BIOL 103 Study Guide - Final Guide: Gastric Acid, Gastrointestinal Tract, Bile Acid
24 Jul 2016
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Mucus: viscous mixture of water, salts, ells and slippery glycoproteins, protects lining of mouth from abrasion and lubricates food pharynx: opens to esophagus(stomach) and trachea(windpipe leads to lungs) tongue: shapes food into ball of food called bolus. Esophagus: peristalsis: allows propulsion and rhythmic cycles of food without gravity striated (active during swallowing) and smooth muscle (peristalsis) Stomach: stores food and begins digestion of proteins secretes gastric juice (hcl and pepsin) to mix with ingested food to create chyme. Hcl disrupts extracellular matrix that binds cells together in meat and plant material, ph of 2 denatures proteins. Pepsin: acid converts pepsinogen to pepsin (protease) which begins breakdown and digestion of exposed peptide bonds from hcl. Chemical digestion by gastric juice facilitated by churning action of the stomach, mixing stomach contents. Site of most enzymatic hydrolysis of macromolecules from food. Duodenum: first 25 cm, chime from stomach mixes with digestive juices from pancreas, liver, and gallbladder and epithelial cells.
