Tear Secretion Review

Questions and Answers

What is the main function of tears?

To express emotions

To nourish the eye by maintaining a balance of its ingredients (correct)

To produce proteins like lysozyme and serum albumin

To protect the eye from dust and other infectious agents

What type of proteins are found in tears?

No proteins are present in tears

Only apolipoproteins H and phospholipase A2

Only lipophilin C

Including lysozyme, serum albumin, and other proteins (correct)

What is the name of the factor present in onions that induces tear secretion?

Lipophilin C

Apolipoproteins H

Phospholipase A2

Thiopropanal S-oxide (correct)

What is the primary defence agent in tears?

Secretory IgA Signup and view all the answers

What are the three layers of the precorneal (tear) film?

Lipid, aqueous, and mucous Signup and view all the answers

What is the name of the disorder caused by a defect in tear secretion?

All of the above Signup and view all the answers

Why do females tend to cry more than men?

Because they have a better ability to express emotions Signup and view all the answers

How many types of tear secretion are there?

Three Signup and view all the answers

What is the function of the lipid layer in the tear film?

To act as a hydrophobic barrier Signup and view all the answers

What percentage of the total refractory power of the eye is attributed to the tear film?

Two-thirds Signup and view all the answers

How many square centimeters of area is covered by the tear film?

1-3 square cm Signup and view all the answers

What is the thickness of the tear film in micrometers?

2.7-11 micrometers Signup and view all the answers

Why is crying considered healthy?

Because certain proteins are present in tears Signup and view all the answers

How often do women cry on average in a year?

How many microlitres of tears are secreted per minute?

2 microlitres Signup and view all the answers

What is the width of the puncta that drain tears?

0.3mm Signup and view all the answers

Where are the lacrimal glands situated?

Laterally Signup and view all the answers

What is the function of lactoferrin?

Having antimicrobial activity Signup and view all the answers

What is the primary function of basal tears?

To moisten the eyes Signup and view all the answers

What is the term for the excessive production of tears due to ocular inflammation?

Hyper secretion Signup and view all the answers

Which type of tears is produced in response to pain or external stimulus?

Reflex tears Signup and view all the answers

What is the approximate duration of emotional crying in men?

Two-three minutes Signup and view all the answers

What is the purpose of people crying?

To express emotions Signup and view all the answers

What is the function of lysozyme?

Having antimicrobial activity Signup and view all the answers

What is the main role of the accessory glands in the eye?

To take over tear secretion in the absence of the main gland Signup and view all the answers

Why does an infant cry without weeping?

Due to the absence of a developed nervous system Signup and view all the answers

What physiologically regulates tear secretion?

Cholinergic fibres of the parasympathetic nervous system Signup and view all the answers

What is the risk prevented by the accessory glands?

Dry eye Signup and view all the answers

What is the effect of cocaine on tear secretion?

Stops reflex tears even when exposed to strong gases Signup and view all the answers

What is involved in the regulation of tear secretion?

The parasympathetic nervous system, sympathetic stimulation, and certain peptides Signup and view all the answers

Why are reflex tears stopped even when exposed to strong gases?

Due to the presence of cocaine Signup and view all the answers

What is necessary for normal functioning of the eye?

Either the main gland or the accessory glands Signup and view all the answers

What is dry eye caused by?

Less tears, viral infection, excess evaporation of tears, variation in composition of tears Signup and view all the answers

Who is the author of the article 'Tear biochemistry: a review'?

WDH Gillan Signup and view all the answers

What is the title of the journal where the article 'Diagnostic and Prognostic Features of Sjögren’s Syndrome' is published?

National Journal of Pharmacy Signup and view all the answers

What is the title of the article written by Monica Alves, Rodrigo Nogueira Angerami, and Eduardo Melani Rocha?

Dry eye disease caused by viral infection: review Signup and view all the answers

What is the title of the article written by J.Murube, L.Murube, and A.Murube?

Origin and types of emotional tearing Signup and view all the answers

Who are the authors of the article 'Evaluation of various risk factors of dry eye'?

Renu Magdum, Atreyee K Pradhan, Dhavat P Sukharamwala, Khevna Patel Signup and view all the answers

What is the journal where the article 'Patho-physiology of lachrymal gland in old age' is published?

International Digital Organization for Scientific Information Signup and view all the answers

Who is the author of the article 'The effects of the tear-film dynamics in healthy subjects and dry eye patients'?

Erdélyi Béla MD Signup and view all the answers

Study Notes

Tear Secretion

Tears are a fluid secreted by the lacrimal glands to moisten and nourish the eyes.
Tears contain various biologically active substances, including mucin, electrolytes, proteins (e.g., lysozyme, serum albumin), and other chemicals.
Proteins in tears have important functions, such as defense against infectious agents.

Tear Film

The precorneal (tear) film has three layers: lipid, aqueous, and mucous.
The lipid layer acts as a hydrophobic barrier, preventing overflow of tears.
The aqueous layer contains water and tear proteins, controlling infection and acting as a physiological barrier.
The mucous layer is hydrophilic, with mucin secreted by the lacrimal glands.
Tear film break-up time is used to check the stability of the tear film in dry eye and other disorders.

Types of Tears

There are three types of tear secretion: basal, emotional, and reflex.
Basal tears are secreted continuously to moisten the eyes.
Emotional tears are produced in response to emotional stimuli, such as sadness, anger, or frustration.
Reflex tears are produced in response to pain, external stimuli, or foreign bodies.

Tear Proteins

Over 60 tear proteins are known, including lactoferrin, antimicrobial molecules, and lysozyme.
Lactoferrin has antimicrobial activity and is a carrier protein.
Lysozyme has antibacterial activity.

Tear Secretion Regulation

Tear secretion is regulated physiologically by cholinergic fibers of the parasympathetic nervous system, sympathetic stimulation to the adrenal gland, certain peptides, and humoral factors.
Epidermal growth factors also control tear secretion.

Dry Eye

Dry eye is a symptom caused by low tear secretion, viral infection, excess evaporation of tears, or variation in tear composition.
Dry eye can lead to disorders such as Sjogren's syndrome and crocodile tears.

Interesting Facts

On average, women cry 30-64 times a year, while men cry 6-17 times a year.
The tear secretion rate is 2 microliters per minute or 10 ounces per day.
Crying is considered healthy due to the presence of certain proteins in tears.
Lithium carbonate and sodium valproate help decrease tear film break-up time.

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Description

A brief review of tear secretion, its composition and functions. Learn about the lacrimal glands and the role of tears in eye health.