General Physiology Lecture - Endocrine System PDF

UNIVERSITY OF THE VISAYAS - GULLAS “GENERAL PHYSIOLOGY LECTURE” Prepared by: Mr. Rommeljun Solijon Datiles  Secretion -Test “GENERAL PHYSIOLOGY MYSTERY” Guess me? You are CORRECT! Hyperthyroidism Guess me? You are CORRECT! Hypothyroidism Guess me?  You are CORRECT! P...

UNIVERSITY OF THE VISAYAS - GULLAS “GENERAL PHYSIOLOGY LECTURE” Prepared by: Mr. Rommeljun Solijon Datiles  Secretion -Test “GENERAL PHYSIOLOGY MYSTERY” Guess me? You are CORRECT! Hyperthyroidism Guess me? You are CORRECT! Hypothyroidism Guess me?  You are CORRECT! Polycystic Ovarian Syndrome (PCOS) Guess me? You are CORRECT! Erectile Dysfunction Guess me? You are CORRECT! Diabetes Guess me?  You are CORRECT! Dwarfism - Skeletal Dysplasia Guess me? You are CORRECT! Gonadotropins Guess me? You are CORRECT! Prolactin Hormones Guess me? You are CORRECT! Adrenal Gland Guess me? You are CORRECT! Melatonin Hormone LEARNING OBJECTIVES At the end of the lesson, the student should be able to: 1. discuss the major fuctions of endocrine system and their specific parts; 2. distinguish similarities and differences between neural and hormonal communication; and 3. recognize the importance of endocrine system. ENDOCRINE SYSTEM Communication within the human body involves the transmission of signals to control and coordinate actions in an effort to maintain homeostasis. There are two major organ systems responsible for providing these communication pathways: the nervous system and the endocrine system. The nervous system is primarily responsible for rapid communication throughout the body.  n contrast, the endocrine system relies on only a single method of communication: chemical signaling. Hormones are the chemicals released by endocrine cells that regulate other cells in the body. Hormones are transported primarily via the bloodstream throughout the body, where they bind to receptors on target cells, triggering a response. What is Endocrine System? The Endocrine system is a network of glands and organs located throughout the body. It’s similar to the nervous system in that it plays a vital role in controlling and regulating many of the body’s functions. While the nervous system uses nerve impulses and neurotransmitters for communication, the endocrine system uses chemical messengers called hormones. Function of Endocrine System Despite the huge variety of hormones, there are really only two mechanisms by which hormones trigger changes in cells. Function of Endocrine System Glands Unlike exocrine glands (sweat, salivary), endocrine glands secrete their respective substances directly into the bloodstream rather than through a duct. These endocrine glands belong to the body’s control system and they produce hormones which help to regulate the functions of cells and tissues. The endocrine system involves many organ systems and hormones, many of which are still being investigated and understood. Endocrine Organs The major endocrine organs of the body include the: Ø pituitary, Ø thyroid, Ø parathyroid, Ø adrenal, Ø pineal, Ø thymus glands, Ø the pancreas, and Ø the gonads. Hypothalamus v Hypothalamus. The hypothalamus, which is part of the nervous system, is also considered a major endocrine organ because it produces several hormones. It is an important autonomic nervous system and endocrine control center of the brain located inferior to the thalamus. Functions: Secretes hormones involved in fluid balance, smooth muscle contraction, control of hormone secretion by anterior pituitary gland Pituitary Gland (Master Gland) The pituitary gland is approximately the size of a pea. The pituitary is the most influential gland in the endocrine system. Location. The pituitary gland hangs by a stalk from the inferior surface of the hypothalamus of the brain, where it is snugly surrounded by the “Turk’s saddle” of the sphenoid bone. Lobes. It has two functional lobes- the anterior pituitary (glandular tissue) and the posterior pituitary (nervous tissue). Pituitary Gland (Master Gland) Functions. Secretes multiple hormones that regulate the endocrine activities of the adrenal cortex, thyroid gland, and reproductive organs, and a hormone that stimulates melanin production Hormones of the Anterior Pituitary Hormones of the Posterior Pituitary Thyroid Gland The thyroid gland is a hormone- producing gland that is familiar to most people primarily because many obese individuals blame their overweight condition on their “glands” (thyroid). Functions. Secretes hormones affecting metabolic rate and calcium ion levels in body fluids Thyroid Gland Parathyroid Gland The parathyroid glands are mostly tiny masses of glandular tissue. Functions. Secrete hormone important to regulation of calcium ion levels in body fluids Parathyroid Gland  Adrenal Gland Although the adrenal gland looks like a single organ, it is structurally and functionally two endocrine organs in one. Functions. The two adrenal glands secrete hormones involved with mineral balance, metabolic control, and resistance to stress They also release epinephrine and norepinephrine during sympathetic activation Hormones of the Adrenal Cortex Hormones of the Adrenal Medulla  Pineal Gland The pineal gland, also called the pineal body, is a small cone-shaped gland. Functions. Secretes melatonin, which affects reproductive function and circadian (day/night) rhythms Thymus Gland The thymus gland is large in infants and children and decreases in size throughout adulthood. Functions. Immune response. Pancreatic Islets The pancreas, located close to the stomach in the abdominal cavity, is a mixed gland. Pancreatic Islets  Gonads Functions. growth, metabolism, sexual characteristics as well as activities of organs in reproductive system While the testes are specific to males. Ovaries produce estrogen that is important for reproduction and female sex characteristics. Testes produce testosterone that is responsible for male sex characteristics. Also, it results in increased muscle mass and body hair. Hormones of the Ovaries Hormones of the Testes Other Hormone-Producing Tissues v Placenta The placenta is a remarkable organ formed temporarily in the uterus of pregnant women. The Chemistry of Hormones Mechanisms of Hormone Action Control of Hormone Release The Women’s Hormone: Estrogen The Mother’s Hormone: Progesterone The Men’s Hormone: Testosterone The Stress Hormone: Cortisol The Sleep Hormone: Melatonin Grow Up or Grow Down: Growth Hormone The Milk Hormone: Prolactin The Bitter Hormone: Gastrin The Bloody Hormone: Erythropoietin