DIGESTIVE SYSTEM Digestion Absorption and Transportation of Nutrients

DIGESTIVE SYSTEM Digestion, Absorption, and Transportation of Nutrients

Food enters the oral cavity where it is masticated and mixed with saliva. • Oral Cavity • Mastication • Salivary Amylase

A bolus is formed then swallowed. • Oral Cavity • Bolus formation • Pharynx • Swallowing reflex

Peristalsis moves the food mass through the esophagus. • Esophagus • Peristalsis • Mucus

The lower esophageal sphincter opens to allow food to pass into the stomach. • Esophagus/stomach • Lower esophageal sphincter

The food mass is combined with hydrochloric acid. It is mixed, churned, and liquefied to a substance called chyme. • Stomach • Rugae • Peristalsis • Hydrochloric Acid • Enzymes • Mucus • Formation of chyme

The pyloric sphincter opens to allow passage of small amounts of digestive product into the small intestine. • Stomach/small intestine • Pyloric sphincter

Hormones, secretin and CCK, signal the release of sodium bicarbonate, bile, and pancreatic enzymes. • Small Intestine • Digestion • Secretin • Bile production • Sodium bicarbonate secretion • CCK • Bile secretion • Pancreatic enzyme secretion • Peristalsis

Macronutrients are broken down completely to their simplest counterparts. • Small intestine • Carbohydrates • Monosaccharides • Fats • Fatty acids • Monoglycerides • Proteins • Amino acids

Products of digestion are absorbed through the villi. Villi Microvilli Blood capillaries Lacteal

Fat-soluble nutrients enter the lymph and water-soluble nutrients enter the blood. Villi Microvilli Blood capillaries – amino acids, monosaccharides Lacteal – fatty acids, monoglycerides

Products of digestion that are not absorbed move into the large intestine in preparation for elimination. • Large Intestine (colon) • Salts (absorbed here) • Other waste products • Fiber • Undigested material • Water • Bacteria

Water is absorbed and waste is excreted. • Large Intestine • Water • Feces produced • Rectum/Anus • Excretion

The Digestive System • Alimentary canal • Mouth • Pharynx • Esophagus • Stomach • Small Intestine • Large Intestine • Accessory organs • Liver • Gall Bladder • Pancreas