Endocrinology Overview and Hormone Mechanisms

Endocrinology

• Endocrinology is the study of hormones and glandular abnormalities, including diabetes and thyroid problems.
• Hormones are biologically active substances secreted by glands.
• Endocrine hormones have a biological effect far away from their source.
• Paracrine hormones have a biological effect nearby.
• Autocrine hormones have a local effect.

Hormone Classification

• Proteins: thyroid-stimulating hormone, insulin, parathyroid hormone
• Amino acids: thyroid hormone, epinephrine
• Steroids: cortisol, aldosterone, testosterone

Mechanism of Action of Hormones

• Hormones circulate in the bloodstream, either bound to transporter proteins or free.
• Free hormones are the active form.
• Hormones enter cells to alter biological activity.

Endocrine Glands

• The diagram shows various glands in the body, including the pituitary, thyroid, parathyroid, adrenal, pancreas, ovaries (female), and testes (male).

Endocrine Hypofunction

• Causes of endocrine hypofunction include congenital defects in hormone biosynthesis, autoimmune destruction of glands, surgery or trauma to glands, and infiltration by tumors or infection.

Coordination of Body Functions

• Body functions are coordinated through various systems, including the nervous system (neurotransmitters), the endocrine system (hormones), neuroendocrine (neurohormones), paracrines (secreted into extracellular fluid), autocrines (affecting the same cells), and cytokines (peptides like interleukins, lymphokines, and adipokines).

Blood Sugar Regulation

• High blood sugar requires communication to stimulate body cells to take up sugar
• This is achieved primarily through endocrine communication

Hormone Functions

• Growth and development: Thyroid, growth hormone (GH), sex steroids, cortisol
• Reproduction: Estrogen, testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), thyroid
• Homeostasis: Thyroid, cortisol, insulin
• Environmental changes: Cortisol, thyroid, aldosterone

Endocrine Hormones

• A table lists various glands, their hormones, and associated functions.

Homeostasis and Hormones

• Examples of homeostasis regulated by hormones include thyroid and temperature control; thyroid, parathyroid, and calcium regulation; and pancreas and glucose control.

Pancreas

• Combination organ: exocrine tissues (acini) secrete digestive enzymes into the small intestine, while endocrine tissues secrete hormones (e.g., insulin, glucagon, somatostatin)
• Processes associated with the pancreas include glycogenolysis and gluconeogenesis.

Pancreas (Hormones and Effects)

• A table lists pancreatic hormones and their target tissues along, with their major effects:
• Insulin: targets all cells (particularly in liver, muscle, and fat); effects: stimulates cellular glucose uptake, increased glycogen synthesis, protein and fat synthesis, and decreases blood glucose.
• Glucagon: targets alpha cells in the pancreas; effect: stimulates hepatic glycogenolysis (breakdown) and gluconeogenesis(production of glucose from other sources), increasing blood glucose.
• Somatostatin: targets alpha and beta cells in the pancreas; effect: suppresses secretion of glucagon and insulin.

Disorders of the Pancreas: Diabetes Mellitus

• Diabetes Mellitus is a disorder of glucose metabolism.
• Type I: Insulin deficiency (juvenile onset, closely related to heredity)
• Type II: Insulin resistance (adult onset, related to heredity and obesity).
• Symptoms of untreated type I and II diabetes include polydipsia, polyuria, polyphagia, weight loss, and weakness.
• Severe cases may lead to ketosis or diabetic ketoacidosis

Diabetic Emergencies

• A table details diagnostic signs associated with various diabetic emergencies.

Conclusions

• Hormones are vital for normal growth, development, metabolism, energy, and reproduction
• Hormones are tightly regulated by various systems.
• Hormone imbalances (over or underproduction) cause clinical problems.

Explore the fascinating field of endocrinology, focusing on hormones, glandular abnormalities, and other critical concepts. This quiz covers hormone classification, their mechanisms of action, and the various endocrine glands in the body. Test your knowledge about how hormones operate and their impact on health.