Definitions and descriptions

Definitions and descriptions

Latest | A B C D E F G H I J K L M N O P Q R S T U V W Y Z
There are currently 35 terms in this directory beginning with the letter O.
Occipital lobes (ok-SIP-i-tuhl LOWBS)
The most posterior part of the cerebrum; contain the visual areas
Ocular Trauma
These are eye injuries that may result from blunt or sharp objects or from chemical substances. The management of these injuries is guided by history from the patient and ocular finding by the clinicians.
Oculo-cutaneous Albinism
A congenital disorder characterized by the complete or partial absence of pigment (melanin) in the skin, hair and eyes.
Oculomotor nerves (OK-yoo-loh-MOH-tur)
Cranial nerve pair III; motor to the extrinsic muscles of the eye, the ciliary body, and the iris
Odontogenic cysts
A group of jaw cysts that are formed from tissues involved in odontogenesis (tooth development). Odontogenic cysts are closed sacs filled with fluid, and have a distinct membrane derived from rests of odontogenic epithelium.
Odynophagia
Odynophagia is sharp substernal pain on swallowing that may limit oral intake. It usually reflects severe erosive dis­ease. It is most commonly associated with infectious esophagitis due to Candida, herpesviruses, or CMV, espe­cially in immunocompromised patients. It may also be caused by corrosive injury due to caustic ingestions and by pill-induced ulcers.
Olfactory receptors (ohl-FAK-tuh-ree ree-SEP-ters)
The sensory receptors in the upper nasal cavities that detect vaporized chemicals, providing a sense of smell
Oligodendrocyte (ah-li-goh-DEN-droh-sight)
A type of neuroglia that produces the myelin sheath around neurons of the central nervous system
Oligosaccharide (ah-lig-oh-SAK-ah-ride)
A carbohydrate molecule that consists of from 3–20 monosaccharides bonded together; form “self ” antigens on cell membranes
Oliguria (AH-li-GYOO-ree-ah)
Decreased urine formation and output
Onchocerciasis (River blindness):
Onchocerciasis is a tissue parasitic infestation caused by a filarial worm, Onchocerca volvulus. The microfilariae invade lymphatic system, subcutaneous and deep tissues producing acute inflammation and chronic inflammation at a later stage.
Onycchomycosis
It is defined as infection of the nail plate by fungus. Patients with diabetes or peripheral neuropathy may be at a higher risk.
Oogenesis (Oh-oh-JEN-e-sis)
The process of meiosis in the ovary to produce an ovum
Opportunistic infection (OP-er-too-NIS-tik)
An infection caused by a microorganism that is usually a saprophyte but may become a parasite under certain conditions, such as lowered host resistance
Opsonization (OP-sah-ni-ZAY-shun)
The action of antibodies or complement that upon binding to a foreign antigen attracts macrophages and facilitates phagocytosis (from the Greek “to purchase food”)
Optic chiasma (OP-tik kye-AS-muh)
The site of the crossing of the medial fibers of each optic nerve, anterior to the pituitary gland; important for binocular vision
Optic disc (OP-tik DISK)
The portion of the retina where the optic nerve passes through; no rods or cones are present (Syn.—blind spot)
Oral candidiasis
This is a fungal infection of the oral mucosa caused by Candida infection mainly Candida albicans. Acute oral candidiasis (thrush) is seen most commonly in the malnourished, the severely ill, neonates and HIV-AIDs patients or patients on long term oral corticosteroid use. In chronic oral candidiasis dense white plaques of keratin are formed. Other risks for candidiasis include chronic diseases like diabetes mellitus, prolonged use of antibiotics and ill/poorly fitting dentures.
Oral cavity (OR-uhl KAV-i-tee)
The cavity in the skull bounded by the hard palate, cheeks, and tongue
Orbit (OR-bit)
The cavity in the skull that contains the eyeball (Syn.—eye socket) (from the Latin “circle” or “world”)
Orbital Cellulitis
Orbital cellulitis is an infection of the soft tissues of the orbit posterior to the orbital septum. It may be a continuum of preseptal cellulitis, which is an infection of the soft tissue of the eyelids and periocular region anterior to the orbital septum. Orbital cellulitis may result from an extension of an infection from the paranasal sinuses or other periobirtal structures such as the face, globe, or lacrimal sac, direct inoculation of the orbit from trauma or surgery or as a haematogenous spread from bacteremia.
Orbitofrontal cortex (OR-bih-toh-FRUN-tuhl)
The part of the frontal lobe behind the eye; is concerned with appropriate emotions and behavior, and awareness of the future (Syn.—prefrontal cortex)
Organ (OR-gan)
A structure with specific functions; made of two or more tissues
Oropharyngeal STIS
Oral sex can lead to oropharyngeal STIs (infection of mouth and throat), including human papillomavirus, herpes, gonorrhea, among others. Clinically, it is difficult to diagnose gonococcal or chlamydial pharyngitis reliably.
Oropharynx (OR-oh-FA-rinks)
The middle portion of the pharynx behind the oral cavity; a passageway for both air and food
Osmoreceptors (AHS-moh-re-SEP-ters)
Specialized cells in the hypothalamus that detect changes in the water content of the body
Osmotic pressure (ahs-MAH-tik)
Pressure that develops when two solutions of different concentration are separated by a selectively permeable membrane. A hypertonic solution that would cause cells to shrivel has a higher osmotic pressure. A hypotonic solution that would cause cells to swell has a lower osmotic pressure
Osteoarthritis
It is a common form of arthritis, characterized by degenerative loss of articular cartilage, subchondral bony sclerosis, and cartilage and bone proliferation subsequent osteophyte formation. Gradual onset of one or a few joints involved.
Osteomyelitis
Osteomyelitis is an infection of the bone or bone marrow caused by pyogenic bacteria or mycobacteria or fungi. This condition is most common in children under 12 years. Staphylococci aureus are the most frequent responsible organisms. In patients with sickle cell disease Salmonella species become more common pathogens than in healthy hosts. Can be classified as acute or chronic depending on duration of symptoms.
Osteomyelitis of the jaw
This is an inflammation of the medullary portion of the jaw bone which extends to involve the periosteum of the affected area. The infection becomes established in the bone ending-up with pus formation in the medullary cavity or beneath the periosteum obstructs the blood supply. The infected bone becomes necrotic following ischemia.
Otitis External
It is an inflammatory condition of the pinna and external auditory meatus.
Otitis Media
It is an inflammation of the middle ear cavity. It is considered acute when the inflammation is of less than 2 weeks duration, and chronic when the inflammation is of more than 2 weeks duration with tympanic membrane perforation.
Otitis media with Effusion
It is a multifactoral inflammatory condition in the middle ear with serous or mucous accumulation without ear discharge. It is a residual condition after acute otitis media.
Ovary (OH-vuh-ree)
The female gonad that produces ova; also, an endocrine gland that produces the hormones estrogen and progesterone
Ovum (OH-vuhm)
(Pl.—ova) An egg cell, produced by an ovary
Gafacom
%d bloggers like this: