Symptoms can be serious, and the disease can be fatal â especially for babies, the elderly, and people with weakened immune systems. When influenza pandemics occur, they spread quickly, often killing large numbers of previously healthy people. From 1918 to 1919, a flu pandemic hit the U.S. in three waves.
Enucleation (Eyeball Removal). Enucleation is the removal of an eye. It is an irreversible method of treating various disorders of the eye. Reasons for enucleation include: 1  Severe untreatable trauma, such as a perforated or ruptured eyeball. 2  Uncontrollable glaucoma.
This is located in the SCN which is in the hypothalamus. When it is activated by lots of light (exogenous zeitgebers) entering the eyes the SCN sends a signal to the pineal gland to suppress the release of melatonin, making us feel more awake. Changes in light is an example of an exogenous zeitgeber that gives us a cue as to the time of day.