Endocrine System Flashcards
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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.

<p>False</p> Signup and view all the answers

Why is the hypothalamus sometimes referred to as the 'master control center' of the endocrine system?

<p>Regulates most endocrine functions of the body</p> Signup and view all the answers

Where are the suprarenal (adrenal) glands located?

<p>Superior to the kidneys</p> Signup and view all the answers

The principal mineralocorticoid is ______ that helps regulate levels of ______ in the blood and body fluids.

<p>aldosterone; sodium and potassium ions</p> Signup and view all the answers

The medulla of the suprarenal gland secretes _____________ to enhance the ______________ response of the sympathetic nervous system.

<p>Epinephrine and norepinephrine; 'fight or flight'</p> Signup and view all the answers

Glucocorticoids are hormones that stimulate metabolism of lipids and proteins, and help regulate glucose levels in the blood.

<p>True</p> Signup and view all the answers

What does the cortex of the suprarenal (adrenal) gland produce?

<p>Corticosteroids</p> Signup and view all the answers

How long can iodinated thyroglobulin be stored in a thyroid follicle lumen?

<p>2-3 months</p> Signup and view all the answers

What is the dominant amino acid in thyroglobulin?

<p>Tyrosine</p> Signup and view all the answers

What does thyroid hormone stimulate the anterior pituitary to release?

<p>Growth hormone (GH)</p> Signup and view all the answers

In the thyroid gland, where are iodide molecules converted to iodine?

<p>Thyroid follicle lumen</p> Signup and view all the answers

What is the name of the narrow band of tissue connecting the right and left lobes of the thyroid gland?

<p>Isthmus</p> Signup and view all the answers

How many parathyroid glands are there?

<p>2-6</p> Signup and view all the answers

What cell in the parathyroid gland secretes parathyroid hormone?

<p>Chief (principal) cell</p> Signup and view all the answers

What does parathyroid hormone promote?

<p>Resorption of calcium from bone</p> Signup and view all the answers

What stimulates the secretion of parathyroid hormone from the parathyroid gland?

<p>Low blood calcium level</p> Signup and view all the answers

The parathyroid glands are usually located on which surface of the thyroid gland?

<p>Posterior</p> Signup and view all the answers

The pancreas serves both endocrine and exocrine functions.

<p>True</p> Signup and view all the answers

What does the endocrine portion of the pancreas produce?

<p>Insulin and glucagon</p> Signup and view all the answers

Which pancreatic islet cell type is correctly matched with its product?

<p>Beta cells; insulin</p> Signup and view all the answers

Where is the pancreas located?

<p>Between the duodenum and spleen, just inferior and posterior to the stomach</p> Signup and view all the answers

What do pancreatic acinar cells secrete?

<p>Enzyme-rich pancreatic juice</p> Signup and view all the answers

What occurs when hormones reach their target cells?

<p>The hormone binds to an appropriate receptor on (in) the target cell</p> Signup and view all the answers

How are hormone molecules typically transported to the target cells?

<p>The blood stream</p> Signup and view all the answers

What are two main targets of antidiuretic hormone (ADH)?

<p>The kidneys and blood vessels</p> Signup and view all the answers

When osmoreceptors of the _______________ detect dehydration, a signal to the posterior pituitary gland causes the release of _________________.

<p>Hypothalamus; antidiuretic hormone (ADH)</p> Signup and view all the answers

In general, sensory input to a portion of the neuroendocrine system causes what?

<p>Release of hormones</p> Signup and view all the answers

The G-protein is composed of how many subunits?

<p>Three</p> Signup and view all the answers

What activates the alpha subunit of the G-protein?

<p>GTP replacing GDP</p> Signup and view all the answers

What causes the change in conformation of the G-protein resulting in separation from the membrane-bound receptor?

<p>Ligand binding to the membrane-bound receptor</p> Signup and view all the answers

Where is the G-protein found bound?

<p>Membrane bound receptor on the inside of the cell</p> Signup and view all the answers

The alpha subunit can remain separated from the beta and gamma subunit as long as the ligand remains bound to the membrane bound protein.

<p>True</p> Signup and view all the answers

Ultimately, what is responsible for aldosterone's effects on a cell?

<p>Intracellular proteins</p> Signup and view all the answers

Aldosterone is a what?

<p>Lipid soluble hormone</p> Signup and view all the answers

In the cytoplasm of a cell, what does aldosterone do?

<p>Binds to an intracellular receptor</p> Signup and view all the answers

Aldosterone cannot diffuse directly through the plasma membrane.

<p>False</p> Signup and view all the answers

After aldosterone binds to an intracellular receptor, what happens to the receptor complex?

<p>Moves into the nucleus and binds to DNA</p> Signup and view all the answers

Describe the correct sequence of activities for the cAMP pathway of second messenger activation.

<p>Binding to a signal molecule, activation of the G-protein, activation of adenylate cyclase, increased intracellular cAMP</p> Signup and view all the answers

What is the activity of alpha kinase?

<p>Activate additional proteins through phosphorylation</p> Signup and view all the answers

Which of the following would be another name for second messengers?

<p>Intracellular mediators</p> Signup and view all the answers

What is the final outcome of the Ca2+ second messenger system?

<p>Increase the intracellular levels of calcium</p> Signup and view all the answers

Which of the following is not located in the plasma membrane?

<p>Alpha kinase</p> Signup and view all the answers

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.

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