ANSC 113- Exam 3: Nutrient Processing- Spring 2023

What is prehension and mechanism?

Taking in feed or water via lips or mouth (depending on species)

What type of lips do sheep and goats have?

philtrum (split upper lip)

What type of lips do horses have?

Prehensile lips (soft and flexible)

What is mastication?

reduction of food size by chewing

What is Deglutition?

The act of swallowing

What is regurgitation?

The casting up of undigested material

Which species rely on regurgitation?

Cattle, Sheep, Goats (ruminants)

What species cannot regurgitate?

Horses (one-way esophageal peristalsis)

What is digestion?

The breakdown of feed particles into smaller particles for absorption

What are the 2 types of digestion?

Mechanical and Chemical

What is absorption?

The transfer of substances (i.e. nutrients from GI tract to circulating blood or lymph nodes); most occurs in the intestine

What is the lumen?

Center of GI tract (middle of tube)

What is the mucous membrane or mucosa made up of?

Epithelium

What is the importance of epithelia type?

Epithelia type indicates functionality (epithelia type changes throughout the GI tract and has key factors that describes where in the system it is)

What is the submucosa and what is present in this layer?

Connective tissue, glands and specialized structures are located here

What is the Muscularis?

Muscle; smooth muscle specifically in GI tract and is made up of 2 layers working together

What does the Muscularis allow to occur?

Peristaltic action

What is the Serosa?

The outer covering of the connective tissue

What does the presence of canines and incisors tell about the diet of the species?

Tearing and piercing (pigs)

What does the presence of incisors and check teeth tell us?

Mix of grinding and biting (horse)

What does the presence of a dental pad tell us?

Ruminant animal, used to grind feeds

What is a key feature of the dental pad?

Highly keratinized

How do cattle bring feed into their mouth?

Sweeping motion with the tongue

What are the 3 types of papillae that all ruminant animals possess?

Filiform, Fungiform, vallate

What is the purpose of the papillae on the tongue?

Texture used for grinding and feed manipulation

What type of papillae do ONLY monogastrics have?

Folliate

What type of papillae do ONLY ruminants have?

Conical

What type of papillae lack tastebuds?

Filiform and Conical

What are the 3 pairs of salivary glands?

parotid, submaxillary, sublingual

What are the 4 components of the salivary glands?

Water, Mucin(Mucous), Bicarbonate salts, Enzymes(only in monogastic salivary amylase)

What kind of epithelium does the esophagus possess?

Stratified Squamous

True or False- The esophagus is capable of peristaltic contractions

true

True or False- the esophagus is NOT controlled by the nervous system and GI tract hormones

False

What digestive phase is controlled by the senses? (i.e. mouth watering)

Cepahilic

True or False- The cepahilic phase produces most of the secretions in the digestive phases

False

What digestive phase produces most of the secretions in the digestive phases?

Gastric phase

What is the gastric phase triggered by?

presence of food in the stomach

What is the intestinal phase triggered by?

Presence of chyme acid and/or low pH in the duodenum

True or false- the cardiac sphincter is the entrance point of feedstuffs in the stomach

True

Is the cardia glandular or aglandular?

Glandular, has mucous secretions

Is the esophageal region of the gut (saccus cecus) glandular or aglandular?

Aglandular

True or false- The esophageal region is not pronounced in horses

False

Is the esophageal region also known as the forestomach in ruminants?

Yes

True or false- the reticulum is lined with mucous membranes

True

What is an important function of the "honeycomb" structure of the reticulum?

To trap hardware and foreign debris

True or False- The reticulum acts as a pacemaker fro digestive feedstuffs leaving the rumen-reticule complex

true

Is the rumen glandular or aglandular?

Aglandular

True or false- The rumen is absent of papillae

False

What section of the ruminant stomach is filled with gas when they possess an enlarged left abdominal cavity? (Bloat)

The rumen

What are the 4 main functions of the rumen?

Storage, soaking, physical mixing and breakdown, and fermentation

What structures aid in physical mixing and breakdown of the rumen?

External grooves and internal pillars that form sacs

What types of microorganisms are present in the rumen?

