DIGESTIVE Flashcards
purpose of digestive system
- energy
- growth
- essential nutrients for cells
what are the 4 essential nutrients
- amino acids -> proteins
- fatty acids
- vitamins
- minerals
define undernourishment and malnourishment
undernourishment - diet that consists of less chemical energy than required
Malnourishment - long-term absence of essential nutrients
what are the stages of digestion
- ingestion - act of eating
- digestion - process of breaking down food into small enough molecules
- absorption - uptake of nutrients by the body
- elimination - passage of undigested material out of the digestive compartment
what is the benefit of compartments
reduce risk of animal digesting its own cells and tissues
intracellular vs extracellular digestion
intra - food particles engulfed by endocytosis and digested with food vacuoles (in cells)
extra - breakdown of food particles outside of cells (compartments)
what are the mammalian accessory glands
salivary glands, pancreas, liver, gallbladder
explain basic mammal digestive process
food enters mouth, mechanical breakdown via teeth and chemical via saliva, tongue shapes bolus. moves into esophagus and moved to stomach via peristalsis. stomach has gastric juices for chemical digestion into chyme, churning. chyme enters small intestine (duodenum) where chemical digestion occurs via bile, pancreatic juice, lots of absorption of nutrients occurs. peristalsis moves chyme to large intestine for water absorption, then to rectum and anus.
explain chemical digestion occurring in the stomach
gastric juice = HCl for sterilisation and pepsin for protein digestion.
parietal cells secret H and Cl separately, cheif cells secrete pepsinogen which is activated by presence of pepsin and HCl
what do goblet cells do in stomach
goblet cells produce mucus to protect stomach lining from gastric juices
explain digestion in small intestine
in duodenum -> pancreas secretes enzymes (proteins) that are activated in duodenum. Gallbladder secretes bile to digest fats
lining of intestine called brush border secretes enzymes
many microvili for absorption
difference in liver and gall bladder
liver produces bile, gall bladder stores it
what is the ceacum
aids in the fermentation of plant material and connects where small and large intestine meet
haustral contraction vs peristalsis
hastral contractions - slow, movement of segments, one movement (large intestine)
peristalsis - waves of contraction (small intestine)
compare teeth of carniivore, herbivore, omnivore
carnivore - sharp, larger canines and incisors used for ripping. jagged premolars, molars crush and shred food. May have carnassials (sharp centre)
herbivore - broad, ridged surfaces to grind plant material. incisors flat for biting peices of vegetation, some canines absent. many have diastema/no cheek teeth. Hard palate for crushing
omnivores - adapted to meat and veg, two incisors for biting, pointed canines but shorter for tearing, premolars for grinding, molars for crushing (small)
