Mammalian Endocrine System Overview

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Questions and Answers

What system do mammals utilize to coordinate the activities of their tissues?

Endocrine regulation system

Digestive network system

Neurosecretory system (correct)

Circulatory communication system

Which organ plays a key role in maintaining blood glucose levels?

Kidney

Heart

Pancreas

Liver (correct)

What is the primary focus of hormonal regulation in the adult mammal's metabolism?

Accelerate weight loss

Maintain optimal body mass (correct)

Increase muscle mass

Enhance physical endurance

Which hormones are involved in mediating the regulation of blood glucose levels?

Insulin, glucagon, epinephrine, and cortisol Signup and view all the answers

What consequence may arise from defective insulin signaling?

Diabetes Signup and view all the answers

What role do microbial symbionts play in the gut?

They release products that influence gut hormone release. Signup and view all the answers

How can weight reduction be achieved according to the content?

By adding probiotics or prebiotics to the gut. Signup and view all the answers

Which hormone is classified as orexigenic?

Ghrelin Signup and view all the answers

What is the importance of maintaining optimal body mass?

It is a priority for the adult mammal. Signup and view all the answers

What percentage of the U.S. population is affected by diabetes mellitus?

Approximately 9% Signup and view all the answers

What are hormones primarily produced and released from?

Tissues Signup and view all the answers

Which function is NOT associated with hormones?

Regulating body temperature Signup and view all the answers

What type of signaling does the neuroendocrine system primarily utilize?

Hormonal signaling Signup and view all the answers

What is a characteristic of metabotropic receptors?

They activate or inhibit downstream enzymes Signup and view all the answers

How do water-insoluble hormones interact with cells?

They readily enter the cell and bind to nuclear receptors Signup and view all the answers

Which of the following is NOT an intracellular consequence of ligand-receptor interaction?

Blocking of enzyme activity Signup and view all the answers

What is a primary role of the neuroendocrine system in mammals?

Coordinate the activities of tissues with the CNS Signup and view all the answers

What is one difference between ionotropic and metabotropic receptors?

Ionotropic receptors open or close ion channels Signup and view all the answers

What role does glucagon play in blood glucose regulation?

Stimulates glycogen breakdown Signup and view all the answers

Which hormone is secreted by the pancreas to counter low blood glucose levels?

Glucagon Signup and view all the answers

What process is inhibited by glucagon to help raise blood glucose levels?

Glycolysis Signup and view all the answers

Why is maintaining adequate blood glucose levels especially important?

The brain requires a continuous supply of glucose Signup and view all the answers

During fasting, which fuel is primarily mobilized from adipose tissue?

Fatty acids Signup and view all the answers

What type of fuel provides the highest caloric equivalent for a normal-weight man at the start of a fast?

Triacylglycerols Signup and view all the answers

How does the liver help in maintaining blood glucose levels during fasting?

By synthesizing and releasing glucose Signup and view all the answers

Which fuel source is least available in a normal-weight man at the beginning of a fast?

Glycogen Signup and view all the answers

What primary issue is suggested to contribute to insulin resistance in type 2 diabetes according to the Lipid Toxicity Hypothesis?

Abnormal lipid storage in muscle and liver Signup and view all the answers

What effect does weight loss have on insulin sensitivity in type 2 diabetes management?

Reduces lipid burden and restores insulin sensitivity Signup and view all the answers

What does the activation of AMPK by exercise primarily aid in?

Aiding weight loss Signup and view all the answers

Which medication class primarily stimulates insulin secretion by the pancreas?

Sulfonylureas Signup and view all the answers

What is the mechanism through which biguanides like metformin help manage type 2 diabetes?

Decrease glucose production in the liver Signup and view all the answers

What role does irisin play in white adipose tissue?

Stimulates development of beige adipocytes Signup and view all the answers

What is a direct target of thiazolidinediones in the treatment of type 2 diabetes?

PPARγ receptors in various tissues Signup and view all the answers

How does bariatric surgery benefit type 2 diabetes patients?

