This document discusses steroid hormones and their functions. It states that cholesterol is the precursor for five major classes of steroid hormones: progestagens, glucocorticoids, mineralocorticoids, androgens, and estrogens. These hormones act as powerful signal molecules that regulate many organismal functions. For example, progesterone prepares the uterus for embryo implantation and is essential for maintaining pregnancy. Androgens promote male secondary sex characteristics, while estrogens promote female secondary sex characteristics and participate in the ovarian cycle along with progesterone.

3. Fig. 4-5a, p. 77

46. Steroid Hormones. Cholesterolisthe precursor of thefivemajorclasses of steroid hormones:progestagens, glucocorticoids, mineralocorticoids, androgens, and estrogens . These hormones are powerfulsignalmoleculesthatregulate a host of organismalfunctions. Progesterone, a progestagen, prepares thelining of theuterusforimplantation of anovum. Progesteroneisalsoessentialforthemaintenance of pregnancy. Androgens of malesecondary sex characteristics, whereasestrogens (such as estrone) are requiredforthedevelopment of femalesecondary sex characteristics. Estrogens, alongwithprogesterone, alsoparticipate in theovariancycle.

49. ESTRUCTURA QUIMICA DE ACIDOS BILIARES (PRIMARIOS, SECUNDARIOS) 1rias Ac. Cólico 2rias Acido Deoxicólico Colesterol Ac. Quenodeoxicólico

52. COMPOSICION DE LA SECRECION BILIAR (0.5-1 L/d) COMPONENTE CONCENTRACION (mmol) Electrolitos Na+ 140-165 K + 3-7 Cl - 80-120 HCO3 - 10-55 Ca 2+ 2.5-6.5 Mg 2+ 1.5-3.0 Aniones Orgánicos Acidos Biliares 3-45 Bilirrubina 1-2 Lípidos Lecitina 140-800 mg7dl Colesterol 100-320 mg/dl Proteínas 1-20 mg/ml Péptidos y Aminas Glutatión 3-5 Glutamato 1-2.5 Aspartato 0.4-1 Glicina 0.5-2.5