Endocrine Regulation: Basic Concepts

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What is the primary concern of endocrine physiology?

Defining anatomical boundaries
Maintaining various aspects of homeostasis (correct)
Producing steroids and amines
Regulating the autonomic nervous system

What is a characteristic of the endocrine system?

It operates as a centralized system
It operates as a distributed network (correct)
It is defined by distinct anatomical boundaries
It functions independently of the nervous system

What is the most common type of hormone?

Steroid hormones
Heterodimer hormones
Peptide hormones (correct)
Amine hormones

What is a characteristic of peptide hormones?

Many are heterodimers with a common α chain (C) Signup and view all the answers

Why does the number of hormones and their diversity increase in higher life forms?

Because of the added challenges in providing for homeostasis (B) Signup and view all the answers

What is a common feature of hormone families?

They have similar structural and functional characteristics (D) Signup and view all the answers

What is the primary function of the steroidogenic acute regulatory protein (StAR)?

Transferring cholesterol from the outer to inner mitochondrial membrane leaflet (D) Signup and view all the answers

What is the primary mechanism of controlling synthesis of amine and steroid hormones?

Regulating the production of key synthetic enzymes and substrate availability (C) Signup and view all the answers

What is the effect of phosphorylation on StAR?

Activation of StAR (C) Signup and view all the answers

What is the first intermediate in the steroid biosynthetic pathway?

Pregnenolone (C) Signup and view all the answers

What is the purpose of processing large polypeptide chains into smaller hormone molecules in peptide hormone synthesis?

To provide a level of genetic economy (A) Signup and view all the answers

Why are hormone precursors typically inactive?

To provide an additional measure of regulatory control (D) Signup and view all the answers

What is the role of extracellular signals in the regulation of steroid biosynthesis?

Activation of protein kinases (A) Signup and view all the answers

What is the role of nuclear receptors in regulating hormone transcription?

To bind to specific regions of peptide hormone genes (A) Signup and view all the answers

What is the characteristic of some hormone secretion?

Pulsatile manner (D) Signup and view all the answers

What is the rate-limiting first step in the synthesis of pregnenolone?

Transfer of cholesterol from the outer to inner mitochondrial membrane leaflet (D) Signup and view all the answers

How does thyroid hormone regulate TSH expression?

By directly suppressing TSH expression via the thyroid hormone receptor (D) Signup and view all the answers

What is the effect of elevated levels of circulating glucose on insulin mRNA?

It stimulates the translation of insulin mRNA (C) Signup and view all the answers

What is the ultimate result of the concerted action of hormones in the body?

Maintenance of homeostasis (D) Signup and view all the answers

What happens to certain hormones when they pass through the pulmonary circulation or the liver?

They are destroyed (B) Signup and view all the answers

Which of the following hormones is NOT a key contributor to homeostasis?

Growth hormone (C) Signup and view all the answers

What type of receptors do hydrophilic hormones, such as peptides and catecholamines, bind to?

Cell surface receptors (B) Signup and view all the answers

What is the effect of hormone binding on the second class of nuclear receptors?

Removal of a co-repressor and recruitment of a co-activator (C) Signup and view all the answers

What is the primary function of Sex hormone–binding globulin (SHBG) in the plasma?

To bind testosterone and 17β-estradiol (B) Signup and view all the answers

What is the primary mechanism of action for hydrophobic hormones?

Binding to nuclear receptors (A) Signup and view all the answers

What is the effect of regulating the expression and secretion of carrier proteins on hormone bioavailability?

It increases the bioavailability of hormones (B) Signup and view all the answers

What is the consequence of altering the levels of binding proteins or displacing hormones bound to them in a pathophysiologic setting?

It may have clinical implications for endocrine homeostasis (D) Signup and view all the answers

What is the role of the anatomic relationship of sites of release and action of hormones in their regulation?

It plays a key role in hormone regulation (C) Signup and view all the answers

What is the function of transcortin in the plasma?

To bind progesterone, cortisol, and other corticosteroids (B) Signup and view all the answers

What is the result of the equilibrium between the SBP-hormone complex and the free hormone in the plasma?

Only the free hormone can diffuse across cell membranes (B) Signup and view all the answers