Exam (elaborations) BSC 2346 (BSC2346) BSC 2346 Module 10 Lab Worksheet: Endocrine System

BSC 2346 Module 10 Lab Worksheet: Endocrine System.Introduction This week’s lab will focus on the major endocrine glands and the hormones they secrete. Objectives Objectives for this week’s lab include: 1) Identify the location of the major endocrine glands, 2) Map out the hormonal secretion of and influence of the major endocrine glands, and 3) Identify the role of major endocrine hormones, and 4) Describe the negative feedback mechanism to maintain homeostasis. Overview The endocrine system regulates the body’s actions and metabolic activity through the use of chemical messengers called hormones. Hormones, produced by endocrine glands, are secreted directly into the blood stream, travel throughout the body and influence the actions and activity of various cells. It’s a complex mechanism of how a hormone directly influences a cell but a cell needs to have a specific receptor on its plasma membrane to bind a specific hormone. If a cell has a specific hormone, it is referred to as a target cell. Each hormone will have a unique and specific influence on cellular activity that may include: reproduction activities, growth and development, electrolyte, water and nutrient balance in the blood, metabolism and even influence our immune system. Once a cell binds a hormone through its receptor, the response and impact of that hormone can vary greatly. Some hormones have an almost instantaneous effect on that cell (such as epinephrine, aka- adrenaline) to an effect that can last days to even months (such as growth hormone). Hormonal levels are maintained by a negative feedback mechanism. As hormonal levels rise in the blood and affect the target cells, it causes a negative feedback loop to initiate the inhibition of further hormone production and secretion from its endocrine gland. Through this mechanism, hormonal homeostasis is maintained within a very narrow range and is vital because any imbalances to hormonal levels can cause drastic changes in the body’s physiology and can cause conditions such as, type 2 diabetes and hypothyroidism. Materials  Endocrine gland models Pre-Lab Evaluation Questions The pre-lab evaluation questions must be answered prior to lab and demonstrated to your lab instructor. You must read through the assigned chapter readings, lab introduction, objectives, overview and procedure to answer these questions. Please cite your work for any reference source you utilize in answering these questions. 1. In your own words, briefly describe how the endocrine system helps to maintain homeostasis within the body. The endocrine system is a process that relate with the glands and their hormone to regulate specific target in our body. Endocrine help maintain homeostasis when need more energy or resting, play the role for sexual function, signal the bone and tissue for growing, maintain the heartbeat, sugar level, calcium level, fluid level in body. 2. Explain how the thyroid gland and the parathyroid gland help to maintain homeostasis of blood calcium levels? The thyroid gland also secretes a hormone called calcitonin that is produced by the parafollicular cells. Calcitonin is released in response to a rise in blood calcium levels. It appears to have a function in decreasing blood calcium concentrations by: • Inhibiting the activity of osteoclasts • Increasing osteoblastic activity • Decreasing calcium absorption in the intestines • Increasing calcium loss in the urine The parathyroid glands are tiny, round structures usually found embedded in the posterior surface of the thyroid gland. These epithelial cells produce and secrete the parathyroid hormone (PTH), the major hormone involved in the regulation of blood calcium levels, in response to low blood calcium levels by  Stimulating osteoclasts to release of calcium from the bones into the interstitial fluid.  Inhibit the activity of osteoblasts  Increased reabsorption of calcium (and magnesium) in the kidney tubules from the urine filtrate 3. The thyroid gland also produces two hormones that influence our body’s metabolism. What are those two hormones and the difference between them? What element/molecule is vital to provide proper function to these two hormones? In general and overall, what effect do these two hormones have on the body’s function? The thyroid hormones, T3(triiodothyronine) and T4 (thyroxine), are often referred to as metabolic hormones because their levels influence the body’s