen

Major feed/digesta storage site

Digestion thru anaerobic fermentation

Contain billions of microorganisms

Type of microorganisms change w/feed type

What is the role of microbes in the rumen

Break down feed

Digest fibre to produce energy (75% of the energy supply)

What happens if there is too much acid produced in rumen

Ruminal acidosis — low pH

What is the primary source of protein in ruminants

Bacteria grown (mainly comprised of protein)

What do the microbes in the rumen make

Vit K and B

Why are microbes in the rumen important

Allow for use of non-protein nitrogen sources such as urea and ammonia

What is the temperature of the ruminant digestive system

38-41 degrees c

What does the cattle provide to the microbes

Diet

What can impact the microbial population of the rumen

Environmental harms

Diet

How long does it take to change/adapt ruminal microbial populations

14-21 days

What are some characteristics of the reticulum

Pouch-like structure

Honey-comb structure

Similar function to rumen

Esophageal groove

What is the esophageal groove

Muscular folds that come together to bypass rumen, reticulum, and omasum

What is the role of the omasum

water absorption

Site for SCFA absorption

What does the abomasum do

true stomach, chemical digestion

Which of the four stomach chambers contains glands

Abomasum

What is the main difference between monogastric and ruminant digestion

Monogastric: principally by enzymes (hindgut fermentation)

Ruminant: foregut fermentation and can break down more complex carbs than mammals

What methods are used for genetic improvement

Genetic selection

AI

Embryo transfer (ET)

What is reproduction influenced by

nutrition and genetics, stress, external environment, disease

What is the role of the male in reproduction

Produce large #'s of viable male sex cells (spermatozoa)

Deliver sperm to proper place in female repro system at right time

Provide 50% of genetic makeup

What are the primary structures of the male reproductive system in poultry

Testes

Epididymis

Ductus deferents

Cloaca

Where are the testes located in poultry

Internal, not in scrotum

Do poultry have a copulatory organ

No

If poultry do not have copulatory organ how is sperm transferred

Cloaca kiss

What is the function of testicles

produce sperm cells and testosterone

What is the role of the scrotum

To regulate the temperature of the testes for optimal sperm production.

Do poultry have a scrotum

No

What is the inguinal canal

Short passage by which structures pass from abd to genitals

What is an inguinal hernia?

Testicles may go back into body cavity and viscera can enter the scrotum

What are seminiferous tubules and what are they responsible for

Large coiled tubes w/in testicles where sperm cells develop

Main site for sperm production

What are leydig/interstitial cells and what are they responsible for

Located between seminiferous tubules

Produce male sex hormone testosterone for libido

What hormone controls the leydig cells

luteinizing hormone (LH)

What is the epididymis and its role

Coiled tube in each testes

Storage site for sperm prior to ejaculation

Where sperm maturation occurs

What is different about the epididymis in birds

Relatively short in comparison

Lies on dorsomedial surface of testes (hilus)

Head body and tail cannot be distinguished

What is the function of the epididymis in birds

Storage and transport of spermatids