Hormonal Secretion and Mechanisms Quiz

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Questions and Answers

What is the role of cAMP in hormonal secretion?

It regulates biosynthesis and secretion of hormones by peripheral glands. (correct)

It directly promotes water reabsorption in kidneys.

It enhances the replication of hormone-producing cells.

It inhibits the production of sex cells.

Which hormone is specifically associated with stimulating the growth of bones?

Prolactin

Corticotropin

Vasopressin

Somatotropin (correct)

What is the primary action of corticotropin on fat tissue?

Inhibiting glucose absorption

Stimulating glucose absorption and fat mobilization (correct)

Increasing fatty acid storage

Promoting protein synthesis

Which hormone is NOT involved in fat mobilization through the cAMP mechanism?

Somatotropin Signup and view all the answers

What symptom is associated with the hypersecretion of somatotropin?

Gigantism or acromegaly Signup and view all the answers

What effect does the catabolism of fatty acids have in the liver?

It increases the production of ketone bodies. Signup and view all the answers

Which amino acid is essential for the biological activity of insulin?

Asparagine Signup and view all the answers

What is the primary action of free insulin?

To influence all insulin-sensitive tissues. Signup and view all the answers

What is a characteristic of the insulin receptor?

It is a glycoprotein. Signup and view all the answers

Which factors increase the secretion of insulin?

High levels of glucose and asparagine. Signup and view all the answers

What action involves the hormone acting as an allosteric effector at the cell membrane?

Membrane type of action Signup and view all the answers

Which components are involved in the membrane-intracellular type of action?

First messenger, receptor complex and second messenger Signup and view all the answers

Which of the following can penetrate the lipid layer of the cell membrane?

Steroid hormones Signup and view all the answers

What is the role of the second messenger in the membrane-intracellular type of action?

To trigger biochemical reactions within the cell Signup and view all the answers

Which of the following hormones has a combined type of action?

Iodothyronine Signup and view all the answers

What is the initial form of polypeptide hormones before they are active?

Prohormones Signup and view all the answers

What does the hormone-receptor complex typically influence in the cytosolic mechanism of action?

Gene activity of nuclear chromosomes Signup and view all the answers

Which of the following is NOT involved in the cytosolic mechanism of action?

Membrane transducer proteins Signup and view all the answers

Which hormone is produced by the intestinal chromaffin cells?

Serotonin Signup and view all the answers

What type of hormones are produced by cells in the gastrointestinal tract?

Protein-peptide hormones Signup and view all the answers

Which hormone is NOT a product of the pituitary gland?

Glucose Signup and view all the answers

Which of the following is a function of glucocorticoids?

Metabolism of carbohydrates Signup and view all the answers

What kind of feedback mechanism does the endocrine system predominantly utilize?

Long feedback Signup and view all the answers

Which hormone is primarily produced by the pancreas?

Insulin Signup and view all the answers

Which of the following describes the relationship between neural impulses and hormone release?

Neural impulses trigger the release of regulatory hormones from the hypothalamus. Signup and view all the answers

What is the primary target of tropic hormones secreted by the anterior pituitary gland?

Thyroid gland and adrenal cortex Signup and view all the answers

What type of steroid hormones are produced by the adrenal cortex that primarily affect carbohydrate metabolism?

Glucocorticoids Signup and view all the answers

Which hormone is primarily responsible for the secretion of aldosterone?

Adrenoglomerulotropin Signup and view all the answers

What is the primary function of hormones in the endocrine system?

To enable remote action and regulate metabolism Signup and view all the answers

What is a consequence of glucocorticoids on protein metabolism?

Decrease protein synthesis Signup and view all the answers

Which gland is responsible for secreting oxytocin and vasopressin?

Hypotalamus Signup and view all the answers

What effect does aldosterone have on sodium and potassium levels in the kidneys?

Increases both sodium reabsorption and potassium excretion Signup and view all the answers

Which hormone is associated with the control of metabolism in peripheral tissues?

Thyroxine Signup and view all the answers

Which disease is caused by hypercorticoidism resulting from hypersecretion of corticotropin?

Cushing's Disease Signup and view all the answers

What type of hormones are responsible for controlling aldosterone secretion in the adrenal cortex?

Adrenoglomerulotropin Signup and view all the answers

How do glucocorticoids primarily travel in the plasma?

Transported by transcortin proteins Signup and view all the answers

What is one of the primary effects of aldosterone on the epithelial cells of the distal tubules of the kidney?

Increases the reabsorption of sodium and chloride Signup and view all the answers

Which of the following hormones is produced by the pancreas?

