General Characteristics. Flashcards
What is the major function of the digestive system?
To take nutrients from the environment and place them into circulation.
How does the digestive system take nutrients from the environment and place them in circulation?
It transforms them from large molecules into much smaller molecules that can then be absorbed.
What are the 3 groups of nutrients that are taken in by the digestive system?
Fats.
Carbohydrates.
Proteins.
Can fats, proteins and carbohydrates be absorbed into the blood?
No, they must be reduced to their constituents.
What part of fats can be absorbed into circulation?
Fatty acids.
What part of carbohydrates can be absorbed into circulation?
Monosaccharides such as glucose.
What part of proteins can be absorbed into circulation?
Amino acids.
What are the 2 methods that the digestive system uses to break down nutrients?
Mechanical methods.
Chemical methods.
What collective name is given to the organs that support the digestive system?
The accessory organs.
What are the 3 fundamental processes that are used by the digestive system?
Motility.
Secretion.
Absorption.
How does the GI tract use motility to help with digestion?
Muscles mix and crush food up to make it smaller.
Is GI tract motility a form of mechanical or chemical digestion?
Mechanical.
How does the GI tract use secretions to help with digestion?
The secretions contain substances such as digestive enzymes etc that will help with digestion.
How does the GI tract use absorption to help with digestion?
It absorbs the nutrients from the digestive system into the blood.
Are GI tract secretions a form of mechanical or chemical digestion?
Chemical digestion.
What are the 2 main controlling factors of the digestive system?
The nervous system.
Hormones.
What are the 2 major criteria within digestion that must be controlled?
Adaptation to quantity and quality of food.
Synchronicity between different organs within the digestive system.
What dictates the food an animal can eat?
The environment that the animal is in.
What are the 2 major functions of the mouth?
The mechanical breakdown of food.
The secretion of saliva.
What is the major function of saliva?
It lubricates food.
What is the oesophagus?
The passageway between the mouth and the stomach.
What is the function of the stomach?
Chemical digestion of food.
Liquefaction of food.
What is the function of the liver?
It provides bile salts that help with the digestion of fats.
What is the function of the pancreas?
It releases major digestive enzymes.
What is the function of the small intestine?
It provides enzymes for chemical digestion.
Absorption of nutrients and water.
What is the function of the large intestine?
Absorption of water.
Faeces formation.
Bacterial fermentation.
What is the name of the process by which the dietary macromolecules are broken down?
Hydrolysis.
What are proteins broken into following hydrolysis?
Amino acids.
What are carbohydrates broken into following hydrolysis?
Monosaccharides.
What are fats broken into following hydrolysis?
Fatty acids and glycerol.
What happens to proteins after they are absorbed by the body?
They can be used for energy.
They can be used as structural components within cells.
What happens to fats after they are absorbed by the body?
They are used as energy or are stored as fat.
What happens to monosaccharides after they are absorbed by the body?
They are used as energy or are stored as fat.
What collective name is given to the products from the breakdown of macromolecules?
Micromolecules.
What is the general shape of a carnivores stomach and intestine?
Small stomach.
Short small intestine.
Short large intestine.
What is the general shape of a ruminants stomach and intestine?
Large fermentation chamber.
Small true stomach.
Long small intestine.
Short large intestine.
What is the general shape of a horses stomach and intestine?
Small stomach.
Long small intestine.
Small large intestine.
What are the components of a birds stomach?
Crop.
Pro-ventriculus.
Gizzard.
Small intestine.
Large intestine.
What acts as the teeth and stomach in the bird?
The pro-ventriculus and the gizzard.
What is the function of the crop in a bird?
It is used for storing food.
What kind of epithelium is found in the inside of the digestive system?
Columnar epithelium.
Except in the mouth and rectum where it is stratified squamous epithelium.
What are the 2 plexi that are found in the walls of the digestive system?
The myenteric plexus.
The submucosal plexus.
What is a plexus?
A collection of nerves.
What are the layers of the walls of the GI tract?
Mucosa.
Submucosa.
Muscularis.
Serosa.
What part of the GI tract of ruminants has different layers within the walls?
The forestomach.
What cells cover the villi of the intestines?
Epithelial cells.
What is the function of the epithelial cells that cover the villi of the intestines?
They are involved in the absorption of nutrients.
What is the lifespan of the epithelial cells that cover the villi of the intestines?
2-3 days.
What controls the release of secretions and the motility of the digestive tract?
Sensors within the digestive tract.
When will the sensory cells increase or decrease the motility of the GI tract or the amount of secretions that are released into the GI tract?
When they detect food entering the GI tract.
How do the sensory cells of the GI tract detect food entering the GI tract?
Via mechanoreceptors (stretch receptors).
