29 Questions
Which of the following electrolytes is NOT typically found in saliva?
Barium
Which enzyme is responsible for breaking down carbohydrates in saliva?
Amylase
Which of the following immunoglobulins is commonly found in saliva?
IgA
What is the primary function of lysozyme in saliva?
Killing bacteria
Which of the following molecules is NOT typically found in saliva?
DNA
What is the primary effect of neurotransmitters on acini and intercalated ductal cells?
Initiation of exocytosis
What is the characteristic of saliva secreted during parasympathetic stimulation?
Watery and profuse
Which type of salivary gland is the main contributor to stimulated saliva?
Parotid gland
What is the typical daily production of saliva?
0.5-1.5 liters
What is the primary factor that maintains the pH of saliva near neutrality?
Neutralizing buffering activity of saliva
What is the characteristic of stimulated saliva compared to unstimulated saliva?
More alkaline and higher bicarbonates
Which type of salivary gland is responsible for secreting a mix of serous and mucous secretions?
Submandibular and minor salivary glands
What is the primary function of sympathetic nerve stimulation in salivary glands?
Enhancing contraction of myoepithelial cells
What is the primary mechanism of salivary protein secretion in the absence of stimulation?
Exocytosis of granules by constitutive and constitutive-like secretory pathways
Which of the following is a function of mucin in saliva?
Forming a protective barrier against noxious stimuli and microbial toxins
What is the primary function of salivary amylase?
Digestion of starch into glucosa and maltose
Which of the following is NOT a function of saliva?
Regulation of blood pressure
What is the primary mechanism of regulated salivary secretion?
Major regulated secretory pathway
What is the primary function of salivary buffering capacity?
Limiting the action of acidogenic plaque bacteria
Which of the following is a function of the apical secretory membrane of salivary cells?
Secretion of saliva into the lumen
What is the primary function of salivary lipase?
Breakdown of triglycerides into diglycerides and fatty acids
What is the primary function of mucin in saliva?
To protect the mouth and maintain oral health
In which part of the cell does the carbohydrate addition and modification of secretory proteins occur?
Golgi apparatus
What is the process by which salivary glands secrete saliva?
Exocytosis
What is the consequence of a deficiency in salivary secretion (xerostomia)?
All of the above
Where are secretory proteins initially synthesized?
Rough endoplasmic reticulum
What is the term for the fusion of the secretory granule membrane with the apical cell membrane?
Fusion pore
What is the role of the Golgi apparatus in secretory protein synthesis?
Carbohydrate addition and modification
What is the final step in the secretion of saliva?
Release of saliva into the oral cavity
Study Notes
Composition of Saliva
- Saliva contains electrolytes such as calcium, phosphate, fluoride, sodium, chloride, potassium, bicarbonate, magnesium, and iodine.
- Secretory proteins and enzymes in saliva include mucin, amylase, lipase, lysozyme, lactoferrin, peroxidase, proline-rich protein, histatin, and cystatin.
- Small organic molecules present in saliva are glucose, fatty acids, amino acids, urea, and uric acids.
- Immunoglobulins found in saliva are IgA, IgG, and IgM.
- Other components of saliva include cyclic adenosine monophosphate (cAMP)-binding proteins and serum albumin.
Pathways of Salivary Secretion
- Salivary secretion occurs through multiple pathways, including:
- Constitutive and constitutive-like pathways (resting secretion between meals)
- Minor regulated secretory pathway (response to low levels of stimulation)
- Major regulated secretory pathway (response to stimulation)
Functions of Saliva
- Protection:
- Mechanical washing action flushes away food debris and bacterial toxins
- Lubricant saliva forms a protective barrier against noxious stimuli and microbial toxins
- Salivary proteins form the salivary pellicle, a protective membrane
- Washing and buffering action limit the action of acidogenic plaque bacteria
- Buffering:
- Salivary proteins and bicarbonate, phosphate ions limit the action of acidogenic plaque bacteria and enamel demineralization
- Saliva interferes with optimal pH required for growth and colonization of micro-organisms
- Digestion:
- Mechanical: bringing food bolus into solution for swallowing
- Chemical: action of amylase enzyme digests starch into glucose and maltose
- Action of lipase enzyme digests triglycerides into diglycerides and fatty acids
Regulation of Salivary Secretion
- Parasympathetic stimulation:
- Results in secretion of profuse watery saliva
- Induces myoepithelial cell contraction
- Sympathetic stimulation:
- Results in secretion of intermittent thick viscid fluid
- Enhances contraction of myoepithelial cells
Normal Saliva
- Daily production: 0.5-1.5 liters
- Unstimulated salivary flow rate: 0.3-0.4 ml/min
- pH of saliva: 6.7-7.3
- Resting pH of saliva: not below 6.3
Stimulated and Unstimulated Saliva
- Unstimulated saliva: mix of serous and mucous secretions from submandibular and minor salivary glands
- Stimulated saliva: mainly from parotid gland
- Stimulated saliva accounts for more than 60% of daily salivary production
- pH of stimulated saliva: more alkaline than unstimulated saliva
Composition of Saliva
- Electrolytes: calcium, phosphate, fluoride, sodium, chloride, potassium, bicarbonate, magnesium, and iodine
- Secretory proteins and enzymes: mucin, amylase, lipase, lysozyme, lactoferrin, peroxidase, proline-rich protein, histatin, and cystatin
- Small organic molecules: glucose, fatty acids, amino acids, urea, and uric acid
- Immunoglobulins: IgA, IgG, and IgM
- Other components: cyclic adenosine monophosphate (cAMP)-binding proteins and serum albumin
Learn about the various components of saliva, including electrolytes, proteins, enzymes, and other molecules. Test your knowledge of the different substances present in saliva.
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