Hemodynamics describes the physical principles and forces involved in blood circulation.

See also Hemoglobin.

(Hb) Hemoglobin is the major endogenous oxygen-binding molecule, responsible for binding oxygen in the lung and transporting it to the tissues by means of the circulation. Hemoglobin is contained in very high concentration in the red blood cells.
Hemoglobin is a Fe chelate tightly binding one Fe ion in its II oxidation state where it carries the charge 2+. If an oxygen molecule is bound to Hb, Hb is called oxyhemoglobin, if no oxygen molecule is bound it is called deoxyhemoglobin. When hemoglobin is oxidized (i.e. in a hematoma), Fe2+ is transformed into Fe3+. The resulting hemoglobin is then called metoxyhemoglobin (Hb Fe3+).

(Hz) The standard SI unit of frequency.
Definition: The number of repetitions of a periodic process per unit time. It is equal to the old unit cycles or oscillations each second of a simple harmonic motion. The unit is named for the German physicist Heinrich Rudolf Hertz.
Larger units are
kilohertz (kHz) = 1 000 Hz
megahertz (MHz) = 1 000 kHz
gigahertz (GHz) = 1 000 MHz

From Hitachi Medical Corporation (HMC), sales, marketing and service in the US by Hitachi Medical Systems America Inc.
The HI VISION™ 5500 - EUB-5500 fully digital ultrasound system delivers the latest generation of signal processing technology, sophisticated transducer design, and a host of features and options for advanced imaging capabilities across a wide range of clinical situations. This system is compatible with all Pentax ultrasound endoscopes.

From Hitachi Medical Corporation (HMC), sales, marketing and service in the US by Hitachi Medical Systems America Inc.;
Powerful, flexible, and fast, the HI VISION™ 8500 - EUB-8500 diagnostic ultrasound scanner combines leading edge technologies with user-oriented operation for exceptional imaging and functionality.
Available exclusively on the 8500, SonoElastography provides a new perspective on the physical properties of tumors and masses by determining and displaying the relative stiffness of tissue.