HDL

High-density lipoproteins. High density lipoproteins (HDL): the “good” cholesterol. HDL carry cholesterol in the blood from other parts of the body back to the liver, which leads to its removal from the body. So HDL help keep cholesterol from building up...

Hemianopsia

Loss of one half of the field of vision (the area that can be seen by each eye when staring straight ahead). Can occur in isolation or affecting both eyes. The most common form of vision loss due to pituitary tumors is loss of the outer half of vision in both...

Herniation

Bulging of tissue through an opening in a membrane, muscle or bone. A protrusion of an organ or part through connective tissue or through a wall of the cavity in which it is normally enclosed — called also rupture. A brain herniation is the displacement of brain...

Hormone (Adj. Hormonal)

A chemical “messenger” which is made and secreted by an endocrine gland and which targets one or more parts of the body, modifying its structure or changing the way it works. Hormones are chemical substances having a specific regulatory effect on the...

Hormone Replacement Therapy

The name given to a form of treatment in which missing or deficient hormones can be replaced, the body being encouraged to behave normally as if it were making the hormones naturally. Doses are designed to mimic normal blood levels and vary depending on the...