Digestion Flashcards
What is digestion
The chemical and physical breakdown of food into small soluble molecules
What is absorption
The taking into the body of specific compounds
What is elimination
The expulsion of materials not absorbed into the body. Excretion, not including urine
What is the 10 step pathway of food
1) oral cavity
2) pharynx
3) epiglottis
4) esophagus
5) stomach
6) duodenum
7) small intestine
8) large intestine (+ appendix)
9) rectum
10) anus
What are the 3 main accessory organs and their main function
1) liver, makes bile
2) gall bladder, stores bile
3) pancreas, makes some enzymes
What do the substances made in the accessory organs drain through
The common bile duct
What is salivary amylase
A neutral enzyme produced by the salivary glands that dissolves starch into maltose (disaccharide)
What is pepsin
An acidic enzyme produced by the stomach that digests proteins into peptides
Secreted as inactive pepsinogen, turned to pepsin by low pH
What is pancreatic Amylase
A basic enzyme produced by the pancreas that digests starch into maltose
What is trypsin
A basic enzyme produced by the pancreas that digests peptides into smaller peptides
What is lipase
A basic enzyme produced by the pancreas that digests fat into glycerol and fatty acids
What are the peptidases
Multiple basic enzymes that are produced by the small intestine that digest peptides into amino acids
What is maltase
A basic enzyme produced by the small intestine that digests maltose into glucose
What is nuclease
A basic enzyme produced by the small intestine and pancreas that digests nucleic acids into nucleotides
What is Diomedea exulans
The wandering Albatross
What needs to be formed in the mouth prior to swallowing
A bolus (food ball) made by mouth, teeth, tongue, and saliva
While swallowing how does the esophagus move the bolus to the stomach
Through peristalsis, a rhythmic contraction of the esophagus and intestine which runs along the tube and pushes food material in one direction
What is saliva
A mixture of water, mucus, and enzymes like salivary amylase
What are the three functions of saliva
Lubricates food
Forms the bolus
Salivary amylase digests starch
What controls the digestive juice
The nervous system and endocrine system (hormones)
What are gastric juices made of
Water, pepsinogen (inactive enzyme pepsin), and hydrochloric acid (HCl)
What cells secrete pepsinogen
Chief cells
What cells secrete HCl
Parietal cells
What are the 4 functions of gastric juices
Lowers pH
Pepsin (activated by low pH) digests large proteins to small amino acid chains (peptides)
Food becomes semi-liquid acid chyme
Kills bacteria
What hormone causes the stomach to release juices
Gastric
What can excess acid lead to
Ulcers
What does the pancreas release into the duodenum
Pancreatic juices
Sodium bicarbonate
4 main enzymes
What does sodium bicarbonate do in the small intestine
It acts like a buffer to neutralize the stomach acid bringing the ph to around 7.5 (slightly basic)
What are the four enzymes release by the pancreas + functions
- pancreatic amylase (digests starch)
- trypsin (digests peptides)
- lipase (digests lipids)
- nuclease (digests DNA + RNA to nucleotides)
What 2 hormones control the pancreatic juices
CCK (Cholecystokinin)
Secretin
How long does it take the stomach to empty
2-6 hours
What is absorbed directly by the stomach
Alcohol
Aspirin
Candy
Etc
How long is the small intestine
Roughly 6 m
What is the duodenum
The first 20-25 cm of the small intestine
What 4 main enzymes are produced in the small intestine + functions
Maltase (maltose -> glucose)
Peptidases (Small peptides -> amino acids)
Nucleases (DNA/RNA -> nucleotides)
Lactase (lactose -> glucose)
What happens to the monomers after enzymatic digestion in the small intestine
They are absorbed into the blood
What are trophic levels
Essentially levels of consumption in an ecosystem
Ex producers
Primary consumers
Secondary consumers
Etc
What is bile
A product produced by the liver, stored in gall bladder that enters the duodenum
A chemical with salts that digests fats making it easier for lipase to work on them
What cells produce insulin
Islets of langerhans
What does insulin do
Acts on the cell membranes opening the protein gates In the membrane to slow glucose to enter from the blood