The mouth and oesophagus Flashcards
What is digestion?
The process of conversion of dietary nutrients into a form that the small intestine can absorb.
What are is the mouth?
The mouth is lined by mucous membranes - oral mucosa - makes sure secretions can work together properly.
Secretions in the mouth - saliva, salivary amylase, mucus and lysozyme.
What are lysozymes?
Lysozyomes are important as they have antimicrobial action, which makes sure microbes don’t enter the body.
What are the teeth?
Mastication - chewing the food.
Decreases the particle size so they have a larger surface area.
This allows better action of the digestive enzymes.
What is the tongue?
The papillae contain taste buds that has gustatory cells - taste receptors.
It prepares food for swallowing - cohesive bolus, so smooth transition into oesophagus.
Important for motility.
What is saliva?
The main secretion, containing mostly water, as well as electrolytes, mucus, amylase and lysozymes.
It is very important for motility, taste and cleaning the mouth.
Where does saliva come from?
There are 3 pairs of salivary glands innervated by the parasympathetic autonomic nervous system.
The submandibular gland produces the majority of the saliva, so if the other two glands are affected, the overall effect is not too big.
What is a salivary gland?
An exocrine gland - it contains branched ductal system which releases secretory products - saliva.
They produce serous secretions - protein, and mucous secretions - lubricant.
Dots ensure the secretions are carried to the right place.
What are acinar cells?
Round cells that produces saliva by transporting ions (Na, K, Cl) across cell membranes.
Also secrete enzymes, proteins and other substances.
Saliva is hypotonic and alkaline.
Why is saliva hypotonic?
Where saliva is produced it is isotonic - equal proportion of electrolytes and water.
By the time is travels around most of the ions are reabsorbed, so mostly water remains - hypotonic.
Why is it important saliva is alkaline?
Saliva is 6.2-7.6 pH, and has a buffering capacity.
This is important because it contains amylase which needs specific pH to work efficently.
What are Goblet cells?
Or ductal cells, these are for lubrication, hydration and cytoprotection.
It keeps the oral mucosa moist and prevents dehydration and cell death.
It protects oral and oesophageal mucosa from damage.
What is Sjogren’s syndrome?
Autoimmune condition that affects salivary and tear glands which results in dry mouth and eyes.
Associated with rheumatoid arthritis - commonly affects women.
What does dry mouth cause?
Reduced motility
Slow digestion
Infection
Less hydration can cause tooth decay
What is mumphs?
A viral infection that causes parotitis.
Bilateral swelling of the parotid gland.
Can be prevented by the MMR vaccine.
What is the oesophagus?
A muscular tube that connects the pharynx to the stomach.
The main secretion is mucus - for motility.
What are the muscle types of the parts of the oesophagus?
Upper third contains striated muscle, lower third contains smooth muscle, middle third contains a mixture of both.
What are the phases of swallowing?
Oral preparatory phase
Oral transport phase
Pharyngeal phase
Oesophageal phase
What is the oral preparatory phase?
Food is manipulated and masticated in the mouth, this increases the surface area and reduces the consistency so it can be swallowed.
What is the oral transport phase?
The tongue propels food posteriorly and prepares it to trigger the pharyngeal swallow.
What is the pharyngeal phase?
Once the pharyngeal swallow is triggered, bolus is transported through the pharynx.
This has coordinated closure of the epiglottis and cessation of breathing and relaxation of the upper oesophageal sphincter.
This ensures digestion isn’t mixed with respiration.
What is the oesophageal phase?
Oesophageal peristalsis carries the bolus from the upper oesophageal sphincter to the lower oesophageal sphincter.
It is involuntary, smooth muscle.
What is GORD?
Gastro-oesophageal reflux disease - where acid leaks from the stomach into the oesophagus.
Affects the lining of the oesophagus.
What are the causes of GORD?
Obesity, hernia, drugs which lower tone at the lower oesophageal sphincter, pregnancy and tumours.
