Define the control of tear production, Biology

Assignment Help:

Define the control of tear production.

Control of Tear Production

The lacrimal secretary system was initially thought to be comprised of two parts, basic secretors and reflex secretors. Basic secretion corresponds to the accessory glands of Krause and Wolfring and reflex secretion to the main lacrimal gland.

Now, it is thought that all lacrimal glands respond as a single unit. The aqueous Eyelids, Lacrimal and Tear Film portion of tear fluid consists of reflex and basic secretois. Basic secretion occurs under sympathetic control (by blood flow regulation through the gland). Reflex secretion is controlled by the main lacrimal gland under parasympathetic control. There are two types of reflex secretion-peripheral and central reflex. Peripheral reflex occurs by stimulation of 5th nerve in the cornea. Central reflex occurs by the stimulation of the retina or psychogenic events. The aqueous component functions in hydration, lubrication, and oxygenation of the tear film. The lipid portion of tear fluid is secreted by the meibomian glands and functions in lubrication and prevents evaporation. The mucus layer is secreted by goblet cells and converts the corneal epithelium from a hydrophobic to a hydrophilic layer.


Related Discussions:- Define the control of tear production

What are the genotypes, What are the genotypes and respective blood types o...

What are the genotypes and respective blood types of the ABO system? Since the alleles are IA, IB and i the possible genotypes are IAIA (blood type A), IAIB (blood type AB), IB

Magnetic resonance imaging (mri), M a g n etic resonance imagin...

M a g n etic resonance imaging (MRI): It is in use as a clinical diagnostic tool since 1980. The distribution of hydrogen nuclei (protons), present in cellular wa

Explain the causes of steatorrhoea, Q. Explain the Causes of steatorrhoea? ...

Q. Explain the Causes of steatorrhoea? The list of possible underlying causes of steatorrhoea includes: • Malabsorption • Malabiorptian of fats in small intestine •

Explain about peptic ulcer, Q. Explain about Peptic Ulcer? Peptic ulcer...

Q. Explain about Peptic Ulcer? Peptic ulcers are one of the more serious forms of gastrointestinal disorders of the gastrointestinal tract particularly the stomach. The prevale

Define about the lactose, Define about the Lactose? Lactose has a molec...

Define about the Lactose? Lactose has a molecular structure consisting of galactose and glucose. It is of interest because it is associated with lactose intolerance which is th

Define about the listing plane, Define about the Listing Plane Listing ...

Define about the Listing Plane Listing proposed that only horizontal movements  of  the  eye  are performed around a vertical axis  in  the equatorial plane and vertical moveme

How is the yolk sac formed, How is the yolk sac formed? What is the functio...

How is the yolk sac formed? What is the function of the yolk sac? The yolk sac is formed from the covering of the vitellus by some cells originated from the primitive gut. T

Describe the the growth of the plants in the 2 groups, There has not been r...

There has not been rain for several months. A biologist is driving down the highway and notices that a large number of corn fields have corn that is wilted and short. She wonders i

Explain lipolysis, Lipolysis What do we mean by lipolysis? Hydrolysis o...

Lipolysis What do we mean by lipolysis? Hydrolysis of ester bonds in lipids is called lipolysis. This may occur by enzyme action or by heat and moisture, resulting in the liber

State the major function of the cell membrane, State the major function of ...

State the major function of the cell membrane A major function of the cell membrane is to maintain the characteristic integrity of the cell by forming a selective barrier betwe

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd