90 Questions
What is the result of glucose increasing the interaction of insulin mRNA with RNA-binding proteins?
Increased insulin stability and translation
What is the main difference between peptide hormones and steroids in terms of secretion?
Peptide hormones are secreted through exocytosis, while steroids are secreted through diffusion
What is the purpose of posttranslational processing steps in hormone production?
To increase the stability of hormones in circulation
What is the role of RNA-binding proteins in insulin mRNA regulation?
To enhance the translation of insulin mRNA
What is the net effect of glucose-mediated insulin mRNA regulation?
A more precise and timely regulation of insulin levels
What is the common pathway that all hormones enter after synthesis?
Either the constitutive or regulated secretory pathway
What is the relationship between pulsatile secretion and the activity of oscillators in the hypothalamus?
The oscillators regulate the membrane potential of neurons, leading to pulsatile secretion
What is the significance of pulsatile secretion in terms of information conveyed to target tissues?
It conveys different information compared to a steady exposure to a single concentration of the hormone
What is a challenge posed by pulsatile secretion in therapeutic hormone replacement?
Ensuring the hormone is released in a pulsatile manner
What factor influences circulating levels of hormones in addition to secretion rate and nature?
The rate of hormone degradation and/or uptake
What is affected by the affinity of a hormone for plasma carriers?
The circulating levels of hormones
What is the relationship between pulsatile secretion and the release of pituitary and other downstream hormones?
Pulsatile secretion causes the release of pituitary and other downstream hormones in a similar pulsatile manner
What type of receptor allows for a wider dynamic range of regulation of genes targeted by a hormone?
Steroid receptor
What is the purpose of feedback regulation in endocrine physiology?
To control the further release of a hormone
What is the function of negative feedback in endocrine systems?
To inhibit the initial release of a hormone
In which situations is positive feedback typically seen?
In settings that need to gather momentum for an eventual outcome
What type of feedback control system is most common in the body?
Negative feedback loop
What is the purpose of feedback control loops in evaluating patients with suspected endocrine disorders?
To provide diagnostic strategies
What is the main concern of endocrine physiology?
Maintaining homeostasis
What makes the endocrine system distinct from other physiological systems?
It operates as a distributed network
What type of hormones are the most numerous?
Peptide hormones
What is the reason for the increase in hormone diversity from simple to higher life forms?
To add challenges in providing for homeostasis
What determines the specificity of certain peptide hormones?
The β chain
What is a characteristic of hormones that can be grouped into families?
They have similar structures and activate similar receptors
What is the role of Sex hormone–binding globulin (SHBG)?
To bind testosterone and 17β-estradiol
What is the effect of binding proteins on hormone loss in the urine?
They reduce the rate of hormone loss in the urine
What is one way to regulate the availability of hormones that bind to carrier proteins?
Regulate the expression and secretion of the carrier proteins
What can alter levels of binding proteins or displace hormones that are bound to them?
Some medications
Why is the anatomic relationship of sites of release and action of hormones important?
Because it plays a key role in the regulation of hormones
What is the purpose of binding proteins in the bloodstream?
To provide a source of hormone that can release free hormone as the equilibrium changes
What is the primary concern of endocrine physiology?
Maintaining homeostasis in various physiological processes
What is characteristic of the endocrine system compared to other physiological systems?
It operates as a distributed network
What is the significance of peptide hormones being heterodimers with a common α chain and a specific β chain?
They allow for specificity in their action
What is the reason for the increased diversity of hormones in higher life forms?
To provide for homeostasis in more complex organisms
What is the role of the central nervous system and the autonomic nervous system in the endocrine system?
They often influence the endocrine system, along with circulating messengers
What is characteristic of hormones that can be grouped into families?
They have structural similarities and activate similar receptors
What is the primary factor that regulates the membrane potential of neurons, leading to pulsatile secretion?
Oscillators in the hypothalamus
What is the result of pulsatile secretion on the target tissues that it acts upon?
It conveys different information to the target tissues
What is one of the factors that influence the circulating levels of hormones in addition to the rate of secretion and its nature?
The rates of hormone degradation and uptake
What is a challenge posed by pulsatile secretion in therapeutic hormone replacement?
It may prove necessary to replace a particular hormone that is normally secreted in a pulsatile manner
What is the role of the hypophysial blood flow in pulsatile secretion?
It carries hormone releasing factors to the pituitary gland
What is the relationship between the affinity of a hormone for plasma carriers and its circulating levels?
The higher the affinity, the higher the circulating levels
What is a possible advantage of having multiple hormones derived from the same precursor?
Genetic economy
Why are hormone precursors typically inactive?
To provide an additional level of regulatory control
How do nuclear receptors regulate peptide hormone genes?
By binding to gene promoters
What is the effect of elevated glucose levels on insulin mRNA translation?
Stimulation of insulin mRNA translation
What is the function of specific proteases in hormone synthesis?
