Endocrine System Overview: Pituitary and Thyroid

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Questions and Answers

What is one of the primary actions of thyroid hormones?

Inhibit skeletal growth

Decrease cardiac output

Increase tissue metabolism (correct)

Lower body temperature

Which condition is primarily responsible for causing hyperthyroidism in many females aged 30-50?

Toxic multinodular goiter

Graves' disease (correct)

Toxic adenoma

Secondary pituitary adenoma

What is the estimated weight of the adult thyroid gland?

20 to 25 g

10 to 15 g

15 to 20 g (correct)

5 to 10 g

How do thyroid hormones affect cholesterol levels in the serum?

Decrease serum cholesterol levels Signup and view all the answers

What anatomical feature connects the right and left lobes of the thyroid gland?

Isthmus Signup and view all the answers

What is the primary effect of thyroxine on mental development?

Stimulates mental development Signup and view all the answers

Which of the following is NOT a cause of hyperthyroidism?

Inadequate iodine intake Signup and view all the answers

What physiological effect do thyroid hormones have on catecholamines?

Increase sensitivity to catecholamines Signup and view all the answers

What condition may lead to hyperpigmentation due to increased ACTH levels?

Addison's disease Signup and view all the answers

Which hormone is primarily responsible for lowering blood glucose levels?

Insulin Signup and view all the answers

Which of the following statements best describes Type II Diabetes Mellitus?

Insulin resistance is the most probable cause. Signup and view all the answers

What is one of the effects of insulin on carbohydrate metabolism?

Stimulates glycogenesis Signup and view all the answers

What might happen if Addison's disease is not urgently detected and treated?

Dehydration and shock Signup and view all the answers

What is the primary composition of insulin?

51 amino acids in a peptide chain Signup and view all the answers

What is a common result of long-term diabetes mellitus regarding life expectancy?

Reduced life expectancy Signup and view all the answers

What happens to protein metabolism in the presence of insulin?

It has an anabolic effect. Signup and view all the answers

What is a common characteristic of type I diabetes mellitus compared to type II diabetes mellitus?

Weight loss is often evident Signup and view all the answers

Which of the following statements best describes insulin's role in diabetes mellitus?

Insulin levels increase early and decrease later in type II Signup and view all the answers

What type of infections are commonly associated with diabetes mellitus?

Skin infections such as abscesses and furuncles Signup and view all the answers

Which of the following is a characteristic symptom of type II diabetes mellitus?

Frequent urination Signup and view all the answers

Which complication is most closely associated with diabetes mellitus that directly affects the eyes?

Diabetic retinopathy Signup and view all the answers

What is the likely outcome of peripheral neuropathy in diabetes patients?

Increased risk of amputations Signup and view all the answers

In diabetes, what is a common renal complication noted in the early stages?

Fat atrophy at insulin injection sites Signup and view all the answers

Which demographic is most commonly affected by type I diabetes mellitus?

Children and adolescents Signup and view all the answers

Which class of oral antidiabetic agents promotes the release of insulin from the pancreas?

Sulphonylurea Signup and view all the answers

What is the primary action of Dipeptidyl peptidase-4 inhibitors?

Decrease blood sugar by increasing incretin levels Signup and view all the answers

Which oral antidiabetic agent increases anaerobic glycolysis?

Biguanides Signup and view all the answers

What is a major effect of Gliflozines (SGLT2 inhibitors)?

Inhibit renal glucose reabsorption Signup and view all the answers

Which oral antidiabetic agent acts as an insulin sensitizer?

Glitazones Signup and view all the answers

What condition is a fundamental risk factor in the metabolic syndrome?

Overweight/obesity Signup and view all the answers

Which of the following agents decreases gastric emptying and promotes insulin secretion?

Glucagon-like peptide-1 receptor agonists Signup and view all the answers

Which of the following agents is specifically known to inhibit intestinal glucose absorption?

Alpha-glucosidase inhibitors Signup and view all the answers

What is a common symptom of hyperthyroidism related to appetite and weight?

Loss of weight in spite of increased appetite Signup and view all the answers

Which of the following is NOT a cardiovascular symptom of hyperthyroidism?

Hypotension Signup and view all the answers

What is the characteristic eye symptom associated with hyperthyroidism?

Exophthalmos (protrusion of the eyeballs) Signup and view all the answers

Which investigation result is generally indicative of hyperthyroidism?

Increased thyroid hormones (T3 and T4) Signup and view all the answers

What treatment might be used to control heart rate in a patient with hyperthyroidism?

B-Blockers Signup and view all the answers

Which physical symptom related to the nervous system is commonly associated with hyperthyroidism?