Promotes better control of blood glucose Signup and view all the answers

What is one possible fate of pyruvate formed from amino acids?

Formation of acetyl-CoA Signup and view all the answers

What is the primary role of alanine in the liver?

Deamination to yield pyruvate Signup and view all the answers

Which of the following statements is true regarding white adipose tissue (WAT)?

It releases TAGs in response to epinephrine. Signup and view all the answers

What is the key function of uncoupling protein 1 (UCP1)?

To dissipate the H+ gradient as heat Signup and view all the answers

Which energy pathway primarily supports slow-twitch muscle fibers?

Oxidative phosphorylation Signup and view all the answers

What function does creatine kinase serve during exercise?

Regenerates ATP from ADP Signup and view all the answers

What happens to lactate produced during intense exercise?

It is converted to glucose in the liver. Signup and view all the answers

Which energy source does the heart primarily rely on?

Fatty acids Signup and view all the answers

What is a distinguishing feature of fast-twitch muscle fibers?

Faster ATP consumption rates Signup and view all the answers

What triggers the hydrolysis of stored TAGs in white adipose tissue?

Activation of lipases by epinephrine Signup and view all the answers

What unique characteristic of brown adipose tissue (BAT) supports its thermogenic function?

Rich in mitochondria Signup and view all the answers

How do beige adipocytes differ from white adipocytes?

They develop more mitochondria under certain stimuli. Signup and view all the answers

Which metabolic pathway is primarily active in neurons?

Oxidative phosphorylation Signup and view all the answers

What is the main metabolic role of the circulatory system in relation to organ function?

To transport hormones and metabolites Signup and view all the answers

Study Notes

Hormonal Regulation and Integration of Mammalian Metabolism

Tissues in mammals are connected by a neurosecretory system that coordinates their activities using chemically diverse hormones.
This signaling system is highly specific and multidirectional, linking tissues to each other and to the central nervous system.
A striking division of labor exists among tissues and organs, with each reflecting its specialized metabolic role and capabilities.
The circulatory system plays a crucial role by transporting hormonal signals and metabolites between all tissues.

Hormone Structure and Action

Hormones are small molecules or proteins produced in one tissue, released into the bloodstream, and carried to other tissues.
They act through specific receptors to trigger changes in cellular activities.
Hormones coordinate the metabolic activities of multiple tissues and organs.
The neuroendocrine system coordinates metabolism in mammals.

Neuronal and Endocrine Signaling

Neuronal signaling involves nerve cells releasing neurotransmitters to act on nearby cells (distance <1 µm).
Endocrine signaling involves hormones carried in the bloodstream to act on cells or organs at a longer distance (>1 m).

Hormones Act through Specific High-Affinity Cellular Receptors

Ligand-receptor interactions can trigger various intracellular responses.
These include the generation of second messengers to regulate enzymes, the activation of receptor tyrosine kinases, the opening or closing of ion channels affecting membrane potential, or the mediation of gene expression by nuclear hormone receptors impacting how gene expression takes place.

Metabotropic and Ionotropic Surface Receptors

Metabotropic receptors on cell surfaces activate or inhibit downstream enzymes in response to hormones.
Ionotropic receptors, also on cell surfaces, directly open or close ion channels in the plasma membrane.
Both types trigger rapid physiological or biological responses.

Water-Insoluble Hormones Pass Through the Plasma Membrane

Water-insoluble hormones readily enter cells and bind to receptor proteins within the nucleus to modulate gene expression.
These hormones frequently promote maximal responses after hours or days.

Hormones Are Chemically Diverse

Hormones can be categorized by their chemical nature (protein, peptide, catecholamine, endocannabinoid, steroid, etc.).
Each hormone class has a distinct synthetic pathway and mode of action.

Endocrine, Paracrine, and Autocrine Hormones

Endocrine hormones are released into the bloodstream, targeting cells throughout the body.
Paracrine hormones are released into the extracellular space, affecting neighboring cells.
Autocrine hormones affect the same cell that releases them.

