L4 From start to finish Flashcards
What are the major salivary glands?
- Parotid glands
- Sublingual gland
- Submandibular glands
Where are the tonsils found?
The pharynx
What is the role of saliva?
- Lubrication and cleaning
- Facilitation of taste
- Protection against acid and bacteria - through antibacterial enzymes, bicarbonate and calcium ions
- Digestion (salivary amylase and lingual lipase)
How do we divide the tongue?
Into thirds - the posterior third and the anterior two third.
How many deciduous teeth do we have?
20 - 10 at the top and 10 at the bottom
How is saliva production controlled?
Almost entirely due to neural control
- Both parasympathetic (watery) and sympathetic (mucoid) activity increase secretion
- PS controlled by salivatory centre in the brain stem, driven by:
Local stimuli (taste and touch in the mouth)
- Central stimuli (smell & sight of food, etc)
(learned) reflex – think of Pavlov’s dogs
What are the muscles of mastication?
- Masseter muscles
- Temporal muscles
- Temporalis
- Terigoid muscles open the mouth
- Pterygoid nerve
Which cranial nerves affect the muscles of mastication?
Unlike most of the other facial muscles, which are innervated by the facial nerve (or CN VII), the muscles of mastication are innervated by the trigeminal nerve (or CN V). More specifically, they are innervated by the mandibular branch, or V3.
What is the process of saliva production?
A salivon is the secretory unit of the salivary gland A salivon consists of acinus, intercalated duct & striated duct Acinus secretes the basic materials of the saliva & as it passes through the intercalated and striated ducts undergoes modification and this final modified material is the saliva.
Initial isotonic fluid, containing (mainly) NaCl, protein, and/or mucus
As it passes along the duct, salt reabsorption and HCO3- (and K+) secretion leads to a hypotonic, alkaline fluid.
What is the main source of salivary amylase and proline-rich proteins?
Parotid gland
Parotid gland.
- Largest salivary gland
- Predominantly serous secretion
- About 50% of salivary volume
- Main source of salivary amylase and proline-rich proteins
- Parasympathetic supply via CN IX (glossopharyngeal)
- Sympathetic supply from superior cervical ganglion
Submandibular gland
- Mixed serous & mucous secretion
- About 45% of salivary volume
- Main source of lysozyme and lactoperoxidase
- Parasympathetic supply via CN VII
(facial -> chorda tympani -> lingual nerve) - Sympathetic supply from superior cervical ganglion (travels with facial artery)
Sublingual gland
- Predominantly mucous secretion
- About 5% of salivary volume
- Main source of lingual lipase
- Parasympathetic supply via CN VII (facial)
- Sympathetic supply from superior cervical ganglion
What is the difference between taste sensors and odour receptors?
Taste sensors are specialised epithelia and odour receptors are nerve cells.
What are the different stages of swallowing?
voluntary phase, pharyngeal phase and oesophageal nerve
What is the cephalic phase of GI activity?
The cephalic phase of digestion is the gastric secretion that occurs even before food enters the oral cavity. It results from the visual, olfactory, and auditory inputs to the brain induce anticipatory responses to prepare the gastrointestinal tract for the meal. The more intense is the stimulation.
What nerve supplies the parotid gland?
CN IX Glossopharyngeal nerve
What nerve supplies the submandibular gland?
CN VII Facial
Which nerve supplies the sublingual gland?
CN VII Facial
What is the cephalic phase of GI activity mediated by?
- Mediated by the parasympathetic nervous system
- Salivary secretion via facial and glossopharyngeal nerves (CN VII and IX)
- Control of GI motility and secretion via vagus (CN X)
- Vagus also carries afferent fibres which contribute – feedback system.
What is the optimum pH of amylase?
pH 7
Saliva is therefore partially alkaline to neutralise the bolus as it goes down into the proximal duodenum
What is the optimum pH of lipase?
pH 4
Lingual lipase is stable in the stomach but denatured by pancreatic proteases, It works together with gastric lipase.
