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Glossary of Physiology Terms – O
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Obesity
Definition:
A condition of having an excessive amount of body fat.

Related glossary terms/phrases:
Body Mass Index

See also:
Body Mass Index Calculator



Oliguria
Definition:
Refers to an abnormally low volume of urine production. Generally, a urine production rate of less than 400 mL/day is referred to as oliguria.

Related glossary terms/phrases:
Polyuria

Other resources:
Oliguria (Wikipedia)



Oophorectomy
Definition:
Surgical removal of one or both ovaries.

Also known as ovariectomy

See:
Ovariectomy



Organ of Corti
Definition:
Auditory sensory organ within the inner ear cochlea, where the inner and outer hair cells are located.

Related glossary terms/phrases:
Cochlea



Otoacoustic emissions
Abbreviation:
OAEs

Definition:
Otoacoustic emissions (OAE) are sounds that arise from the organ of Corti within the cochlea of the inner ear in response to sound stimulation. They are thought to result from vibrations of cochlear outer hair cells (OHC) in response to stimulation by sound. Otoacoustic emissions are inaudible to the human ear, but can be recorded by placing a small recording device in the external auditory meatus (ear canal).

Otoacoustic emissions have clinical diagnostic value and are measured as part of hearing exams. In the newborn, otoacoustic emissions are recorded in order to detect blockage in the middle ear cavity (e.g., as a result of fluid accumulation) or external ear canal.



Ouabain
Definition:
Ouabain binds to and inhibits the transport activity of the Na+/K+/ATPase (i.e., sodium pump).

Ouabain is plant derived and belongs to the class of drugs referred to as cardiac glycosides. Similar to other cardiac glycosides, ouabain increase heart muscle contractility. However, ouabain is used only experimentally and not in humans (as for example digoxin is for the treatment of congestive heart failure).

There is some evidence that ouabain may be produced endogenously in humans.

Related glossary terms/phrases:
Vanadate

Other resources:
Ouabain (Wikipedia)



Outward current
Definition:
In electrophysiological convention, a positive current value or upward deflection of the current trace is typically referred to as an outward current. A positive current value (i.e., outward current) can reflect either the movement of positive ions (cations) out of the cell or negative ions (anions) into the cell.

Related glossary terms/phrases:
Inward current

See also:
Neuronal Action Potential - Pharmacological Inhibition of Na+ and K+ Channels



Ovariectomy
Definition:
Surgical removal of one or both ovaries.

Also known as oophorectomy

Related glossary terms/phrases:
Oophorectomy



Overshoot
Definition:
Refers to that part of the action potential where the membrane potential is positive (inside with respect to the outside).

See figure.

See also:
Neuronal Action Potential - Important Features of the Neuronal Action Potential



Overweight
Definition:
Body weight that exceeds the normal or standard weight range. The standard range is generally determined based on height and frame size.

Related glossary terms/phrases:
Body Mass Index

See also:
Body Mass Index Calculator



Oxyntic cells
Definition:
Parietal cells

See:
Parietal cells









Posted: Sunday, November 28, 2010
Last updated: Sunday, January 10, 2016