Week 1 Flashcards
How is saliva produced?
It is a 2 stage process - initially isotonic containing NaCl, protein and mucus.
It then passes through the salivary duct where K+ and bicarbonate is secreted and salt is era sorted to form a alkaline fluid.
What does the soft palate and epiglottis do?
Prevents food going the wrong way, directs it to the oesophagus.
What is the neural control for water and mucoid secretion in saliva production?
Water: parasympathetic
Mucoid: sympathetic
What are the names of the 3 main salivary glands?
Parotid, submandibular and sublingual.
What secretions does the parotid produce and how much of the salivary volume does it release?
The parotid is mainly serous secretion.
Releasing 25% of the salivary volume
What enzymes/proteins does the parotid secrete?
Amylase and Proline.
What is the innervation of the parotid?
Parasympathetic via CN IX (glossopharyngeal)
Sympathetic via cervical plexuses.
What secretions and how much of salivary volume does the submandibular gland secrete?
The submandibular releases a serous and mucous mix.
70% of the salivary volume.
What enzymes/proteins does the submandibular release?
The submandibular releases lysozyme and lactopeptidase.
What is the innervation of the submandibular and sublingual gland?
Parasympathetic via CN VII
Sympathetic via superior cervical ganglion.
What secretions and how much of the salivary volume does the sublingual gland secrete?
Sublingual mainly secretes mucous
Contributing 5% to the salivary volume.
What enzyme/protein does the sublingual secrete?
Lingual lipase.
At what sites can amylase cut starch and other polysaccharides?
Alpha amylase can only cut at the alpha1-4 sites.
Starch has alpha1-4 sites and alpha1-6 sites.
What are the 3 types of tastebuds?
The 3 types are fungiform, filiform and circumvallate.
What sensors are salty and sour stimuli detected through?
Salty and sour stimuli are through ion channel based sensors.
How are sweet, Unami and bitter stimuli detected?
Sweet, Unami and bitter stimuli are through GPCR based sensors.
What does the cardia of the stomach secrete, and why?
The cardia secrets HCO3- to neutralise
What does the cardia of the stomach connect with?
The cardia of the stomach connects with the oesophagus.
What does the fundus and the body of the stomach secrete?
The fundus and body secrete: H+, intrinsic factor, mucus, HCO3-, pepsinogens and lipase.
What is the fundus and body used for?
The fundus and body are the main store area - half a litre to 1 litre.
What does the pylorus of the stomach secrete?
The pylorus secretes mucus (lubricant) and HCO3-
The pylorus is also focused on breakdown of foods
What is gastric motility?
It is an active process which involves the grinding and churning (antrum) by peristaltic waves to accept and accommodate food.
Emptying at the antrum and pylorus is caused by feedback from duodenum.
What is the vaso-Vaal reflex?
The vaso-vagal reflex allows lots of food to be stored in the stomach without a rise in pressure. Stretch receptors signal via the vagus.
A signal then descends to act on enteric nervous system which cause relaxation and dilation of fundus.
How is gastric emptying controlled?
Particles less than 1-2mm can only pass through pyloric sphincter.
The duodenum senses acid delivery, amino acids and lipids, so it secretes hormones (CCK, secretin GIP(gastric inhibitory peptide)) which decrease gastric motility and emptying.
