Salivary Secretion, Function and Regulation Flashcards
What are the components of the alimentary tract?
Mouth
Pharynx
Esophagus
Stomach
Small intestine
Large intestine
Rectum & Anus
Accessory digestive organs
Teeth
Tongue
Salivary glands
Liver
Gall bladder
Pancreas
Functions of the digestive system
Digestion
Absorption
Secretion
Motility
What are the three salivary glands?
Parotids
Submandibulars
Sublinguals
Characteristics of saliva
Volume = 1000 to 1500 ml/day
Colourless
pH = 6.0 to 7.0
What are the components of salivary secretion?
Water (99.5%) and solids (0.5%)
Components of solid part of salivary secretion
Inorganic Constituents
Organic Constituents
What are the inorganic constituents of salivary secretion?
K+, HCO3-, Na+, Cl-, Ca2+ and phosphorus
What are the organic constituents of salivary secretion?
Ptyalin (α amylase), lingual lipase, mucin, IgA, Lysozymes, lactoferrin, and glycoprotein haptocorrin
(PALM GLITCH)
What are the properties of lactoferrin?
Oxidizes iron which prevents the bacteria from utilizing it for its growth
What are the properties of haptocorrin?
Carry vit B12 and protect it from low pH
What are the two types of salivary secretion?
Serous secretion
Mucous secretion
What are the components of serous secretion of saliva?
Ptyalin(α-amylase)
Extracellular fluid
What are the components of mucous secretion of saliva?
Mucinfor lubricating and for protecting surfaces
What ions does saliva contain large quantities of?
K+and HCO3−
What ions does saliva contain smaller quantities of?
Na+and Cl-
Describe the mechanism of salivary secretion
Acini secrete primary salivary secretion that contains ptyalin and/or mucin in a solution of ions
Na+is actively reabsorbed from all the salivary ducts andK+is actively secreted due the effect of aldosterone hormone.
Cl- is passively reabsorbed following Na+ and HCO3 is secreted in exchange with Cl-
Saliva composition in faster flow rate (excessive salivation)
Higher Na+ and Cl-
Lower K+
Saliva composition in slower flow rate (dry mouth)
Lower Na+ and Cl-
Higher K+
What are the functions of saliva?
DALA TOAST
Digestion of starch by α-amylase
Antibacterial function
Lubricate food bolus along with mucins
Alkaline pH neutralizes any gastric secretions that reflux into the esophagus
Prevents tooth decay
Aids speech by facilitating movements of the lips and tongue
Serves as a solvent for the molecules that stimulate the taste buds
Facilitates swallowing by keeping the mouth moist
Where does the parasymathetic nervous system originate from?
Superiorandinferior salivatory nucleiin the brain stem
How does parasympathetic stimulation affect salivary secretion?
Postganglionic parasympathetic neurons release Acetylcholine (ACh) that acts on muscarinic receptors (M3) on the salivary gland
This causes an increase in the second messengers inositol triphosphate (IP3), diacylglycerol (DAG), and intracellular calcium (Ca2+)
What effect does parasympathetic stimulation have on salivary secretion?
Induce salivation (serous secretion)
Dilates the blood vessels
Where does the sympathetic nervous system originate from?
Superior cervical ganglia
How does sympathetic stimulation affect the salivary gland?
Norepinephrine (NE) acts on B adrenergic receptors and increase cAMP
What effect does sympathetic stimulation have on salivary secretion?
Increase protein secretion (Mucinous)
Lowers volume of primary saliva and a low flow rate
Vasoconstricts the blood vessels via α adrenergic receptor
What is xerostomia?
Deficient salivation
Causes of xerostomia?
Sjogren syndrome
Radiotherapy
Autoimmune disease
Drugs
What is sialorrhea?
Hyper-secretion of saliva
What are the causes of sialorrhea?
Neuromuscular dysfunction
Mental retardation
Parkinsonism
Drugs
