NUTRI: DIGESTION AND ABSORPTION

• Digestion is the body’s ingenious way of breaking down foods into nutrients in preparation for absorption.
• Absorption is the uptake of nutrients by the cells of the small intestine for transport into either the blood or the lymph.
• The Gastrointestinal (GI) tract is a flexible muscular tube that extends from the mouth, through the esophagus, stomach, small intestine, large intestine, and rectum to the anus.
• The lumen is the inner space within the GI tract.
• The mouth frames the oral cavity, which contains four basic taste sensations: sweet, sour, salty, bitter, and umami.
• The tongue provides taste sensations and moves food around the mouth, facilitating chewing and swallowing.
• The parotid glands are the largest of the salivary glands and are located just anterior and inferior to the pinna (auricle) of the ear.
• Salivary glands are housed within the mucous membranes of the mouth and tongue.
• The pharynx receives food and air from the mouth, and air from the nasal Cavities.
• The esophagus is a muscular tube that connects the pharynx to the stomach, approximately 25.4 cm (10 in) in length, located posterior to the trachea.
• The esophagus has a sphincter muscle at each end.
• The stomach has four main regions: cardia, fundus, body, and pylorus.
• Gastric juice contains two main enzymes: pepsin and rennin.
• Pepsin is a stomach enzyme that serves to digest proteins found in ingested food.
• The small intestine secretes enzymes that digest all energy-yielding nutrients to smaller nutrient particles; cells of wall absorb nutrients into blood and lymph.
• The large intestine, or colon, has a primary function of finishing absorption of nutrients and water, synthesizing certain vitamins, forming feces, and eliminating feces from the body.
• Accessory Organs of Digestion include the liver, pancreas, and gallbladder.
• Bile is the greenish-yellow fluid (consisting of waste products, cholesterol, and bile salts).
• Peristalsis is a wavelike muscular contraction of the GI tract that pushes its contents along.
• Segmentation is the circular muscles of the intestines rhythmically contracting and squeezing their contents.
• Villi are fingerlike projections from the folds of the small intestine; singular villus.
• Microvilli are tiny, hairlike projections on each cell of every villus that can trap nutrient particles and transport them into the cells; singular microvillus.
• Probiotics are living microorganisms found in foods and dietary supplements that, when consumed in sufficient quantities, are beneficial to health; pro = for, bios = life.