Lab 14 Endocrine System PDF

**LAB 14 ENDOCRINE SYSTEM** [At the end of this exercise, you should be able to:] 1. Discuss the difference between endocrine and exocrine glands. 2. Identify and name the major endocrine glands and tissues from models and slides. 3. List the hormones produced by each gland and describe t...

**LAB 14 ENDOCRINE SYSTEM** [At the end of this exercise, you should be able to:] 1. Discuss the difference between endocrine and exocrine glands. 2. Identify and name the major endocrine glands and tissues from models and slides. 3. List the hormones produced by each gland and describe the function of each hormone. 4. Describe the effect the specified hormones have on their target tissues. 5. Give examples of how hormones maintain homeostasis. 6. Describe the consequences of hyposecretion and hypersecretion of hormones discussed in the lab. 1. Before placing it on the stage, observe the slide against a piece of white paper to help you identify large structures that you should be focusing on. Can you correlate what you know about the anatomy of the organ with what you see on the slide? Does the tissue have lobes or is it solid? Does the pattern or colour of the stain change in different parts of the tissue? 2. We are observing organs and tissues, so the 4x and 10x objective lenses will be most useful (40x is most useful for observing small groups of cells and organelles). Always begin by scanning the whole slide using the 4x lens for large structures. 3. At 10x, scan an area of the slide that resembles the photomicrographs and drawings to see the structures listed for each tissue. Do you see patterns in how the cells are grouped together? Is there obvious connective tissue throughout the sample or is it found on the outside? Endocrine glands are well vascularized -- note the placement of the capillaries and blood vessels. PART A: THE HYPOTHALAMUS AND PITUITARY GLAND ============================================ **Figure 14.2 Medial view of the left half of the brain showing the location of the hypothalamus, infundibular stalk and pituitary.** 2. **Histology of the Pituitary gland.** -------------------- -- anterior pituitary -------------------- -- 3. **Hormones released by the Pituitary gland.** +-----------------+-----------------+-----------------+-----------------+ | | Growth Hormone | | | | | (GH) | | | +-----------------+-----------------+-----------------+-----------------+ | | Thyroid-Stimula | | | | | ting | | | | | Hormone (TSH) | | | +-----------------+-----------------+-----------------+-----------------+ | | | | | +-----------------+-----------------+-----------------+-----------------+ | | Luteinizing | | | | | Hormone (LH) | | | +-----------------+-----------------+-----------------+-----------------+ | | -- | | | | | -- | | | | | | | | | | ----------- | | | | | Prolactin | | | | | ----------- | | | +-----------------+-----------------+-----------------+-----------------+ | | | Adrenal glands | | +-----------------+-----------------+-----------------+-----------------+ | | | Melanocytes in | | | | | skin | | +-----------------+-----------------+-----------------+-----------------+ | | Oxytocin | | | +-----------------+-----------------+-----------------+-----------------+ | | | | | +-----------------+-----------------+-----------------+-----------------+ PART B: THE THYROID AND PARATHYROID GLANDS ========================================== 1. **Anatomy of the Thyroid and Parathyroid glands.** D:\\Users\\sconnors\\AppData\\Local\\Microsoft\\Windows\\Temporary Internet Files\\Content.Word\\pap14\_fig\_18\_10a\_ul.jpg 2. **Histology of the Thyroid and Parathyroid glands.** a. b. Tortora and Derrickson, Principles of Anatomy and --------------- ------------------- thyroid gland parathyroid gland --------------- ------------------- +-----------------+-----------------+-----------------+-----------------+ | | | | | +-----------------+-----------------+-----------------+-----------------+ | | | | | +-----------------+-----------------+-----------------+-----------------+ | | | parathormone | | | | | | | | | | or parathyroid | | +-----------------+-----------------+-----------------+-----------------+ PART C: THE SUPRARENAL (ADRENAL) GLANDS ======================================= -- ----------- -- --------------------------------------------------------------------------------------------------------- Increases sodium and water reabsorption in kidneys, increases blood pressure Regulates metabolism, reduces inflammation, helps body respond to stress Involved in the development of male secondary sex characteristics, minor role in females \-\-\-\-- Prepare the body for fight-or-flight response, increase heart rate, blood pressure, and glucose release -- ----------- -- --------------------------------------------------------------------------------------------------------- PART D: THE PANCREATIC ISLETS ============================= 1. **Anatomy of the Pancreas.** 2. **Histology of the Pancreas.**  -- -- -- ------------------------------------------------------------------------------------------------------------ Secrete digestive enzymes (amylase, lipase, proteases) and buffers to aid digestion in the small intestine Stimulates the liver to release glucose into the bloodstream, raising blood glucose levels Lowers blood glucose levels by promoting glucose uptake into cells and storage in the liver -- -- -- ------------------------------------------------------------------------------------------------------------ PART E: THE GONADS ================== 1. **Anatomy of the Gonads.** pap10e\_28\_13a\_ul.jpg pap10e\_28\_03a\_ul.jpg -- -- -- -- 2. **Histology of the Ovaries.** a. **Primordial follicles** are very numerous at the outer edge of the cortex. These contain the immature oocytes. b. Under the influence of FSH from the anterior pituitary, primordial follicles develop into **primary follicles**. Primary follicles can be identified by the single layer of cuboidal epithelium (**follicular cells**) surrounding them. More mature primary follicles will have a follicular cell layer 5 or 6 cells deep, which are now referred to as **granulosa cells**. c. Stimulated by FSH, primary follicles develop into **secondary follicles**. These can be identified by the large pool of fluid (follicular fluid in the antrum) sandwiched between two layers of cuboidal epithelium. The layer of granulosa cells surrounding the oocyte secretes estrogens. **Figure 14.13 Secondary follicle, magnified 70x.