Questions and Answers
What does the pancreas produce?
What is the role of insulin?
Regulates blood sugar levels by facilitating the uptake of glucose into tissues.
What is glucagon responsible for?
Raises blood glucose concentration.
How are hormones classified?
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What are peptide hormones?
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What is the function of second messengers?
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What characterizes steroid hormones?
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What is the role of aldosterone?
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Glucocorticoids promote decreased glucose levels.
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What is the primary function of parathyroid hormone (PTH)?
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Which hormones are secreted by the adrenal medulla?
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The hormone that stimulates uterine contractions during childbirth is called ______.
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What is a mnemonic for remembering the products of the anterior pituitary?
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Which of the following hormones is considered a direct hormone?
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What is the significance of calcium (Ca2+) in the body?
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Study Notes
Pancreas and Hormones
- The pancreas produces insulin and glucagon, which regulate blood glucose levels.
- Insulin is primarily synthesized by beta cells in the pancreatic islets and is the main anabolic hormone, promoting glucose uptake into tissues.
- Glucagon, secreted by alpha cells, increases blood glucose levels by triggering the release of sugar stores.
Hormone Classification
- Hormones can be classified into three categories: peptides, steroids, and amino acid derivatives.
- Peptide hormones are chains of amino acids and are unable to cross the plasma membrane, requiring extracellular receptors for signal transduction.
Peptide Hormones Mechanism
- Peptide hormones act as first messengers, binding to surface receptors and initiating a signaling cascade, often involving second messengers like cAMP.
- Examples of peptide hormones include insulin, glucagon, and growth hormone.
Steroid Hormones Characteristics
- Steroid hormones, derived from cholesterol, can easily cross cell membranes. Their receptors are typically located intracellularly.
- Effects of steroid hormones take longer to manifest but are usually longer-lasting compared to peptide hormones due to their action on DNA.
Amino Acid-Derived Hormones
- These hormones are derived from tyrosine and tryptophan. Key examples include epinephrine, norepinephrine, and melatonin.
- Catecholamines, a subset of amino acid-derived hormones, are produced by the adrenal glands and play roles in the stress response.
Hormonal Actions and Feedback Mechanisms
- Direct hormones act directly on target tissues, while tropic hormones stimulate other endocrine glands to produce hormones.
- Parathyroid hormone (PTH) and calcitonin are antagonistic; PTH increases blood calcium, while calcitonin decreases it.
Blood Calcium Regulation
- Calcium (Ca2+) is essential for bone structure, muscle contraction, and blood clotting. PTH raises blood calcium levels, while calcitonin lowers them.
- PTH promotes calcium absorption in the gut, decreases renal excretion, and stimulates vitamin D activation.
The Renin-Angiotensin-Aldosterone System (RAAS)
- RAAS regulates blood pressure and fluid balance; low blood pressure stimulates renin release, leading to the formation of angiotensin II, which causes aldosterone secretion.
- Aldosterone promotes sodium retention and, consequently, water retention, increasing blood volume and pressure.
Stress Response Hormones
- Cortisol is released during stress and raises blood sugar levels, whereas catecholamines like epinephrine provide a rapid response during acute stress.
- Both cortisol and catecholamines increase blood glucose, supporting energy metabolism during stress.
Hormone Regulation and Interaction
- The interplay between insulin (which decreases blood glucose) and glucagon (which increases it) maintains glucose homeostasis.
- Hormones that raise blood glucose levels, such as growth hormone, glucocorticoids, and epinephrine, are referred to as counterregulatory hormones.
Anterior and Posterior Pituitary Hormones
- The anterior pituitary secretes tropic hormones (FSH, LH, ACTH, TSH) and direct hormones (prolactin, GH).
- Oxytocin and ADH are synthesized in the hypothalamus and released by the posterior pituitary, playing roles in childbirth and water balance.
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Description
Test your knowledge of the endocrine system with this set of flashcards focused on key terms like pancreas and insulin. Understand how hormones regulate important bodily functions and the impact they have on metabolic processes. Perfect for students studying endocrinology or related subjects.
