Questions and Answers
What are the two broad classes that hormones can be divided into?
Which of the following is not a type of lipid-soluble hormone?
What are steroid hormones derived from?
Cholesterol
What are the two thyroid hormones mentioned?
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What is nitric oxide categorized as?
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Which of the following is not a water-soluble hormone type?
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How are amine hormones synthesized?
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What do peptide hormones consist of?
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What are eicosanoid hormones derived from?
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How do most water-soluble hormones circulate in the blood?
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How do most lipid-soluble hormones circulate in the blood?
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List one function of transport proteins for lipid-soluble hormones.
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Study Notes
Classification of Hormones
- Hormones can be categorized into two main classes based on solubility: lipid-soluble and water-soluble.
Lipid-Soluble Hormones
- Include steroid hormones, thyroid hormones (T3 and T4), and nitric oxide (NO).
- Characteristics of steroid hormones: derived from cholesterol, exhibit a diverse range of functions due to unique chemical groups on their core structure.
- T3 and T4 hormones: produced by attaching iodine to tyrosine, possess two benzene rings, enhancing their lipid solubility.
- Nitric oxide (NO): operates as both a hormone and neurotransmitter, synthesized by nitric oxide synthase.
Water-Soluble Hormones
- Comprise amine hormones, peptide and protein hormones, and eicosanoid hormones.
- Amine hormones: synthesized from the decarboxylation of amino acids, retaining the amino group, with catecholamines (epinephrine, norepinephrine, dopamine) derived from tyrosine and histamine from histidine.
- Peptide hormones: chains of 3 to 49 amino acids; examples include antidiuretic hormone and oxytocin. Protein hormones consist of 50 to 200 amino acids, such as human growth hormone and insulin.
- Eicosanoid hormones: derived from arachidonic acid, include prostaglandins and leukotrienes, acting as local hormones and potentially as circulating hormones.
Hormone Transport in Blood
- Water-soluble hormones circulate freely in the blood plasma without attachment to other molecules.
- Lipid-soluble hormones are transported bound to proteins, synthesized by liver cells, enhancing their solubility in blood.
Functions of Transport Proteins
- Temporarily increase water solubility of lipid-soluble hormones for better circulation.
- Slow kidney filtration and hormone loss in urine.
- Maintain a reserve of hormones readily available in the bloodstream.
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Description
This quiz explores the two main classes of chemical hormones based on their solubility: lipid-soluble and water-soluble hormones. It provides insights into the characteristics and examples of each class, such as steroid hormones and thyroid hormones. Test your knowledge on the differentiation between these hormone types.