22 Questions
What is the role of thyroid hormones in metabolism?
Increasing basal metabolic rate
T4 and T3 are active when bound to carrier proteins.
False
What is the function of thyroid hormones in terms of protein synthesis?
Stimulating protein synthesis
Thyroid hormones increase the use of _______ and _______ for ATP production.
glucose and fatty acid
What is the role of thyroid hormones in the development and growth of tissues?
Regulating development and growth of nervous tissue and bones
Thyroid hormones decrease cardiac output.
False
Match the following carrier proteins with their role in thyroid hormone transportation:
Thyroxine-Binding Globulin = Carrier protein for thyroid hormones Transthyretin = Carrier protein for thyroid hormones Albumin = Carrier protein for thyroid hormones
What is the role of thyroid hormones in lipolysis?
Stimulating lipolysis
Which of the following is regulated by Thyroid Hormone?
Energy levels
TSH stimulates the release of Thyroxine.
True
What is the primary function of Prolactin?
stimulates lactation
Prolactin is regulated by dopamine, estrogens, and ________________.
infant suckling at breast
Match the hormones with their corresponding functions:
TSH = Regulates thyroid hormone secretion Prolactin = Stimulates lactation Thyroxine = Regulates metabolism and energy levels
What is the mechanism of TSH regulation?
Negative feedback loop
What is the role of TRH in the regulation of thyroid hormone secretion?
Stimulates the pituitary gland to release thyroid-stimulating hormone (TSH)
The levels of downstream hormones can stimulate the secretion of upstream hormones.
False
What is the role of thyroid hormones in the body?
Regulate metabolism
The half-life of water-soluble hormones is typically _______________________.
shortest
Match the following hormones with their site of metabolism:
Water-soluble hormones = Kidneys Lipid-soluble hormones = Liver
What is the role of TSH in the regulation of thyroid hormone secretion?
Stimulates the thyroid gland to produce thyroid hormones
Most hormones are protein-bound in the bloodstream.
False
What is the function of the negative feedback loop in the regulation of hormone secretion?
Maintains balance within the system
Study Notes
Thyroid Hormones
- Thyroid hormones play an essential role in metabolism and are used by all cell types in the body
- Biological roles:
- Increase basal metabolic rate
- Increase number of mitochondria (except in brain, spleen, and testes)
- Stimulate synthesis of Na+/K+ ATPase
- Increase body temperature
- Stimulate protein synthesis
- Increase use of glucose and fatty acid for ATP production
- Stimulate lipolysis
- Increase cardiac output
- Enhance actions of catecholamines
- Regulate development and growth of nervous tissue and bones
Carrier Proteins
- Thyroid hormones are lipid-soluble and must travel through the bloodstream on carrier proteins
- 3 key carrier proteins:
- Thyroxine-Binding Globulin
- Transthyretin
- Albumin
Thyroid Hormone Regulation
- T4 and T3 are inactive when bound to carrier proteins
- Active T4 and T3 referred to as “free T4” and “free T3” (fraction not bound to carrier proteins)
- Free T4 and T3 trigger thyroid gland to release Thyroxine, regulating:
- Weight
- Energy levels
- Internal temperature
- Metabolism
- And more…
Negative Feedback
- Upon increased thyroid hormone, synthesis and release of TSH is inhibited
- Example of negative feedback loop: TRH stimulates the pituitary gland to release TSH, which stimulates the thyroid gland to produce thyroid hormones
Prolactin Regulation
- Prolactin stimulates lactation
- Regulated by:
- Prolactin-inhibiting peptides
- Dopamine (primary control)
- Estrogens
- Infant suckling at breast (neuronal)
Hormone Removal
- Hormones are removed from the body through:
- Degradation by intracellular enzymes
- Excretion by kidneys or liver
- Half-life varies from a few seconds to a week
- Water-soluble hormones are rapidly removed by kidneys and have the shortest half-life
- Lipid-soluble hormones are metabolized by the liver and have a longer half-life
This quiz covers the biological roles of thyroid hormones in the body, including their effects on metabolism and cellular processes. Learn about the functions of T3 and T4 hormones and their impact on the body.
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