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a) Acne (labeled whitehead) on a person’s cheek. B) A drawing of skin with a yellow bubble labeled pus. This is below a raised region on the skin.
(a) Acne is a bacterial infection of the skin that manifests as a rash of inflamed hair follicles (folliculitis). The large whitehead near the center of the cheek is an infected hair follicle that has become purulent (or suppurative), leading to the formation of a furuncle. (b) An abscess is a pus-filled lesion. (credit b: modification of work by Bruce Blaus)
A table labeled types of skin lesions. Crust is shown as a raised region on the surface of the skin. Cyst is shown as a large white sphere in the upper layers of the skin. Macule is shown as a dark mark on the surface. Papule is shown as a raised bubble on the surface. Pusture is shown as a large yellow sphere in the upper layers of the skin. Ulcer is a large cavity in the skin. Vesicle is a small blue bubble in the upper regions of the skin. Wheal is a small blue bubble on the surface of the skin.
Numerous causes can lead to skin lesions of various types, some of which are very similar in appearance. (credit: modification of work by Bruce Blaus)
  • How can asymptomatic health care workers transmit bacteria such as MRSA to patients?

Anatomy and microbiota of the eye

Although the eye and skin have distinct anatomy, they are both in direct contact with the external environment. An important component of the eye is the nasolacrimal drainage system, which serves as a conduit for the fluid of the eye, called tears . Tears flow from the external eye to the nasal cavity by the lacrimal apparatus, which is composed of the structures involved in tear production ( [link] ). The lacrimal gland , above the eye, secretes tears to keep the eye moist. There are two small openings, one on the inside edge of the upper eyelid and one on the inside edge of the lower eyelid, near the nose. Each of these openings is called a lacrimal punctum . Together, these lacrimal puncta collect tears from the eye that are then conveyed through lacrimal ducts to a reservoir for tears called the lacrimal sac , also known as the dacrocyst or tear sac .

From the sac, tear fluid flows via a nasolacrimal duct to the inner nose. Each nasolacrimal duct is located underneath the skin and passes through the bones of the face into the nose. Chemicals in tears, such as defensins , lactoferrin , and lysozyme , help to prevent colonization by pathogens. In addition, mucins facilitate removal of microbes from the surface of the eye.

Diagram of an eye. Above the eye is the lacrimal gland. At the point nearest the nose is the punctums and tubes leading to the lacrimal sac and nasolacrimal duct.
The lacrimal apparatus includes the structures of the eye associated with tear production and drainage. (credit: modification of work by “Evidence Based Medical Educator Inc.”/YouTube)

The surfaces of the eyeball and inner eyelid are mucous membranes called conjunctiva . The normal conjunctival microbiota has not been well characterized, but does exist. One small study (part of the Ocular Microbiome project) found twelve genera that were consistently present in the conjunctiva. Abelson, M.B., Lane, K., and Slocum, C.. “The Secrets of Ocular Microbiomes.” Review of Ophthalmology June 8, 2015. http://www.reviewofophthalmology.com/content/t/ocular_disease/c/55178. Accessed Sept 14, 2016. These microbes are thought to help defend the membranes against pathogens. However, it is still unclear which microbes may be transient and which may form a stable microbiota. Shaikh-Lesko, R. “Visualizing the Ocular Microbiome.” The Scientist May 12, 2014. http://www.the-scientist.com/?articles.view/articleNo/39945/title/Visualizing-the-Ocular-Microbiome. Accessed Sept 14, 2016.

Use of contact lenses can cause changes in the normal microbiota of the conjunctiva by introducing another surface into the natural anatomy of the eye. Research is currently underway to better understand how contact lenses may impact the normal microbiota and contribute to eye disease.

Questions & Answers

Digestion of food is completed in __
Amina Reply
difference btwn hausteria and appears
Raviha Reply
numerical and molecular taxanomy
Dhanshri Reply
difference btwn hausteria and appesorium
Raviha
full life cycle of plasmodium parasite
Emmah Reply
what are ways of handling sharps
namugenyi Reply
never recap or bend a sharp objects
benita
what are some medicine in treating patient with meningitis
Freeman
describe the process of platelet formation
Joy Reply
what is parasitic helminths
Sadiya Reply
list three categories of symbiotic relationships.
mary Reply
parasitis,mutualism and comensalism.
mary
what's the difference between microbial intoxication and infectious diseases
dranimva Reply
microbial intoxication results when a person ingests a toxin or a poisonous substance that has been produced by a microbe while infectious disease results when a pathogen colonize the body and subsequently cause disease.
mary
weighing balance is needed in lab of microbiology for weighing?
amna Reply
It is mainly used for media preparation and product testing purpose.
Nakaweesi
thank you for your joining
nuur
what is microbiology
Shamsuddeen Reply
study of living organisms that are too small to be visible with naked eye
Marah
yes
Ahmed
microbiology is the study of microscopic organisms, either unicellular(single cell), multicellular( cell colony), or acellular (lacking cell).
munachimso
Microbiology is the study of microorganisms that cannot be seen with the necked eyes but by the help of microscope.
Fuseini
is the word Atypical or a typical bacteria. .am confused pliz help
MUWANGUZI Reply
typical bacteria
Zulpha
okay thank you what does that mean
MUWANGUZI
atypical means that it has some characters from bacteria not all characters ...but tybical means that it has all the characters that bacteria have
Reham
thank you Zulpha
MUWANGUZI
some examples please
MUWANGUZI
thank you Reham
MUWANGUZI
1) typical bacteria contain a cell wall whereas atypical bacteria usually do not contain a cell . 2) typical bacteria can be either Gram-positive or Gram-negative while atypical bacteria remain colorless with Gram staining. 3) cells of typical bacteria are large ,while cells of the atypical small
Marah
Example of atypical : Mycoplasma pneumoniae , chlamydophila pneumoniae , legionella
Marah
what is micro biology
Jauharah Reply
is the study of organisms which can't be viewed by our necked eyes
Egumat
Because it preexisting causing secondary infection after collateral damage of normal microbota
Rafaa Reply
combinations of drugs that can't be taken together and why
Grace Reply
Antagonism: the combined action is less than that of the more effective agent when used alone). All these effects may be observed in vitro (particularly in terms of bactericidal rate) and in vivo والله اعلم
Lenovo

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Source:  OpenStax, Microbiology. OpenStax CNX. Nov 01, 2016 Download for free at http://cnx.org/content/col12087/1.4
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