The Endocrine System With nervous system coordinates the function of all body systems Regulates homeostasis through hormones

Hormones Over 50 hormones Secretions enter blood Effect target cell, tissue, organ Most only affect a few types of cells

FUNCTIONS OF HORMONES Help regulate: 1. Metabolism/homeostasis 2. ICF & ECF balance 3. Contraction of smooth and cardiac muscle 4. Reproductive system Control growth & development

Feedback Loops

Hypothalamus GHRH GnRH TRH GHIH CRH PRH ADH PIH OXT Maintains homeostasis by sending hormones to other glands. The Hormones below signal other glands: GHRH TRH CRH ADH OXT GnRH GHIH PRH PIH

Pituitary Gland Often called the master gland because it secretes hormones that control other endocrine glands Structurally divided into two parts: Anterior Pituitary Gland (Adenohypophysis) Posterior Pituitary Gland (Neurohypophysis)

Human Growth Hormone (hGH) or Somatotropin The most abundant anterior pituitary hormone Stimulates growth of body cells Stimulates protein synthesis Inhibits protein breakdown Stimulates lipolysis (fat breakdown) Inhibits the use of glucose as a fuel for metabolism

Thyroid Located just below the larynx Only gland that can store its secretory product in large quantities normally about a 100 day supply

Actions of Thyroid Hormones (T3 and T4) Regulates oxygen utilization and basal metabolic rate Regulates cellular metabolism Works in conjunction with hGH to regulate growth and development catecholamines Enhances the actions of epinephrine - norepinephrine

Adrenal glands Superior to each kidney Two regions Adrenal Cortex Outer region Makes up the majority of the gland ACTH  Cortisol (Hydrocortisone) Adrenal Medulla The inner portion of the gland Epinephrine and Norepinephrine (Adrenaline and Noradrenaline)

Pancreas The endocrine tissue of the pancreas is called the Pancreatic Islets or Islets of Langerhans Alpha Cells - secrete Glucagon raises blood sugar Beta Cells - secrete Insulin lowers blood sugar

Endocrine System Concept Map

STRESS Anything that disrupts homeostasis May be physical May be related to life situations

General Adaptation Syndrome (GAS) Three stages Body’s response to stress

Alarm Stage Body is preparing for stress Body’s way of dealing with a stressor

Body changes during alarm Increase blood pressure Increase heart rate Muscles tense Decrease in blood supply to digestive system More mentally alert Better hearing and eyesight Sweating Dry mouth More blood and glucose to muscles

Resistance stage Body is dealing with the stress Body is trying to keep going Body’s way of dealing with prolonged stress

Exhaustion stage Body is worn out Major fatigue Increase in cortisol levels Decrease in K+ Immune system is depressed Illness may occur

Diseases and Disorders of the Endocrine System

Acromegaly caused by the hypersecretion of hGH during adulthood also caused by steroid and hGH use bones of hands, feet, and skull thicken eyelids, lips, and tongue enlarge skin thickens and develops furrows

Cretinism caused by hyposecretion of thyroid hormones during fetal development Dwarfism usually severely mentally retarded yellowish skin color

Diabetes Mellitus Caused by Hyperglycemia symptoms include: polyuria - polydipsia polyphagia - glucosuria Two Types or Categories of Diabetes Type I Diabetes: usually insulin dependent Type II Diabetes: not usually insulin dependent, but can become so Diabetes Insipidus – Diabetes caused by intense thirst and urination.

Type I Diabetes (IDDM) pancreas does not produce insulin suffiecient insulin requires regular injections of insulin most commonly develops in individuals younger than 20 years old (Juvenile Onset Diabetes Mellitus)

Type II Diabetes also called Maturity Onset Diabetes much more common type of Diabetes (over 90% of Diabetes cases) most often occurs in individuals over 40 most individuals are overweight or clinically obese blood glucose levels can usually be controlled by diet, exercise, and weight loss and control

Complications from Diabetes Blindness Kidney failure Neuropathy Slow healing—leads to necrosis Necrosis often causes gangrene Gangrene leads to amputation

Diabetic ulcer of the big toe

Gangrene caused by neglect

Treatments for Diabetes regular insulin injections Special diet artificial pancreas transplantation of the pancreas transplantation of clusters of Islet Cells injection of fetal Islet Cells Insulin pump

Dwarfism caused by a hyposecretion of hGH during the growth years causes slow bone growth epiphyseal plates close before normal height is reached other organs of the body may also fail to grow and develop treatment requires administration of hGH during childhood

Gigantism caused by the hypersecretion of hGH during childhood abnormal increase in bone length and size of other organs the person is very tall with normal body proportions

Cushing’s Syndrome caused by hypersecretion of glucocorticoids, especially cortisol results in redistribution of body fat spindly arms and legs rounded moon - faced appearance hanging abdomen with stretch marks or Striae individuals often bruises easily poor wound healing

Myxedema--tissue swelling caused by hypothyroidism during the adult years causes facial tissue to swell and look puffy about 5 times more common in females

Myxedema--tissue swelling other symptoms include: Bradycardia - low body temperature lethargy muscle weakness dry skin and hair - easily gains weight sensitivity to cold - hypersensitive to drugs 34

Pretibial myxedema

Graves’ Disease caused by hyperthyroidism may have a slightly enlarged thyroid gland (Goiter) causes the eyes to protrude (Exophthalmos)

Graves’ Disease an autoimmune disorder increased metabolism heat intolerance increased sweati insomnia weight loss nervousness tremors of hands 37

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