HORMONE REGULATION JANUARY

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. If the variable becomes high, the mechanism acts to bring it back down. If the variable becomes low, the mechanism brings it back up.  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 type 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. release of ep. / nor-ep by adrenals) Often there is just one stimulus that a gland responds to. Occasionally there are multiple stimuli (ex: release of aldosterol by adrenal glands)

EXAMPLE OF MULITIPLE STIMULI: ALDESTERONE RELEASE

DIABETES MELLITUS Diabetes is a disorder characterized by abnormally high levels of blood sugar (hypoglycemia) Facts 347 people world-wide have diabetes. 7 th 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 insulin-producing cells of the pancreas, which means that little to no insulin can be produced Genetic risk factors and environmental triggers ~5% of cases Type II (adult-onset) 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 Gestational diabetes occurs in ~5% of pregnant women. Disease usually disappears when pregnancy is over.

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 Stem cells More convenient glucose monitoring and insulin delivery Watch me!

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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?