GI System Flashcards
What nutrient are plants high in?
Fibre
Why do herbivores need specific adaptations?
plants are high in fiber and cellulose is hard to digest
Adaptations of herbivores
Symbiotic bacteria in gut
Grinding teeth
Amylase within saliva
Carnivore Adaptations
Short digestive tract
Sharp teeth
No amylase in saliva
Omnivore Adaptations
Medium digestive tracts
Tearing and grinding teeth
Amylase within saliva
What do animals need in order to construct organic molecules?
A source of organic carbon and nitrogen
Role of linoleic acid
Synthesised components of signalling molecules and membrane phospholipids
What can a fatty acid deficiency lead to?
Infertility and impaired lactation
What is scurvy caused by?
A lack of Vitamin C
Intracellular digestion
Food particles are engulfed by endocytosis and digested within food vesicles
Extracellular digestion
Food particles are broken down outside of cells and occurs in compartments which are continuous with the outside of the body
Amylase - site of action
Mouth
Duodenum
End products of chemical digestion by amylase
Maltose
Glucose
Protease - Site of action
Stomach
Duodenum
Lipase - site of action
Duodenum
Where does mechanical digestion occur?
Mouth
Oesophagus
Stomach
SI
Mechanical digestion in the oesophaus
The food is made into a bolus at the back of the mouth. This is pushed down the oesophagus by rings of muscles, in a contraction known as peristalsis
What is gastric juice made up of?
HCl and Pepsin
What protects the stomach lining from gastric juices?
Mucus
Bile
A green liquid made in the liver but stored and released by the gall bladder into the small intestines
Role of bile
Helps digest fats and increase pH so enzymes can work well in the small intestine
Roles of the Gall Bladder
Storage of bile and release into the duodenum when required
Absorption of water and concentration of bile
Major functions of bile
Fatty acid metabolism
Excretion of waste products
Kill off bad microbes
Blood sugar metabolism
Role of the pancreas
Releases enzymes into the small intestine that help digest our food
Small Intestine
The longest part of our digestive system
Made from microscopic villi which help increase the SA so more nutrients can be absorbed more quickly
Adaptations of the small intestine
Large SA:V ratio
Epithelial cells of the villi have numerous microvilli
Paneth cells
One of the main cells types of the epithelium, which provide host defence against the microbes in the small intestine
What happens when paneth cells are exposed to bacteria?
The secrete a number of antimicrobial molecules which help maintain the GI barrier
Large intestine
Mainly indigestible food and water enter the large intestine
It’s job is to absorb water back into the body
Large intestine
Mainly indigestible food and water enter the large intestine
It’s job is to absorb water back into the body
