Medicine & BodyGreek → English
Hypotonic
/ˌhaɪpəˈtɑnɪk/adjective
Having fewer dissolved particles than the fluid it is compared with, or, of muscle, abnormally slack.
The Greek roots
ὑπό
hypó
under, below
τόνος
tónos
stretching, tension
Literally: “under-stretched”
The story of the word
The opposite number of hypertonic, with ὑπό, under, in place of ὑπέρ. A hypotonic solution holds fewer dissolved particles than the cell sitting in it, so water crosses inward and the cell swells; put a red blood cell in pure water and it bursts. Paediatric neurology uses the muscle sense, and hypotonia is what a doctor is testing for when an infant is described as floppy.
- How it travelled
- Ancient Greek → scientific coinage → English
- First recorded
- 19th century
Same family
hypertonicisotonichypothesistonic
In a sentence
Rinsing the sample in a hypotonic buffer swells the nuclei enough to count them.
Marathon runners who drink only water can go dangerously hypotonic in the blood.