Physiology of Mastication Swallowing Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Describe the mechanisms involved in chewing.

A
  1. Mechanical breakdown:
    - Grinds and breaks up food into smaller pieces.
    - ^ surface area for salivary enzymatic digestion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe the mechanisms involved in salivation.

A
  1. Lubrication:
    - Mix food with saliva (salivary amylase), starts enzymatic digestion.
    - Facilitates swallowing softens and lubricates food (mucus).
    - Stimulates taste buds: reflex= ^ in salivary, gastric, pancreatic and bile secretion to prepare for arrival of food.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

List the salivary glands.

A
  • Parotid glands 20-25% largest and saliva is serous/ watery
  • Submandibular glands 70-75% (major and mixed serous + viscous)
  • Sublingual glands 3-5% most viscous saliva
  • Minor glands
    *Total production = 1-2 Litres/ day.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

List the composition of saliva.

A
  • 99.5% H2O; 0.5% electrolytes and protein.
  • Proteins:
    1. Salivary α-amylase (starch)
    2. Lingual lipase (dietary lipids)
    3. Mucins (glycoproteins)
    4. IgA and lysozyme (immune defence)
  • Hypotonic: Low Na+ and Cl-, high K+ and HCO3-
  • pH 6.0 - 8.0
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

List the functions of saliva.

A
  • Begins digestion of dietary starches
  • Lubrication facilitates swallowing
  • Oral Hygiene:
    1. Antibacterial action: Lysozymes: lyses and destroys certain bacteria. IgA: respond to bacteria and maintain homeostasis of oral microbiota.
    2. Buffering: rich in bicarbonate buffers, neutralise acids from food and bacteria
    3. Flushes away food particles, epithelia etc.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Explain the control of salivary secretion and xerostomia.

A
  • Xerostomia: dry mouth resulting from reduced or absent saliva flow.
    1. Simple (unconditioned) salivary reflex:
  • Chemoreceptors and pressure receptors respond to pressure of food.
  • Initiate impulses in afferent nerves to salivary center.
  • Parasympathetic efferent impulses via extrinsic autonomic nerves transmitted to salivary glands = ^ salivation.
    2. Acquired (conditioned) salivary reflex:
  • Occurs without stimulation
  • Learned response based on experience (thinking, smelling)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Outline the oral phase of swallowing/ deglutination.

A
  • Oral / Buccal (voluntary) bolus is rolled from mouth to pharynx.
  • Involves: Masticatory, buccinator, floor of mouth, lips (orbicularis oris muscle), tongue.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Outline the pharyngeal phase of swallowing/ deglutination.

A
  • Pharyngeal reflex: bolus moves from pharynx to oesophagus.
  • Involves palate, pharynx, larynx, and tongue.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Outline the oesophageal phase of swallowing/ deglutination.

A
  • Oesophageal reflex: bolus moves from oesophagus to stomach.
  • Involves UES, LES, closure of nasopharynx, raising of larynx, epiglottis closing, peristalsis.
    *LES= lower oesophageal sphincter.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the control of the lower oesophageal sphincter and its role in achalasia.

A
  • Impaired swallowing due to excess LES tone, weak oesophageal peristalsis and failure of LES relaxation.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Identify the causes of vomiting and the reflexes involved.

A
  • Defence mechanism of GI tract to elimination of harmful substances.
  • Pharyngeal (gag) reflex (vagus nerve).
  • Stimulation of vomiting (emetic) centre in medulla, integrates input and modulates response
    to noxious stimuli, multiple pathways
How well did you know this?
1
Not at all
2
3
4
5
Perfectly