tear
Sign in to savethumb|upright=1.15|Human tears Tears (tear film) are a transparent fluid secreted primarily by the lacrimal glands (tear gland) found in the eyes of all land mammals. According to the mode of production, tears are classified into four types: basal, closed eye, emotional, and reflex. The basal rate of tear secretion is ~0.5–2.2 μL/min, and irritation can increase secretion by up to ~100-fold, reaching ~300 μL/min. Tears are made up of water, electrolytes, proteins, lipids, and mucins that form layers on the surface of eyes. The four types of tears differ significantly in their composition. upr
AI overview
Tears are a clear fluid produced by glands in the eyes of all land mammals, made up of water, electrolytes, proteins, lipids, and mucins that coat the eye's surface. They come in four different types—basal, closed eye, emotional, and reflex—each with distinct compositions, and their production can increase dramatically in response to irritation.
AI-generated from the Wikipedia summary — may contain errors.
Article
15 sectionsContents
- Physiology
- Chemical composition
- Drainage of tear film
- Types
- Nictitating membrane
- Neurology
- Human culture
- Pathology
- Bogorad's syndrome
- Keratoconjunctivitis sicca ([[Dry eye syndrome|dry eye disease]])
- Familial dysautonomia
- Pseudobulbar affect
- See also
- References
- External links
thumb|upright=1.15|Human tears Tears (tear film) are a transparent fluid secreted primarily by the lacrimal glands (tear gland) found in the eyes of all land mammals. According to the mode of production, tears are classified into four types: basal, closed eye, emotional, and reflex. The basal rate of tear secretion is ~0.5–2.2 μL/min, and irritation can increase secretion by up to ~100-fold, reaching ~300 μL/min. Tears are made up of water, electrolytes, proteins, lipids, and mucins that form layers on the surface of eyes. The four types of tears differ significantly in their composition. upright=1.15|thumb|Anatomy of lachrymation, showing Some of the functions of tears include lubricating the eyes (basal tears), removing irritants (reflex tears), and also aiding the immune system. Tears also occur as a part of the body's natural pain response. Emotional secretion of tears may serve a biological function by excreting stress-inducing hormones built up through times of emotional distress. Tears have symbolic significance among humans.
== Physiology ==