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Unit 5 Notes: Digestion Basics, The Mouth,
and The Esophagus
• Organs:– Oral Cavity– Esophagus– Stomach– Small Intestine– Large Intestine
• Functions:– Metabolize biomolecules.– Absorb useful nutrients into blood stream.– Excrete waste, irritating or non-useful compounds.
(1) Digestion Basics
(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(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!