The Endocrine System the body s network of glands

The Endocrine System the body’s network of glands Stephanie B Kim T

The Main Functions • To maintain homeostasis • Promote permanent structural change – Instrumental in: • • • Regulating mood Growth and development Tissue function Metabolism Sexual function and reproductive processes.

Endocrine System

Glands • Groups of tissue that produce and secrete a produce – Endocrine • Discharge their goods near the organ they control or into the body’s blood system – Exocrine • Release products onto some body surface through a tube or duct

Target Organs • Each type of hormone affects only specific tissue cells or organs • Messages can be delivered to every cell in the body – One gland transmits instructions on how to use glucose • Messages can directly regulate only one or two body functions – One gland sends a message to the kidneys that determines how much water is removed from the body to make urine

Hormones (set in motion) • Chemicals produced in one part of the body that affect the activity of a specific group of cells and tissues within a target organ • Most are composed of amino acids • Hormone regulation – Input from the nervous system – Chemicals in the blood – Environment – Negative Feedback Loop

Hypothalamus (the master of the master) • Not a gland • Region of the brain containing many control centers for body functions and emotions • Regulates the activity of the pituitary by producing a specialized set of chemicals —releasing hormones

Pituitary Gland (master gland) • Controls and coordinates the secretion of other endocrine glands • Anterior – 4 trophic hormones—they control the activity of other endocrine glands – 2 growth hormones • Posterior – Serves as a storage chamber that holds antidiuretic hormones (ADH) and oxytocin (OT)

• Thyroid-stimulating hormone regulates secretion of hormones produced by the thyroid gland • Adrenocorticotropic hormone —controls the production of hormones by the adrenal cortex, the outer layer of the adrenal gland • Follicle-stimulating hormone—gonadotrophins (gonad growers) regulate gonads, or sexual organs • Luteinizing hormone—gonadotrophins—when an egg cell has reached maturity, LH triggers its release from the ovary—in males, FSH works in concert with LH to regulate production of sperm, male reproductive cells, and testosterone • Prolactin—causes milk production after the birth of a baby • Growth hormone (GH)—general metabolic hormone, affects the way cells work throughout the body – Stimulates body cells to grow and divide, helps new cells take up and use nutrients

Posterior • ADH and OT are chemicals made by nerve cells in the hypothalamus – Drain into the posterior part of the gland – Enter the bloodstream when signaled by the nervous system • ADH helps maintain water in the body – Reduces the amount of water that the kidneys excrete • The primary target organs of oxytocin are the uterus and breasts

Thyroid Gland • TSH’s target organ • Thyroxine and Triiodothyronine – Regulate the rate at which glucose is used by cells to make energy – Need iodine to produce these two hormones • Calcitonin—control the amount of calcium and phosphate in the blood – If there is an excess of calcium in the blood, the anterior pituitary releases calcitonin

Parathyroid Gland • Parathyroid hormone (PTH)— works with calcitonim to regulate calcium levels in the blood, the effect of one opposes the effect of the other – PTH, activated when calcium levels in the blood drop • increases blood calcium – Target organs are bones, kidneys, and the small intestine

Adrenal Gland • Medulla (central portion)—when the body is under stress, nerve fibers stimulate the adrenal medullas, causing them to pump their hormones into the bloodstream – Epinephrine (adrenaline) and Norepinephrine (noradrenaline) • increase the heart rate, strengthen the heartbeat, elevate blood pressure, speed up breathing, and slow digestive processes • Changes get more oxygen and glucose into the blood and raise thinking to higher level of alertness

• Cortex (outer)—produces aldosterone, cortisol, sex hormones – Aldosterone—helps regulate the amount of water and minerals, or electrolytes, in the body • Direct the kidneys either to remove or leave the minerals – Cortisol—keeps blood glucose levels constant, targets every cell in the body • Slows swelling after an injury • Helps reduce discomfort by inhibiting the release of pain-causing secretions, prostaglandins

Reproductive Glands (Gonads) • Estrogen and Progesterone • Estrogen—stimulates the maturation of reproductive organs and development of secondary sex characteristics • Help maintain pregnancy and prepare breast to produce milk, working with progesterone prepares the uterus to receive a fertilized egg

• Testosterone – Bring about the development of secondary sex characteristics – Maturation of the reproductive system – Development of the male sex drive

Pancreas • Exocrine part of the pancreas makes digestive juices that flow through a duct to the upper end of the small intestine • Endocrine part is made up of thousands of small patches of cells (islets of Langerhands) scattered through the pancreas – maintain stable levels of glucose in blood

