L4 From start to finish

Question 1

What are the major salivary glands?

Answer 1

• Parotid glands
• Sublingual gland
• Submandibular glands

Question 2

Where are the tonsils found?

Answer 2

The pharynx

Question 3

What is the role of saliva?

Answer 3

• Lubrication and cleaning
• Facilitation of taste
• Protection against acid and bacteria - through antibacterial enzymes, bicarbonate and calcium ions
• Digestion (salivary amylase and lingual lipase)

Question 4

How do we divide the tongue?

Answer 4

Into thirds - the posterior third and the anterior two third.

Question 5

How many deciduous teeth do we have?

Answer 5

20 - 10 at the top and 10 at the bottom

Question 6

How is saliva production controlled?

Answer 6

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

Question 7

What are the muscles of mastication?

Answer 7

• Masseter muscles
• Temporal muscles
• Temporalis
• Terigoid muscles open the mouth
• Pterygoid nerve

Question 8

Which cranial nerves affect the muscles of mastication?

Answer 8

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.

Question 9

What is the process of saliva production?

Answer 9

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.

Question 10

What is the main source of salivary amylase and proline-rich proteins?

Answer 10

Parotid gland

Question 11

Parotid gland.

Answer 11

• 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

Question 12

Submandibular gland

Answer 12

• 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)

Question 13

Sublingual gland

Answer 13

• 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

Question 14

What is the difference between taste sensors and odour receptors?

Answer 14

Taste sensors are specialised epithelia and odour receptors are nerve cells.

Question 15

What are the different stages of swallowing?

Answer 15

voluntary phase, pharyngeal phase and oesophageal nerve

Question 16

What is the cephalic phase of GI activity?

Answer 16

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.

Question 17

What nerve supplies the parotid gland?

Answer 17

CN IX Glossopharyngeal nerve

Question 18

What nerve supplies the submandibular gland?

Answer 18

CN VII Facial

Question 19

Which nerve supplies the sublingual gland?

Answer 19

CN VII Facial

Question 20

What is the cephalic phase of GI activity mediated by?

Answer 20

• 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.

Question 21

What is the optimum pH of amylase?

Answer 21

pH 7

Saliva is therefore partially alkaline to neutralise the bolus as it goes down into the proximal duodenum

Question 22

What is the optimum pH of lipase?

Answer 22

pH 4

Lingual lipase is stable in the stomach but denatured by pancreatic proteases, It works together with gastric lipase.