GI 3 - Salivation + Swallowing Flashcards

1
Q

What are the functions of saliva?

A
  • Protects oral cavity (keeps mucosa wet and neutralises bacterial acid)
  • Moistens and lubricates food
  • Begins digestion (enzymes)
  • Solvent for taste molecules
  • Can be involved in the transfer of disease
  • Allows structures to pass over each other smoothly, for phonation
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2
Q

Approx. how much saliva do we produce per day?

A

1.5 L

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3
Q

What percentage of total saliva production is produced by each gland?

A

~ 70% Submandibular gland
~ 25% Parotid gland
~ 5% Sublingual gland

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4
Q

Name the 3 salivary glands:

A

1) Submandibular gland
2) Sublingual gland
3) Parotid gland

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5
Q

Do the salivary glands secrete serous or mucous fluids?

A
Parotid = serous
Submandibular = seous + mucous
Sublingual = mucous
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6
Q

List the constituents of saliva:

A
  • Water
  • Mucins
  • Alpha-Amylase
  • Lingual lipase
  • Electrolytes
  • Kallikrein
  • Immune proteins (IgA, Lyzozyme, Lactoferrin)
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7
Q

Name the 2 cell types responsible for saliva production:

A
  • Acinar cells

- Ductal cells

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8
Q

When saliva leaves the acinus into the duct of the gland, is it hypotonic, isotonic, or hypertonic to plasma?

A

ISOTONIC

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9
Q

When saliva leaves the duct of the salivary gland, is it hypotonic, isotonic or hypertonic to plasma? Why?

A

HYPOTONIC
- Ductal cells remove Na+ and Cl- from saliva
- Tight junctions between ductal cells prevent movement of water
= Less ions = hypotonic

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10
Q

Saliva contains Kallikrein. How does this protease increase the blood flow to the salivary glands?

A

It produces bradykinin, which causes vasodilation allowing an increase in blood flow

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11
Q

How does saliva change at high flow rates (when stimulated by parasympathetic fibres)?

A
  • Becomes more isotonic
  • More alkaline
  • Higher enzyme content
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12
Q

The parasympathetic fibres to the salivary glands hitch-hike on cranial nerves to reach their destination. Which cranial nerves are involved?

A

Submandibular + Sublingual = CN VII (Chorda Tympani)

Parotid = CN IX Glossopharyngeal

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13
Q

Are the salivary glands stimulated by parasympathetic or sympathetic fibres?

A

Parasympathetic fibres

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14
Q

How can otitis media lead to a dry mouth?

A
  • Otitis media may damage Chorda tympani nerve which runs through the middle ear.
  • Chorda tympani contains the parasympathetic nerve fibres which stimulate the submandibular and sublingual salivary glands
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15
Q

What is xerostomia? What can it be caused by?

A

Dry mouth

  • Medications - antidepressants, antihistamines
  • Anxiety
  • Chemo- + Radiotherapy
  • Sjogrens autoimmune disease
  • Dehydration
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16
Q

What are the complications of xerostomia?

A
  • Increased plaque and tooth decay
  • Gum disease
  • Mouth sores
  • Fungal infections
  • Inflamed tongue
  • Difficulty eating
  • Poor taste
  • No seal for false teeth
17
Q

What are some causes of parotiditis?

A
  • Viral infection (mumps, AIDs)
  • Bacterial infection (s.aureus)
  • Stone
  • Tumour
  • Diabetes
  • Alcoholism
  • Bulimia
18
Q

Why is parotiditis painful?

A

Parotid gland is enclosed in tight sheath, so when inflamed it pushes against this sheath

19
Q

Where are the 4 main narrowings of the oesophagus? Why is it important to know these?

A

1) Junction of pharynx and oseophagus
2) Where crossed by arch of aorta
3) Where compressed by left main bronchus
4) Oesophageal hiatus

  • Help predict where foreign bodies have lodged
20
Q

Name the 3 phases of swallowing:

A

1) Oral
2) Pharyngeal
3) Oesophageal

21
Q

Do the vocal cords abduct or adduct during swallowing?

A

Adduct, to protect the airways

22
Q

How long is the oesophageal phase of swallowing?

A

~ 9 seconds

23
Q

How do babies breathe and swallow at the same time?

A
  • Larynx elevates, epiglottis enters nasopharynx like a ‘boulder in a stream’
  • Milk goes around epiglottis into oesophagus
  • Babies breathe through their nose at same time
24
Q

Which cranial nerves are involved in the gag reflex?

A

CN IX Glossopharyngeal = afferent

CN X Vagus = efferent

25
Q

Name the afferent nerve of the gag reflex:

A

CN IX glossopharyngeal

26
Q

Name the efferent nerve of the gag reflex:

A

CN X vagus

27
Q

What is GORD?

A

Gastro-Oesophageal Reflux Disease

  • Stomach contents regurgitate up oesophagus due to incompetent lower oesophageal sphincter
  • Results in heartburn, cough, sore throat, dysphagia
28
Q

What are the risk factors for GORD?

A
  • Obesity
  • Pregnancy
  • Hiatus hernia
  • Smoking
  • Alcohol
29
Q

What are the common complications of GORD?

A
  • Oesophagitis
  • Oesophageal stricture
  • Oesophageal ulcer
  • Barrett’s oesophagus
30
Q

What is the treatment for GORD?

A
  • Lifestyle changes
  • Antacids
  • H2 antagonists
  • Proton pump inhibitors
  • Surgery