A Digestive Journey: “a trip through the donut hole”. Some Important Definitions. INGESTION – the taking of nutrients. DIGESTION – the breakdown of complex organic molecules into smaller components by enzymes . ABSORPTION – the transport of digested nutrients to tissues of the body.
INGESTION – the taking of nutrients.
DIGESTION – the breakdown of complex organic molecules into smaller components by enzymes.
ABSORPTION – the transport of digested nutrients to tissues of the body.
EGESTION – the removal of waste food materials from the body.
NOTE: the purpose of sphincters is to prevent food from going in the reverse direction (i.e. reflux from the stomach into the esophagus).
Enable the stomach to contract & expand.
- Hydrochloric acid or HCl(secreted by parietal cells) softens food and activates pepsinogen to pepsin
- pepsin breaks down PROTEIN into short chains of AA’s
- Gastrin induces secretion of more mucus
Enzyme Action:(all released into the small intestine)
1) lipase – digests fat
2) amylase – further breakdown of carbohydrates
3) trypsin – breaks down protein into short chains of amino acids
- produces bile (emulsifies FAT into little fatty
- extracts absorbed nutrients or toxins from blood
- decomposes toxins (ie. Alcohol, drugs)
- key role in regulating body metabolism (homeostasis)
- manufactures many essential body proteins
- regulates the balance of hormones
- regulates body cholesterol
- high concentration of catalase enzymes that play key role in decomposing toxins (i.e. Alcohol).
- collects and concentrates the bile that it receives from liver
- releases bile to duodenum
- gall bladder contracts in reaction to hormone cholecystokinin (CCK) to release bile into the duodenum.
3 Parts Duodenum, Jejunum, Ileum
- see pancreas
- Secretin to reduce acidity from food coming from stomach
2) JEJUNUM & ILEUM
1) peptidases- break down short chain of amino acids into individual amino acids
2) disaccharidases- breaks disaccharides into simple sugars
- synthesis of melatonin= skin pigment
- about 1.5 m in length
- divided into 3 parts:
Rectum - STORAGE of stool
Anus – EXPELS WASTE from the body
Take 10 cue cards (one for each “station” and accessory organ in the digestive system.
FRONT of the cue card will represent the structure.
- write the name of the organ
- draw/sketch or print then glue on a labelled diagram
BACK of the cue card will represent the functions.
- types of physical & chemical digestion
- specific functions
- enzyme action
- hormonal action
QUIZ YOURSELF by:
- putting the cue cards in order
- having someone read one side of the card and you indicate what is on the other side.
FRONT - Structure
Station #2 – The Esophagus
BACK - Function