Biology - 6.2 Flashcards
Accessory Organs
Liver
Pancreas
Gallbladder
Digestive system
Ingestion
Digestion
Absorption
Egestion
Hydrolysis
Chemical Digestion
Salivary Amylase
Begins to break down starch into simple sugars (disaccharides)
Bolus
Chewed up food
SOP: Saliva
Mouth
SOP: Mucus
Mouth, stomach, small and large intestine
SOP: Enzymes
Mouth, stomach, pancreas, small intestine
SOP: Acid
Stomach
SOP: Bile
Liver
SOP: Bicarbonate
Pancreas and small intestine
Function of saliva
Lubricates mouth to aid swallowing
Function of mucus
Protects cell lining in digestive tract
Function of enzymes
Promote digestion of food masses into particles small enough for absorption into blood
Function of acid
Promotes digestion of protein
Function of bike
Aid digestion of data in small intestine
Function of bicarbonate
NeutraliZes stomach acid when it reaches the small intestine
Esophagus
Directs food from mouth to stomach
How does food move through the esophagus?
Peristalsis
Peristalsis
A wavelike series of muscular contractions and relaxations
Esophageal Sphincter
Controls entry to stomach and prevents acidic contents of stomach from backing up into the esophagus
3 Functions of stomach
- Storage
- Digestion
- Pushing food into the small intestine
Pyloric Sphincter
Controls exit of the stomachs contents into the small intestine
How is chyme produced?
Small pieces of food + gastric juice
Function of gastric juice
Responsible for chemical digestion of stomach
What makes up gastric juice?
Water Mucus Salts HCl Enzymes
pH of HCl
1 to 3
Function of HCl
- Acidic environment begins to soften and break down proteins in chyme
- Kills most bacteria
3 methods of protection in stomach
- Secretes gastric juice until food is present
- Secrete mucus which protects stomach lining from gastric juice
- Produces pepsin which remains inactive until HCl is present
Segmentation
Chyme sloshes back and forth between segments of the small intestine while food is pushed along by peristalsis
Function of small intestine
Complete digestion of macromolecules and to absorb their component subunits
3 Regions of small intestine
- Duodenum
- Jejunum
- Ileum
Duodenum
Site for chemical digestion of the chyme received from the stomach
Function of Jejunum and ileum
Absorb nutrients and to push the remaining undigested material into the large intestine
Function of lymph vessels
Conduct absorbed substances from the small intestine into the bloodstream and the lymphatic system
Function of pancreas
Delivers pancreatic fluid to duodenum
What enzymes are in pancreatic fluid?
Trypsin
Pancreatic amylase
Lipase
Function of trypsin, pancreatic amylase and lipase
Trypsin: digest protein
Pancreatic amylase: digests starch in small intestine
Lipase: digests fat
What happens after enzymes from pancreas are released into duodenum?
- Activated by enzymes secreted from lining
- Digest proteins
- Bicarbonate neutralizes HCl and gives chyme pH of 8
Function of liver
Secretes bile
Function of bile salts
Assists lipase in digesting fats because they are partly soluble in water and partly soluble in fats
Function of gallbladder
Stores bile
How is bile injected into the duodenum ?
Fat-containing chyme causes gallbladder to contract and bile is sent through a duct to the duodenum
Function of carbohydrases
Digest carbs
Function of lipases
Digest fats
Function of proteases
Digest larger polypeptides
Function of nucleases
Digest nucleic acid