Digestion and Absorption

Question 1

digestion

Answer 1

obtaining nutrients essential for body processes from food
includes acquisition and dividing of foods into smaller parts

Question 2

digestion tract function

Answer 2

prepare nutrients for absorption
store nutrients
build useful products
reject unused and broken down residue

Question 3

absorption

Answer 3

crossing the epithelium and entering the blood
must have absorption to utilize nutrients

Question 4

why do animals digest food?

Answer 4

food not ingested in a suitable state
physical nature of feed determines
-gathering apparatus for uptake
-type of digestive system required for digestion

Question 5

carnivores

Answer 5

meat eaters
simplest digestive tract (monogastric)

Question 6

herbivores

Answer 6

plant eaters
most complex digestive tract
ruminant or monogastric and hind gut fermenters (horses)

Question 7

omnivores

Answer 7

plant and meat eaters
intermediate digestive tract

Question 8

feed utilization steps

Answer 8

1. selection: selection of appropriate food relies on all 5 senses, also learned aversions
2. prehension: process of getting food into mouth, claws and paws, lips, tongue, teeth
   3.mastication: chewing, divides food particles, mixes with saliva
3. deglutition: swallowing
4. digestion: physical changes-chewing, swallowing, crushing, peristaltic potions,, chemical changes- enzymes, bacteria, microorganisms, digestive juices
   6.absorption: crossing epithelium, utilization of nutrients
   7.circulation: transport of nutrients to site of storage and use via blood or lymph
5. metabolism: cell level utilization- anabolism(tissue growth) and catabolism (tissue breakdown)
6. excretion: body voids material- defecation, urination, sweat, exhale, wearing off cells

Question 9

avian digestive system

Answer 9

lack of teeth- lack of digestion in mouth
gizzard-super muscular, can breakdown tough feed and crop- enlargements of esophagus
proventriculus- like a stomach
small intestine
ceca- between small and large intestine, where fermentation takes place of forage

Question 10

mouth

Answer 10

functions: take in food, prehension differs with species, taste, chew (mastication), mix with saliva
mastication: physical reduction of feed to increase surface area
carnivores- large canines and incisors for tearing and little chewing
herbivores- specialized molars for chewing and grinding
saliva: add moisture to feed, aid in chewing, aid in swallowing
amylase- digestive enzyme that starts to breakdown simple sugars in the feed

Question 11

esophagus

Answer 11

muscular tube
pharynx to stomach (cardia)
begins with striated (voluntary) –> ends with smooth muscle (involuntary)
dogs and ruminants striated throughout
angle of attachment in horses discourages regurgitation

Question 12

reticulum

Answer 12

“honeycomb”
-where food first drops, grinding and transfer
-traps objects “hardwear disease”
reticular groove
-young ruminants
-transfer milk from esophagus to abomasum (bypass rumen system to true stomach)
-non functional after weaning

Question 13

reticular groove “esophageal groove”

Answer 13

-young ruminants
-transfer milk from esophagus to abomasum (bypass rumen system to true stomach)
-non functional after weaning
-muscular contractions close the groove

Question 14

rumen

Answer 14

covered in papilla -increased surface area for absorption and function
fermentation vat- anaerobic breakdown of feed (without oxygen)
largest compartment >40 gallons
ecosystem of microbes
-bacteria, protozoa, and fungi
-produce volatile fatty acids (VFAs) and microbial cell protein

Question 15

rumen development

Answer 15

only abomasum developed in newborn ruminant
-little fermentative capability: size, musculature, microbial population
development requires solid feed and microbes
2-3 months of age

Question 16

influence of diet on rumen development

Answer 16

milk only diet: papillae is very smooth
milk and hay: more developed papillae
milk and grain: ^^

Question 17

fermentation

Answer 17

occurs primarily in reticulum and rumen
rumen microbial population: symbiotic relationship (both benefiting)
majority bacteria, then protozoa, with fungi and yeast in smaller amounts
products of fermentation: VFA, gas (methane, carbon dioxide), heat, microbial crude protein, B vitamins, vitamin K

Question 18

rumination

Answer 18

re-chewing coarse material
-diet dependent
6-10 hours per day
steps in the process:
-regurgutation
-remastifaction
-reensalivation
-reswallowing
reduces particle size and increases salivary flow

Question 19

eructation

Answer 19

expelling gases produced from microbial fermentation
peak fermentation = 12-30L of gas/hr
failure to expel gases= bloat

Question 20

omasum

Answer 20

“many plies”, pages of a book
-moves particles from rumen to abomasum
-continue to grind roughage
-aborption of water

Question 21

abomasum

Answer 21

“true stomach”
functions exactly like a monogastric stomach
glandular portion of stomach
uses hydrochloric acid and other enzymes to digest feed

Question 22

stomach

Answer 22

ruminant: 4 compartments (3/4 of abdominal cavity)
monogastric (non ruminant): one compartment, size varies

Question 23

glandular stomach

Answer 23

stomach in monogastric, abomasum in ruminants
function:
-mixing action
-acid secretion
-enzyme secretion
digested food leaves the stomach as chyme
-mixture of food and digestive juices

Question 24

stomach anatomy

Answer 24

regions:
-esophagel (non glandular)
-cardiac (mucus)
-fundic (mucus, HCl (parietal cells), pepsin (chief cells)
-pyloric (mucus)

Question 25

small intestine

Answer 25

similar arrangement and function for monogastric and ruminnat animals
-3 segments
duodenum: attached to stomach (pyloric sphincter), primary site of digestion, begins absorption
jejunum: middle segment, absorption
ileum: final segment, absorption, attaches to cecum via ileo-cecal valve

Question 26

large intestine

Answer 26

3 segments: cecum, colon, rectum
function
-fermentative digestion (no enzyme secretions, relies on microbes washed out of small intestine)
-absorption of water, VFAs, vitamins, and minerals (no absorption of lipid (fatty acids) or protein (amino acids)