What do all these have in common ants

What do all these have in common? ants rattlesnake termites sea urchin turtle cow cod pigs feet monkey brains squid sheep eyeballs snails octopus seaweed worms

Food n. Food – contains nutrients Ø Nutrients are substances in foods that the human body can digest, absorb, and use for its metabolism.

Ø Humans are heterotrophic and therefore, must ingest food. Ø Food includes nutrients and roughage (fiber). Ø Roughage (also called fiber) is indigestible material in foods.

Nutrients carbohydrates, proteins, lipids, minerals, vitamins, and water.

III‑ 1. Human Nutrition Ø Nutrition includes those Nutrition activities by which organisms obtain and process nutrients needed for energy, growth, repair and regulation.

Ø Vitamins, minerals, and water are small molecules and can be absorbed without digestion. Ø Carbohydrates, lipids, and proteins require digestion.

Ø Nutritional requirements vary with an individual's age, sex and activities.

How does food become feces? food feces

Digestion - the process of breaking food down into a smaller, simpler form, so it can be used by the cell(s) of an organism

Place these in order from smallest to largest (from simple to most complex) • • Organ systems Cells Tissues Organs

Simple • Cells • Tissues • Organs Complex • Organ systems

Levels of Organization in the Human Body

Salivary glands mouth epiglottis esophagus liver tongue stomach pancreas Small intestine Large intestine anus appendix rectum

liver Gall bladder stomach pancreas

The human digestive system consists of a system continuous "one‑way" tube and the assisting accessory organs.

How is food processed in the mouth?

Oral Cavity

1. Oral Cavity (mouth) Ø Ingestion of food occurs through the mouth (oral) cavity which contains the teeth, tongue, and the openings from the salivary glands.

incisors cut (bite) food canines rip, grip, tear food

incisors premolars grind, crush food canines molars crush food

What is the function of the teeth?

ØThe teeth function in the mechanical breakdown of food which serves to increase the surface area of the food for enzyme action.

plaque

What are the functions of the tongue?

Functions of the Tongue pushes food around mouth and between teeth • mixes food with saliva • tastes the food - mmmm! •

Functions of the Tongue forms mass of food for swallowing • pushes food to the back of throat (pharynx) for swallowing •

What are those bumps on her tongue?

What is the tongue made of?

Tongue composed of skeletal muscle with an outer layer of mucous membrane

Taste Zones Bitter Sour Salt Sweet

WRONG!

Salivary Glands

Ø The chemical digestion of carbohydrates begins here. Ø The salivary glands secrete saliva which contains the enzyme amylase which digests starch into disaccharides.

Functions of Saliva • lubricates food • contains lysozyme • contains salivary amylase

This happens later on! (Not in the mouth) disaccharide monosaccharide

Composition of Saliva 95% water • mucus • salivary amylase • lysozyme •

uvula ?

Swallowing animation http: //www. youtube. com/watch? v=Yg_k. Aq. Blp 9 Y https: //www. youtube. com/watch? v=p. Nc. V 6 y. Afq-g https: //www. youtube. com/watch? v=b 20 VRR 9 C 37 Q Good for review of entire dig. system

How does food get to the stomach even if you’re upside down?

Peristalsis The wavelike muscular contractions that push food through the digestive tube

Peristalsis • http: //www. youtube. com/watch? v=YH 3 U_ SLp 9 G 0&feature=related • http: //www. youtube. com/watch? v=f 6 y 5 Syk bq. JE&feature=related

How is the action of peristalsis like surfing a wave?

Peristalsis

Endoscope

CHEW BEFORE YOU SWALLOW!

2. Esophagus Ø As a result of swallowing, food moves into the esophagus. Ø This begins the peristaltic action of the esophagus which moves the food to the stomach and through the GI tract.

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

stomach

Inside the Stomach

1. Stomach Ø The stomach is a muscular organ in which food is temporarily stored, liquefied to chyme, and where protein digestion begins. ØIts lining contains gastric glands which secrete enzymes and hydrochloric acid.

Stomach muscular organ stores food mechanical digestion

Stomach chemical digestion gastric juice pepsin and HCl chemically digests protein

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

·Chief cells: secrete pepsin, a proteolytic enzyme ·G cells: secrete the hormone gastrin

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

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

1) The chemical digestion of which nutrient begins in the stomach? 2) The _____ glands secrete _____ which contains the enzyme _______which digests starch into ________.