** From Tortora and Derrickson, Principles of Anatomy and Physiology, 14th Ed., Copyright © 2014 by Biological Sciences Textbooks, Inc. and Bryan Derrickson. This material is used by permission of John Wiley & Sons, Inc. ------------- -- ovary slide ------------- -- -- -- -- ---------------------------------------------------------------------------------------------------------------------------------------- Regulate the menstrual cycle, promote the development of female secondary sexual characteristics, and prepare the uterus for pregnancy Inhibits FSH secretion, helping regulate the menstrual cycle Relaxes the uterine muscles and ligaments, aids in childbirth by softening the cervix Prepares the uterus for pregnancy, maintains the uterine lining during pregnancy Inhibits FSH secretion, helping regulate sperm production Stimulates the development of male secondary sexual characteristics, regulates sperm production -- -- -- ---------------------------------------------------------------------------------------------------------------------------------------- PART F: THE PINEAL GLAND ======================== 1. **Anatomy of the Pineal gland.** 2. **Histology of the Pineal gland.** 3. **Hormones produced by the Pineal gland.** -- -- -------------------------------------------------------------------------------- Regulates sleep-wake cycles (circadian rhythm) and seasonal biological rhythms -- -- -------------------------------------------------------------------------------- PART G: THE THYMUS GLAND ======================== 1. 2. 3. +-----------------------+-----------------------+-----------------------+ | | | -- | | | | -- | | | | | | | | ------------------- | | | | --------------------- | | | | --------------------- | | | | --------------------- | | | | --------- | | | | Stimulates the deve | | | | lopment and maturatio | | | | n of T lymphocytes (T | | | | cells) in the immune | | | | system | | | | ------------------- | | | | --------------------- | | | | --------------------- | | | | --------------------- | | | | --------- | | | | | | | | Enhances the immune | | | | response by promoting | | | | the maturation of | | | | lymphocytes | | | | | | | | Aids in the | | | | development and | | | | differentiation of T | | | | cells | | | | | | | | Promotes the | | | | differentiation and | | | | maturation of T | | | | lymphocytes (T cells) | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ | | | | +-----------------------+-----------------------+-----------------------+ PART H: SUMMARY OF ENDOCRINE DISORDERS ====================================== -- ----------------------------------- --------------------------------------------------------------------------------------------------------------------------------------------- Hyposecretion of hGH pituitary dwarfism hypersecretion of hGH Causes **gigantism** in children (excessive growth) or **acromegaly** in adults (abnormal bone and tissue overgrowth) hyposecretion of ADH Leads to **diabetes insipidus**, causing excessive thirst and urination due to the kidneys\' inability to retain water Hyposecretion of thyroid hormones hyperthyroidism Overproduction of thyroid hormones, leading to weight loss, rapid heartbeat, nervousness, and heat intolerance (e.g., **Graves\' disease**) lack of iodine Causes **goiter** (thyroid gland enlargement) and **hypothyroidism**, since iodine is essential for thyroid hormone production leading to high blood glucose levels and the need for insulin therapy **Insulin resistance**, leading to high blood glucose levels and eventually beta cell dysfunction Causes **hypoglycemia**, leading to dizziness, confusion, sweating, and even loss of consciousness due to low blood glucose levels -- ----------------------------------- --------------------------------------------------------------------------------------------------------------------------------------------- PART I: HORMONE ABBREVIATIONS ============================= THF human growth hormone ------ -------------------------------- thyroid-stimulating hormone OT follicle-stimulating hormone luteinizing hormone hGH prolactin adrenocorticotropic hormone TF melanocyte-stimulating hormone oxytocin TSH antidiuretic hormone triiodothyronine MSH thyroxine calcitonin FSH parathyroid hormone aldosterone PRL androgens dehydroepiandrosterone ACTH epinephrine norepinephrine LH glucagon insulin ADH estrogens progesterone T~3~ relaxin inhibin PTH testosterone melatonin NE thymosin thymic humoral factor T~4~ thymic factor thymopoietin DHEA Epinephrine and norepinephrine Explain why hormones only affect specific cells and not all body cells. ### Paracrine - **Definition**: Paracrine signaling involves the release of signaling molecules that affect **nearby** target cells. - **How It Works**: The signaling molecules (like growth factors, cytokines) are released into the **extracellular fluid** and affect nearby cells, which have receptors for those molecules. The effect is localized to cells in the surrounding area. - **Example**: In the immune system, cytokines released by one immune cell can affect nearby immune cells to coordinate an immune response. ### 2. Autocrine - **Definition**: Autocrine signaling occurs when a cell releases signaling molecules that affect **itself**. - **How It Works**: The cell produces and secretes a signaling molecule, and the same cell also has receptors that respond to this molecule, leading to a self-regulating process. - **Example**: Some cancer cells use autocrine signaling to stimulate their own growth, by producing growth factors that bind to their own receptors. ### 3. Holocrine - **Definition**: Holocrine secretion involves the **entire cell** disintegrating and releasing its contents. - **How It Works**: The cell accumulates its secretory product, and as the cell matures, it ruptures and releases the product. This type of secretion is typically seen in glands with a high turnover of cells. - **Example**: Sebaceous glands in the skin secrete sebum through a holocrine mechanism, where the whole cell breaks down to release its contents. ### 4. Apocrine - **Definition**: Apocrine secretion involves the **partial loss of the cell** along with its secretory product. - **How It Works**: The cell's cytoplasm is pinched off along with the secretion, leaving behind part of the cell membrane. The cell remains intact after the release and can continue secreting. - **Example**: Sweat glands in the armpits and genital area release their products through an apocrine mechanism, along with some cellular material.