Nutrition and Digestive Physiology Flashcards
What is nutrition?
summation of ingested compounds that maintain physiological functions
What is digestion?
reduction in particle size to the point of being soluble (absorbed)
What is a nutrient?
chemical substance absorbed from digestive tract, required to maintain physiological function
What is diet?
what is digested
What do animals require?
water, energy, protein, minerals, and vitamins
What are the classes of nutrients?
water, carbohydrates, fat, proteins, minerals, and vitamins
What are the common features of the digestive system?
prehension, mastication, digestion, nutrient absorption, water absorption
What are the two types of digestion?
chemical and microbial
Where does energy come from?
carbohydrates, lipids (fat and oil)
What is prehension?
grasping or seizing or getting food into the mouth
What is mastication?
grinding or reducing particle size of food (chewing)
What are the 5 types of diet?
carnivore, herbivore, omnivore, granivore, frugivore
What are the two types of herbivores?
ruminants and non-ruminants
what is a ruminant?
have rumen
What is rumen?
compartments in stomach
Do cows have 4 stomachs?
no, they are ruminants so they have 4 compartment
What kind of digestion do carnivores have?
chemical
What do carnivores eat?
meat, >80% animal based diet
What does meat provide?
complete protein, minerals, vitamins, energy (fats and lipids, protein can be used for energy)
What do omnivores eat?
meat and plant materials
What kind of digestion do herbivores have?
chemical (some microbial but is species dependent)
Can omnivores digest plant material?
not capable of digesting high fiber diets
What can be supplemented from non-animal sources? For what?
protein and B-Complex vitamins; omnivores
What plant materials do omnivores eat?
seeds, fruits, tubers (like soil growing plants)
What kind of digestion do herbivores have?
Microbial fermentation, and chemical
What is produced (?) during microbial fermentation?
volatile fatty acids and vitamins
What is digested (?) during chemical digestion?
soluble CHO’s (carbohydrates), protein, microbes
What do herbivores eat?
plants; primarily forages
Where does protein digestion start?
stomach
Where does carbohydrate digestion start?
mouth
Where does microbial digestion occur?
in the rumen; in the cecum for non-ruminants
What does lipase?
breaks down lipids (fats and oils) into fatty acids
Where does water absorption happen?
large intestine
What digestion process occurs in the mouth?
mastication (mechanical grinding) and also chemical digestion through saliva
In a baby ruminant animal, what part of stomach would be the biggest? Why?
abomasum; acts as a true stomach
What happens in the small intestine of ruminants?
enzymes work to break down
What happens in the large intestine of ruminants?
water absorption
What kind of diet has a monogastric digestive system?
carnivore, omnivore
What kind of diet has a ruminant stomach?
herbivore
What kind of diet has a modified monogastric digestive system?
carnivore, omnivore, granivore, frugivore, insectivore
What species has modified monogastric digestive system?
avian
What happens in the crop?
has mucus lining and fluid to moisten food; stores food, small amount of fermentation
What is the proventriculus?
the stomach for birds, but not a lot of digestion occurs here; secretes HCl and digestive enzymes
What happens in the gizzard?
mechanical grinding happens (is very muscular)
What happens in the Ceca?
microbial digestion
Are acids sour or bitter?
sour
Are bases sour or bitter?
bitter
What is pH?
“power of hydrogen” (0-14)
What happens when an acid is mixed with water?
yields H+ ions
What happens when a base is mixed with water?
yields OH- ions
What does pepsin do?
break down protein
What do mucous cells do?
secrete an alkaline mucus that protects the epithelium against shear stress and acid
What do parietal cells do?
secrete hydrochloric acid
What do chief cells do?
secrete pepsin, a proteolytic enzyme
What do G cells do?
secrete the hormone gastrin
What are the two parts of the small intestine?
proximal and distal
What does the proximal part of the small intestine do?
digestion; further breakdown of feed, protein, fats, and carbohydrates
What does the distal part of the small intestine do?
nutrient absorption; absorption of food starts occuring
What does peptidase do?
break down proteins
What happens in the rectum?
stores waste until ready to be expelled
What is the digestive enzyme in the mouth? What does it digest?
Amylase, it starts digesting carbohydrates
During digestion, what are proteins broken down into?
peptides and then amino acids
What is a nickname for the cecum?
blind pouch
What kind of diet has a larger cecum? Why?
non-ruminant herbivores; microbial digestion happens only here for them instead of also in a rumen
What is the digestion order for monogastric digestive systems?
mouth, esophagus, stomach, small intestine, cecum (appendix), large intestine
What happens in the stomach?
chemical digestion of soluble carbohydrates and proteins
What happens in the cecum?
microbial fermentation of non-soluble carbohydrates to volatile fatty acids and absorption
What happens in the large intestine of non-ruminant herbivores?
absorption of water and additional nutrients, recovery of water and electrolytes
What is the digestion order for non-ruminant herbivores?
mouth, esophagus, stomach, small intestine, cecum, distal large intestine
What does the rumen do?
microbial fermentation
What does the abomasum do?
acts as true stomach
What does the omasum do?
acts like a strainer; absorbs water and nutrients from the feed and then transfers it
What does the reticulum do?
bigger things go here, serves as a gatekeeper, anything not broken down is trapped in reticulum; Collects larger particles from rumen and moves smaller particles into omasum
What does the omasum contain?
tissues that make it more efficient
What is the rumen’s main energy source?
volatile fatty acids
What is the largest part of the stomach in a mature ruminant herbivore?
rumen
How is the stomach of a ruminant herbivore different for a calf?
Calf has a larger abomasum and has a way for milk to go straight into the abomasum by shutting parts off
What does the rumen(?) produce?
volatile fatty acids
What are the three volatile fatty acids?
Butyrate, propionate, acetate
What aids in microbial digestion in the rumen?
bacteria, protozoa, fungi
What happens with the volatile fatty acids?
absorbed across rumen wall and into the blood stream, lead to production of ATP
What is the formula for Acetic acid?
C2H4O2
What is the formula for Propionic acid?
C3H6O2
What is the formula for Butyric acid?
C4H8O2
What is the order of digestion for ruminants?
mouth, esophagus, stomach (rumen, reticulum, omasum, abomasum), small intestine, large intestine
What happens in the ceca?
there are two ceca at junction of large and small intestines for birds; microbial digestion
What is the order for the modified monogastric digestive tract?
esophagus, crop, proventriculus, gizzard, small intestine, ceca, large intestine, cloaca
For what does mouth mastication not occur? What happens instead?
Avians; they have no teeth so they break feed into small sizes with their beak and feet, they also have their gizzard which does mastication
What are the parts of the proximal portion of the small intestine? Distal?
duodenum; ilium and jejunum
