GI System Flashcards
What are the digestive organs of the GI
Oesophagus
stomach
small I
Large I
What are the Accessory Organs and what are they in the GI
An organ that helps with digestion but is not part of the digestive tract.
The accessory digestive organs are the tongue, salivary glands, pancreas, liver, and gallbladder
What is a brief overview of digestion?
- Mechanical Breakdown
- Prehension (grasping/seizing)
- Mastication
- Motility - Chemical breakdown:
- Secretion
- Digestion - Absorption
- Metabolism
- Egestion
What is Prehension?
- Getting something into your mouth
lips, tongues, teeth
What is Mastication
Chewing
What is Motility
Movement of the gut - can change with chemicals
What is digestion (strictly speaking)
chemical breakdown (done by enzymes) of substances
What is the difference between egestion and excretion
egestion: get rid of substances that has never been absorbed in the first place
excretion: get rid of substances that have been absorbed into the blood stream
What are the roles of a) teeth b) salivary glands c) Stomach d) Liver/ gall bladder/ pancreas e) SI f) LI in digestion
a) teeth - mechanical breakdown
b) salivary glands - secretion
c) Stomach - motility/ secretion
d) Liver/ gall bladder/ pancreas - secretion
e) SI - motility/ digestion/ absorption
f) LI - motility/ fermentation/ absorption/ egestion
What are the digestive processes in the head?
- Prehension
- movement of food into oral cavity (lips, tongue, teeth, head movement) - Mechanical Breakdown
- mastication (reduce size food particles - Salivation
- Mucous to lubricate food
- saliva contains amylase in some species to start the digestion of carbs
What are 3 types of salivary gland
- mandibular - around jaw
- buccal - cheek area
- sublingual - under tongue
mixture of
What are the different types of salivary secretions?
- Serous- if saliva secreted to fill up a part of GI to create good environment for digestion to occur
- mucous - enable lubrication of food so it can pass easily down GI
What is the main type of saliva in the complex stomached animals
- complex = ruminants
2. Mainly serous saliva to provide optimum conditions for fermentation
What is the composition of saliva?
- dependant on diet and which glands are stimulated*
1. Mucin (+ water = mucus)
2. amylase (omnivores/ horses NOT carnivores/ ruminants)
3. Bicarbonate (neutralise/ buffering = create constant pH for digestion)
4. Phosphate (buffering) (ruminants)
5. Lysozyme/ antibodies (reduce infection = prevent bacteria)
6. Protein binding tannins (leaf and bud eaters)
7. Urea (ruminants)
How is salivary secretion and digestive juices secreted
- SS = only neural
sympathetic - reduced, para = increased - DJS = neural and hormonal