To process polypeptide chains into mature hormones
What is the role of thyroid hormone in regulating TSH expression?
Inhibition of TSH expression
What is the primary function of plasma carriers for specific hormones?
To act as a reservoir of inactive hormones and smooth hormonal fluctuations
What type of hormones are mostly bound to large proteins called steroid binding proteins?
Steroid hormones
Which of the following is NOT a function of plasma carriers?
Enhancing the activity of bound hormones
What is the significance of the bound hormone reservoir?
It helps smooth fluctuations in hormonal levels over time
What determines the biological activity of hormones in target tissues?
The amount of free hormone
Why are steroid hormones mostly bound to proteins?
Because they are hydrophobic
What is the result of hormones being destroyed by passage through the pulmonary circulation or the liver?
A marked curtailment of the temporal window for hormone action
What is the ultimate outcome of the concerted action of hormones in the body?
Maintenance of homeostasis
Which hormones are key contributors to homeostasis?
Thyroid hormone, cortisol, parathyroid hormone, vasopressin, mineralocorticoids, and insulin
How do hydrophilic hormones, such as peptides and catecholamines, exert their acute effects?
By binding to cell surface receptors
What is the function of the first class of nuclear receptors?
Direct stimulation of transcription
What is the mechanism of action of the second class of nuclear receptors?
Removal of a transcriptional co-repressor and recruitment of a co-activator
What is the primary advantage of having multiple hormones derived from the same precursor?
Genetic economy
How do nuclear receptors regulate peptide hormone gene expression?
By binding to specific motifs in the regulatory regions of hormone genes
What is the significance of hormone precursors being inactive?
To allow for precise regulation of hormone production
What is the role of specific proteases in hormone synthesis?
To process hormone precursors into mature hormones
How do changes in substrate availability affect hormone synthesis?
By controlling the production of key synthetic enzymes
What is the effect of elevated glucose levels on insulin mRNA translation?
Stimulation of insulin mRNA translation
What is the primary function of the steroidogenic acute regulatory protein (StAR)?
Trafficking of cholesterol from outer to inner mitochondrial membrane
What is the effect of phosphorylation on the steroidogenic acute regulatory protein (StAR)?
Activation of StAR
What is the result of the activation of StAR by phosphorylation?
Conversion of cholesterol into pregnenolone
What is the significance of the rate-limiting step in the synthesis of the steroid precursor, pregnenolone?
It allows for the regulation of hormone secretion in response to homeostatic cues
What is the role of extracellular signals in the regulation of StAR expression?
They phosphorylate transcription factors that upregulate StAR expression
What is the characteristic of hormone secretion that relates to the fact that some hormones are secreted in a pulsatile manner?
It is a continuous process
What is the primary effect of hormone destruction by the pulmonary circulation or liver?
Curtailment of the temporal window of hormone action
What is the primary mechanism of action of hydrophobic hormones?
Exerting effects via nuclear receptors
Which of the following hormones is NOT a key contributor to homeostasis?
Growth hormone
What is the effect of hormone binding to nuclear receptors on transcription?
Stimulation of transcription
What is the primary function of hormones in the body?
Maintenance of homeostasis
What is the characteristic of hydrophilic hormones, including peptides and catecholamines?
They bind to cell surface receptors
What is the primary function of Sex hormone–binding globulin (SHBG) in the plasma?
To increase the solubility of lipid-based hormones in the blood
What is the consequence of altering the expression and secretion of carrier proteins in the plasma?
Altered regulation of hormone synthesis and secretion
What is the primary advantage of having multiple hormones derived from the same precursor?
Enhanced regulation of hormone synthesis and secretion
What is the primary mechanism by which hormones are regulated in the plasma?
Binding to carrier proteins
What is the consequence of displacing hormones from their carrier proteins in the plasma?
Altered regulation of hormone synthesis and secretion
What is the primary role of transcortin in the plasma?
Binding to corticosteroids
What is the primary purpose of the feedback control mechanism in the endocrine system?
To maintain a steady state of hormone regulation in the body
What is the characteristic of negative feedback control systems in the body?
They are involved in the inhibition or dampening of the initial hormone release mechanism
What is the role of feedback control loops in the evaluation of patients with suspected endocrine disorders?
To provide a diagnostic strategy for evaluating patients with suspected endocrine disorders
What is the benefit of the wider dynamic range of regulation of genes targeted by a hormone in the latter class of receptor?
It allows for a wider range of regulation of genes targeted by the hormone
What is the characteristic of positive feedback control systems in the body?
They are typically seen in settings that require momentum for an eventual outcome
What is the purpose of the network of feedback responses in the endocrine system?
To maintain a steady state of hormone regulation in the body
Learn about the fundamental concepts of endocrine physiology, including the role of hormones in maintaining homeostasis and the distributed network of glands and circulating messengers. Understand how the endocrine system operates under the influence of the central nervous system. Test your knowledge of the basics of endocrine regulation.
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