digestive system Flashcards
what is digestion
the breakdown of food into smaller particles
what are the main events of digestion
ingestion,
digestion, absorption and egestion
what is ingestion
food taken in through mouth
what is absorption
digested food passes into bloodstream
egestion
removal of unabsorbed waste from the body
what are the four types of teeth
molars, pre molars, canines and incisors
what are the functions of molars and pre molars
crush and grind
what are the functions of canines
grip and tear
what are the functions of incisors
cut and slice
what is the dental formula
2[I2/2 C1/1 P2/2 M3/3]
mechanical digestion in the mouth
teeth crush and grind food into bolus
chemical digestion in mouth
saliva is produced from salivary glands and it contains lysozyme, amylase, mucus and water and it break down the food
what happens after the food is chewed into a bolus
it is pushed to the pharynx and the epiglottis closes over the trachea and the food travels down the eosophagus
what is peristalsis
the wave of muscular action i the walls of the alimentary canal that moves food along
what muscle does the food go through
cardiac sphincter muscle
what gastric juices are produced by the gastric glands in the stomach
mucus pepsinogen and hydrochloric acid
what does mucus do
it coats the stomach and prevents self digestion
what does pepsinogen do
it activates pepsin which converts proteins to peptides
what does hydrochloric acid
kills bacteria, loosens fibrous and cellular foods and activates pepsinogen and salivary amylase
what makes chyme
the contraction of the stomach wall churns and digests the food turning it to chyme which is passed into the duodenum
what are 2 glands associated with the small intestine
pancreas and liver
what is the function of pancreas
it secretes hormone insulin and digestive materials which then form pancreatic juices which contain sodium bicarbonate [which neutralises chyme] and enzymes like amylase and lipase.
where is bile made ,stored and secreted
liver, gall bladder, bile duct
how do the enzymes and neutralised chyme enter the duodenum
pancreatic duct
what does the duodenum do
digestive enzymes are produced from the cell lining of the duodenum. The duodenum is mainly for digestion
how is the small intestine adapted for absorption
the ileum and duodenum are both lined with villi for absorption.
what does the villi do
the villus absorbs nutrients like glucose amino acids and the capillaries carry them to the hepatic portal vein. This takes them to the liver where some are stored and released. Excess amino acids are turned to urea and released through the hepatic vein
how is faeces formed
the liquid waste enters the large intestine and water is reabsorbed turning t to faeces
where is faeces stored and egested
rectum and anus
what liuqid is the in the lacteal
lymph
what does the lymph do
the lymph transports protein coated fats to the blood stream through the lymph vessels.
what do the cells of the villus do
absorb fatty acids and glycerol reforming them to fats
