Podcast
Questions and Answers
What is the primary role of receptors in hormone action?
What is the primary role of receptors in hormone action?
Which of the following hormones primarily uses the mobile receptor mechanism for its action?
Which of the following hormones primarily uses the mobile receptor mechanism for its action?
Which statement accurately describes the fixed membrane receptor mechanism?
Which statement accurately describes the fixed membrane receptor mechanism?
What occurs when a water-soluble hormone binds to its receptor?
What occurs when a water-soluble hormone binds to its receptor?
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What is the consequence of cyclic AMP (cAMP) activation within a target cell?
What is the consequence of cyclic AMP (cAMP) activation within a target cell?
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Which hormone mechanism primarily regulates gene expression?
Which hormone mechanism primarily regulates gene expression?
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What happens to cyclic AMP after it has acted in a target cell?
What happens to cyclic AMP after it has acted in a target cell?
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How do amino acid derivative hormones typically function within cells?
How do amino acid derivative hormones typically function within cells?
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Study Notes
Hormone Action
- Hormones maintain homeostasis in the body.
- Hormone receptors are specific to each hormone.
- Receptor sensitivity depends on receptor number and affinity.
- Receptor location varies: cell membrane (e.g., protein hormones, catecholamines), cytoplasm (e.g., steroid hormones), or nucleus (e.g., thyroxine).
- Hormone types include peptides, polypeptides, proteins, steroids, iodothyronines (thyroid hormones), and amino acid derivatives.
- Membrane-bound receptor hormones don't enter cells; they trigger second messengers to change cell metabolism.
- Intracellular receptor hormones regulate gene expression or chromosome function by interacting with the genome.
Mechanism of Hormone Action
- Two main mechanisms:
- Fixed membrane receptor mechanism
- Mobile receptor mechanism
Fixed Membrane Receptor Mechanism
- Water-soluble hormones (amines, proteins) use this mechanism.
- These hormones can't pass through the lipid cell membrane.
- They bind to cell membrane receptors.
- Binding activates adenyl cyclase, producing cAMP (cyclic AMP).
- cAMP acts as a secondary messenger, activating enzymes to alter biochemistry.
- Phosphodiesterase deactivates cAMP.
Mobile Receptor Mechanism
- Lipid-soluble hormones (e.g., fatty acids, steroids) use this mechanism.
- These hormones can easily pass through the plasma membrane.
- They bind to intracellular receptors.
- This hormone-receptor complex activates enzymatic activity, initiating changes.
- The hormone-receptor complex initiates DNA transcription.
- mRNA is translated into proteins causing cellular biochemical changes.
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Description
Explore the intricate actions of hormones in maintaining homeostasis within the body. This quiz covers various hormone types, their receptors, and mechanisms of action, including fixed and mobile receptor systems. Test your understanding of how hormones interact with cells and regulate biological functions.
