Examples of parathyroid hormone in the following topics:
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- Parathyroid glands produce parathyroid hormone, which is responsible for specific physiological responses in the body related to calcium.
- The parathyroid glands are small endocrine glands that produce parathyroid hormone.
- There are two major types of cells that make up parathyroid tissue: oxyphil cells and chief cells, the latter of which actually produce parathyroid hormone.
- Another function of the parathyroid glands is to secrete parathyroid hormone, which causes the release of the calcium present in bone to extracellular fluid.
- The parathyroid glands produce parathyroid hormone (PTH) which increases blood calcium concentrations when calcium ion levels fall below normal.
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- Blood levels of calcium are regulated by the parathyroid hormone, which acts on the bones, kidneys, and intestines to keep levels constant.
- Blood calcium levels are regulated by parathyroid hormone (PTH), which is produced by the parathyroid glands.
- The hormone calcitonin, which is produced by the parafollicular (or C) cells of the thyroid, has the opposite effect on blood calcium levels as PTH.
- Parathyroid hormone (PTH) is released in response to low blood calcium levels.
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- Hormones such as parathyroid hormone, growth hormone, and calcitonin are also required for proper bone growth and maintenance.
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- Specialized cells in the pancreas (part of the endocrine system) sense the increase, releasing the hormone insulin.
- However, if an animal has not eaten and blood glucose levels decrease, this is sensed in a different group of cells in the pancreas: the hormone glucagon is released, causing glucose levels to increase.
- If calcium levels decrease, specialized cells in the parathyroid gland sense this and release parathyroid hormone (PTH), causing an increased absorption of calcium through the intestines and kidneys.
- The hormone oxytocin, made by the endocrine system, stimulates the contraction of the uterus.
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- Lipid-derived (soluble) hormones such as steroid hormones diffuse across the lipid bilayer membranes of the endocrine cell.
- Other lipid-soluble hormones that are not steroid hormones, such as vitamin D and thyroxine, have receptors located in the nucleus.
- The hormone-receptor complex stimulates transcription of specific genes in the same way that steroid hormones do.
- VDR activation in the intestine, bone, kidney, and parathyroid gland cells leads to the maintenance of calcium and phosphorus levels in the blood and to the maintenance of bone content.
- In the nucleus, the hormone-receptor complex binds to a DNA sequence called a hormone response element (HRE), which triggers gene transcription and translation.
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- The main endocrine glands, which we will learn about in this section and in the following ones, are the pituitary (anterior and posterior), thyroid, parathyroid, adrenal (cortex and medulla), pancreas, and gonads.
- The anterior pituitary produces seven hormones: growth hormone (GH), prolactin (PRL), thyroid-stimulating hormone (TSH), melanin-stimulating hormone (MSH), adrenocorticotropic hormone (ACTH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH).
- Anterior pituitary hormones are sometimes referred to as tropic hormones because they control the functioning of other organs.
- These regulatory hormones can be releasing hormones or inhibiting hormones, causing more or less of the anterior pituitary hormones to be secreted.
- Negative feedback then regulates how much of these regulatory hormones are released and how much anterior pituitary hormone is secreted.
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- All hormones in the human body can be divided into lipid-derived, amino acid-derived, and peptide hormones.
- One of the key, distinguishing features of lipid-derived hormones is that they can diffuse across plasma membranes whereas the amino acid-derived and peptide hormones cannot.
- The primary class of lipid hormones in humans is the steroid hormones.
- Examples of steroid hormones include estradiol, which is an estrogen, or female sex hormone, and testosterone, which is an androgen, or male sex hormone.
- The structures of peptide hormones (a) oxytocin, (b) growth hormone, and (c) follicle-stimulating hormone are shown.
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- The release of hormones can be triggered by changes in the blood ("humor"), by the actions of other hormones, or by neurological stimuli.
- Hormonal stimuli refers to the release of a hormone in response to another hormone.
- A number of endocrine glands release hormones when stimulated by hormones released by other endocrine glands.
- The anterior pituitary, in turn, releases hormones that regulate hormone production by other endocrine glands.
- The hypothalamus stimulates the anterior pituitary gland, via hormones, to release thyroid-stimulating hormone (TSH).
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- Hormones are chemical messengers that relay messages to cells that display specific receptors for each hormone and respond to the signal.
- All multicellular organisms produce hormones; plant hormones are also called phytohormones.
- Hormones mediate changes in target cells by binding to specific hormone receptors.
- Cells can have many receptors for the same hormone, but often also possess receptors for different types of hormones.
- Cells respond to a hormone when they express a specific receptor for that hormone.
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- Amino acid-derived hormones and polypeptide hormones are not lipid-derived (lipid-soluble or fat-soluble); therefore, they cannot diffuse through the plasma membrane of cells.
- Lipid-insoluble hormones bind to receptors on the outer surface of the plasma membrane, via plasma membrane hormone receptors.
- Unlike steroid hormones, lipid-insoluble hormones do not directly affect the target cell because they cannot enter the cell and act directly on DNA.
- The effect of a hormone is amplified as the signaling pathway progresses.
- Describe the events that occur when a hormone binds to a plasma hormone receptor