Digestive System

Front 1

mouth

Back 1

*first part of digestive system
*chewing
*mechanical: chewing
*chemical: saliva contains amylase (the breakdown of starch into sugar)

Front 2

Pharnyx

Back 2

* stationed behind the mouth and the nasal cavity
* has epiglottis which goes up when one is breathing.

Front 3

Esophagus

Back 3

*peristalsis pushed down food.

Front 4

stomach

Back 4

Mechanical: churning
chemical: protease (pepsin)
*stores food.
*pepsin: degrades food protein into peptides.
*stomach is a muscular bad. It's elastic and can stretch to accommodate food.
*Parietal cells: stomach epithelium cells that secrete HCl which causes the pH to be very acidic.
*Gastric juice: hcl,pepsin and hormones secreted by the stomach (parietal,chief, enteroendocrine cells).
Pepsin: protease works best in acidic environment
*banana shape with a rough lining (rugae) sack that is closed off above from the esophagus: cardiac sphincter and closed off below from the small intestine called the pyloric sphincter.

Front 5

Liver

Back 5

*makes bile from cholesterol and stores it in the gall bladder
* nutrient metabolism and stores vitamins
*makes glycogen from glucose.
*Gluconeogenesis from glycerol and amino acids
*breaks down fat, makes lipoproteins which transports fats, makes cholesterol which makes bile.
*stores vitamins and iron
*blood glucose is regulated by the liver: glycogenesis (too high) and glucogenesis (too low)
* also detox: metabolizing alcohol and removing ammonia from blood.

Front 6

Gall bladder

Back 6

*stores bile and concentrate bile.
*Bile : breaks down fats into small droplets for lipase.

Front 7

Pancreas

Back 7

*makes enzymes for the small intestine
*is the major source for all digestive enzymes
*produces: amylase, protease, lipase and ribonuclease for the small intestine.
* Has bicarbonate HCO3- to neutralize the acid in the stomach.
*Exocrine: all enzymes made in the pancreas flows through a duct into the small intestine

Front 8

Small intestine

Back 8

*absorbs nutrients and water
*amylase
*pepsin
*lipase (essential role in transport and processing of dietary lipids in the small intestine.
*nuclease (enzyme capable of cleaving phosphodiester bonds between nucleotides.
* absorbs digested foods into the capillaries and fats into the lacteal.
*Active and passive transport occurs
*villi vs micro villi
* duodenum,jejonum, Ileum.

Front 9

large intestine

Back 9

*absorbs only water remaining from small intestine
*parts of the large intestine are :ascending colon, transverse colon, descending colon, sigmoid colon, rectum and cecum (contains appendix).
*ferments undigested nutrients into gas
*produce vitamin K (important for clotting).

Front 10

Rectum

Back 10

*stores feces.
*anal spincter is at the end of the rectum and opens to the anus.

Front 11

Saliva

Back 11

*saliva is a big component of the first process in digestion.
*is a lubricant that help to dissolve food.
* has mucin: a protein that lubricates the food.
*Saliva has amylase; which breaks down polysaccharides (starch and glycogen)
*saliva has antibodies and lysozymes which kills pathogens.

Front 12

epiglottis , pharynx and esophagus

Back 12

Epiglottis: cartilage; closes up the airway when swallowing
Pharynx: between mouth and esophagus (throat).
*muscle tube which route food to the esophagus
Esophagus: moves food to the stomach by peristalsis.

Front 13

Goblet cells

Back 13

*secrets mucus in the lining of the stomach to protect it from acid and from self digestion.

Front 14

Active vs passive transport in small intestine

Back 14

* Active transport
-low glucose in the lumen flows to high glucose in the enterocyte.
- Na K pump and Na glucose symport.
*Passive transport: high glucose from the enterocyte to low glucose in the extracellular fluid to the blood.

Front 15

Villi vs microville in the intestine

Back 15

* villi is all the extensions on the surface of the intestine
*microvilli is the extensions on individual absorptive cells.