Quantcast Accessory structures of the eye - The Sensory System

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
 
e. Muscles of the Eye. The structure of the eye includes the muscles of the
eye--intrinsic muscles and extrinsic muscles. Intrinsic muscles include the two
involuntary muscles within the eye--the iris and the ciliary muscles. The iris regulates
the amount of light which can enter the eye. The iris does this by dilating (opening
more) and by constricting (opening less). The extrinsic muscles are composed of four
rectus muscles (superior muscles, inferior muscles, medial muscles, and lateral
muscles) and two oblique muscles (superior muscles, and inferior muscles). The
extrinsic muscles move the eye within the orbit. The eye is the only organ with both
voluntary and involuntary muscles.
1-4.
ACCESSORY STRUCTURES OF THE EYE
The site of accessory structures of the eye are as follows: eyebrows, eyelashes,
eyelids, conjunctiva, and lacrimal apparatus.
a. Eyebrows. The eyebrows are made up of several rows of hair above the
upper eyelids. The eyebrows form an arch at the junction of the upper eyelid and the
forehead and structurally resemble the hairy scalp. The hairs are generally coarse and
grow toward the side of the face.
b. Eyelashes. Eyelashes are a row of hairs which project from the border of
each eyelid. Eyelashes coming from the upper eyelid are usually long and turn upward;
eyelashes from the lower eyelid are generally short and turn downward. Sebaceous
glands at the base of eyelash hair follicles pour a lubricating fluid into the follicles.
When these glands become infected, a sty forms.
c. Eyelids. Each eyelid consists of epidermis, dermis, subcutaneous
connective tissue, fibers of oculi muscle, a tarsal plate, tarsal glands, and a conjunctiva.
The epidermis, dermis, and subcutaneous connective tissue make up the skin of the
eyelid. The tarsal plate is a thick fold of connective tissue that forms part of the inner
wall of each eyelid. The tarsal plate gives form and support to the eyelids. The
conjunctiva is a mucous membrane which lines the inner aspect of the eyelids as well
as the visible portion of the cornea (the glossy, transparent part of the cornea).
d. Lacrimal Apparatus. This is the term used for a group of structures that
manufacture and drain away tears. Included are the lacrimal glands, the execratory
lacrimal ducts, the lacrimal canals, the lacrimal sacs, and the nasolacrimal ducts.
(1)  Lacrimal gland. A lacrimal gland is located in the upper outer corner of
each orbit. The lacrimal glands secret lacrimal fluid through small ducts into the space
between the external surface of the eyeball and the upper eyelid.
MD0582
1-6



Medical News
Ebola scare boosts business for US company
The Ebola scare has subsided in the United States, at...
medicalxpress.com
Sperm can carry Ebola for 82 days: WHO
Sperm can carry the Ebola virus for at least 82...
medicalxpress.com
The 65-Minute Minute Clinic
(MedPage Today) -- CVS needs to reconsider its walk-in clinic...
medpagetoday.com
Atherosclerosis a Signal for Brain Drain?
(MedPage Today) -- Plaque burden was linked to cognitive impairment...
medpagetoday.com
Research examines relationship between domestic abuse and football
A report, published today by the Scottish Centre for Crime...
medicalxpress.com
'Chatty' cells help build the brain
The cerebral cortex, which controls higher processes such as perception,...
medicalxpress.com
Obama Officials Seek to Clarify Abortion Coverage Rules
(MedPage Today) -- Implementing 2010 compromise language proves troublesome....
medpagetoday.com
Tweet of the Week: A Hungry Patient Walks Into a Hospital
(MedPage Today) -- Hospital staff use few words to inform...
medpagetoday.com
Metals in local groceries may impact kids health
A survey of metal concentrations in 253 food and beverages...
medicalxpress.com
Duality in the human genome
Humans don't like being alone, and their genes are no...
medicalxpress.com
Real-time volume imaging of hearts
A new ultrasound system from Siemens enables doctors to carry...
medicalxpress.com
Smoking rates halve since 1970s in Britain
The number of smokers in Britain has more than halved...
medicalxpress.com
The palaeolithic diet and the unprovable links to our past
We still hear and read a lot about how a...
medicalxpress.com
Understanding psychosis and schizophrenia
A report published today by the British Psychological Society's Division...
medicalxpress.com
How do Tourette's patients react to visual stimulation with their own self-image?
Tourette's syndrome is characterised by tics caused in many by...
medicalxpress.com
Beijing adopts smoking ban for public places: state media
China's capital on Friday passed a smoking ban for all...
medicalxpress.com
Johns Hopkins docs, researchers explain why you and your family should get vaccinated against the flu
One little stick can save your life. The flu shot...
medicalxpress.com
British scientists trial 15-minute Ebola test in Guinea
British researchers are to conduct trials in Guinea on a...
medicalxpress.com
Behavioral interventions to prevent progression to diabetes equally effective in men and women
Behavioural and drug interventions aiming to prevent people with prediabetes...
medicalxpress.com
Thai parliament votes to ban commercial surrogacy
Thailand's parliament has voted to ban commercial surrogacy after outrage...
medicalxpress.com
 


Privacy Statement - Copyright Information. - Contact Us

comments powered by Disqus

Integrated Publishing, Inc.
9438 US Hwy 19N #311 Port Richey, FL 34668

Phone For Parts Inquiries: (727) 755-3260
Google +