Peptide Hormones

Peptide hormones are synthesized as proproteins, activated through proteolytic cleavage upon release.
They vary in size from 3 to over 200 amino acid residues.
Examples include insulin, glucagon, somatostatin, calcitonin, and hypothalamic/pituitary hormones.

Insulin is a Peptide Hormone

Insulin is a small protein with two polypeptide chains (A and B) joined by disulfide bonds.
It is synthesized on ribosomes in the pancreas as preproinsulin, stored as proinsulin, and converted to active insulin by proteases when blood glucose is elevated.

Some Peptide Prohormones Can Yield Multiple Products

Pro-opiomelanocortin (POMC) is a proprotein cleaved to produce several active hormones, with different tissues expressing different proteases, determining which active hormones are generated.

Some Hormones Are Released by a "Top-Down" Hierarchy of Neuronal and Hormonal Signals

The CNS orchestrates hormonal signals, receiving input from multiple internal and external sensors.
The hypothalamus acts as the coordination center for the endocrine system, integrating CNS signals and producing releasing factors.

Top-Down Hormone Release

At each level of a hormonal cascade, feedback inhibition of earlier steps is possible.

Neuroendocrine Origins of Hormone Signals

The posterior pituitary contains axons from the hypothalamus.
The anterior pituitary receives releasing factors from the hypothalamus carried by blood vessels.

Hormonal Cascades Result in Large Signal Amplifications

At each stage of a hormonal cascade, there's amplification of the initial signal.
The cortisol cascade illustrates this, with a significant amplification effect from the initial hormonal signal to the final hormonal response.

"Bottom-Up" Hormonal Systems Send Signals Back to the Brain and to Other Tissues

Some hormones are produced in the digestive tract, muscle, and adipose tissue.
They communicate the current metabolic status to the hypothalamus regulating nutrient metabolism.

Adipokines

Adipokines are peptide hormones produced in adipose tissue signaling the adequacy of fat reserves.
Leptin is released when adipose tissue is well-filled and acts in the brain to inhibit feeding.
Adiponectin is released when adipose tissue is depleted and acts in the brain to stimulate feeding.

Ghrelin and Incretins

Ghrelin is produced in the gastrointestinal tract when the stomach is empty, stimulating feeding.
Incretins are peptide hormones produced in the gut after a meal, increasing insulin secretion and decreasing glucagon secretion.

Neuropeptide Y, Peptide YY, and Irisin

Neuropeptide Y (NPY) is a hormone produced in the hypothalamus and adrenal glands, promoting feeding and reducing energy expenditure.
Peptide YY (PYY3–36) is produced in the intestine and signals satiety in the brain.
Irisin is a peptide hormone produced in muscle, converting white adipose tissue into beige adipose tissue.

Peptide Hormones That Act on Feeding Behavior and Fuel Selection in Mammals

Table summarizing peptide hormones' production sites, target tissues, and actions.

Tissue-Specific Metabolism

Specialized metabolic functions of different mammalian tissues, highlighting their unique roles.

The Liver Processes and Distributes Nutrients

The liver is a central processing and distribution organ for nutrients.

The Liver Has Two Main Cell Types

Kupffer cells are phagocytes essential for immune function.
Hepatocytes transform dietary nutrients and deliver them to other tissues.

Carbohydrates

Glucose 6-phosphate can be exported as glucose, used for glycogen or fatty acid synthesis, entered into the citric acid cycle, or the pentose phosphate pathway.

Metabolic Pathways for Glucose 6-Phosphate in the Liver

Diagram illustrating glucose 6-phosphate's metabolic pathways in hepatocytes.

Xenobiotics

Xenobiotics are compounds not naturally occurring but are products of human activity.
Examples include drugs, food additives, and preservatives.
NADPH is essential for xenobiotic metabolism in the liver.

Amino Acids

Amino acids can synthesize liver and plasma proteins, enter blood to other organs, serve as biosynthetic precursors, and function in the liver or be converted to pyruvate or ammonia.
Ammonia is converted to urea.

