Master this deck with 21 terms through effective study methods.
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Maltose is a disaccharide sugar formed from two glucose units. It is digested by the enzyme maltase, which breaks it down into two glucose molecules.
The end products of digestion are glucose, amino acids, and fatty acids along with glycerol. These products are small, simple, and soluble, allowing for absorption by the epithelial cells of intestinal villi.
Glucose is absorbed into the blood through active transport, which requires energy to move glucose molecules against their concentration gradient into the bloodstream.
Saliva is alkaline (pH > 7) to provide an optimum pH for the enzyme salivary amylase, which begins the digestion of starch. It also neutralizes acids formed in the mouth to prevent tooth decay.
Peristalsis is a series of wave-like muscle contractions that move food through the digestive tract, specifically from the mouth to the stomach through the esophagus.
Gastric juice, composed of pepsin and hydrochloric acid, initiates protein digestion, provides an acidic environment (pH 2) for pepsin to function, and helps kill bacteria.
The stomach performs mechanical digestion of food, chemical digestion of proteins via pepsin and hydrochloric acid, kills bacteria, and stores food before gradually releasing it into the duodenum.
Bile is an alkaline fluid produced in the liver and stored in the gallbladder. It neutralizes the acidic mixture of food and gastric juice entering the duodenum and contains bile salts for emulsifying fats.
Pancreatic juice contains three key enzymes: amylase (digests starch), trypsin (digests proteins), and lipase (digests emulsified fats into fatty acids and glycerol).
The ileum completes the digestion of food and absorbs the digested nutrients. Enzymes present on the membranes of the epithelial lining facilitate the final breakdown of nutrients.
Bile salts are crucial for the emulsification of fats, breaking them down into smaller droplets to increase the surface area for lipase action, enhancing fat digestion.
Hydrochloric acid in the stomach creates an acidic environment that activates pepsinogen to pepsin, aids in protein digestion, and helps kill harmful bacteria ingested with food.
Mucus protects the stomach lining from being digested by pepsin and hydrochloric acid, preventing damage to the stomach wall.
The sphincter muscle at the bottom of the stomach relaxes to allow the gradual release of chyme into the duodenum, regulating the flow of partially digested food.
Emulsification is the process of breaking down large fat globules into smaller droplets, which increases the surface area for enzymes like lipase to act on, facilitating fat digestion.
Bile pigments, which are waste products from the breakdown of hemoglobin, are excreted with feces, contributing to the color of stool.
Pepsin is an enzyme that begins the digestion of proteins in the stomach by breaking them down into smaller polypeptides.
The low pH (around 2) of the stomach is optimal for the activity of pepsin, allowing it to effectively digest proteins, while inhibiting the activity of other enzymes that function better in neutral or alkaline conditions.
Digestion in the small intestine involves the breakdown of food into its constituent nutrients, which are then absorbed through the intestinal walls into the bloodstream for use by the body.
The alkaline nature of bile is significant because it neutralizes the acidic chyme from the stomach, creating a suitable pH for the action of digestive enzymes in the small intestine.
Epithelial cells in the small intestine have microvilli that increase surface area, allowing for efficient absorption of nutrients through diffusion and active transport mechanisms.