Severe, recurrent nausea and vomiting that affectpregnant women especially during the first trimesters of pregnancy, but whichcan persist during the whole gestation. Weight loss and electrolyte imbalance can also be manifest. It is the extreme form of what is colloquially referred to as ‘morning sickness’, a condition that affects 70-80% of pregnant women. The degree …
Category Archives: Uncategorized
Hyoid bone
A fine bone lying inferior to the mandible (jawbone) and from which the larynx is suspended (see figure below). Front view of the larynx showing the position of the horseshoe-shaped hyoid bone and other laryngeal structures. It is unconnected to any other bone, and is thus the only bone in the body that ‘floats’. See Larynx
Hydrocephalus (or hydrocephaly)
Commonly referred to as ‘water on the brain, and first described by Hippocrates of Chios (460-377 BP), it is a disorder in which there is an obstruction of cerebrospinal fluid, which then accumulates in the ventricles (internal or non-communicating hydrocephalus) or in the sub-arachnoid spaces (external or communicating hydrocephalus), leading to an increase in intracranial pressure. …
Hydrolysis
A chemical reaction in which the action of water or its ions (hydrogen, hydroxyl) breaks down a substance into smaller molecules. See Adenosine triphosphosphate (ATP), Glycogen
Hydraulics
A long-standing branch of engineering that is part of the more general field of fluid dynamics. It is concerned with the use of the properties of water and other liquids (as well as gases), at rest or in motion, to perform mechanical tasks using the principles of hydrostatics and hydrodynamics. In engineering, the hydraulic principle …
Hydramnios (or polyhydramnios)
See Oligohydramnios
Hunyh-Feldt epsilon
A correction factor that is smaller than 1 if the sphericity assumption in a repeated measures ANOVA is violated. The factor is multiplied with F, making the test more conservative. This factor is comparable to the Greenhouse-Geisser epsilon, but it tends to be less conservative. See Analysis of variance (ANOVA), Greenhouse-Geisser epsilon, Mauchly test, Repeated …
Huntington’s disease (or chorea)
An inherited adult-onset disorder of the nervous system due to a dominant gene mutation on chromosome 4 causing neurological degeneration, especially to GABA-ergic neurons in the caudate nucleus and putamen of the basal ganglia. Signs include uncoordinated movements, irritability, and attention span deficits. Leads to death with 15-20 years of onset. The first thorough description …
Human Connectome Project (HCP)
Human Genome Project (HGP)
Officially started in 1990, it is an international research effort to map the estimated 30,000 genes in human DNA and to completely sequence the 3 billion chemical base bases that make up these genes. Findings, collected in shared databases, are expected to provide better diagnoses and treatments for a range of human disorders, some of which, …