Possible Fates of Pyruvate and Acetyl CoA from Amino Acids

Pyruvate can be converted into glucose/glycogen or acetyl-CoA.
Acetyl-CoA can undergo citric acid cycle oxidation to produce ATP or convert to lipids for storage.

Metabolic Pathways for Amino Acids in the Liver

Diagram illustrating metabolic pathways of amino acids in hepatocytes.

Metabolism of Amino Acids from Muscle

During prolonged fasting, muscle protein is broken down to amino acids.
Alanine is transported to the liver and converted to pyruvate for gluconeogenesis.
Ammonia is converted to urea for excretion.

Lipids

Lipids can be converted to liver lipids, undergo beta-oxidation to form acetyl-CoA and NADH, be incorporated into plasma lipoproteins, and bound to albumin for transport.

Possible Fates of Acetyl CoA from Lipids

Acetyl-CoA from lipids can be oxidized in the citric acid cycle producing ATP, converted into ketone bodies (acetoacetate and β-hydroxybutyrate), or used for biosynthesis of cholesterol, steroid hormones, and bile salts.

Metabolic Pathways for Lipids in the Liver

Diagram illustrating metabolic pathways of lipids in hepatocytes.

Adipose Tissues Store and Supply Fatty Acids

Adipose tissue consists of adipocytes storing triglycerides (TAGs) and sterol esters.

WAT Releases TAGs in Response to Epinephrine

Lipases, stimulated by epinephrine/phosphorylation, hydrolyze stored triglycerides (TAGs) to release free fatty acids (FFAs).
Insulin decreases lipase activity.

Brown and Beige Adipose Tissues Are Thermogenic

Brown adipose tissue (BAT) and beige adipocytes contain more mitochondria and capillaries compared to white adipocytes and produce heat (thermogenesis).

Uncoupling Protein 1 is Responsible for Thermogenesis

Uncoupling protein 1 (UCP1) facilitates the dissipation of the H+ gradient generated in mitochondria to produce heat in low-temperature environments.

Beige Adipocytes

Beige adipocytes can be generated after cold exposure or beta-adrenergic stimulation.

Muscles Use ATP for Mechanical Work

Myocytes (skeletal muscle cells) utilize ATP for muscle contraction.
Slow-twitch muscles rely on oxidative phosphorylation for ATP production, are rich in mitochondria and blood vessels, and are resistant to fatigue.
Fast-twitch muscles can generate large amounts of tension but tire more quickly.

Energy Sources for Muscle Contraction

Energy sources for muscle contraction shifts from glycogen based during high-intensity exercise, to fatty acids, blood glucose and ketone bodies at rest or during low-intensity exercise.

The Creatine Kinase Reaction

Creatine kinase rapidly regenerates ATP from ADP via phosphocreatine.
This shuttle transfers ATP equivalents to sites requiring ATP for muscle function.

Phosphocreatine Buffers ATP Concentration During Exercise

Muscle contraction doesn't significantly change ATP concentration due to the phosphocreatine-ATP buffering system.

The Cori Cycle

Lactate produced during muscle activity is transported to the liver.
In the liver, lactate is converted back into glucose to replenish muscle glycogen stores.

Shivering Thermogenesis

Rapidly repeated muscle contractions produce heat to maintain body temperature (37°C).

The Heart Mainly Uses FFAs as an Energy Source

Heart muscles obtain nearly all ATP through oxidative phosphorylation.
Fatty acids are the primary fuel source, though glucose and ketone bodies can also be utilized aerobically.

The Brain Uses Energy for Transmission of Electrical Impulses

Neurons primarily use glucose for energy production through oxidative phosphorylation to produce ATP needed for electrical impulse transmission.
While ketones can be used during extreme starvation, glucose is usually the preferred fuel.

Neurons Can Oxidize β-Hydroxybutyrate

Neurons can use β-hydroxybutyrate as fuel during prolonged fasting or starvation.
This enables the brain to use body fat as an energy source and spare muscle proteins.

