Oral and Esophageal Physiology Flashcards
What is the function of mastication?
Forms round bolus for deglutition
What nerve controls the muscles of mastication?
V3 (Mandibular branch of the Trigeminal nerve)
Achalasia
Increased esophageal tone at lower esophageal sphincter
GERD
Decreased esophageal tone at upper esophageal sphincter
What are the main muscles of the lips?
Orbicularis Ori
What are the main muscles of the cheek?
Buccinator
What are the main muscles of mastication?
Masseter, Temporalis
What are the main muscles of opening jaw/grinding?
Lateral Pterygoid Muscles (lowering jaw and moving sideways)
What are the functions of Saliva?
- Digestive
- Additional
- Protective
- Other examples
What are the protective functions of saliva?
- Dilution
- Buffering
- Lubrication
- Remineralization
- Antimicrobial actions
- Healing
- Cleansing
What are other examples of functions of saliva?
- Grooming
- Thermoregulation
- Olfactory signals
What are Additional examples of functions of saliva?
- Speech
- Excretion
- Trophic
- Social interaction
What are Digestive examples of functions of saliva?
- Chewing
- Bolus formation
- Swallowing
- Amylase, Lipase
- Taste
What are two main functions of Saliva?
- Has amylase which initiates digestion of carbohydrates
2. Creates lubrication/gel surrounding bolus
What secretes saliva?
Lobulated Exocrine Gland
What is the function of duct cells?
Acinus and ionic content of saliva is modified by duct cells.
What are seven components in salivary secretions?
- Water
- Digestive enzymes: salivary alpha-amylase (ptyalin), lingual lipase, RNAse, DNAse
- Mucins
- Defense molecules: Lysozyme, secretory immunoglobulin (IgA), lactoferrin, peroxidase, defensins
- Epidermal and nerve growth factors
- Bicarbonate
- Sex hormones
What suggests an endocrine role of saliva as well?
Some salivary substances are secreted into the blood, suggesting endocrine role.
What are the two types of salivary glands?
- Serous (watery, amylase)
2. Mucous (mucin) cells contain serous demilunes
What controls saliva flow rate?
Myoepithelial cells
How much saliva is produced/day?
1.5 L/day
What is the percentage of saliva produced by the parotid glands?
25% volume
What is the percentage of saliva produced by the submandibular glands?
70% volume
What is the percentage of saliva produced by the sublingual glands?
5% volume
What is the Parotid saliva made up of?
Entirely serous, watery
What is the submandibular saliva made up of?
Mixed serous and mucous
What is the sublingual saliva made up of?
Mainly mucous saliva
Why is saliva an alkaline solution?
Salivary duct cells secrete K+, HCO3-, Ca++, Mg++, phosphate to prevent demineralization of the tooth enamel and are impermeable to water
What is the pH of the oral cavity?
6.3
What is the oral cavity pH associated with?
When food is consumed, carbohydrates –> are fermented by bacteria producing lactic acid.
What nerves control the parasympathetic autonomic nervous system that controls saliva secretion?
Glossopharyngeal and facial
What nerves control the sympathetic autonomic nervous system that controls saliva secretion?
Cervical sympathetic chain
How does the parasympathetic ANS control saliva secretion?
Acts through VIP and ACh on muscarinic receptors to increase secretion of watery saliva.
How does the sympathetic ANS control saliva secretion?
Acts through NE on beta1-and alpha1 adrenergic receptors to secretion of viscous saliva.
What things stimulate the salivary nucleus of the medulla?
Higher centers Esophagitis Vomiting Water Brash Pressure in mouth
What things neg. stimulate the salivary nucleus of the medulla?
Sleep
Fatigue
Fear
What things stimulate the higher centers of the salivary pathway?
- Smell
- Taste
- Sound
- Sight
Mastication:
Mechanical digestion by teeth and tongue
Salivary amylase:
Activated by Cl- in saliva and hydrolyzes alpha-1,4 glycosidic linkages in starch. Active until acid penetrates the bolus
Lingual lipase:
Breaks down triglycerides
When are salivary enzymes increased?
During pancreatic insufficiency and in neonates
What functions is the tongue critical for?
Clearing obstructions, initiating swallowing, speech and taste
What innervates the tongue muscle?
Hypoglossal (XII)
What nerves terminate in the nucleus of the tractus solitariuss?
Glossopharyngeal (IX) and Facial (VII) sensory fibers