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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).
The sympathetic nervous system's primary process is to stimulate the body's fight or flight response. It is, however, constantly active at a basic level to maintain homeostasis. [4] The sympathetic nervous system is described as being antagonistic to the parasympathetic nervous system.
Autonomic nervous system, showing splanchnic nerves in middle, and the vagus nerve as "X" in blue. The heart and organs below in list to right are regarded as viscera. The autonomic nervous system has been classically divided into the sympathetic nervous system and parasympathetic nervous system only (i.e., exclusively motor).
The paired submandibular glands (historically known as submaxillary glands) are major salivary glands located beneath the floor of the mouth.In adult humans, they each weigh about 15 grams and contribute some 60–67% of unstimulated saliva secretion; on stimulation their contribution decreases in proportion as parotid gland secretion rises to 50%. [1]
By the turn of the 19th century, it was agreed that the stimulation of sympathetic nerves could cause different effects on body tissues, depending on the conditions of stimulation (such as the presence or absence of some toxin). Over the first half of the 20th century, two main proposals were made to explain this phenomenon:
The most notable physiological effects from autonomic activity are pupil constriction and dilation, and salivation of saliva. [8] The autonomic nervous system is always activated, but is either in the sympathetic or parasympathetic state. [8]
The primary endogenous agonists of the sympathetic nervous system are the catecholamines (i.e., epinephrine [adrenaline], norepinephrine [noradrenaline], and dopamine), which function as both neurotransmitters and hormones. Sympathomimetic drugs are used to treat cardiac arrest and low blood pressure, or even delay premature labor, among other ...
Parasympathetic stimulation evokes a copious flow of saliva. Parasympathetic innervation to the salivary glands is carried via cranial nerves . The parotid gland receives its parasympathetic input from the glossopharyngeal nerve (CN IX) via the otic ganglion , [ 14 ] while the submandibular and sublingual glands receive their parasympathetic ...