Digestion in the mouth and stomach Flashcards
What is digestion?
The breakdown of nutrients we eat into simpler organic compounds that can be absorbed by the body
Types of digestion
Chemical which changes the substance and involves enzymes, bile and HCL, Mechanical which changes the substances shape and size and involves chewing/churning
Roles of the digestive system
Digestion, Absorption and elimination
Chemical digestion in the mouth
Enzyme salivary amylase produces polysaccharides (sugars such as maltose)
Six functions of saliva
Lubricates the mouth, Dissolves food, holds food together, rinses teeth, contains antibodies and contains salivary amylase
4 types of teeth
Incisors for biting or cutting, canines for tearing, premolars and molars for crushing ad grinding
Dental formula
Top number- No. and type of tooth in half of the upper jaw, Low number- No. and type of tooth in half of the lower jaw
How does swallowing happen
Tongue moves pushing the bolus into the back of the mouth (pharynx), soft palate closes of nasal cavity, epiglottis closes of trachea, bolus passes down into oesophagus to the stomach (peristalsis)
Scientific name for swallowing
Deglutition
Peristalsis
Happens due to the relaxation of the circular muscles in the oesophagus which moves the food along to the stomach
Layers of the alimentary tube
Mucosa, Submucosa, Muscle layer, Serosa
Function of the cardiac sphincter
Separates the oesophagus from the stomach which prevents the backflow of food
Mechanical digestion in the stomach
Oblique muscle layer as well as a circular and longitudinal layer which allows for churning which mechanically digest the food as well as mixes the food with gastric juice for chemical digestion
What do gastric pits contain?
Contains gastric glands which secrete gastric juice
What happens in gastric pits?
HCL activates inactive pepsinogen and converts it into active pepsin which is able to breakdown proteins into polypeptides
