Questions and Answers
Where is the pituitary gland located?
Hypophysial fossa
What does the hypothalamo-hypophysial portal system connect?
Hypothalamus to adenohypophysis
What is the function of antidiuretic hormone (ADH)?
Increases water retention from renal tubules
The posterior pituitary produces both inhibiting and releasing hormones.
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Why is the hypothalamus sometimes referred to as the 'master control center' of the endocrine system?
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Where are the suprarenal (adrenal) glands located?
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The principal mineralocorticoid is ______ that helps regulate levels of ______ in the blood and body fluids.
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The medulla of the suprarenal gland secretes _____________ to enhance the ______________ response of the sympathetic nervous system.
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Glucocorticoids are hormones that stimulate metabolism of lipids and proteins, and help regulate glucose levels in the blood.
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What does the cortex of the suprarenal (adrenal) gland produce?
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How long can iodinated thyroglobulin be stored in a thyroid follicle lumen?
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What is the dominant amino acid in thyroglobulin?
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What does thyroid hormone stimulate the anterior pituitary to release?
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In the thyroid gland, where are iodide molecules converted to iodine?
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What is the name of the narrow band of tissue connecting the right and left lobes of the thyroid gland?
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How many parathyroid glands are there?
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What cell in the parathyroid gland secretes parathyroid hormone?
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What does parathyroid hormone promote?
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What stimulates the secretion of parathyroid hormone from the parathyroid gland?
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The parathyroid glands are usually located on which surface of the thyroid gland?
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The pancreas serves both endocrine and exocrine functions.
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What does the endocrine portion of the pancreas produce?
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Which pancreatic islet cell type is correctly matched with its product?
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Where is the pancreas located?
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What do pancreatic acinar cells secrete?
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What occurs when hormones reach their target cells?
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How are hormone molecules typically transported to the target cells?
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What are two main targets of antidiuretic hormone (ADH)?
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When osmoreceptors of the _______________ detect dehydration, a signal to the posterior pituitary gland causes the release of _________________.
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In general, sensory input to a portion of the neuroendocrine system causes what?
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The G-protein is composed of how many subunits?
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What activates the alpha subunit of the G-protein?
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What causes the change in conformation of the G-protein resulting in separation from the membrane-bound receptor?
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Where is the G-protein found bound?
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The alpha subunit can remain separated from the beta and gamma subunit as long as the ligand remains bound to the membrane bound protein.
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Ultimately, what is responsible for aldosterone's effects on a cell?
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Aldosterone is a what?
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In the cytoplasm of a cell, what does aldosterone do?
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Aldosterone cannot diffuse directly through the plasma membrane.
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After aldosterone binds to an intracellular receptor, what happens to the receptor complex?
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Describe the correct sequence of activities for the cAMP pathway of second messenger activation.
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What is the activity of alpha kinase?
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Which of the following would be another name for second messengers?
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What is the final outcome of the Ca2+ second messenger system?
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Which of the following is not located in the plasma membrane?
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Study Notes
Pituitary and Hypothalamus Functions
- The pituitary gland resides in the hypophysial fossa of the skull.
- The hypothalamo-hypophysial portal system connects the hypothalamus to the adenohypophysis, facilitating hormone signal transmission.
- Antidiuretic hormone (ADH), also known as vasopressin, plays a crucial role in increasing water retention in renal tubules.
- The posterior pituitary does not produce inhibiting or releasing hormones; it instead releases hormones produced by the hypothalamus.
- The hypothalamus controls most endocrine system functions, earning it the title "master control center."
Adrenal Glands Overview
- Suprarenal (adrenal) glands are positioned superior to the kidneys.
- Aldosterone is the principal mineralocorticoid responsible for regulating sodium and potassium ion levels in blood and body fluids.
- The adrenal medulla secretes epinephrine and norepinephrine to enhance the "fight or flight" sympathetic nervous system response.
- Glucocorticoids stimulate lipid and protein metabolism while regulating blood glucose levels.
Thyroid Gland Insights
- Iodinated thyroglobulin can be stored in thyroid follicle lumens for 2-3 months.
- Tyrosine is the dominant amino acid found in thyroglobulin.
- Thyroid hormones encourage the anterior pituitary to release growth hormone (GH).
- Iodide conversion to iodine occurs within the thyroid follicle lumen.
- The isthmus is the narrow tissue band connecting the right and left lobes of the thyroid gland.
Parathyroid Gland Functions
- There are typically 2-6 parathyroid glands located on the posterior surface of the thyroid gland.
- Chief (principal) cells in the parathyroid glands secrete parathyroid hormone (PTH), which promotes calcium resorption from bones.
- Low blood calcium levels stimulate the secretion of parathyroid hormone.
Pancreas and Hormonal Functions
- The pancreas has both endocrine and exocrine functions, producing insulin and glucagon as its endocrine output.
- Beta cells in the pancreatic islets are responsible for insulin production.
- The pancreas is located between the duodenum and the spleen, positioned just inferior and posterior to the stomach.
- Pancreatic acinar cells secrete enzyme-rich pancreatic juice essential for digestion.
Hormonal Communication and Mechanisms
- Hormones bind to specific receptors on target cells to exert their effects.
- Hormones are transported to target cells via the bloodstream.
- Antidiuretic hormone (ADH) primarily targets the kidneys and blood vessels to regulate bodily fluid balance.
- Upon detecting dehydration, hypothalamic osmoreceptors signal the release of ADH from the posterior pituitary.
G-Protein Signaling Mechanism
- A G-protein consists of three subunits.
- The alpha subunit of the G-protein is activated when GTP replaces GDP.
- Ligand binding to a membrane-bound receptor triggers a conformational change in the G-protein, causing separation from the receptor.
- Alpha subunits can persist separated from beta and gamma subunits as long as the ligand remains bound.
- Aldosterone functions through intracellular proteins to affect target cells.
Aldosterone and Second Messenger Pathways
- Aldosterone is classified as a lipid-soluble hormone and binds to intracellular receptors in the cytoplasm.
- After aldosterone binds to its receptor, the receptor complex moves to the nucleus to bind DNA and initiate gene expression.
- The cAMP pathway includes steps of signal molecule binding, G-protein activation, adenylate cyclase activation, leading to increased intracellular cAMP.
- Alpha kinase, an important enzyme, activates proteins through phosphorylation.
- Second messengers are also termed intracellular mediators.
- The overall result of the Ca2+ second messenger system is an increase in intracellular calcium levels.
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Description
Test your knowledge of the endocrine system with these flashcards. This quiz covers key concepts about the pituitary gland, hypothalamus, and related hormones. Perfect for students learning about human physiology and anatomy.
