vomiting http://www.youtube.com/watch?v=Ub58JoML_3Y http://www.youtube.com/watch?v=5zOevLN3Tic&feature=related http://www.youtube.com/watch?v=_tXzKpmRrFs&feature=related

Is vomiting peristalsis? No, it’s reverse peristalsis

Peristalsis http://www.youtube.com/watch?v=YH3U_SLp9G0&feature=related http://www.youtube.com/watch?v=o18UycWRsaA&feature=related

Inside the Stomach

The Stomach

- stores food (muscle relaxes) Stomach muscular organ - stores food (muscle relaxes) - mechanical digestion muscular contractions churn food

Stomach - chemical digestion gastric juice pepsin and HCl enzyme that chemically digests protein to dipeptides

Levels of Organization in the Human Body

Tissues in the stomach Muscle Produce pepsin Produce HCl Produce mucus = what life process? Muscle Produce pepsin synthesis Produce HCl Produce mucus Produce gastrin (hormone that stimulates production of HCl)

Mucous cells: secrete a basic mucus that protects the epithelium against shear stress and acid Parietal cells: secrete HCl

Chief cells: secrete pepsin, an enzyme that breaks down proteins G cells: secrete the hormone gastrin

HCl in Stomach Denatures proteins Activates pepsin Kills bacteria; other microorganisms Dissolves minerals

How does the denaturation of proteins by HCL affect chemical digestion? Denaturation of proteins by HCL exposes more surface area to enzymes, increasing the efficiency of digestion

- polypeptides (several amino acids in a chain) Hydrochloric acid provides an optimum pH for the activity of gastric protease (pepsin). Pepsin breaks down proteins to: - polypeptides (several amino acids in a chain) - dipeptides (2 amino acids attached).

Stomach Mucosa Tissue that produces mucus Mucus - a viscous fluid consisting of glycoproteins Mucus protects stomach lining from acidity of HCl

Acid reflux - acid from stomach backs up into esophagus What is heartburn? Acid reflux - acid from stomach backs up into esophagus

Cow stomach research Holy Cow! http://www.youtube.com/watch?v=dY4QkhwQMRA

2. unchewed food goes to RUMEN and RETICULUM HOW COW DIGESTS: 1. cow swallows food 2. unchewed food goes to RUMEN and RETICULUM 3. cow stores food in RUMEN and RETICULUM 4. cow is now tired and rests 5. when she is hungry gain she will cough up some unchewed food (called cud!) 6. it will chew it completely and swallow it again 7.the cud goes to OMASUM and  ABOMASUM 8.in  OMASUM and  ABOMASUM food is fully digested

A Gastric Ulcer

Ulcer open sore in the mucus membrane resulting from localized breakdown of tissues

Bacteria cause ulcers

2) The chemical digestion of which nutrient begins in the stomach? 1) The _____ glands secrete _____ which contains the enzyme ____________ which digests starch into _______________. salivary saliva Salivary amylase dissacharides 2) The chemical digestion of which nutrient begins in the stomach? protein

Small intestine

Partially digested, liquefied food enters the small intestine. The small intestine is a long, convoluted tube in which the major portion of food is digested. Partially digested, liquefied food enters the small intestine.

What are accessories?

liver 1 gall bladder 2 pancreas 3

Bile is produced in the liver and stored in the gall bladder. Accessory organs, the gall bladder and pancreas, empty their secretions into the small intestine. Bile is produced in the liver and stored in the gall bladder.

Bile is not an enzyme, but a chemical that emulsifies (physically break apart) fat

How does this affect the chemical digestion of fat? bile fat fat

emulsification increases the surface area of fats for more efficient chemical digestion

Chemical Digestion The pancreas secretes several enzymes including intestinal protease, lipase, and amylase. Intestinal glands that line the intestinal wall secrete protease, lipase, and maltase.

Twenty amino acids are necessary for body maintenance and repair. Amino acids are temporarily stored and distributed to the cells as needed for protein synthesis. Twenty amino acids are necessary for body maintenance and repair.

* The chemical digestion of proteins, lipids, and carbohydrates is completed in the small intestine.

What are the end products of digestion? Nutrient End - Products Proteins Lipids Carbohydrates Amino acids Fatty acids and glycerol Simple Sugars

How do the end products of digestion get to our cells?

Absorption The passage of the end products of digestion into the blood The process by which usable materials are taken into an organism The passage of materials across a cell membrane into the cell

esophagus liver Gall bladder Small intestine rectum

villi

microvilli

Lacteal (small lymph vessel) Capillary (tiny blood vessel) microvilli

Capillaries and small lymphatic vessels, lacteals, extend into the villi.

