Digestive system Flashcards
(18 cards)
what is the system responsible for:
1-ingestion of food.
2-Digestion of food.
3-Absorption of food.
4-Egestion (elimination of food)
The digestive organs
-1-the mouth
2-the pharynx
3-the esophagus
4-the stomach
5-small intestine
6-large intestine
Accessory Organs
1-salivary glands
2-the pancreas
3-the liver
Digestion-consist of
mechanical-physical
chemical-enzymes
Digestion
is the breakdown of the complex food molecules into simpler molecules that could be absorbed by the body.
Digestion-mechanical
includes the breakdown of the food without any change in its molecular structure(smaller particles)
Digestion-chemical
bigger molecules are dismantled into smaller molecules which are different in structure.
The mouth(oral cavity)
-Mastication (chewing) of food.
-mixing masticated food with saliva.
-Allowing for sense of taste.
-Initiation of swallowing by the tongue
The mouth-saliva
secreted by the salivary glands, it is slightly alkaline and, includes salivary amylase as well as mucus.
Functions of saliva
-moistens the food for easy swallowing.
-dissolves the food for discerning taste by the tongue
-contains salivary amylase which digests starch into disaccharides.
-act as a natural cleanser for teeth (isn’t a substitute for toothpaste and a toothbrush though)
The pharynx
the base of the tongue plus the muscular pharynx result in the involuntary reflex of deglutition (swallowing) of food towards the esophagus.
The oesophagus
-is a muscular tube that conducts the food to the stomach by peristalsis (slow rhythmic contractions)
-its cells also secrete mucous that helps as a lubricant to move the food.
The stomach
-acts as a storage for food.
-is made of three muscle layers, from the outside to the inside are the longitudinal muscle layer, the circular muscle layer and the oblique muscle layer.
-The inner lining of the stomach is called the mucosa it contains the glands of the stomach and is corrugated forming the rugae
-has two sphincters, the cardiac sphincter and the pyloric sphincter.
-secretes gastric juice
The small intestine and pancreas
-digestion and absorption take place in the small intestine.
-the small intestine is a muscular tube extending from the pyloric sphincter to the ileocecal sphincter about 6-7 metres long.
The small intestine and pancreas- 2
1-it is made of three segments namely, the duodenum, jejunum, and the ileum.
2-The duodenum is only 20-30 cm long.
3-the duodenum receives enzymes secreted from the liver and pancreas.
The pancreas
-Trypsinogen
-Erepsin
-Pancreatic amylase
-pancreatic lipase
Digestion of protein
Starts in the mouth
proteins>pepsin>shorter-chain peptides
macronutrients-digestive system
proteins, carbohydrates, lipids
