GI Salvia Flashcards
What is saliva?
A mix of water, electrolytes, mucus and enzymes.
Where is saliva produced?
In the salivary glands- parotid, submandibular and sublingual.
Where is unstimulated saliva mainly produced?
The submandibular glands.
Where is stimulated salvia mainly produced?
The parotid glands.
What type of saliva is produced from the parotid glands?
A serous, watery secretion.
What type of saliva is produced from the submandibular glands?
A mixed serous and mucous secretion.
What type of saliva is produced from the sublingual glands?
A predominantly mucous secretion.
What is the function of saliva?
It is a lubricant of mastication to allow swallowing and speach. It acts as a bicarbonate/carbonate buffer to quickly neutralise acids so the mouths pH remains at approx 7.2.
What cells are the salivary ducts made of?
Two types of epithelial cells acinar cells and ducts.
What are the types of acinar cells?
Serous and mucous.
What are serous acinar cells?
Small central ducts secreting water and alpha amylose. They are dark staining and have a nucleus in the basal third.
What are mucous acinar cells?
Large central ducts secreting mucous. They are pale staining and have nucleus in the base of the cell.
What are the two main types of ducts from small to large?
Interlobular ducts drain into the main excretory duct.
What parts are the interlobular ducts split into?
The intercalated and striated regions.
What are the intercalated interlobular ducts?
They are short narrow duct segments connecting the acini to larger striated ducts. They are made of cuboidal epithelium.
What are the striated interlobular ducts?
The major site of NaCl reabsorbtion. The basal membrane is highly folded and there are micro villi for large SA. HCO3- is pumped out against the concentration gradient. Cells are filled with mitochondria.
How is primary saliva different to the saliva at the in the main excretory duct?
Primary saliva is isotonic with an ionic composition resembling that of plasma. Through the interlobular ducts NaCl is reabsorbed and HCO3- is excreated into the saliva.
What is the defense function of the salivary glands?
Salivary glands secrete saliva which washes away food particles, bacteria and viruses. They are also surrounded by lymphatic systems which are linked to the thoracic duct and blood vessels.
What are the salivary flow statistics?
800-1500 ml a day, ph-6.2-7.4, flow rate- 0.3-7 ml/min.
What is the innervation of the parotid gland?
It recieves parasympathetic input from the glossopharyngeal nerve (CN IX) via the otic ganglion and sympathetic innervation from T1-T3 from the superior cervical ganglion.
What is the innervation of the submandibular gland?
Parasympathetic from the facial nerve (CN VII) via the submandibular ganglion.
Sympathetic from T1-T3 from the superior cervical ganglion.
What is the innervation of the sublingual gland?
Parasympathetic from the facial nerve (CN VII) via the submandibular ganglion.
Sympathetic from T1-T3 from the superior cervical ganglion.
What is the parasympathetic neurotransmitter in the salivary glands?
Acetylcholine and substance P
What is the sympathetic neurotransmitter in the salivary glands?
Norepinephrine, which is then received by β-adrenergic receptors causing increase cAMP and therefore more saliva excreation.