Insulin Signup and view all the answers

Which central gland primarily produces releasing hormones that control the secretion of tropic hormones?

Hypotalamus Signup and view all the answers

Which of the following is a symptom associated with Addison's Disease?

Reduced resistance to emotional stress Signup and view all the answers

What is a characteristic feature of hormone action?

Strict specificity for biological action Signup and view all the answers

Corticosteroids are used to treat which of the following conditions?

Asthma Signup and view all the answers

Which of the following is NOT a result of elevated glucocorticoids in the blood?

Decreased fatty acids Signup and view all the answers

Which hormone is classified as a parahormone?

Thymosin Signup and view all the answers

What is the role of calcitonin in the endocrine system?

Lower blood calcium levels Signup and view all the answers

Which hormone is produced by the adrenal medulla?

Adrenaline Signup and view all the answers

Study Notes

Hormones

The endocrine system secretes chemical regulators called hormones into the blood and lymph.
Hormones are produced in gland cells and regulate metabolism and development.
Hormones have remote action and strict specificity, meaning one hormone cannot replace another. Their action is very potent, requiring small amounts for organism activity.
Hormone-secreting glands are categorized as central and peripheral.

Central Glands

Hypothalamus: produces releasing and inhibiting hormones; vasopressin and oxytocin.
Pituitary gland: produces tropic hormones, including thyrotropin, corticotropin, gonadotropin, follitropin, lutropin, prolactin, somatotropin, melanotropin.
Epiphysis: produces melatonin and adrenoglomerulotropin.

Peripheral Glands

Thyroid: produces iodothyronines (T3 and T4) and calcitonin.
Parathyroid: produces parathyroid hormone (PTH).
Pancreas: produces insulin and glucagon.
Adrenal glands (cortex): produces corticosteroids (hydrocortisone, corticosterone), and mineralocorticoids (aldosterone). Also secretes small amounts of sex hormones.
Adrenal glands (medulla): produces epinephrine and norepinephrine.
Sex glands (testes and ovaries): produce androgens, estrogens, and gestagens.
Placenta: produces hormones including estrogen, gestagens, and placental lactogen.
Thymus: produces thymosin.

Hormone-like Compounds

Endocrine functions are also performed by other biologically active compounds similar to hormones (hormone-like compounds, hormonoids, local hormones, para hormones).
These compounds act locally at the site of production.
Examples include compounds produced in the gastrointestinal tract (gastrin, secretin), cells of the gastrointestinal tract, intestinal chromaffin cells (serotonin), connective tissue (heparin, histamine), kidneys, seminal vesicles (prostaglandins).

Chemical Structure of Hormones

Protein-peptide hormones are synthesized as inactive prohormones.
These hormones become active after extracellular activation by enzymes like peptidases.
Examples of prohormones include proinsulin, proparathyroid hormone, angiotensinogen, and progastrin.
Hormones have varying chemical structures: polypeptides, amino acid derivates, and steroids.

Neuroendocrine Relationship

Regulatory hormones from the hypothalamus stimulate/inhibit the anterior pituitary gland.
The anterior pituitary gland secretes tropic hormones that act on secondary target glands (thyroid, adrenal cortex, testes/ovaries).
Hormones from the secondary target glands influence the final target tissues (muscles, liver, other tissues).
The posterior pituitary gland secretes hormones (oxytocin and vasopressin) produced in the hypothalamus.

Mutually Exclusive Relationship of Endocrine System

The hypothalamic hormones trigger pituitary hormone release to control peripheral hormones and associated metabolic processes.
Short and long feed-back loops maintain homeostasis.
Specific target peripheral cells/organs metabolize regulated substances (glucose, amino acids, fatty acids).

Hormonal Control

Hormones act through different mechanisms.
Membrane Type of Action: Hormones bind to membrane receptors, affecting membrane permeability to specific substances (glucose, amino acids).
Membrane-Intracellular Type of Action: These hormones trigger a second messenger cascade, modifying cellular functions by impacting enzyme activity, permeability, and gene expression.
Cytosolic Mechanism of Action: Hormones can cross the cell membrane and bind to cytosolic or nuclear receptors. These complexes control gene activity, influencing metabolism and cell function.

Hormones of Hypothalamo-Hypophyseal System

The anterior pituitary (adenohypophysis): produces tropic hormones for peripheral glands.
The posterior pituitary (neurohypophysis): releases hypothalamic hormones (oxytocin and vasopressin).
The hormones have specific structures: glycoproteins, cyclic octapeptides, etc
The hypothalamus produces releasing and inhibiting factors that control pituitary hormone secretion.

