35 Questions
Which type of hormones are lipophilic and can pass through the cell membrane?
Corticosteroids
Where do peptide and protein hormones bind within the cell?
Cell membrane
Which hormone class includes catecholamines and thyroid hormones?
Amino Acid Derivatives
Which hormone is responsible for regulating hair growth and sex drive?
Testosterone
What type of mutation in the androgen receptor (AR) gene leads to impaired sperm development or masculinization?
Small insertions or deletions
Which syndrome is characterized by external female genitals but lacking internal female organs?
Complete Androgen Insensitivity Syndrome (CAIS)
What does the Mullerian Duct Inhibitor do in males?
Causes mullerian ducts to degenerate
What is the effect of defective androgen receptor (AR) on Wolffian ducts and genitals?
$ ext{No response to androgens}$
What hormone is used in hormone replacement therapy for females with Androgen Insensitivity Syndrome?
Estrogen
What is secreted by testicles and prevents the development of internal female sex organs in males?
Mullerian Duct Inhibitor
What is the genetic makeup of individuals with Androgen Insensitivity Syndrome?
XY male
Which enzyme produces cAMP, leading to the activation of PKA?
Adenylyl cyclase
What is the function of IP3 in cellular signaling?
Binds to smooth ER receptors and signals calcium release
Which hormones stimulate glucose mobilization in liver cells through similar signaling pathways?
Glucagon and epinephrine
What is the role of PKA in cellular responses?
Catalyzes the transfer of phosphates from ATP to serine or threonine residues of protein substrates, promoting gene expression
Which hormones have opposing effects on glucose metabolism?
Insulin and glucagon
What type of receptors do steroid hormones, such as cortisol, act through?
Intracellular receptors
Which type of hormone receptor is located inside the cell and can bind to hormones such as estrogen and testosterone?
Intracellular receptors
What is the main function of protein kinase activation in hormone action?
Activate or deactivate intracellular proteins by phosphorylation
Which hormone is primarily responsible for regulating blood glucose levels by lowering it?
Insulin
What stimulates the secretion of aldosterone through the renin-angiotensin-aldosterone pathway?
Decrease in blood pressure
Which hormone acts on the kidneys to promote sodium and water retention, ultimately increasing blood pressure?
Angiotensin 2
What is the main function of G-protein coupled receptors (GPCRs) in hormone signaling?
Activate second messenger systems
Which hormone is secreted by the hypothalamus, stimulating the synthesis and release of Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) from the pituitary gland?
Gonadotropin Releasing Hormone (GnRH)
Which hormone regulates water balance?
Vasopressin
Which gland produces parathyroid hormone (PTH), raising calcium blood levels?
Parathyroid gland
What causes Diabetes Insipidus?
Inadequate response to vasopressin
Which hormones require iodine for their production?
$Thyroxine (T4)$ and $Triiodothyronine (T3)$
Which part of the adrenal glands is stimulated by the sympathetic nervous system and secretes catecholamines?
Medulla
What regulates enzymes controlling carbohydrate and lipid metabolism?
Thyroid hormones
Which hormone stimulates the synthesis and release of Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) from the pituitary gland?
Gonadotropin Releasing Hormone (GnRH)
When does sexual differentiation occur during development?
Between the 1st and 6th week
What determines male sex?
Y chromosome
What regulates blood glucose levels?
Insulin
Which hormone maintains male secondary sex characteristics?
Testosterone
Study Notes
- Molecular Endocrine system focuses on signals transduction and receptors.
- Gonadotropin Releasing Hormone (GnRH) is secreted by the hypothalamus, stimulating the synthesis and release of Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) from the pituitary gland.
- The hypothalamus is part of the brain, acting as an integration and control center, connected to the pituitary gland.
- The pituitary gland consists of anterior pituitary hormones, including TSH, ACTH, LH, FSH, GH, and Prolactin, and posterior pituitary, which includes distal axons of hypothalamus magnocellular neurons producing oxytocin and vasopressin.
- Vasopressin regulates water balance, while oxytocin regulates reproductive behavior and stimulates milk ejection and uterine contractions.
- Anterior pituitary disorders, like pituitary dwarfism, acromegaly, and Gigantism, can result from a tumor causing a decrease in hormonal output, or hyperplasia of pituitary gland resulting in abnormally high levels of growth hormone.
- Diabetes Insipidus is a disorder where large volumes of hypotonic or dilute urine are produced due to the absence or inadequate response to vasopressin.
- The thyroid gland secretes thyroid hormones, which include Thyroxine (T4) and Triiodothyronine (T3), and requires iodine to produce them. Thyroid hormones bind to receptors in the nucleus and regulate enzymes controlling carbohydrate and lipid metabolism.
- The parathyroid gland produces parathyroid hormone (PTH), which raises calcium blood levels and stimulates the intestinal absorption of calcium.
- The adrenal glands have the medulla, which is stimulated by the sympathetic nervous system and secretes catecholamines (epinephrine and norepinephrine), and the cortex, which is stimulated by anterior pituitary hormone ACTH and secretes corticosteroids.
- The pancreas has exocrine and endocrine functions, with endocrine function governed by islets of Langerhans, which secrete insulin and glucagon to regulate blood glucose levels.
- Sexual differentiation occurs between the 1st and 6th week of development, and the 7th week marks the start of primary reproductive organ development, with hormones produced from the organs determining the sex of the embryo.
- The Y chromosome determines male sex, with the SRY gene directing the synthesis of testicular determine factor (TDF), which binds to DNA and causes the differentiation of cells from genital ridges into testes.
- Male hormonal regulation is controlled by the hypothalamus, with GnRH causing the release of FSH and LH, which stimulate sperm production in the testes and testosterone production in the interstitial cells.
- Androgens, like testosterone, maintain male secondary sex characteristics and stimulate inhibin production, which downregulates FSH synthesis and inhibits FSH secretion.
Test your knowledge of G protein and cyclic nucleotide signaling with this quiz. Explore the activation of Protein Kinase A, second messenger molecules, and the cellular responses triggered by G protein activation.
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