Digestive System 2 Flashcards
What are the intestines
Elgongated tube normally divided into small and large intestines
What is the process called by which food moves along the digestive tract
Peristalsis
What protects the gut tube walls
Mucous protects the gut tube walls from enzymes
What provides lubrication in the gut
Mucous
Intestinal glands produce what and what do they breakdown.
Enzymes to breakdown carbohydrates, proteins and lipids
What nutrients are absorbed back into the intestines
Carbohydrates
Amino acids
Fatty acids
Water
Small intestine are often ______ but _______ in diameter
Long, small
What are the 3 regions of the small intestine
Duodenum
Jejunum
Ileum
What is the duodenum
First part of the small intestine which receives chyme from the stomach and exocrine secretions from the liver and pancreas
Brunners glands in the walls of the duodenum help what
Help to neutralise acid from the stomach
The large intestine is ______ but ______ than the small intestine
Shorter, wider
What does the large intestine pass to
The anal opening or the cloaca
What does the rectum act as
A store
What are sphincter muscles in the intestine
Control release of content
What is the cloaca
Derived from the proctodeum at the end of the embryonic gut tube
What animals is the cloaca not present in
Fish or most mammals
What is the coprodeum
The large intestine empties here
What do goblet cells secrete
Mucus
What do enteroendocrine cells secrete
Hormones
What do enterocytes do
Absorb water and electrolytes
Water absorption takes place where
Large intestine
How do you maximise nutrient intake
Increase time food spends in the digestive tract to maximise nutrient intake
What is the spiral valve
Helical partition in the gut tube that forces food to wind around a spiral channel, increasing the time spent in the intestines
What are the longitudinal folds in larval called
Typhlosole
For is the crop used for
Temporary storage
What is the spiral valve
Helical partition in the gut up that forces food to wind around a spiral channel therefore increase time spent in the intestines and also increase SA
In lower vertebrates what issues do th y have How many bones of the “basic plan” th the large intestine
The do not concentrate urine well so electrolytes and water released by kidneys resorbed by large intestine
What does retrograde peristalsis do
Push digesta from cloaca to large intestine for further resorption
What is the GALT
Gut Associated Lymphatic Tissue
What is the function of the GALT
Defence against ingested pathogens and parasites
Large intestine empties where
Coprodeum
Urogenital empties where
Urodeum
Down regulation after food has been digested does what
Decrease in cell proliferation (birds and mammals) or epithelial folding (reptiles)
Mechanical breakdown of food allows what
Allows pieces to b reduced in size and then swallowed
What is mastication
Chewing
What may be used to grind food against stones
Gizzard
Carnassial teeth allow for what
Allow soft, sinewy food to be sliced
What kind of food do carnivores eat
Relatively low fibre
What types of food do herbivores eat
Fibrous, cellulose rich food
The front teeth in herbivores do
Front teeth snip vegetation and back teeth grind food to break down tough outer layer
What is the function of the back teeth of omnivore
Used to compress hard, brittle foods such as nuts and seeds
What enzymes breakdown food
Proteases (proteins), lipases (fats), cellulases, amylase (carbohydrates)
What are the end products of digestion
Amino acids, sugars, fatty acids, vitamins, minerals
What is cellulose
A structural component of all plants and as such is an extremely important carbohydrate
Is cellulose insoluble or soluble
Insoluble and very resistant is o chemical attack
Can vertebrate species make cellulose
No
What are the four stages of gastric fermentation
Swallow -> mix-> re-mastication-> passage
How is food mixed and then regurgitated
Complicated waves of contraction
What is intestinal fermentation
Microbial digestion of cellulose in the intestine
What animals does intestinal fermentation occur
Birds, rabbits, horses and pigs
What is gastric fermentation good at
Extracting the most from low-quality foods
Nutrients being released early in the digestive tract allows what
More time to absorb them and being able to re-chew food enables a thorough mechanical breakdown of the plant cell walls
What gas is used in the gastric fermentation
Nitrogen is used as a resource (not a waste product) important in low diets
What is taken into the camels rumen and turned into ammonia
Urea
What are the advantages of intestinal fermentation
Food passes through much of the digestive tract prior to fermentation which allows soluble nutrients such as glucose, proteins and carbohydrates to be absorbed before fermentation starts. These nutrients may be lost in gastric fermentation.
Much faster which allows quick absorption of high quality nutrients and release of low quality component of forage.
What do some intestinal fermenters also practice
Coprophagy and re-ingest faeces to pass nutrients through the digestive tract a second time
The smaller the animal, the ________ the metabolic rate, the greater the need to digest nutrients quickly
Higher
Small herbivores are more like to be what fermenters
Intestinal
Large herbivores are most likely to be what fermenters
Gastric
Many plants use toxins for what
A form of defence- chemicals make food unpalatable or actually poisonous
What animals use toxins as a defence
Amphibians
What does ruminant saliva contain
Proteins that bind with tannins to reduce the toxicity and reduce effects on digestibility
What do tannins do
Will normally bind with proteins making them hard to digest
Ruminants who eat a large quantity of tannin-rich food will have what
Large salivary glands