The Brain Uses ATP to Create and Maintain the Electrical Potential

The Na+/K+-ATPase creates and maintains the electrical potential across neuron membranes for nerve impulses through an electrogenic ATP-driven antiporter.

Blood Carries Oxygen, Metabolites, and Hormones

Blood transports nutrients, waste products, oxygen, carbon dioxide, and hormones to various regions of the body.

The Three Types of Blood Cells

Erythrocytes (red blood cells) carry oxygen and carbon dioxide.
Leukocytes (white blood cells) are crucial for the immune system.
Platelets help in blood clotting.

The Composition of Blood

Blood plasma consists mainly of water and dissolved solutes.
Plasma proteins (including albumin, immunoglobulins, lipoproteins, and others) make up a substantial portion of the plasma solids.

Physiological Effects of Low Blood Glucose

Insufficient blood glucose levels can trigger different physiological symptoms—from subtle neurological changes to severe neurological abnormalities.

Hormonal Regulation of Fuel Metabolism

Hormones (insulin, glucagon, epinephrine, cortisol) meticulously regulate blood glucose levels by manipulating various metabolic processes in tissues like the liver.

Maintaining Blood Glucose Levels Requires the Combined Actions of Multiple Hormones

Maintaining blood glucose levels requires a coordinated effort from multiple hormones.

Insulin Counters High Blood Glucose in the Well-Fed State

Insulin influences the uptake of glucose by tissues and its storage in glycogen/triacylglycerol.
The table details the effect of insulin on different metabolic pathways.

The Well-Fed State: The Lipogenic Liver

Insulin action in the well-fed state promotes glycogen and TAG storage in the liver and muscle tissue.

Pancreatic β Cells Secrete Insulin in Response to Changes in Blood Glucose

Blood glucose levels prompt the pancreas to secrete insulin and halt the secretion of glucagon.

Glucose Regulation of Insulin Secretion by Pancreatic β Cells

Increased ATP levels in pancreatic beta cells close ATP-gated potassium (K+) channels.
This process depolarizes the cell membrane, causing voltage-gated calcium (Ca2+) channels to open.
The consequent rise in cytosolic Ca2+ triggers insulin release through exocytosis.

A Simple Feedback Loop Limits Insulin Release

Insulin release is regulated by a feedback loop involving glucose levels. Decreased glucose levels signal the pancreas to slow or cease insulin secretion.

ATP-Gated K+ Channels in β Cells

ATP-gated K+ channels contain Kir6.2 and SUR1 subunits.
Sulfonylurea drugs act on SUR1, closing the channels and stimulating insulin release.

Glucagon Counters Low Blood Glucose

Glucagon plays a vital role in increasing blood glucose in the fasting state by stimulating glycogen breakdown and increasing gluconeogenesis.

The Fasted State: The Glucogenic Liver

Glucagon, when blood glucose lowers, stimulates glucose synthesis, and mobilizes TAGs in the liver and adipose tissue.

During Fasting and Starvation, Metabolism Shifts to Provide Fuel for the Brain

During fasting or starvation, the body adapts by shifting substrate sources to primarily provide the brain with glucose to maintain bodily functions.

Fuel Metabolism in the Liver During Fasting

Low insulin and high glucagon levels promote fatty acid mobilization from adipose tissue into the liver.
The liver converts fatty acids into ketone bodies for transport to other tissues (including the brain).

Plasma Concentrations During Starvation

Glucose levels decline within approximately two days of starvation.
Ketone body levels (particularly β-hydroxybutyrate) dramatically increase after approximately four days of starvation, indicating their usage as an alternative energy source.

Epinephrine Signals Impending Activity

Epinephrine stimulates glycogen breakdown to mobilize glucose, promoting metabolic changes, and increasing ATP production, promoting fatty acid mobilization, and lowering insulin secretion all intended to prepare the body for higher activity.