Why does the small intestine have this structure? 3 2 1{ Why does the small intestine have this structure? (folds, villi, microvilli) 1 –intestinal fold 2 – villi 3 – microvilli

 Absorption In the Small Intestine The lining of the small intestine contains numerous villi (small fingerlike projections) which increase the surface area of the small intestine to improve absorption.

Surface area of the small intestine

overview till stomach http://www. youtube. com/watch Villi - freezes towards the end http://www.youtube.com/watch?v=P1sDOJM65Bc&feature=related https://www.youtube.com/watch?v=6nonjzzCSUU villi http://www.youtube.com/watch?v=_GTQBiZni6w&feature=related

Fatty acids and glycerol are absorbed through the villi into the lacteals and are transported in the lymph. Monosaccharides and amino acids are absorbed through the villi and enter the capillaries to be transported to the liver where they are temporarily stored.

Functions of the Liver Absorbs and stores nutrients Produces bile Detoxifies poisons in the blood Removes waste products, old RBCs from blood

The breakdown of glycogen releases glucose for transport. Glucose is temporarily stored as the polysaccharide glycogen (animal sugar) in the liver. The breakdown of glycogen releases glucose for transport.

What are two major functions of the small intestine? Digestion and Absorption

2) What are the three enzymes secreted by the pancreas? 1) The gall bladder releases _____ and the pancreas secretes _____ into the small intestine for chemical digestion. bile enzymes 2) What are the three enzymes secreted by the pancreas? Protease, lipase, amylase

Chyme is acidic. Why doesn’t chyme cause ulcers in the small intestine? The pancreas produces sodium bicarbonate which neutralizes the acidity of chyme in the small intestine. It also creates a basic pH for the optimal activity of pancreatic and intestinal enzymes

Diarrhea http://www.youtube.com/watch?v=ln_crYIBw00&feature=related http://www.youtube.com/watch?v=BYW6C44zo24&NR=1&feature=endscreen

In one day your body makes: 1 LITER OF SALIVA 1-3 LITERS OF GASTRIC JUICE 1-2 LITERS OF PANCREATIC JUICE 2-3 LITERS OF INTESTINAL JUICE

Functions of the Large Intestine Reabsorbs water from food mass Absorbs vitamins Contains bacteria which: make vitamin K digest organic substances compete with dangerous bacteria in food Elimination (egestion) of undigested waste

What happens when water is not reabsorbed by the large intestine?

Diarrhea intestinal disturbance increased peristaltic activity of the large intestine decreased water absorption results in increased, multiple, watery feces; may result severe dehydration especially in infants.

What happens when too much water reabsorbed by the large intestine?

Constipation

Constipation sluggish peristaltic movement too much water is reabsorbed the solid waste hardens large intestine is emptied with difficulty

5. Large Intestine Undigested food and water enter the large intestine where excess water is absorbed as needed. During egestion, strong peristaltic action forces feces out through the anus.

Feces Bacteria (50%) Cellulose Bile Mucous Dead cells

What is this? The appendix

Function of Appendix? “second stomach” for digestion of plant matter houses a “backup supply” of good intestinal bacteria

What is this?

Appendicitis is an inflammation of the appendix due to infection.

Other Malfunctions of the Digestive System Ulcers are open sores in the interior wall of the digestive tract, most often in the stomach or the upper portion of the small intestine. The acid in gastric juice irritates the sores and causes pain or discomfort.

Colon Cancer

Endoscope

Colorectal Cancer SEER Incidence Rates. by Race and Ethnicity, U. S

Colorectal Cancer U.S. Death Rates* by Race and Ethnicity, 1975–2005

Colon cleansing http://www.youtube.com/watch?v=4Yziam3q7hE

Gallstones

Gallstones

Gallstones are an accumulation of hardened cholesterol and/or deposits in the gall bladder.

liver

Enjoy Your Lunch!

Human digestion (vocabulary) nutrients digestion absorption fiber anus pharynx esophagus large intestine small intestine saliva salivary glands stomach rectum liver pancreas Peristalsis chyme villi

pancreas

liver gall bladder

These are called essential amino acids. Although humans can convert one amino acid into another, eight cannot be synthesized and must be consumed as part of the diet. These are called essential amino acids.

Cholesterol Bile Acid

(left) and stomach lining (right) Normal esophagus (left) and stomach lining (right) Esophageal cancer (stomach lining on left)