Ø Hydrochloric acid provides an optimum p. H for the hydrolytic activity of gastric protease. ØUnder the influence of this enzyme, proteins are digested into polypeptides and dipeptides (amino aicds).

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

A Gastric Ulcer

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

Bacteria cause ulcers

The Stomach

·Mucous cells: secrete an alkaline mucus that protects the epithelium against shear stress and acid ·Parietal cells: secrete hydrochloric acid! ·Chief cells: secrete pepsin, a proteolytic enzyme ·G cells: secrete the hormone gastrin

1) The chemical digestion of which nutrient begins in the stomach? 2) The _____ glands secrete _____ which contains the enzyme _______which digests starch into ________.

Ø Hydrochloric acid provides an optimum p. H for the hydrolytic activity of gastric protease. ØUnder the influence of this enzyme, proteins are digested into polypeptides and dipeptides (amino aicds).

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

Small intestine

Ø Accessory structures, the gall bladder and pancreas, empty their secretions into the small intestine. * The secretion from the gall bladder is bile. Ø Bile is produced in the liver and stored in the gall bladder.

liver gall bladder

liver gall bladder pancreas

fat bile fat

emulsification increases the surface area of fats for subsequent chemical action.

Ø Bile is not an enzyme, but a chemical that emulsifies (physically break apart) fat which serves to increase the surface area of fats for subsequent chemical action.

pancreas

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

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

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

esophagus liver rectum Gall bladder Small intestine

villi

microvilli Why does the small intestine have this structure? (folds, villi, microvilli)

3 1 2 1 –intestinal fold 2 – villi 3 – microvilli

Surface area of the small intestine

overview till stomach http: //www. youtube. com/watch? v=Q-n_Q 0 q. KXzg&feature=related Villi - freezes towards the end http: //www. youtube. com/watch? v=P 1 s. DOJM 65 Bc&feature=related villi http: //www. youtube. com/watch? v=_GTQBi. Zni 6 w&feature=related

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

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

Villus (small intestine) Lacteal Blood capillaries

Villus (small intestine) Lacteal Blood capillaries

villi

1) The gall bladder and pancreas secrete _____and _____ into the small intestine for chemical digestion. 2) What are three enzymes secreted by the pancreas?

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

Ø From there, they are available for distribution by the blood.

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

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

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

Feces Bacteria (50%) Cellulose Bile Mucous Dead cells

B. Mechanism for Chemical Digestion Ø Hydrolysis is the splitting of Hydrolysis large, insoluble molecules into small, soluble molecules with the addition of water. Ø In organisms, this process is regulated by hydrolytic enzymes and is illustrated by the following:

maltose + water maltase glucose + glucose amino acid + protease Proteins + water amino acid + amino acid lipids + water lipase 3 fatty acids + 1 glycerol

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

Constipation is a condition in which the large intestine is emptied with difficulty. Ø Too much water is reabsorbed due to sluggish peristaltic movement and the solid waste hardens.

Diarrhea is a gastrointestinal disturbance characterized by decreased water absorption and increased peristaltic activity of the large intestine. Ø This results in increased, multiple, watery feces. This condition may result severe dehydration especially in infants.

What is this?

Appendicitis is an inflammation of the appendix due to infection.

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

Gallstones

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

Gallstones

Place these in the correct order Correct order • • • Peristalsis Egestion Ingestion Digestion More Digestion Absorption Ingestion Digestion Peristalsis More Digestion Absorption Egestion

Design a controlled experiment to test the effect of pepsin concentration on the digestion of egg white Design an experiment to test the effect of substrate concentration on the activity of pepsin Design an experiment to find the optimum p. H for the activity of pepsin

Design an experiment to find the optimum p. H for the activity of pepsin 1 2 3 4 HCL pepsin water HCL 1 capillary tube

Design an experiment to test the effect of substrate concentration on the activity of pepsin 1 2 3 4 pepsin water HCL 5 g protein 10 g protein 15 g protein 10 g protein

Design a controlled experiment to test the effect of pepsin concentration on the digestion of egg white 1 2 3 4 10 ml pepsin 15 ml pepsin 25 ml pepsin 10 ml water 10 ml HCL 10 ml HCL 1 capillary tube