Cortisol Signals Stress, Including Low Blood Glucose

Cortisol, a glucocorticoid produced by the adrenal cortex, plays a critical role in regulating metabolism and responses to stress.
It acts by increasing blood glucose, promoting mobilization of fatty acids from adipose tissue & the breakdown of proteins, thus stimulating gluconeogenesis.

Cortisol Acts on Muscle, Liver, and Adipose Tissue

Cortisol impacts muscle, liver, and adipose tissue metabolism during stress, increasing fatty acid release, protein breakdown, and gluconeogenesis to maintain blood glucose.

Obesity and the Regulation of Body Mass

BMI is calculated from weight/height² and classifies individuals as underweight, normal, overweight, or obese.
Obesity is related to increased likelihood of many diseases.

Fates of Excess Dietary Calories

Excess dietary calories are either stored as fat or used for additional exercise.

Adipose Tissue Has Important Endocrine Functions

Adipose tissue performs endocrine-related functions by releasing various peptide hormones like leptin and adiponectin.

Leptin is an Adipokine

Leptin, produced by adipose tissue, regulates feeding behavior and energy expenditure to maintain adequate fat reserves.

Obesity Caused by Defective Leptin Production

Mice with defective leptin genes exhibit obesity-related characteristics and can be reversed through leptin injection.

The Leptin Receptor

Leptin receptors are primarily located in the arcuate nucleus of the hypothalamus regulating body weight.

Hypothalamic Regulation of Food Intake and Energy Expenditure

Hypothalamus regulates food intake and energy expenditure in response to leptin and norepinephrine signals to adipocytes.
This process activates protein kinase A, triggering fatty acid mobilization & promoting heat generation in mitochondria.

Leptin Stimulates Production of Anorexigenic Peptide Hormones

Leptin influences neurons in the arcuate nucleus, stimulating a-MSH release and inhibiting NPY release, affecting appetite and food intake behavior.

Hormones That Control Eating

Various hormones like leptin, a-MSH, NPY, ghrelin, PYY3-36, and GLP-1 exert feedback mechanisms in the hypothalamus to control feeding behavior.

Leptin Triggers a Signaling Cascade That Regulates Gene Expression

Leptin stimulates receptor dimerization and phosphorylation-dependent gene expression events, impacting the POMC gene, mitochondrial synthesis in brown/beige adipocytes, and ucp1 expression.

Leptin and Human Obesity

Leptin levels tend to correlate with body weight but leptin injections don't universally reverse obesity in humans (possibly due to downstream issues).

Adiponectin Acts through AMPK to Increase Insulin Sensitivity

Adiponectin acts through AMPK to stimulate fatty acid uptake and oxidation, halt fatty acid synthesis, and increase insulin sensitivity in muscle and liver tissues.

The Role of AMPK in Maintaining Energy Homeostasis

AMPK activation is stimulated by adiponectin and a low ATP/AMP ratio, which promotes energy expenditure and balances anabolic and catabolic processes.

AMPK Coordinates Catabolism and Anabolism in Response to Metabolic Stress

AMPK coordinates various metabolic processes and energy expenditure in tissues and organs during fasting, exercise, or other metabolic stress.

The mTORC1 Pathway Coordinates Cell Growth with the Supply of Nutrients and Energy

mTOR is a vital serine/threonine kinase in the mTORC1 complex regulating various cellular processes in response to nutrient availability.
mTORC1 is also regulated by multiple factors (amino acids, signals, etc.).

The mTORC-Ragulator-Rag Complex on the Lysosomal Surface

The Ragulator-Rag complex integrates intracellular and external signals related to energy levels, amino acid availability, and growth factors, coordinating mTORC1 activation with cellular requirements.

mTORC1 Activation Signals and the Cellular Process it Activates

Diagram illustrating how multiple signals trigger mTORC1 activation and the various cellular processes it impacts (protein synthesis, metabolism, etc.).

Diet Regulates the Expression of Genes Central to Maintaining Body Mass

Diet influences the expression of genes associated with fat and carbohydrate metabolism using transcription factors like peroxisome proliferator-activated receptors (PPAR).

