PowerPoint Presentation - The Human Digestive System

THE NUTRITION FUNCTION I.The digestive system.

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The nutrition function.Taking in of nutrients(found in food) which are organic substances and mineralions, containing raw materials or energyfor growth and tissue repair, absorbing andassimilating them.In multicellular organisms, several systems take part in this function.Digestive system.Respiratory system.Circulatory system.Excretory system.

Intimately interlinked.

Endocrine and nervous system also participate.

Digestive System Processes.Ingestion : Intake of food into the body through mouth.Digestion: The process ofbreak-down of large,insoluble food molecules into small, water solublemolecules using mechanical andchemical processes.Absorption : The process of passing digested food molecules across the wall of the intestine into the blood or lymph.Assimilation : The movement of digested food molecules into the cells of the body where they are used, becoming part of the cells.Egestion :Passing out of undigested food, in theform of faeces, through the anus.

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(physical)Enzymatic reactions to improve digestion of

Digestive System OrganizationGastrointestinal tract.Accessory glands.

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Digestive System OrganizationGastrointestinal tract. Direct link/path between organs, 8m. Shape varies. Secrete mucus (mjuks) or digestive juices.StructuresMouthPharynxEsophagusStomachSmall intestineLarge IntestineRectumAccessory glands.

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Digestive System Organization.Gastrointestinal tract.

Accessory organs.Not part of the path of food, but play a critical role.Include: Salivary glands, liver, gall bladder, and pancreas

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MouthEpiglottis is a flap-like structure at the back of the throat that closes over the trachea preventing the bolus from entering it.

CHEWING: Teeth mechanically break down food into small pieces. SALIVATION: Tongue mixes food with saliva (contains amylase (mlez), which helps break down starch).SWALLOWING: the tongue push the bolus towards the pharynx.

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Saliva (slav) is a watery liquid released by salivary glands.

Starts digestion of starch molecules: AMYLASE (mlez). Destroys some bacteria: LYSOZYME (laszam).Eases the bolus into the pharynx and esophagus: MUCIN (mjusn).

PHARYNXIt is a common passageway for air and food.It participates in swallowing

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EsophagusApproximately 20-25cm longFunctions include:Secretes mucusMoves food from the throat to the stomach using muscle movement called peristalsis (prstlss)If acid from the stomach gets in here thats heartburn (cardia at the entering of the stomach stops reflux).

15A good way to describe peristalsis is an ocean wave moving through the muscle.These diagrams dont separate the esophagus from the mouth functions, you might want to talk about what happens in the mouth too.

StomachJ-shaped muscular bag that stores the food you eat, and digests it.Mixes food with digestive juices that contain enzymes to break down proteins (pepsine) and lipids.HYDROCHLORIC ACID in the stomach kills bacteria, and supports enzymes work. It absorbs water, alcohol and some drugs.

Food in the stomach is called chyme (kam), once it has mixed with gastric juices.

The stomach takes around 4 hours to do its job on the food, depending on what kinds of food are digested.

17The stomach takes around 4 hours to do its job on the food, depending on what kinds of food are digested.

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Small IntestineSmall intestines are roughly 7 meters long, finishing in the ileocecal valve.

Intestine walls have finger-like projections called villi, to increase surface area.

The villi are covered in microvilli which further increases surface area for absorption.

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Small IntestineNutrients from the food pass into the bloodstream through the small intestine walls.

Establishes an optimal pH for enzymes.Secretes digestive enzymes.Absorbs:80% ingested water.Vitamins.Minerals.Carbohydrates.Proteins.Lipids.

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When the chyme mixes with intestinal juices, and secretions from liver and pancreas, it transforms into chyle (kal).

The first part of intestine (duodenum) receives following secretions.Pancreatic juice from pancreas.Bile juice from liver.

LiverDirectly affects digestion by producing bileBile helps digest fat.Filters out toxins and waste including drugs and alcohol.

Bile does not contains any enzymes.Bile contains bile salts which acts on fats.Bile salts break fats up into smaller fat droplets which can be more easily digested by lipase.

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23Livers can regenerate missing pieces if necessary. Is one of the largest organs in the body.

GallbladderStores bile from the liver, releases it into the small intestine. Bile is realeased through the ampulla of Vader.Fatty diets can cause gallstones.

24Explain to students that removing the stones typically means removing the gallbladder, but that the body eventually adjusts to not having the bile stored.

PancreasProduces digestive enzymes to digest fats, carbohydrates and proteins.Regulates blood sugar by producing insulin, a hormone.Pancreatic juice also neutralizes the acid liquid from the stomach.

25Explain the difference between the two types of diabetes. In type 1, the pancreas fails to produce enough insulin. In type 2, the body stops responding properly to the insulin it creates.

After digestion, simpler molecules are obtained:Monosaccharides. Glycerol and fatty acids.Amino acids.

Those nutrients are absorbed through the small intestine inner layer. Capillaries collect them.

Large IntestineAbout 15 m long.Accepts what small intestines dont absorb.

Functions Bacterial digestion Ferment carbohydrates Protein breakdownAbsorbs more water. Concentrates wastes.

27Depending on the maturity of the group, you can talk about the feces leaving via the anus.Mention the appendix at the bottom of the ascending colon and that it might have been used long ago but is not todayMention the (last one if the audience is mature enough)

Large Intestine

Portions of the large intestine, ascending, transverse, descending, sigmoid, and Rectum.

The rectum is the short term storage which holds feces before it is expelled).

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https://www.youtube.com/watch?v=8YXKklSxW30

Write the name of each colored organ:Green:Red:Pink:Brown:Purple:Green:Yellow:

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Howd you do?Green: EsophagusRed: StomachPink: Small IntestineBrown: Large IntestinePurple: LiverGreen: Gall BladderYellow: Pancreas

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References and LinksInner body: http://www.innerbody.com/Your Digestive System and How It WorksDigestive system diagram comes from this siteThe Real Deal on the Digestive SystemPancreas: Introduction and IndexYour Gross and Cool Body - Digestive System

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