ENDOCRINE SYSTEM

We just finished up studying the Endocrine system (ES). I want to discuss some of the parts of the Endocrine system and their function. The ES works with the Nervous system to help maintain homeostasis. The ES releases hormones into the blood stream to control body cells. The Pituitary gland is the "master gland" of the ES. It secretes hormones that control other endocrine glands. They hypothalamus is the "master of the pituitary gland". It is the major link between the nervous and endocrine systems. It helps to regulate the secretion of hormones from the anterior pituitary. Stimuli causes changes in hypothalamic activity. They hypothalamus regulates body temperature, hunger, sexual behavior, fear, and rage. The hormones released from the pituitary gland and the hypothalamus are very important in regulation of growth, development, and metabolism. A hormone is a molecule that is released in one part of the body to change the physiological effect of target cells in another part of the body. We discussed steroidal hormones, thyroid hormones, and Protein hormones. Steroidal hormones are lipid soluble, therefore they must use a transport protein to travel through the ECF/blood, usually Albumin. Their receptors are in the nucleoplasm or cytoplasm. The half life of steroidal hormones is slower and lasts a long time (7-10 days). They induce target cells to make proteins. Examples of steroidal hormones are Aldosterone, Cortisol, Testosterone, and Estrogens. Thyroid hormones are produced in the thyroid gland. Their secretory products are stored in large supply. They control your basal metabolic rate, increase protein synthesis, increase breakdown of triglycerides, and stimulate body growth. Examples of thyroid hormones are T3 and thyroxine. Protein hormones are water soluble, therefore they don't need to use a transport protein to travel through the ECF/blood. Their receptors are in the plasma membrane. Their effects are quicker and don't last long (hours). The effect on the proteins is to change the activity of the proteins already in the target cells (if already activated will deactivate it, if not activated will activate it). Examples of protein hormones are Oxytocin, ADH, LH, FSH, and ACTH.
The study of the ES was especially interesting to me because I just recently had my thyroid checked. My levels were high suggesting sub clinical hypothyroidism. My symptoms were fatigue, increased need for sleep, and mood swings. I was just started on Levothyroxine to help boost the production of TSH. Since beginning the medication I have noticed that I am less tired and happier. I am also hoping that it will boost my metabolism and maybe I'll lose some weight.