ENDOCRINE SYSTEM January 27-28, 2016 Endocrine Disorders Gigantism excess growth hormone during childhood Endocrine Disorders Acromegaly excess growth hormone after closure of epiphiseal plates Endocrine Disorders Growth Hormone Deficiency (pituitary dwarfism) underproduction of growth hormone as a child Endocrine Disorders Grave’s Disease excess thyroid hormones Endocrine Disorders Hypothyroidism underproduction of thyroid hormones Endocrine Disorders Cushing’s Syndrome– excessive cortisol Endocrine Disorders Addison’s Disease– underproduction of cortisol Endocrine System Controls and regulates the body through hormones • Hormones are chemical messengers that travel through the blood to one or more target organs • Major processes regulated include • Growth • Reproduction • Stress response • Water / nutrient / electrolyte balance • Metabolism Hormones Are produced by a gland travel through bloodstream bind to /enter cells of target organ(s) change cell function of target organ(s) Hormones How do hormones change target cells? • Change membrane permeability / electrical state • Promote synthesis of certain proteins • Activate or inactivate enzymes • Stimulate mitosis (cell division) Major Types of Hormones 1. Steroids • Diffuse across cell membrane and nuclear membrane (lipid- soluble!) • Bind to a receptor protein in nucleus • Receptor – steroid complex increases transcription of certain genes, resulting in the production of certain proteins Examples: sex hormones, corticosteroids Major Types of Hormones 2. Amino-acid based (amines, peptides, and proteins) • Bind to a receptor protein on cell membrane • Receptor starts a series of events that produce a specific change in the function of the cell Examples: insulin, oxytocin, GH, melatonin, calcitonin, etc. Non-steroidal hormones always use second messenger molecules – molecules that are produced within the target cell as a result of the binding of the hormone with the receptor Quick Review 1. What are the two types of hormones, and what is the major difference between them? • steroids – can cross cell membrane, bind to receptor inside nucleus • nonsteroidal (amino-acid based) – cannot cross cell membrane, bind to receptor on cell membrane 2. Which type of hormone produces second messenger molecules? • Nonsteroidal (amino-acid based) produce second messenger molecules. After binding to a receptor on the cell membrane, an enzyme catalyzes the production of the second messenger, which in turn, brings about the cellular changes. Quick Review Wait a minute, then show with fingers 3. Which of the following is NOT one of the major processes controlled by hormones? a. b. c. d. Body coordination Growth and development Electrolyte balance Cellular metabolism Quick Review Wait a minute, then show with fingers 4. Which of the following is NOT a typical effect of hormones on target cells? a. Mitosis is stimulated b. Enzymes are activated c. Proteins are synthesized d. Cellular mutations develop Control of Hormone Release Hormones regulate body functions by producing specific effects in target cells. Disorders can develop if too much or too little hormone is secreted. How does the body determine when/how much hormones to release? The release of nearly all hormones occurs as part of negative feedback mechanisms. Review: Compare and Contrast Negative and Positive Feedback Mechanisms Negative feedback mechanisms maintain the levels of a variable (e.g. body temperature) within a narrow range. The output acts to change the direction of the stimulus. Example: Body temperature regulation Positive feedback mechanisms dramatically increase a variable (e.g. contractions) until a certain endpoint (e.g. childbirth) is reached. The output acts to increase the stimulus Example: labor contractions Example: Blood Sugar Regulation Example: Blood Calcium Regulation Stimulus of Hormone Release Even when glands are part of a negative feedback loop, there must be some stimulus that triggers the release of hormones. What was stimulus in the previous two examples? Blood sugar level and calcium level. Non-hormonal chemicals like these are called humoral stimuli. There are three basic types of stimuli that cause the release of hormones. 1. Humoral stimuli (non-hormone chemicals in the blood and body fluids) 2. 3. ?? ?? Stimulus of Hormone Release Even when glands are part of a negative feedback loop, there must be some stimulus that triggers the release of hormones. What was stimulus in the previous two examples? Blood sugar level and calcium level. Non-hormonal chemicals like these are called humoral stimuli. There are three basic types of stimuli that cause the release of hormones. 1. Humoral stimuli (non-hormone chemicals in the blood and body fluids) 2. Hormonal stimuli (other hormones – e.g. TSH, ACTH, FSH, LH, PRL) 3. Neuronal stimuli (e.g. Often glands respond to multiple release of ep. / stimuli (Ex: release of nor-ep by adrenals) aldosterol by adrenal glands) Example of Multiple Stimuli: Aldosterone release Diabetes Mellitus Diabetes is a disorder characterized by abnormally high levels of blood sugar (hypoglycemia) Facts • 347 people world-wide have diabetes. • 7th leading cause of death in the US • Leading cause of kidney failure, non-traumatic limb amputation, and adult-onset blindness in US • Major contributor to heart attack and stroke Major Types of Diabetes Type I (juvenile-onset) • Occurs when the immune system attacks the insulinproducing cells of the pancreas, which means that little to no insulin can be produced • Genetic risk factors and environmental triggers • ~5% of cases Gestational diabetes occurs in ~5% of •Type II (adult-onset) pregnant women. Disease usually disappears when pregnancy is over. • Too little insulin is produced and/or cells become insulin- resistant • Obesity and inactivity are major risk factors, but genetics also play a role • ~90% of cases Symptoms of Diabetes Symptoms develop more rapidly and are more severe for Type I diabetes. Additional symptoms found with Type 1 diabetes include: • Acetone smell to breath • Lethargy • Deep, labored breathing Complications of Diabetes Hyperglycemia (high blood sugar) damages blood vessels and nerves, leading to the major complications listed below. Note: it’s the high blood sugar that causes the damage. The better blood sugar is controlled, the less complications will arise. Treatment of Diabetes •Type I diabetes • Healthy diet and exercise • Blood glucose monitoring (multiple times a day) • Insulin injections (multiple times a day) or pump •Type II diabetes • Weight loss • Healthy diet and exercise • Blood glucose monitoring • Medicines to increase the body’s production of insulin • Medicines to combat insulin resistance and help glucose enter cells • Insulin injections Many new treatments in the development stage, including • Pancreas transplants Watch me! • Stem cells • More convenient glucose monitoring and insulin delivery Game! • Round 1: • Bet on 1, 2, 3, 4, 5, or 6 • On your mark … • Round 2: • Bet on blue, yellow, gray, green, or red. • Ready, set, go! Closure • What were our objectives, and what did you learn about them? • What was our learner profile trait and how did we exemplify it? • How does what we did today address our unit question?