47 Questions
Which type of hormone is insulin classified as?
Small peptide
How do hormones elicit specific responses from distant cells and organs?
By binding to specific receptors on the cell surface or within the target cell
Which hormone is responsible for regulating water retention in the body?
Vasopressin or antidiuretic hormone (ADH)
What is the primary source of hormones in the body?
Particular glands or groups of cells
What does the presence of negative feedback regulation in the endocrine system mean?
The system will attempt to correct perturbations in levels of the effector hormone with compensatory changes in levels of tropic hormones.
What do increased tropic hormone levels with low target hormone levels indicate?
Primary failure of the target endocrine organ.
What do low tropic hormone levels with high target gland hormone levels indicate?
Autonomous hormone secretion by the target endocrine organ.
Why is timing of the sample critical for some hormones?
Because of the circadian rhythm of hormone release.
What is a further factor to take into account in hormone testing?
Whether or not secretion of the hormone is pulsatile.
What is an effective way of detecting subtle perturbations of the circadian rhythm in hormone levels?
Employing multiple testing to build up a profile of hormone levels at several points in the day.
What does provocative testing involve?
Measuring hormone levels after a relevant stimulus has been applied.
What is a common stimulus used in provocative testing?
A high dose of tropic hormone.
Why do endocrinologists commonly employ multiple testing for hormone levels?
To build up a profile of hormone levels at several points in the day.
What is the purpose of using provocative testing in hormone assessment?
To assess the maximal capacity of the endocrine gland or system being tested.
What is a potential stimulus used in provocative testing to mimic stress?
Severe insulin-induced hypoglycemia.
Which type of receptors act as ligand-activated transcription factors?
Nuclear hormone receptors
What do antagonists do when they bind to receptors?
Prevent activation by agonists
How are small or hydrophobic hormones transported in the blood?
Bound to carrier proteins
What is the purpose of 24-hour urine collection in hormone assessment?
To provide an integrated assessment of hormone production
How can urinary concentrations of hormones be used in diagnostic settings?
To diagnose pregnancy
What do pheochromocytomas produce?
Catecholamines
What does laboratory testing of endocrine systems aim to determine?
If the system is functioning abnormally
What influences the clinical interpretation of plasma hormone levels?
Binding protein levels
What is the purpose of measuring hormone levels in biological samples?
For clinical assessment and diagnosis
What is the role of local metabolism of hormones near their receptors in some endocrine systems?
To affect hormone potency and activity
What do agonists do when they bind to receptors?
Activate the receptor
How does hormone inactivation occur?
Through metabolism and excretion
Which type of intrinsic plasma membrane proteins directly link hormonal exposure to gene expression patterns?
Nuclear hormone receptors
What is the function of antagonists in hormone regulation?
Bind without activating the receptor
How are small or hydrophobic hormones transported in the blood?
Bound to carrier proteins
What is the purpose of 24-hour urine collection in assessing hormones?
To provide an integrated assessment of hormone production
How can urinary concentrations of hormones be used in diagnostic settings?
To diagnose endocrine tumors
What do pheochromocytomas produce?
Catecholamines
What is the aim of laboratory testing of endocrine systems?
To determine if the system is functioning abnormally
What influences the clinical interpretation of plasma hormone levels?
Binding protein levels, hepatic function, and the nutritional and hormonal milieu
What are hormones?
Chemical substances produced by specific glands or cells, secreted into the bloodstream, and elicit specific responses from distant cells and organs
Which of the following is an example of a cholesterol derivative hormone?
Cortisol
What is the function of some hormones in the body?
Transmit important environmental cues and calibrate metabolic processes involved in maintaining homeostasis
How is the effective translation of the magnitude of the stimulus into the amount of hormone released achieved?
It varies depending on the stimulus
What are the types of molecules that function as hormones?
Aminoacid derivates, tripeptides, small peptides, glycoproteins, cholesterol derivates
What is the function of some hormones in the body?
Transmit important environmental cues and calibrate metabolic processes for homeostasis
How is the effective translation of the magnitude of the stimulus into the amount of hormone released achieved?
Achieved in varying ways depending on the stimulus
What are examples of cholesterol derivative hormones?
Cortisol, aldosterone, testosterone, estradiol
Which type of hormone is cortisol classified as?
A cholesterol derivative hormone
What is the primary source of hormones in the body?
Endocrine glands
How are small or hydrophobic hormones transported in the blood?
Bound to carrier proteins
What influences the clinical interpretation of plasma hormone levels?
Age and gender
Study Notes
Endocrine Systems and Hormone Regulation
- G-protein coupled receptors and tyrosine kinase receptors are two types of intrinsic plasma membrane proteins that mediate the action of hormones and peptides.
- Nuclear hormone receptors act as ligand-activated transcription factors, directly linking hormonal exposure to gene expression patterns.
- Agonists activate receptors upon binding, while antagonists bind without activating the receptor, preventing activation by agonists.
- Hormone inactivation occurs through metabolism and excretion, with varying clearance rates for different hormones.
- Some endocrine systems involve local metabolism of hormones near their receptors, affecting hormone potency and activity.
- Small or hydrophobic hormones are transported in the blood bound to carrier proteins, extending their half-life and affecting their measurement in clinical settings.
- Measurement of hormone levels in plasma, serum, urine, or other biological samples is crucial for clinical assessment and diagnosis.
- 24-hour urine collection is used to assess hormone excretion and provide an integrated assessment of hormone production.
- Urinary concentrations of hormones or their metabolites can be used in diagnostic settings, such as for the diagnosis of pregnancy or secretory adrenal tumors.
- Pheochromocytomas, rare neoplasms that produce catecholamines, lead to signs of excess catecholamine effects and can be diagnosed through elevated plasma and urinary levels of catecholamines and their metabolites.
- Laboratory testing of endocrine systems aims to determine if the system is functioning abnormally and to localize the functional defect, often involving immunoassays and measurement of tropic hormones.
- Clinical interpretation of plasma hormone levels is influenced by binding protein levels, hepatic function, and the nutritional and hormonal milieu.
Test your knowledge of endocrine systems and hormone regulation with this quiz. Explore topics such as receptor types, hormone inactivation, local metabolism, hormone transport in the blood, measurement of hormone levels, diagnostic uses of urinary hormone concentrations, and laboratory testing for endocrine system assessment.
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