BIOD 151 Exam 6 Diagrams

There are two main categories of hormones: peptide hormones and steroid hormones. Peptide hormones can be derived from proteins, peptides, or catecholamines. Peptide hormones activate existing enzymes in the cell. Peptide hormones tend to act relatively quickly but for a short period of time. Steroid hormones are derived from cholesterol by a series of metabolic reactions. Steroids act more slowly than peptides because it takes more time to synthesize new proteins than to activate enzymes that are already present in the cell. There are two types of glands: endocrine and exocrine glands. Endocrine glands are ductless, secreting their contents directly into the bloodstream for distribution throughout the body. Exocrine glands have ducts that secrete their contents into an epithelial surface ex. salivary glands secreting salivary amylase into the mouth. Endocrine Organs ● Aldosterone’s primary target organ is the kidney, where it promotes renal absorption of sodium and renal excretion of potassium. The blood sodium level is particularly important to the maintenance of blood pressure. Too much sodium causes retention of fluid and increases blood pressure. Therefore, too much aldosterone will cause increased and potentially high blood pressure.