Physiology of Mouth, pharynx and oesophagus Flashcards Preview

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Flashcards in Physiology of Mouth, pharynx and oesophagus Deck (22)
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1
Q

What are the functions of saliva?

A

Lubricates food for swallowing
Helps with taste
Digestion (starch and lipids)
Protects oral cavity (destroy bacteria, alkaline environment)

2
Q

How much saliva is produced each day?

A

800 - 1500ml each day

3
Q

What is the pH range for saliva?

A

pH 6.2 - 8.0

4
Q

Is saliva hypotonic or hypertonic?

A

Hypotonic

5
Q

If a solution has high osmolarity/osmolality, does it have high or low concentration?

A

High concentration

6
Q

What ions is saliva composed of?

A

High [K+], [HCO3-] and [Ca2+] (relative to plasma)
Low [Na+] and [Cl-] (relative to plasma)
thiocynate ions (antibacterial)

7
Q

What enzymes is saliva composed of?

A

Digestive enzymes – salivary α-amylase, lingual lipase

Antibacterial agents – thiocynate ions, proteolytic enzymes (e.g. lysozyme), antibodies

8
Q

What is the difference between serous and mucous saliva?

A

Serous - has enzymes

Mucous - no enzymes

9
Q

Describe the structure of salivary glands.

A

Bunch of grapes appearance
Initial secretion by acini (lined by acinar cells). Ducts (lined by duct cells) modify this secretion. Myoepithelial cells contract to eject saliva

10
Q

What modifications happen at the ducts for saliva production?

A

Absorption of Na and Cl from saliva
Secretion of K and HCO3 into saliva
Ductal cells impermeable to water, so saliva is hypotonic

11
Q

What occurs in primary secretion of saliva production?

A

Isotonic ultrafiltrate from plasma diffuses through acinar cells.
Mixes with enzymes or mucins and drains into ducts

12
Q

What type of saliva is highly modified (resting or stimulated)?

A

Resting - very hypotonic and neutral pH. Slaiva flow rate is lower and so more time for ductal modification

13
Q

Which ion is selectively stimulated when saliva production is stimulated?

A

HCO3 - (increases with increasing flow rate)

14
Q

What is xerostomia?

A

Dry mouth

15
Q

What are some causes of xerostomia?

A

dehydration, side effects, radiation therapy, Sjögren’s syndrome (autoimmune destruction of salivary and lacrimal glands)

16
Q

What are the 5 taste classifications?

A

Sweet, sour, bitter, salty and umami

17
Q

What kind of receptors are taste receptor cells?

A

Chemoreceptors

18
Q

What is the lower oesophageal sphincter? and its function?

A

Physiological sphincter at the gastro-oesophageal junction
Prevents reflux of gastric contents into the oesophagus
Higher resting basal tone

19
Q

What 4 components form the ‘physological sphincter’ (Lower oesophageal sphincter)

A

Right crus of diaphragm
Acute angle of oesophagus entering stomach
Mucosal folds at the junction
+ve intra-abdominal pressure

20
Q

What are the three phases of swallowing?

A

Oral, pharyngeal and oesophageal

21
Q

What happens in the pharyngeal phase of swallowing?

A

Soft palate elevates – blocks of nasopharynx
Respiration inhibited
Glottis closes
Larynx elevates
Epiglottis tilts to cover opening of larynx

22
Q

What type of clinician can assess dysphagia?

A

Speech and language therapists (SALT)