Transcript Part B
BIO 265 – Human A&P Chapter 16 – Part B - Endocrine Glands Intro. To Endocrine Glands – Figure 16.1 Pituitary Gland and Hypothalamus The pituitary gland secretes 9 major hormones that regulate numerous body functions – The hypothalamus regulates the secretory activity of the pituitary gland – Important structures: • Infundibulum • Posterior pituitary (composed of nervous tissue) • Anterior pituitary (true gland tissue) – Figures from other text Pituitary Gland and Hypothalamus Regulation of hormone secretion – Anterior pituitary • The hypothalamus secretes releasing or inhibiting hormones • Figure from other text Pituitary Gland and Hypothalamus – Posterior pituitary (neurohormones) – Figure Pituitary Gland and Hypothalamus Hormones of the Pituitary Gland – Table 16.1 Pituitary Gland and Hypothalamus Hormones of the Anterior Pituitary – Some of these are tropic hormones that regulate the secretion of hormones from other glands – Gonadotropins – control the production of sex hormones as well as gametes • Luteinizing hormone (LH) and Follicle stimulating hormone (FSH) • Regulation by gonadotropin releasing hormone (GnRH) – Figure 18.3 • More in chapter 28. Pituitary Gland and Hypothalamus – Growth hormone (GH) – stimulates growth in most tissues and regulates metabolism • stimulates the breakdown of fats in adipose tissue • Secretion is stimulated by stress and low blood glucose levels • Figure 18.6 Pituitary Gland and Hypothalamus – Thyroid stimulating hormone (TSH) – others Thyroid Gland Location in the body – Figures 16.1 and 16.7 Thyroid Gland Hormones: – Calcitonin – what does this do? – Thyroid Hormones - Triiodothyronine (T3) and thyroxine (T4) • These interact with intracellular receptors • They affect metabolism and growth of tissues • Regulation of secretion – Figure and CD animation Parathyroid Glands Secretes Parathyroid Hormone (PTH) – What does this hormone do? – Bone – increased osteoclast activity – Kidney – increased reabsorption of calcium and production of Vit. D – Intestines –increases calcium uptake – Figure 16.11 and CD animation Adrenal Glands Location – Figure 16.1 and 16.12 Adrenal Glands – Composed of an inner medulla and an outer cortex – The adrenal cortex produces aldosterone • This increases sodium reabsoption in the kidneys • which increases water reabsorption and therefore blood volume • How would this hormone be related to ADH? Adrenal Glands – The adrenal medulla produces epinephrine (adrenalin) and norepinephrine (noradrenalin) – These hormones bind to adrenergic receptors that function through G-protein systems – Regulation and functions – Figure 16.15 The Pancreas The pancreas is both an endocrine gland and an exocrine gland – Exocrine – acini (digestive enzymes) – Endocrine – pancreatic islets (islets of Langerhans) – Figure 16.1 Pancreas Effect of glucagon – Affects the liver – It increases glycogen breakdown and glucose synthesis and secretion – When would glucagon be released? Pancreas Effect of insulin – Target tissues: liver, adipose tissue, and skeletal muscle – Binds to a membrane-bound receptor and increases glucose uptake • Glucose is then converted to glycogen in muscle and liver cells and fat in adipose cells – Without insulin adipose tissue and skeletal muscle take up and use very little glucose and amino acids Pancreas Regulation of insulin secretion? Figure 16.17 and CD animation Pancreas Diabetes mellitus – Type 1 or insulin-dependent diabetes mellitus • Caused by the autoimmune destruction of pancreatic islets • Only 3% of total diabetes cases • Usually seen in young people – Type 2 Diabetes (insulin independent or adultonset diabetes) • Results from the inability of tissues to respond to insulin • Cause is unknown (genetic?) Pancreas • It is sometimes referred to as insulin resistance • 97% of total diabetes cases Reading Reading Sections in Chapter 16