Unit 5 Notes: Digestion Basics, The Mouth, and The Esophagus

(1) Digestion Basics Organs: Functions: Oral Cavity Esophagus Stomach Small Intestine Large Intestine Functions: Metabolize biomolecules. Absorb useful nutrients into blood stream. Excrete waste, irritating or non-useful compounds.

(2) Dig. In The Mouth Both Mechanical & Chemical Digestion Mechanical: Teeth chewing + grinding breaks down food into smaller units Chemical: Enzymes in saliva breaks down parts of food

(3) Saliva & Digestion Saliva = Spit Lubricates food for esophageal transfer Contains an enzyme called AMYLASE… Breaks down starch  maltose

(4) Saliva Reflexes Parasympathetic release of saliva Causes: Pressure in mouth Smell / Sight of food Thinking about food Emotional connection to food

(5) Bolus Bolus = chewed up food, mixed with saliva. Bolus travels from mouth  esophagus.

(6) Deglutition Buccal Phase (Voluntary): (A.K.A. – Swallowing) Buccal Phase (Voluntary): Tongue moves bolus into pharynx Pharyngeal-Esophageal Phase (Involuntary): Epiglottis closes over larynx Bolus moves into esophagus

(7) In The Esophagus Bolus moves from esophagus  stomach Food moves through esophagus using PERISTALSIS: Peristalsis = Involuntary contraction of muscle Wave-like contractions push food down Like a tube of toothpaste!