Short note Saliva

Anatomy & physiology::

Topic:

** Saliva
Saliva is a viscous(অাঠা‌লো),colorless(বর্নহীন) secretion of salivary gland(গ্রন্থি).
It is mainly secreted from the salivary glands.
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*There are 3 pairs(জোড়া):
i)parotid gland(25%)
ii)sub mandibular gland(70%)
iii)sub lingual(5%)
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*Features(‌বৈ‌শিষ্ট্য)::
>Daily secretion:1200-1500ml
>Colour: colorless
>P^H : 6.0-7.4
>Reaction : slightly acidic
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*Composition(গঠন)::
1) Water---> 99.5%
2) Solid---> 0.5%
*Solid: 
i) Inorganic : HCO^-3,Na^+,K^+,NaCl,KCl.
ii) Organic : Enzyme,Lingual lipase,Immunoglobulin-IgA,Lactoferrin,Lysozymes,Antigen-A & B, mucin.
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*Function(কাজ)::
1) Digestion(হজম): saliva initiates(অারম্ব করা) digestion(হজম) of carbohydrate by salivary alfa-amylase.
2)Defensive(অাত্তরক্ষা): Immunoglobulin IgA,lactoferrin,lysozyme provide(প্রদান করা) defense(প্র‌তিরক্ষা) against(‌বিরু‌দ্ধে) infection(সংক্রমন).
3) Lubricating(পি‌চ্ছিল করা): saliva wet(‌বেজা) and lubricate(‌পি‌চ্ছিল) the oral cavity thus helps in swallowing(‌গিলে ফেলা)::
i) Swallowing:: It is the process by which bolus(‌পিন্ড) of food is propelled(তা‌ড়িত) backward‌পিছ‌নে towards the stomach.It takes about 9-12second.
ii) Mastication(‌চিবা‌নো): When the food is taken into the mouth it is ground under the teeth by a process called mastication.
It is due to alternative contraction(সং‌কোচন) and relaxation(প্রসারন) of muscles concerned with the movement of lower jaw.
_______________Lecture: Dr. Monjurol sir.
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