GI 3 - Salivation + Swallowing Flashcards Preview

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Flashcards in GI 3 - Salivation + Swallowing Deck (30):

What are the functions of saliva?

- 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


Approx. how much saliva do we produce per day?

1.5 L


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

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


Name the 3 salivary glands:

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


Do the salivary glands secrete serous or mucous fluids?

Parotid = serous
Submandibular = seous + mucous
Sublingual = mucous


List the constituents of saliva:

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


Name the 2 cell types responsible for saliva production:

- Acinar cells
- Ductal cells


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



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

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


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

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


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

- Becomes more isotonic
- More alkaline
- Higher enzyme content


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

Submandibular + Sublingual = CN VII (Chorda Tympani)
Parotid = CN IX Glossopharyngeal


Are the salivary glands stimulated by parasympathetic or sympathetic fibres?

Parasympathetic fibres


How can otitis media lead to a dry mouth?

- 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


What is xerostomia? What can it be caused by?

Dry mouth

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


What are the complications of xerostomia?

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


What are some causes of parotiditis?

- Viral infection (mumps, AIDs)
- Bacterial infection (s.aureus)
- Stone
- Tumour
- Diabetes
- Alcoholism
- Bulimia


Why is parotiditis painful?

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


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

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


Name the 3 phases of swallowing:

1) Oral
2) Pharyngeal
3) Oesophageal


Do the vocal cords abduct or adduct during swallowing?

Adduct, to protect the airways


How long is the oesophageal phase of swallowing?

~ 9 seconds


How do babies breathe and swallow at the same time?

- 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


Which cranial nerves are involved in the gag reflex?

CN IX Glossopharyngeal = afferent
CN X Vagus = efferent


Name the afferent nerve of the gag reflex:

CN IX glossopharyngeal


Name the efferent nerve of the gag reflex:

CN X vagus


What is GORD?

Gastro-Oesophageal Reflux Disease
- Stomach contents regurgitate up oesophagus due to incompetent lower oesophageal sphincter
- Results in heartburn, cough, sore throat, dysphagia


What are the risk factors for GORD?

- Obesity
- Pregnancy
- Hiatus hernia
- Smoking
- Alcohol


What are the common complications of GORD?

- Oesophagitis
- Oesophageal stricture
- Oesophageal ulcer
- Barrett's oesophagus


What is the treatment for GORD?

- Lifestyle changes
- Antacids
- H2 antagonists
- Proton pump inhibitors
- Surgery

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