Mechanism of Action of Hypophyseal Hormones

Tropic hormones act on peripheral glands or tissues.
Cyclic adenosine monophosphate (cAMP) mediates their effects in target cells.
cAMP influences biosynthesis, specific gland secretions, and sex cell functions and nervous system functioning.

Direct Effects on Peripheral Tissues

Corticotropin (ACTH) regulates fat mobilization.
Gonadotropins and prolactin have direct effects on tissues like mammary glands and fat mobilization.
Melanotropin produces melanin.
Somatotropin (growth hormone) primarily affects cartilage and bone growth as well as overall organ growth.
Vasopressin (ADH) controls water reabsorption, blood pressure, and muscle contraction.
Oxytocin directly affects uterine muscle contraction, milk release, and potentially fat metabolism.

Thyroid Hormones

Iodothyronines (T3 and T4) regulate energy metabolism, cell division, and differentiation.
Calcitonin affects calcium and phosphorus metabolism.

Hyperfunction (Hyperthyroidism)

Hyperthyroidism, often caused by elevated T3 production, leads to accelerated metabolism, increased body temperature, weight loss, and hyperactivity.
Exophthalmos (protrusion of the eyeballs) is a common symptom

Hypofunction (Hypothyroidism)

Hypothyroidism, characterized by reduced thyroid hormone production, is associated with delayed growth and development in children and impaired mental functions; in adults, with slowed metabolism and lowered body temperature.
This condition can have other related consequences like dry skin, and deposition of mucoid substances in subcutaneous fat.

Parathyroid Glands

Calcitonin (also secreted by the thyroid gland)
Parathyroid hormone (PTH) controls calcium and phosphate balance in the body.

Dysfunction of Parathyroid Glands

Hypoparathyroidism leads to reduced calcium levels, causing neuromuscular hyper-excitability, potential convulsions, and other symptoms.
Hyperparathyroidism increases calcium levels, often due to bone resorption. This can lead to osteoporosis, and calcium deposits.

Pancreas Hormones

The islets of Langerhans (pancreatic islets) produce hormones like insulin (beta cells), glucagon (alpha cells), and somatostatin (delta cells). Also produces pancreatic polypeptide from F cells.

Glucagon

A peptide hormone essential for maintaining blood glucose levels.
Glucagon is produced in response to low blood sugar affecting the liver, fat tissue, and skeletal muscle.
It inhibits protein synthesis while increasing protein break down to increase the formation of glucose.

Insulin

Insulin, a peptide hormone, regulates blood glucose in the system.
Insulin promotes glucose uptake into body tissues; its release is heavily dependent on glucose and calcium levels in the blood.

Disturbances of Endocrine Pancreas

Excessive insulin, either from an insulinoma or from medication overuse, causes hypoglycemia, potentially leading to severe health complications like loss of consciousness or death.
Deficiency in insulin production results in diabetes mellitus, marked by elevated blood glucose (hyperglycemia) and glucose in the urine (glycosuria).

Hormones of Adrenal Glands

Adrenal Medulla: produces and stores epinephrine and norepinephrine.
Adrenal Cortex: produces steroid hormones, including glucocorticoids (hydrocortisone, corticosterone, affecting carbohydrate metabolism) and mineralocorticoids (aldosterone, affecting mineral metabolism. Also produces small amounts of sex hormones.

Glucocorticoids

Glucocorticoids (like hydrocortisone), regulated by ACTH from the pituitary and are influenced by stressors.
These hormones regulate metabolism, stress, and immunity by influencing blood glucose, amino acids, and ketone bodies.

Mineralcorticoids

Mineralcorticoids (like aldosterone) regulate mineral balance.
Aldosterone plays crucial roles in sodium (Na+) and potassium (K+) reabsorption and excretion, thus affecting blood water and electrolyte balance.

Disturbances of Adrenal Glands

Hypercortisolism (Cushing's disease): causes various symptoms; high blood pressure; weight gain; excessive insulin production; abnormal body composition.
Hypocortisolism (Addison's disease): can result from insufficient glucocorticoid and mineralocorticoid hormone production; causes symptoms across multiple organs.

Practical Use of Corticosteroids

Used to treat allergic and autoimmune diseases.
Also employed as immunosuppressant drugs after organ transplantation

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Description

Test your knowledge on the various roles of hormones, their mechanisms of action, and their effects on bodily functions. This quiz covers topics such as the role of cAMP, factors affecting insulin secretion, and the biological activity of insulin. Dive deep into the specifics of hormonal interactions in the human body!