Mode of Action of PPARs

PPARs are ligand-activated transcription factors that bind to specific regions of DNA to regulate target gene expression. - PPAR ligands include fatty acids/derivatives.
PPARs form heterodimers with RXR.

The Three PPAR Isoforms Regulate Lipid and Glucose Homeostasis

Different isoforms of PPARs regulate diverse aspects of lipid and glucose metabolism.

Metabolic Integration by PPARs

Diagram explaining how PPARs coordinate metabolic integration among the liver, adipose tissues, and muscle related to fatty acid oxidation, TAG storage, & insulin sensitivity during metabolic stress.

Short-Term Eating Behavior Is Influenced by Ghrelin, PYY 3-36, and Cannabinoids

Ghrelin stimulates appetite; PYY3-36 inhibits it; and endocannabinoids signal the availability of food.

Variations in Blood Concentrations of Glucose, Ghrelin, and Insulin

Variations in the blood concentrations of glucose, ghrelin and insulin are related to how they are affected by meal timing and other stimuli.

PYY 3-36 Acts to Lessen Hunger After a Meal

PYY3-36 acts on specific neurons in the hypothalamus in response to feeding inhibiting NPY release which contributes to shortening hunger.

Cannabinoids

Endocannabinoids are lipid messengers signaling fatty/sweet food and promoting consumption.
Cannabinoid receptors mediate the psychoactive effects of tetrahydrocannabinol (THC).

Microbial Symbionts in the Gut Influence Energy Metabolism and Adipogenesis

The gut microbiota influences energy metabolism by releasing fermentation products affecting gut hormone release impacting energy and adiposity.

Probiotics and Prebiotics

Weight loss/adiposity may be regulated by introducing probiotics/prebiotics.

Diabetes Mellitus

Diabetes mellitus is a common metabolic disorder in humans characterized by elevated blood glucose levels arising from insulin secretion defects/resistance.

Diabetes Mellitus Arises from Defects in Insulin Production or Action

Type 1 diabetes is often the result of an autoimmune response destroying the insulin-producing cells.

Type 2 Diabetes

Type 2 diabetes is a complex condition often associated with obesity and insulin resistance.

Symptoms and Pathology of Diabetes

Key symptoms often include excessive thirst and urination, and the chronic progression may result in a variety of severe health complications (e.g. cardiovascular disease, renal failure, blindness, neuropathy).

Diagnosis of Diabetes

Common diagnostic procedures for diabetes mellitus include HbA1c and glucose tolerance tests.

Carboxylic Acids (Ketone Bodies) Accumulate in the Blood of Those with Untreated Diabetes

With severely uncontrolled diabetes; fatty acids become the main fuel source resulting in increased ketone bodies.

Untreated Diabetes Can Cause Ketoacidosis

Severe diabetes, uncontrolled, can result in ketosis and acidosis lowering blood pH leading to ketoacidosis.

In Type 2 Diabetes the Tissues Become Insensitive to Insulin

Cells in type 2 diabetes may become resistant to insulin actions leading to hyperglycaemia.
Metabolic syndrome signifies a pre-diabetes diagnostic marker.

The “Lipid Toxicity” Hypothesis

Abnormal lipid storage in tissues can contribute to insulin resistance in type 2 diabetes, influencing various metabolic activities in the body.

Type 2 Diabetes Is Managed with Diet, Exercise, Medication, and Surgery

Various treatments for type 2 diabetes include lifestyle modifications (diet, exercise) and pharmacological approaches targeting different pathways.

Irisin

Irisin is a peptide hormone influencing the development of beige adipocytes and UCP-1 expression.

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Description

Explore the intricacies of the mammalian endocrine system with this quiz, focusing on hormonal regulation, metabolic processes, and the impact of insulin on blood glucose levels. Delve into the role of hormones, microbial symbionts, and the importance of maintaining optimal body mass. This quiz will challenge your understanding of mammalian physiology and endocrine functions.