Bacteria, fungi, protazoa

What are byproducts of bacterial fermentation in the rumen?

CO2 and Methane

What types of vitamins does the rumen bacteria synthesize?

Water soluble vitamins and Vitamin K(which is fat soluable)

True or false- The rumen is capable of synthesizing amino acids and proteins (microbial crude protein)

True

What does the fungi in the rumen breakdown and yield?

Breaks down fibrous feeds (roughages) and yields carbohydrates

What do the Protozoa in the rumen breakdown and yield?

Breaks down carbohydrates and yields VFA's (volatile fatty acids)

True or false- The Omasum is also known as manyplies

True

What is the muscular laminae in the Omasum studded with?

Small, short papillae

True or false- The omasum secretes enzymes

False

What are the 2 main functions of the Omasum?

Reduction of particle size and the absorption of water

What sections of the ruminant stomach are considered the forestomach?

The rumen, reticulum, and omasum

True or False- The esophageal groove is a permanent structure

False, only temporary in early life

What is the main function of the esophageal groove?

Allows for milk to bypass bacterial fermentation in the rumen- reticulo complex directly into the abomasum

When does the esophageal groove "close?"

When the rumen becomes fully developed and the diet has switched to feed based rather than milk based

True or false- The ruminant abomasum is equivalent to the fundic body in a monogastric

True

True or false- The fundic body (also ruminant abomasum) is not secretory

False

What does the fundic region possess that allows it to secrete?

gastric pits

What 2 main structures are present in gastric pits?

Chief cells and Parietal cells

What is the purpose of parietal cells?

secrete HCl (lowers pH) and intrinsic factor

What does the intrinsic factor of parietal cells do?

Acts as a carrier for vitamin B12 and sends it to the liver

What important vitamin is stored in the liver?

Vitamin B12

What is the main purpose of chief cells?

Produce enzymes and enzyme precursors

What 3 main hormones are stimulated by the gastric phase?

Gastrin, Histamine, acetylcholine

What is the main function of the pyloric sphincter?

Control the release of chyme at the endpoint of the stomach

Is the pyloric sphincter glandular or aglandular?

Glandular, secretes mucus to help dilute chyme acid so not to cause damage to the duodenum

What protein is in the pyloric region of the stomach that aids in milk coagulation for young animals?

Renin

What are the 3 main functions of the stomach in general?

Ingested feed storage, muscular movements for physical breakdown, secretion of gastric juices

What chemical compound does HCl require to function in parietal cells?

Carbonic anhydrase

What 3 hormones does HCl stimulate?

Gastrin, histamine, acetylcholine

What are the 3 hormones that inhibit HCl at the end of the stomach?

Cholecystokinin, Gastric Inhibitory peptide, and Secretin

Where do the 3 inhibitors of gastric juices come from?

The liver, pancreas, and duodenum

True or false- Secretin is released due to the presence of food and chyme acid

true

True or false- Pepsinogen requires HCl to convert into pepsin

True

What is the release of Gastrin caused by?

Release caused by stomach dissension and presence of proteins

Are are the 2 main functions of mucus?

Buffer and lubricant

Where is mucus produced when needed as a buffer?

Cardiac and pyloric sphincter

What is the general structure of villi in the small intestine?

Highly folded projections to increase surface area

What are 3 structures that the villi contain?

Arieriole, venue, and lacteal

What are some secretions from the pancreas that are deposited into the duodenum via ducts?

Bicarbonate ions, digestive pro enzymes and enzymes

How does trypsinogen become trypsin?

From enterokinase from SI wall

How does chymotrypsinogen become chymotripsin?

From the action of trypsin

What food molecule does amylase act on?

starch (oligosaccharides to monosaccharides)

What is the purpose of lipase?

Aids in fat breakdown with bile salts (turns triglycerides to fatty acids and glycerol)

When is insulin triggered?

During and following a meal (when blood glucose levels increase)

When is glucagon secreted?

between meals (when blood glucose concentration is getting too low)

Where is bile produced?

The liver, the gallbladder more specifically

What species does not have a gallbladder?

Horses

Through what structure is bile secreted into the duodenum?

Ducts

What is the secretion of bile controlled by?

Cholecystokinin