Digestive System Chemical Digestion of Food

Submaxillary Gland

The Small Intestine.  It is a tube 3cm in diameter and 7m long.  The small intestine is divided into three parts: Duodenum – 1 st 25cmDuodenum – 1 st 25cm Jejunum – 2m longJejunum – 2m long Ileum – 5m longIleum – 5m long

The Large Intestine or Colon  Tube 7cm in diameter.  1 1/2m long  An upside down “U”

Sugars – The Simplest Carbohydrates. Monosaccharides are the simple (single sugars) Ex.: Glucose, Fructose, and Galactose. Disaccharides are composed of two monosaccharides linked together. Ex.: Glucose + glucose  Maltose Glucose + fructose  Sucrose Glucose + fructose  Sucrose

Sugars – the simplest sugars (continued)  Polysaccharides are composed of many monosaccharides joined together into long chains. Ex.: glucose + glucose + glucose + glucose  Starch (there could be hundreds of monosaccharides joined together). Other examples of polysaccharides are: glycogen (animal starch), cellulose, and pectin (can not be digested in humans)

Modern Biology, 1987

Carbohydrates

Carbohydrates - Starches

Proteins Chains of Amino Acids

Fats (Lipids)

Digestion of Carbohydrates

Digestion of Protein

Digestion of Fats

Digestion in Humans Organ Major Physical Activities Major Chemical Action MouthChewingGrindingMoistening Starch→ Disaccharide amylase

Digestion in Humans Organ Major Physical Activities Major Chemical Action EsophagusPersistalsisMoistening None None

Digestion in Humans Organ Major Physical Activities Major Chemical Action StomachMoisteningChurningPeristalsisTwisting Proteins → Smaller Chains of Amino Acids of Amino Acids pepsin

Digestion in Humans Organ Major Physical Activities Major Chemical Action Small Intestine Peristalsis Fat Emulsification Most nutrient ABSORPTION From Pancreas: Starch→ Disaccharide Proteins → Smaller Chains of A.A. Chains of A.A. amylase trypsin

Digestion in Humans Organ Major Physical Activities Major Chemical Action Small Intestine (cont’d) Smaller Chains → Free Of A.A. A.A. Fats → Fatty acids and glycerol glycerol erepsin lipase

Digestion in Humans Organ Major Physical Activities Major Chemical Action Small Intestine (cont’d) Dis’rides → Monos’rides Maltose → Glucose enzyme maltase

Digestion in Humans Organ Major Physical Activities Major Chemical Action Small Intestine (cont’d) Lactose → Glucose Sucrose → Glucose lactase sucrase

Digestion in Humans Organ Major Physical Activities Major Chemical Action Large Intestine Peristalsis Water Absorption Waste Elimination Some vitamins (B12) are synthesized here.

How Your Body Works, p. 118

How the Body Works, p. 119

How Your Body Works, p. 116.

How Your Body Works, p. 116