Questions and Answers
Which gland is divided into pars distalis, pars intermedia, and pars nervosa?
Which component binds to the hormone-receptor complex in the mechanism of hormone action?
What type of hormone is estrogen as shown in the diagram?
Which organ is NOT traditionally part of the endocrine system but also produces hormones?
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How many trophic hormones are produced by pars distalis?
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Which hormone action type is depicted specifically in part (b) of the diagram?
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Which of the following hormones is a steroid?
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Which secondary messenger is likely to be generated when a hormone interacts with a membrane-bound receptor?
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Which of the following is NOT a chemical group of hormones?
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Which type of hormone interaction typically regulates gene expression?
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What is the initial step when a hormone such as FSH triggers a cellular response?
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Which of the following is an example of a physiological response to hormone signaling?
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Which hormone is secreted by the atrial wall of the heart?
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What is the function of erythropoietin?
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Which hormone stimulates the secretion of pancreatic enzymes and bile juice?
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Gastrin acts on which of the following organs?
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Where are intracellular receptors generally located?
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Which hormone inhibits gastric secretion and motility?
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Study Notes
Hormones of Heart, Kidney, and Gastrointestinal Tract
- The atrial wall of the heart secretes atrial natriuretic factor (ANF), which decreases blood pressure.
- The juxtaglomerular cells of the kidney produce erythropoietin, which stimulates erythropoiesis.
- The gastrointestinal tract secretes four major peptide hormones: gastrin, secretin, cholecystokinin (CCK), and gastric inhibitory peptide (GIP).
- Gastrin acts on the gastric glands and stimulates the secretion of hydrochloric acid and pepsinogen.
- Secretin acts on the exocrine pancreas and stimulates the secretion of water and bicarbonate ions.
- Cholecystokinin (CCK) acts on both pancreas and gall bladder and stimulates the secretion of pancreatic enzymes and bile juice.
- Gastric inhibitory peptide (GIP) inhibits gastric secretion and motility.
Mechanism of Hormone Action
- Hormones produce their effects on target tissues by binding to specific proteins called hormone receptors.
- Membrane-bound receptors are present on the cell membrane of the target cells.
- Intracellular receptors are present inside the target cell.
- Binding of a hormone to its receptor leads to the formation of a hormone-receptor complex.
- Each receptor is specific to one hormone, resulting in certain biochemical changes in the target tissue.
Physiological Functions Controlled by Hormones
- Hormones can be divided into groups based on their chemical nature: peptide, polypeptide, protein hormones; steroids; iodothyronines; and amino-acid derivatives.
- Hormones which interact with membrane-bound receptors normally do not enter the target cell, but generate second messengers which regulate cellular metabolism.
- Hormones which interact with intracellular receptors regulate gene expression or chromosome function by the interaction of the hormone-receptor complex with the genome.
Mechanism of Hormone Action (Diagram)
- A hormone (e.g., FSH) interacts with a receptor on a cell membrane, triggering a response that generates a secondary messenger.
- The secondary messenger then initiates biochemical responses, eventually leading to physiological responses like ovarian growth.
Figure 22.5
- A hormone (e.g., estrogen) binds to a hormone-receptor complex on the cell membrane, initiating a cascade of events that lead to the production of protein by binding to a genome in the nucleus.
Chemical Coordination and Integration
- Hormones provide chemical coordination, integration, and regulation in the human body.
- Hormones regulate metabolism, growth, and development of organs.
- The endocrine system is composed of several glands and organs, including the hypothalamus, pituitary, pineal, thyroid, adrenal, pancreas, parathyroid, thymus, and gonads (testis and ovary).
- Some organs, such as the gastrointestinal tract, kidney, and heart, also produce hormones.
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Description
This quiz covers the hormones secreted by non-endocrine glands in the heart, kidney, and gastrointestinal tract. Learn about ANF, erythropoietin, gastrin, and more!