Mindblown: a blog about philosophy.
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Hiccups
A hiccup is an extraordinary type of respiratory movement involving a sudden inspiration (intake of air) due to an involuntary contraction of the diaphragm accompanied by closure of the glottis (the vocal apparatus of the larynx). The abrupt inspiration is the result of a sudden contraction of the diaphragm. Closure of the glottis then halts the incoming air. The column…
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Hiccough
Hiccups happen when the diaphragm, the muscle that separates the chest from the abdomen, suddenly contracts. When that happens, air is taken in, and then the voice box closes shut, which is what causes the “hic” sound. There are different types of hiccups, named after how long they last: A “regular” bout of hiccups can last up to 48…
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Hiatus
An opening, as in the diaphragm. When there is an unusually wide opening in the diaphragm, there can be a hiatus (or hiatal) hernia. In Latin an hiatus is “an opening, gaping mouth, or chasm.” It is derived from the verb “hiare” meaning “to gape or yawn.” Therefore, a “hiatus” is a gaping opening in anything, such as the opening…
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Hiatal
Pertaining to an hiatus, an opening. An hiatal hernia occurs when a part of the stomach protrudes through the diaphragm at the opening where the esophagus normally passes through the diaphragm. “Hiatus” in Latin means an opening.
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HGD
The gene encoding an enzyme called homogentisate 1,2-dioxygenase (also known as homogentisate oxidase). HGD is located on chromosome 3 in region 3q21-q23. Homogentisate oxidase is active chiefly in the liver and kidneys. It is needed to break down the amino acids phenylalanine and tyrosine. Previous steps convert these two amino acids into a molecule called homogentisic acid. Homogentisate oxidase adds two…
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Hg
Symbol for the metallic element mercury. The abbreviation “mm Hg” means millimeters of mercury, the height of a column of mercury, as in a blood pressure reading. Mercury is poisonous to people.
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Hexadactyly
The presence of an extra digit, a sixth finger or toe, which is a very common congenital malformation (birth defect). This condition is called hexadactyly. The word hexadactyly literally means six digits. In medical usage, hexadactyly does not specify whether the six digits are fingers or toes (although in Greek “dactylos” is without equivocation a finger). The 6th…
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Heterotopic
In the wrong place, in an abnormal place, misplaced. From the Greek roots “hetero-” meaning “other” + “topos” meaning “place” = other place. For example, heterotopic bone formation is the formation of bone where it is not normally found, as in muscle.
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Hetero-
Prefix meaning different, as in heteromorphism (something that is different in form) and heterozygous (possessing two different forms of a particular gene). The opposite of hetero- is homo-.
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Herpes zoster
Also called shingles, zona, and zoster. The culprit is the varicella-zoster virus. Primary infection with this virus causes chickenpox (varicella). At this time the virus infects nerves (namely, the dorsal root ganglia) where it remains latent (lies low) for years. It can then be reactivated to cause shingles with blisters over the distribution of the affected nerve accompanied by often intense pain and itching. Herpes…
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