Muscle weakness and fatigue Signup and view all the answers

In which condition would you expect to see a ‘lid lag’ phenomenon?

Hyperthyroidism Signup and view all the answers

What might be an autoimmune marker present in Graves' disease?

Anti-thyroglobulin Ab Signup and view all the answers

Study Notes

MRI and Pituitary Tumors

MRI is essential for accurate diagnosis of pituitary tumors.
Management options include surgical resection or skull irradiation targeting the pituitary gland.

Thyroid Gland Structure

Adult thyroid composed of two lobes located along the trachea.
Lobes connected by an isthmus below the cricoid cartilage.
Average weight of adult thyroid gland is 15 to 20 grams.
Attached to thyroid cartilage and upper trachea, allowing movement during swallowing.

Thyroid Hormones and Their Effects

Thyroid hormone (thyroxin) synthesized within the thyroid gland.
Increases metabolic rate, heat production, and oxygen consumption across body cells.
Stimulates skeletal growth and mental development.
Promotes glycogenolysis, resulting in a diabetogenic effect.
Causes vasodilatation and lowers serum cholesterol levels.
Enhances conversion of carotene to vitamin A in the liver.
Increases sensitivity to catecholamines, elevating heart rate and blood pressure.

Hyperthyroidism (Thyrotoxicosis)

Defined as a clinical state from excess thyroid hormones affecting body tissues.
Common causes include Graves’ disease (primary thyrotoxicosis), toxic multinodular goiter, solitary toxic nodule, and secondary cases due to pituitary adenoma.

Clinical Presentation of Hyperthyroidism

General symptoms: weight loss despite increased appetite, heat intolerance, excessive sweating.
Thyroid-specific findings:
- Graves’ disease presents with diffuse mild enlargement.
- Toxic nodular goiter appears enlarged and nodular.
Nervous system symptoms: irritability, insomnia, muscle weakness, tremors.
Eye symptoms: staring look, lid lag, exophthalmos.
Cardiovascular: tachycardia, arrhythmias, increased systolic pressure.
Gastrointestinal: diarrhea; reproductive: amenorrhea.

Investigations for Hyperthyroidism

Elevated thyroid hormones (T3 & T4) with decreased TSH levels (negative feedback).
Autoimmune markers present in Graves’ disease.
Thyroid scan differentiates between Graves’ disease and other conditions.

Treatment for Hyperthyroidism

Beta-blockers for heart rate control.
Anti-thyroid drugs (e.g., carbimazole) that inhibit hormone synthesis.
Radioactive iodine therapy.
Surgery for patients with significant goiter or nodular goiter.

Addison’s Disease

Characterized by acute adrenal insufficiency: abdominal pain, diarrhea, hypotension, and fatigue.
Symptoms include hyperpigmentation, dehydration, and risk of shock and renal shutdown if untreated.

Insulin and Diabetes Mellitus

Insulin is a peptide hormone composed of 51 amino acids and secreted by β-cells of the pancreas.
Functions include lowering blood glucose, promoting glycogenesis, and inhibiting gluconeogenesis.

Diabetes Mellitus Overview

Chronic hyperglycemia due to insulin deficiency, resistance, or both.
Affects over 120 million people globally, leading to serious health complications.

Type I vs. Type II Diabetes Mellitus

Type I: Insulin-dependent due to β-cell damage, common in younger individuals, ketosis-prone.
Type II: Non-insulin dependent, associated with insulin resistance, usually presents in those over 40, often related to obesity.

Diabetes Clinical Presentation

May be asymptomatic; classic triad: polyuria, polydipsia, polyphagia.
Complications include pruritis, neuropathy, renal issues, and eye problems like diabetic retinopathy.

Diabetes Complications

Renal: diabetic nephropathy leading to chronic kidney failure.
Neurological: peripheral neuropathy, cranial nerve palsies.
Skin: increase in infections and localized fat atrophy at injection sites.

Management Strategies for Diabetes

Dietary modifications: weight reduction, exercise, controlled sugar intake.
Oral antidiabetic medications: sulphonylureas, biguanides (metformin), glitazones, and SGLT2 inhibitors.
Injectable GLP-1 receptor agonists may promote insulin secretion and assist in weight management.

Metabolic Syndrome

Defined as a combination of risk factors contributing to obesity and related complications.

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Description

This quiz covers key aspects of the endocrine system, focusing on the pituitary gland, its associated tumors, and the anatomical structure of the thyroid gland. It addresses management options for conditions like acromegaly and provides insights into the role of MRI in diagnosis. Test your knowledge on these crucial topics in endocrinology.