• Alpha—produce the hormone called glucagon (primary secreted during the night) – Low levels of glucose triggers the release of glucagon from alpha cells – This hormone stimulates the liver to change glycogen into glucose, thus raising blood levels of this lifesustaining sugar • Beta—make another hormone, insulin-lowers the blood levels of glucose (day) – Insulin is released after a meal when glucose is abundant in the body

Pineal Gland • Stimulated by the environment (light) • Secretes melatonin – Targets cells in the brain that help regulate sleep behavior

Thymus • Secretes hormones known collectively as thymosins • Thymosins help change lymphocytes (white blood cells) into T cells – T cells are programmed to attack any foreign substance in the body

Mixed Glands • Pancreas - digestive system – Secretes pancreatic juices into the small intestine • Ovaries and testes - reproductive system – Produce gametes or the male and female reproductive cells • Thymus - lymphatic system – Helps white blood cells to develop in order to fight germs

Diabetes mellitus aka Diabetes

Diabetes can be divided into 3 different types…. • Type 1 Diabetes • Type 2 Diabetes • Gestational Diabetes

Each type’s symptoms are similar • • • extreme thirst and/or hunger excessive urination unusual weight loss fatigue blurred vision skin complications

Type 1 Diabetes (Juvenile Diabetes) • ETIOLOGIES/RISK FACTORS – exact cause is unknown – could be: genetics or autoimmune disorder • TREATMENTS: – regular insulin injections – monitoring blood sugar levels – maintaining a diabetic diet – pancreas or kidney transplant – (experimental) islet cell transplant

Type 2 Diabetes • ETIOLOGIES/RISK FACTORS: – – – – – - body does not produce enough insulin - cells ignore insulin - being overweight or obese - genetics - history of Gestational Diabetes - high blood pressure - age - older adults over the age of 65 are more at risk - inactivity - prediabetes

Type 2 Diabetes ( cont. ) • TREATMENTS: – regular insulin injections – monitoring blood sugar levels – maintaining a diabetic diet – pancreas or kidney transplant – (experimental) islet cell transplant

Gestational Diabetes • temporary • ETIOLOGIES/RISK FACTORS • - hormones produced by placenta have possible blocking affect on insulin • - pancreas not able to produce additional insulin • - family history of diabetes • - obesity • - given birth previously to an overweight child, a stillbirth, or a child with a birth defect • - age

Gestational Diabetes (cont. ) • TREATMENTS: – balanced diet – regular exercise – monitoring blood sugar and fetal growth – insulin injections

International Research • AUSTRALIA – research has provided new evidence that prevention or delaying Type 1 Diabetes is possible – intranasal delivery of an insulin solution • UNITED KINGDOM – testing islet cell transplantations – using stem cell research to search for treatments for Diabetes

Acromegaly • which the anterior pituitary overproduces growth hormone, resulting in abnormal enlargement of the extremities – nose, jaw, fingers, and toes • in children, the disorder produces gigantism

Acromegaly • Tumor causes the anterior pituitary to ignore growth hormones • Inhibiting hormone GHIH, a regulating hormone secreted by the hypothalamus that stops the pituitary from producing GH

Symptoms • • • Headache Visual field loss or double vision Excessive sweating Hoarseness Milk secretion from breast Sleep apnea Carpal tunnel syndrome Joint pain and limitation of motion Muscle weakness Numbness or tingling of skin

• Examination-large “doughy” hands, large feet, large face, enlarged jaw, tongue problems, big forehead, darkened skin in armpits, widely spaced teeth, oily, tough skin, skin pigmentation changes, excessive hair growth in females, high blood pressure, goiter (enlarged thyroid), kyphosis or loss of disc spaces of the spine, osteoporosis, osteoarthritis • Laboratory findings-growth hormone level is high • Imaging-MRI shows pituitary tumor

Treatment • Pituitary microsurgery to remove tumor • Pituitary radiation if surgery fails • Gamma knife radiation treatment (a special type of focused radiation) – Medication to help reduce the secretion of GH – Bromocriptine (helps decrease growth hormone in some patients) – Octreotide (partially shrinks pituitary tumor) • Without treatment individual will most like die early because of the disorder’s effects on the heart, lungs, and brain

Cushing’s Syndrome • Disorder caused by an overproduction of steroids (mostly cortisol) by the adrenal cortex, resulting in obesity and muscular weakness • Caused by a tumor in either the pituitary gland or in one of the adrenal glands • The anterior pituitary secretes adrenocorticotrophic hormone (ACTH), which stimulates the adrenal cortex to release cortisol

Symptoms

Treatment • Surgical removal of either the pituitary tumor or the adrenal tumor • Radiotherapy with yttrium implants – Medical-reduce ACTH with bromocriptine after surgery • If the entire adrenal gland is removed, the patient will have to take steroid medication for the rest of his life