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Presentation on theme: "Digestion."— Presentation transcript:

1 Digestion

2 Colorado State Established in 1870, Fort Collins Colorado.
College Highlight: Colorado State Established in 1870, Fort Collins Colorado. Ranked nationally for its science and engineering programs

3 What is Digestion? The process of converting food into simpler molecules that can be absorbed by cells and used within the body.

4 The Digestive System Mainly Includes:
The mouth Esophagus Stomach Small Intestine Large Intestine Rectum

5 Accessory Organs An organ that helps with digestion but is not part of
the digestive tract. These organelles add secretions to the digestive system Salivary Glands Tongue Pancreas Liver Gallbladder

6 The Mouth Teeth physically break apart food
The process of chewing begins the early stages of mechanical digestion Digestive enzymes released from salivary glands begin breaking down carbohydrates into smaller molecules (chemical digestion)

7 Saliva Helps to moisten food Makes food easier to chew
The amount of saliva released is controlled by the nervous system You often produce saliva in the presence of the smell of food Saliva contains salivary amylase, an enzyme that breaks the bonds of starches into sugar (glucose)

8 Esophagus Esophagus is most commonly referred to as the food pipe
It connects the throat (pharynx) to the stomach Once the food is chewed and becomes a clump it is referred to as the bolus The bolus is propelled down the throat via peristalsis

9 Peristalsis Peristalsis is the contraction of the throat that moves the bolus downwards towards the stomach

10 Epiglottis The epiglottis is a flap of connective tissue that separates the trachea away from the esophagus

11 Stomach The esophagus empties the bolus into the stomach
Large muscular sack that continues mechanical and chemical digestion The three layers that churn and mix food with mucus and gastic juice secreted from the lining of the interior of the stomach Extremely acidic with a pH of 1 Mucus functions to protect the interior lining of the stomach from itself

12 Stomach Cont High acidity activates pepsin an enzyme that begins the digestion of protein Because enzymes that break down carbohydrates cannot function in high acidity they no longer break down carbohydrates in the stomach Chyme is what is produced by the stomach Chyme travels from the stomach through the pyloric valve into the small intestines

13 The Small Intestines Small intestines is made up of three parts, the duodenum, the jejunum and the ileum 6-7 meters long Secretes peptidase that breaks dipeptides into amino acids Secretes other enzymes that break down disaccharides into monosaccharides

14 The Pancreas Does not directly participate in digestion
A gland that secretes the enzymes amylase, trypsin, and lipase into the small intestines Amylase breaks down carbohydrates Trypsin breaks down proteins Lipase breaks down lipids

15 Liver Aids the pancreas Has right and left lobe
Produces bile, a fluid that consists of lipids and salts. Bile dissolves and disperses fat droplets found in fatty foods Bile is stored in the gallbladder


17 Absorption in Small Intestines
Villi are fingerlike projections that line the surface of the small intestine They are adapted for the absorption of nutrients Villi are covered in more projections called microvilli The increased amount of surface area allows for rapid absorption of nutrients By the time the food is leaving the small intestines it has been depleted of all its nutrients


19 Large Intestines Also known as the colon
Functions to remove water from undigested material Water is absorbed quickly across the wall of the large intestines The concentrated waste that remains once water has been removed is excreted out of the body through the rectum

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