miosis
Học thuậtThân thiện
Definition
- Noun:
- Physiology: The reflexive contraction of the sphincter muscle of the iris in response to bright light or certain drugs, resulting in constriction of the pupil.
- Biology/Genetics: A type of cell division that produces reproductive cells (gametes in animals, spores in plants) in sexually reproducing organisms, involving two nuclear divisions that result in four daughter cells, each with half the chromosome number of the original parent cell.
Usage Examples
Noun (Physiological sense):
- The doctor noted the patient's miosis as a normal reaction to the bright examination light.
- Certain opioids can cause pinpoint miosis, a key diagnostic sign.
Noun (Biological sense):
- Miosis is essential for sexual reproduction, as it creates haploid gametes.
- During miosis, genetic material is recombined, contributing to genetic diversity in offspring.
Advanced Usage
"Induced miosis": Pupil constriction caused deliberately by medication, often during eye surgery.
- The surgeon used eye drops to achieve induced miosis for the cataract procedure.
"Argyll Robertson pupil": A condition where miosis occurs in response to focusing on a near object but not to light, often associated with neurosyphilis.
Variants and Related Words
Meiotic (adj): Pertaining to or involving miosis.
- The meiotic process is complex and highly regulated.
Meiosis (n): The more common term for the biological/cytological process of cell division. (Note: 'Miosis' and 'Meiosis' are often used interchangeably in biology, though 'meiosis' is standard. In physiology, only 'miosis' is used for pupil constriction).
Synonyms
- For the physiological sense: Pupillary constriction, pupillary narrowing.
- For the biological sense: Reduction division, meiotic division.
Related Phrases
"Undergo miosis": To experience the process of cell division.
- Germ cells in the ovary undergo miosis to produce ova.
"Exhibit miosis": To show signs of pupil constriction.
- Patients with Horner's syndrome may not exhibit miosis on the affected side.
Notes on Meaning
- The word has two distinct, specialized meanings in different scientific fields (physiology/ophthalmology and cell biology/genetics).
- In clinical medicine, miosis specifically refers to an abnormally or notably constricted pupil.
- In biology, the process is fundamental for generating genetic variation and maintaining chromosome number across generations.
Noun
- reflex contraction of the sphincter muscle of the iris in response to a bright light (or certain drugs) causing the pupil to become smaller
- (genetics) cell division that produces reproductive cells in sexually reproducing organisms; the nucleus divides into four nuclei each containing half the chromosome number (leading to gametes in animals and spores in plants)