Ingestion
process of taking food into digestive tract
propulsion
process of moving food through GI tract
- swallowing
- peristalsis
swallowing vs. peristalsis
swallowing: initiated voluntarily
peristalsis: involuntary; alternate waves of contraction and relaxation of muscle
mechanical digestion
- chewing
- mixing with saliva (tongue)
- churning food in the stomach
- segmentation (small intestines)
chemical digestion
- secreted enzymes chemically digest and breakdown food
- begins in mouth
- completed in small intestine
absorption
- movement of products into blood or lymph
- primarily in small intestine
defecation
excretion of indigestible material
List the roles of salivation
- cleanses the mouth
- dissolves food chemicals so they can be tasted
- moistens & compacts food
- contains enzymes that begin digestion of starches
How is salivation controlled?
- stimulated primarily by the parasympathetic division of the autonomic nervous system in response to activation of chemoreceptors and pressoreceptors
- also triggered by: sight, smell, thought of food, irritations in the lower GI tract (bacteria, spicy food, excess acid)
- sympathetic division of ANS inhibits saliva secretion
Define xerostomia
dry mouth, low levels of saliva production
caused by:
- drug therapy with antihistamines, antidepressants, radiation of salivary glands
Describe stomatitis
- inflammation of one or more areas of the oral mucosa
Describe the cause of stomatitis
- can be due to microorganisms, trauma, chemotherapy, nutritional deficiencies; occurs in individuals with aids
- includes cold sores caused by Herpes simplex virus
Describe angular stomatitis
erosive inflammation with cracking, even ulceration at the corners of the mouth
Describe the cause of angular stomatitis
- risk factors include lack of vitamin B2
- iron-deficient anemia, possibly followed by secondary opportunistic fungal or bacterial infection coming from saliva
- mask wearing
oral thrush
white lesions of Candida albicans on the tongue
mumps
- inflammation of parotid glands (myxovirus)
- in adult males, 25% risk that the testes can be infected and increase testicular temp
tumours of the oral cavity
uncommon and usually benign
infections, stones, or tumours in the salivary glands and treatment
symptoms: swelling of the gland when eating (due to the production of saliva being stimulated)
treatment:
- antibiotics for infection
- dissolve the stones or use a needle to remove them
achalasia
- uncommon disorder of esophageal motility
- decreased peristalsis of esophagus
- loss of tone of GE sphincter in between meals
- decreased relaxation of GE sphincter is response to swallowing
- degeneration of esophageal ganglion cells & atrophy of smooth muscle
