Swallowing + Saliva Flashcards
Which receptors are stimulated by food or drink?
Pressure receptors in the walls of the pharynx
Name the pharyngeal constrictor muscles.
Superior constrictor
Middle constrictor
Inferior constrictor
Which nerve supplies the pharyngeal constrictor muscles?
Pharyngeal branch of vagus nerve
Which nerve supplies the nasopharynx?
Maxillary nerve (V2 of trigeminal nerve)
Which nerve supplies the oropharynx?
Glossopharyngeal nerve
Which nerve supplies the laryngopharynx?
Vagus nerve
How many stages are there to swallowing? Which ones are voluntary and involuntary?
Stage 1: Voluntary
Stage 2: Involuntary
Stage 3: Involuntary
Describe stage 1 of swallowing.
- Food is compresses against roof of mouth and pushed towards oropharynx by tongue
- Buccinator and supra hyoid muscles allow chewing of food
Describe stage 2 of swallowing.
- Nasopharynx is closed off by soft palate - helps to form bolus of food
- Swallowing centre inhibits respiration, raises larynx and closes the glottis - prevents food from entering trachea. Epiglottis covers glottis.
- Pharynx is shortened and widened by elevation of the hyoid bone
What type of muscle surrounds the upper 1/3 of the oesophagus?
Skeletal
What type of muscle surrounds the lower 2/3 of the oesophagus?
Smooth
Describe stage 3 of swallowing.
- Pharyngeal constrictor muscles contract to drive the bolus of food down the oesophagus
- Upper oesophageal sphincter relaxes to let in food. Once food has passed, sphincter closes, glottis opens and breathing resumes
- Peristaltic waves move food down the oesophagus into the stomach - each wave takes 9 seconds to move food to stomach
- Lower oesophageal sphincter remains open and relaxed throughout swallowing
What is the gag reflex?
The reflex elevation of the pharynx. Caused by irritation of oropharynx. Reflex arc between glossopharyngeal and vagus nerves.
Give 3 functions of saliva.
- Lubricant for mastication
- Maintains oral PH at 7.4
- Releases digestive enzymes (alpha amylase) for starch digestion
What is released in the serous secretion of saliva?
Alpha amylase
What is released in the mucous secretion of saliva?
Mucins for lubrication of mucosal surfaces
Which salivary gland secretes serous solution?
Parotid gland
Which salivary glands secrete mucous and serous solution?
Submandibular gland Sublingual glans (mainly mucous though)
List the defences of the oral cavity.
- The mucosa - physical barrier
- Salivary glands - saliva washes away food with bacteria
- Palatine tonsils
- Salivary glands are surrounded by lymphatic system which contains immune cells
Name the two key epithelial tissue of salivary glands.
- Acinar cells (both serous and mucous)
2. Ducts (intralobular and main excretory)
Which nerve provides sympathetic innervation of the parotid gland?
Auriculo-temporal nerve - a branch of the mandibular nerve (a branch of the trigeminal nerve)
Which nerve provides parasympathetic innervation of the parotid gland?
Glossopharyngeal nerve
Which structures pass through the parotid?
External carotid artery
Retromandibular vein
Facial nerve
Which nerve provides sympathetic innervation of the submandibular gland?
Lingual branch of the facial nerve
Which nerve provides parasympathetic innervation of the submandibular gland?
Chorda tympani branch of facial nerve
Which nerve provides sympathetic innervation of the sublingual gland?
Lingual branch of facial nerve
Which nerve provides parasympathetic innervation of the sublingual gland?
Chorda tympani branch of facial nerve
Are the minor salivary glands serous or mucous?
They are all mucous apart from the serous glands of von Eber
What effect does parasympathetic innervation have on the salivary glands?
Stimulates salivary secretion
What effect does sympathetic innervation have on the salivary glands?
Inhibits salivary secretion
What is xerostomia?
Dry mouth - caused by cystic fibrosis, Sjorgren’s syndrome. Salivary output falls to <50%.
What name is given to stones formed from calcium and phosphate ions in the saliva?
Salivary calculi
Where are salivary calculi most common?
Submandibular gland
What is the clinical term for the tear ducts?
Lacrimal glands
What are the consequences of xerostomia?
Bad oral hygiene. Accumulation of plaque. Increased incidence of opportunistic infections
Poor lubrication
Which epithelium lines the lower oesophagus?
Simple columnar
