Search results
Results From The WOW.Com Content Network
Saliva on a baby's lips. Saliva (commonly referred to as spit or drool) is an extracellular fluid produced and secreted by salivary glands in the mouth.In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which DNA can be extracted), enzymes (such as lipase and amylase), and antimicrobial agents (such as secretory IgA, and lysozymes).
In humans, 1200 to 1500 ml of saliva are produced every day. [3] The secretion of saliva (salivation) is mediated by parasympathetic stimulation; acetylcholine is the active neurotransmitter and binds to muscarinic receptors in the glands, leading to increased salivation. [3] [4]
It has also been defined as increased amount of saliva in the mouth, which may also be caused by decreased clearance of saliva. [4] Hypersalivation can contribute to drooling if there is an inability to keep the mouth closed or difficulty in swallowing (dysphagia) the excess saliva, which can lead to excessive spitting.
The sympathetic division typically functions in actions requiring quick responses. The parasympathetic division functions with actions that do not require immediate reaction. A mnemonic to summarize the functions of the parasympathetic nervous system is SSLUDD (sexual arousal, salivation, lacrimation, urination, digestion and defecation).
It is the general visceral efferent (GVE) component of the glossopharyngeal nerve supplying the parasympathetic input to the parotid gland for salivation. It lies immediately caudal to the superior salivatory nucleus and just above the upper end of the dorsal nucleus of the vagus nerve in the medulla.
Without saliva (or the dry mouth feeling you get when you are dehydrated) your body now has to play catch up while extracting the vital nutrients from your meals.
Saliva moistens and softens food, and along with the chewing action of the teeth, transforms the food into a smooth bolus. The bolus is further helped by the lubrication provided by the saliva in its passage from the mouth into the esophagus. Also of importance is the presence in saliva of the digestive enzymes amylase and lipase.
Seromucous glands (mixed) secrete both protein and mucus. Examples include the salivary glands: although the parotid gland (saliva secretion 25%) is predominantly serous, the sublingual gland (saliva secretion 5%) mainly mucous gland, and the submandibular gland (saliva secretion 70%) is a mixed, mainly serous gland.