Digestion Flashcards
How much energy is transferred up each trophic level
10%
1st law of thermodynamics
Energy cannot be created or destroyed
2nd law of thermodynamics
The universe tends to lean towards disorder in a closed system, law of entropy
Rumenants
Organisms with a 4 chamber stomach, foregut fermenters
Rumen
Stomach chamber for fermentation, holds gut bacteria
Pathway for food in rumenants
Mouth>rumen>mouth>rumen>reticulum>omasum>abomasum>pylorus
Cecum
Blind ended sac in the large intestine
Copperphasia
Eating ones own feces to absorb vitamins and amino acids
Proventriculus
Gizzard used for grinding food
Malpighian tubules
Connect into the midgut for excretion similar to the kidneys
Hepatopancreas
Sequesters toxins, stores lipids and glycogen, secretes digestive enzymes, digestion of food particles and absorption of nutrients
Found in crustaceans
amylase
saliva enzyme for food breakdown
digestive diverticula
blind ended sacs that take food into cells for intracellular digestion
batch reactor
alimentary system in which food enters, mixes, and exits all through the same opening ex: hydras
continuous flow stirred tank reactor
continuous input to a stomach where food is mixed and a separate continuous output. continuity is hindered by the organisms metabolic rate ex: ruminants
plug flow reactor
continuous input to uniform lateral digestion to a separate output with little to no mixing
common digestive flow of vertebrates
headgut to the foregut with minimal breakdown, to the midgut where digestion with the stomach and small intestine takes place to the hindgut for absorption and defecation
saliva
secretions of the mouth containing amylase and bicarbonate
gastric juice
secretions of the stomach containing pepsinogen and hydrochloric acid
pancreatic juice
secretions of the pancreas containing trypsinogen, chymotrypsinogen and more, acts as a neutralizing agent
bile
secretion of the gallbladder containing fats, fatty acids, bile salts, pigments, and cholesterol
succus entericus
secretion of the duodenum that acts as a neutralizing agent
volume of secretions
at least 5 Liters a day with most of them being reabsorbed
gut motility
muscular contractions that move food along the digestive tract and serve to mix the contents
sphincters
rings of muscle around the entrances to organs that control movement
peristalsis
propulsive movements that move contents forward
segmentation
rotational movements that serve to mix food and enzymes to promote absorption, no forward movement
glandular salivary secretions
acini, very similar to plasma, contain amylase, peroxidase, lysozymes, and mucin, Na+, Cl-, K+, H2O and H3O- are added
conditional pathway
external simulation starts salivation production, ex: seeing or smelling food
unconditional pathway
presence of food in the mouth stimulates saliva production
cephalic phase
thought of food; increased saliva secretion and gastric and pancreatic activity
gastric phase
food in stomach; forms chyme, distension, short peptides and acidity, gastrin enters from g cells, and pH decreases
chyme
food and salivary secretions mixed
stomach
3 layers of muscle allowing contraction in every direction; longitudinal (up and down), circular, and oblique (left and right)
distension
stretching or bloating to accommodate food
rugae of mucosa
folds of the inner stomach that increase surface area for more digestive enzymes
Lumen
layer of the GI tract walls, open pathway through the tract with multiple exocrine glands secreting into it where absorption takes place
epithilium
mucosa layer of the GI tract wall
submucosa layer
Support layer with external muscle in the GI tract walls
mesentary
attaches the intestines to the abdominal wall
goblet cells
stomach cells that secrete mucus and bicarbonate
parietal cells
stomach cells that secrete pepsinogen to break down proteins and lipase to break down lipids, essential for function
enteroendocrine cells
stomach cells that secrete gastrin and other hormones
zymogen
inactive enzyme forms
kerckring
circular folds in the small intestine that increase surface area
villi
found on the kerckring of the small intestine, covered in microvilli and filled with capillaries for oxygen and bloodflow
bile
gallbladder secretions that serve as a detergent breaking down and surrounding fats
bile salts
gallbladder secretions that serve to breakdown surrounded fat droplets into glycerol and individual fatty acids
biliverdin and biliruben
gallbladder secretions that function as basic buffers and emulsify fats, aid in waste removal, and vitamin absorption
haustra
formed in the large intestine by tenia coli, lumpy sections that serve to increase surface area
colon
area in the large intestine that serve as the primary location for water absorption and waste storage and compaction
rectum and anal canal
location in the large intestine for waste storage, compaction, and excretion
phases of digestion
cephalic to gastric to intestinal/duodenal
enteric nervous system
short reflexes unique to the GI tract
endocrine mechanisms
hormonal controls to regulate digestion, uses endocrine, parocrine, and peptidergic NS
gastroileal reflex
short reflex that leads to increased gastric activity and increased ileum motility
ileogastric reflex
short reflex that leads to ileum distension and decreased gastric motility
intestino-intestinal reflex
short reflex that leads to distension of the small intestine in one section, and a relaxation of the rest of the intestine
short reflexes
type of neural regulation that originate in the enteric nervous system without central nervous system input
long reflexes
type of neural regulation that includes digestive reflexes integrated with the central nervous system such as defecation or salivation
