Letter: h

Hertz – Unit of frequency; 1 Hz equals one cycle per second

Hypoxic hypoxia is commonly referred to as hypoxemic hypoxia (or relative deficiency in the bloodstream), but is described accurately as a condition of relative oxygen deficiency in the tissues caused by low arterial oxygen tension.

The response of pulmonary arterioles to depressed alveolar oxygen tension. The vascular response shunts pulmonary blood flow away from alveoli that are under-ventilated, toward lung regions that are better ventilated, thus minimizing the effect of ventilation-perfusion inequalities in the lung.

Characterized by less than normal pressure or density. Applies to a solution with lower specific gravity than that of another solution taken as a reference.

An increase in the depth of breathing, with or without an increase in the rate of breathing.

As a surface disinfectant, used at the right concentration and pH is effective against most vegetative bacteria, fungi, enveloped and non-enveloped viruses as well as Mycobacterium tuberculosis and bacterial spores if solution remains at high concentration. It is inactivated by organic substances. For sporicidal concentration: 1 part household bleach to 9 parts water; approximately 5,000 ppm free chlorine – good for 24 hours, then need to make fresh again.

Term used to describe an exaggerated response to a foreign substance (i.e., an antigen), which causes tissue damage in a host after repeated challenges, causing the individual to become sensitized. Type I hypersensitivity mediated by IgE antibodies and produces an immediate (minutes to an hour) reaction; e.g. peanut, latex, penicillin allergy. Type IV hypersensitivity is cell mediated and response requires 24-72 hours for the rash-like symptoms to fully express, skin transplants to be rejected, etc.

Location: promontory of sacrum. Serves pelvic plexus and viscera of pelvis. Contains sympathetic elements.

Describes the production of a much higher number of spores per population of a specific spore-forming bacterium than is usually encountered. Hypersporulation increases the likelihood of successful dispersion and of being transmitted to a vulnerable host.

Underdevelopment undevelopment of a tissue or organ.