The adrenal medulla develops from neural tissue and secretes two hormones, epinephrine and norepinephrine. These two hormones are secreted in response to stimulation by sympathetic nerve, particularly during stressful situations. A lack of hormones from the adrenal medulla produces no significant effects.
Premature ventricular contractions (PVCs, PVC) are premature heartbeats originating from the ventricles of the heart. Premature ventricular contractions are premature because they occur before the regular heartbeat. The heart has four chambers. The upper two chambers are the atria, and the lower two chambers are the ventricles.
Giant Papillary Conjunctivitis Go to Academy Store Learn more and Purchase. Giant Papillary Conjunctivitis Giant papillary conjunctivitis (GPC) occurs in primary and secondary forms (Figure 9). All forms of GPC are at least partially caused by chronic ocular allergy. Primary forms of GPC include vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC). Secondary GPC is caused by contact lenses, ocular prostheses, or exposed sutures.