34-1 Negative and Positive Feedback Loops Review Feedback Loops Control hormone levels Negative feedback loop – Hormone release stops in response to decrease in stimulus Stimulus (eating) raises blood glucose levels Pancreas releases insulin in response to elevated blood glucose Insulin helps blood glucose decreases as it is used by the body or stored in the liver Insulin release stops as blood glucose levels normalize

34-2 Negative and Positive Feedback Loops (cont.) Positive feedback loop – As long as stimulus is present, action of hormone continues Infant nursing at mother’s breast  stimulates Oxytocin released  stimulates milk production and ejection from mammary glands Milk release continues as long as infant continues to nurse!

World’s Tallest Men! “Sultan Kosen has been named the world's tallest living man by Guinness World Records. The 29-year-old Turkish man has only recently stopped growing thanks to receiving state-of-the-art treatment in the U.S.” What kind of treatment do you think he had?

Sultan Kosen’s Gigantism (more details) He developed a pituitary tumor as a child, which caused his pituitary gland to produce an excessive amount of growth hormone. "That tumor is not cancerous and it is not a brain tumor," says Dr. Mary Lee Vance, an endocrinologist at the University of Virginia Health System in Charlottesville, Va. "A spontaneous mutation causes the tumor, and it's not hereditary," she explains. Kosen's parents and siblings are all average height.

Pituitary Tumor Kosen was taking medication to stop hormone production, but it wasn’t enough. The solution was gamma knife radiation surgery. This procedure uses focused beams of gamma rays, which deliver high-energy radiation, and is guided by MRI to targeted points in Kosen's brain.

Answer: Sultan Kosen’s medical problem was a pituitary gland tumor. Sultan’s parents and siblings are all of average height, so his condition was not genetic!

Feedback Disruption Normally negative feedback would kick in… once enough growth hormones had been produced and a growth ‘goal’ had been achieved, hormone production would stop. The pituitary tumor prevented this from happening, and the growth hormones kept being produced!

34-8 Common Diseases and Disorders Disease/DisorderDescription AcromegalyToo much growth hormone produced in adults; enlargement of bones and thickened skin Addison’s diseaseAdrenal gland fails to produce enough corticosteroids CretinismExtreme form of hypothyroidism present prior to or soon after birth Cushing’s diseaseHypercortisolism; over-production of cortisol Diabetes insipidusKidneys fail to reabsorb water, resulting in excessive urination; hyposecretion of ADH

34-9 Common Diseases and Disorders (cont.) Disease/DisorderDescription Diabetes mellitus Type I Type II Gestational Chronic disease characterized by elevated blood glucose levels Insulin-dependent diabetes mellitus; usually develops in childhood Noninsulin-dependent diabetes mellitus; primarily in adults but increased incidence in teens Occurs during pregnancy; usually temporary DwarfismToo little growth hormone (somatotropin) produced during childhood

34-10 Common Diseases and Disorders (cont.) Disease/DisorderDescription GigantismToo much growth hormone produced during childhood GoiterEnlargement of thyroid gland, causing swelling in neck; deficiency of iodine in diet Grave’s diseaseHyperthyroidism; antibodies attach to thyroid gland, causing it to produce too much thyroid hormone MyxedemaThyroid gland produces inadequate amounts of thyroid hormone; common in females over 50

34-11 Nervous and Endocrine System Co- operation through STRESS!!!!!!!!!!! (Relax, man) Definition: Stressor – Any stimulus that produces stress. Write down 3 things that cause stress! – Types Physical factors Psychological factors Positive stimuli

Why do we feel stress? Why are some people more stressed than others? How do the nervous and endocrine systems cooperate? Our sensory organs take information from our surroundings and interpret them (nervous system). Based on that information, our brain can tell our body to produce stress-related hormones.

34-13 The Stress Response (cont.) Physiologic response to stress caused by hormone release – General stress syndrome Increased heart rate, respiratory rate, and blood pressure Increase in glucose and fatty acids in blood, which leads to weight loss Prolonged Stress leads to: – Decreased body repair – Susceptibility to illness

34-14 Apply Your Knowledge Match the following: ___ Extreme heatA. Physical stress ___ Death of friendB. Psychological stress ___ Fractured legC. Positive stimulus ___ Wedding ___ Exam ___ Hearing an explosion nearby ___ “A” on an exam ___ Flu ___ Car stolen B B B A A C B C A ANSWER: