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Production and release of anterior pituitary hormones. Hypothalamic tropic hormones control the secretion of hormones in the anterior pituitary.

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The adrenal cortex controls prolonged responses by secreting corticosteroids.
Mineralocorticoids such as aldosterone regulate salt and water balance .
Glucocorticoids such as cortisol regulate glucose metabolism and the immune system.

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Human endocrine glands.

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The adrenal medulla mediates short–term responses by secreting catecholamine hormones. Epinephrine and norepinephrine secreted by the the adrenal medulla enable a rapid ( fight-or-flight ) responses to stress by increasing blood glucose and blood pressure and directing blood to the heart, brain, and skeletal muscles.

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Graves' disease is a form of hyperthyroidism resulting in fluid accumulation behind the eyes . The body produces antibodies to the receptor for TSH, stimulating production of T3 and T4 and bypassing the TSH negative feedback loop.

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Negative feedback in calcium homeostasis.

1. A rise in blood Ca²⁺ causes release of calcitonin from the thyroid gland, promoting Ca²⁺ deposition in bone and reducing reabsorption in kidneys.
   
2. A drop in blood Ca²⁺ causes the parathyroid gland to produce parathyroid hormone (PTH), stimulating the release of Ca²⁺ from bone.
   PTH also promotes reabsorption of Ca²⁺ in kidneys and uptake of Ca²⁺ in intestines.

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Negative feedback in glucose homeostasis.

1. A rise in blood glucose causes release of insulin from beta cells the pancreas, promoting glucose uptake in cells and storage as glycogen in the liver.
   
2. A fall in blood glucose stimulates alpha cells in the pancreas to secrete glucagon, which causes the liver to break down glycogen and release glucose.

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The pineal gland secretes melatonin at night. This biological clock regulates functions related to light, such as seasonal reproduction activities and daily sleep cycles .

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Hormonal regulation of insect development.
Brain hormone stimulates the release of ecdysone, which promotes molting and the development of adult characteristics. Juvenile hormone promotes the retention of larval (juvenile) characteristics.

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A baby sucking at the nipple sends nerve signals to the hypothalamus, where oxytocin is made by neurosecretory cells and stored in the posterior pituitary. When oxytocin circulates to the nipples, it triggers smooth muscle contraction and release of milk.

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In a simple neurohormone pathway, a neurosecretory in the brain secretes a hormone that acts directly on a target effector cell, triggering a response.

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Production and release of posterior pituitary hormones.

Neurosecretory cells in the hypothalamus make antidiuretic hormone ( ADH ) and oxytocin , which are stored in the posterior pituitary.

Nervous signals from the brain trigger release of these neurohormones.

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Hormones regulate body processes, such as the metamorphosis of an anise swallowtail butterfly, by circulating chemical signals that enable internal communication.

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Thyroid hormones are involved in skeletal growth and mental development of children, and regulate blood pressure, heart rate, muscle tone, digestion, and reproductive functions.

The hypothalamus secretes thyroid-releasing hormone (TRH), which stimulates the anterior pituitary to secrete thyroid–stimulating hormone (TSH). TSH then stimulates the thyroid gland to synthesize the thyroid hormones T₃ and T₄.

These hormones exert negative feedback on the hypothalamus and anterior pituitary and inhibit release of TRH and TSH.