Endocrine System and Hormones Quiz

Endocrine System Overview

• The endocrine system controls cell metabolism by releasing hormones into the bloodstream
• Major glands include the pituitary, pineal, adrenal, thyroid, parathyroid, thymus, pancreas, gonads (ovaries and testes), and hypothalamus
• Hormones are triggered by blood chemistry changes, nervous system signals, and responses to other hormones

Anatomy and Physiology of the Pituitary Gland

• The pituitary gland has three parts: anterior, intermediate, and posterior
• It's known as the "master endocrine gland" and controlled by the hypothalamus
• Each part releases specific hormones

Hormones and Their Functions

• Pineal gland: Releases melatonin, impacting the biological clock.
• Pituitary gland:
  • FSH/LH affect ovaries and menstrual cycles, and kidneys in maintaining balance of water
  • ADH regulates the water balance in kidneys
  • Growth hormone impacts growth and cell division.
  • Oxytocin involved in birth contractions
  • Prolactin stimulates milk production
• Thyroid gland: Releases thyroxine which controls metabolic rate
• Adrenal glands:
  • Adrenaline and cortisol involved in stress response
• Pancreas:
  • Insulin regulates blood sugar levels and glucagon increases blood sugar
• Ovaries: Release estrogen and progesterone affecting the menstrual cycle
• Testes: Release testosterone affecting male characteristics

Imaging Considerations

• Radiography is useful in diagnosing metabolic diseases affecting the skeletal system and endocrine disorders (e.g., Cushing's disease)
• MRI is preferred over CT for imaging neuroendocrine disorders; it can diagnose conditions like empty sella syndrome and pituitary adenomas.
• CT is useful to evaluate the pineal gland, assess thyroid/parathyroid conditions, identify adrenal neoplasms, and evaluate adrenal gland enlargement in disease like Cushing's disease

Bone Mineral Density (DXA)

• DXA is crucial for assessing osteoporosis
• Bone density is measured at specific sites like the radius, femoral neck, and lumbar spine
• Results are compared to norms using a T-score to classify bone health.
• Z-scores compare an individual's bone density with a population matched for age, gender, weight, and ethnicity

Nuclear Medicine Procedures

• Iodine-123 (I-123) uptake tests for diagnosing thyroid gland function and detecting nodules
• Used post-surgery or ablation to assess remaining thyroid tissue
• Nuclear medicine imaging using iodine-131 (I-131) to localize medullary tumors in the adrenal glands
• 131I-MIBG used for treating medullary adrenal gland tumors

Skeletal Disorders

• Osteoporosis is a metabolic disorder characterized by decreased bone density, leading to a weakened bone structure.
• Radiography detects advanced cases, early-stage evaluation best done via DXA
• Secondary osteoporosis is often associated with other medical issues, medications, or hereditary factors
• Osteomalacia is caused by a lack of vitamin D, leading to soft, non-calcified bones
• Paget's disease (osteitis deformans) is a metabolic disorder impacting the bones, often starting in older adults

Pituitary Gland Disorders

• Acromegaly is an endocrine disorder occurring in adults caused by excessive growth hormone (GH) secretion by a pituitary adenoma.
• Symptoms include thickened bones, enlarged sella turcica, and changes in the skull, and also include prominence of the forehead, jaw, enlarged hands, and coarser facial features.
• Diagnosis involves MRI of the brain
• Treatment involves surgery and radiotherapy

Diabetes Insipidus

• Diabetes insipidus is caused by insufficient antidiuretic hormone (ADH) production, leading to excessive urination and thirst
• Causes can be neurogenic or nephrogenic related with brain lesions, genetic factors, or acquired renal disorders

Hypopituitarism

• Hypopituitarism is characterized by decreased or absent pituitary hormone production.
• It's caused by several factors including genetic mutations, pituitary infarction, and other medical conditions
• Symptoms vary depending on affected hormones
• Diagnosis involves MRI of the sellar region
• Treatment involves hormone replacement therapy

Adrenal Gland Disorders

• Cushing syndrome results from prolonged steroid use or an overproduction of glucocorticoids, leading to a characteristic round face, fat deposits, thin skin, and menstrual irregularities.
• Diagnostic tests include cortisol analysis, and/or MRI.
• Addison disease is characterized by adrenal insufficiency, resulting from damage to the adrenal cortex.
• Diagnosis involves tests measuring cortisol and ACTH levels
• Adrenal carcinoma is a rare but aggressive tumor of the adrenal glands often metastasizing from other sources.
• Imaging like CT and MRI aid diagnosis
• Surgical removal is required.

Pancreatic Disorders

• Diabetes mellitus is a syndrome characterized by chronic hyperglycemia (high blood sugar), glucose intolerance, and related metabolic alterations.
  • Type 1 diabetes is often genetic, autoimmune-induced destruction of pancreatic beta cells, requiring insulin therapy.
  • Type 2 diabetes is often linked with obesity/sedentary lifestyles, leading to insulin resistance and requiring various therapies
• Metabolic syndrome is identified with 3+ of 5 risk factors associated with risk of Type 2 Diabetes
• It is often identified in individuals who exhibit increased waist circumference, high triglycerides, low HDL cholesterol, high blood pressure, and elevated fasting plasma glucose.

Thyroid and Parathyroid Gland Disorders

• Hyperthyroidism is characterized by excessive thyroid production, impacting many bodily functions.
• Hypothyroidism is characterized by low thyroid production, impacting many bodily functions.
• Hyperparathyroidism is characterized by excess parathyroid hormone (PTH), impacting bone and kidney health.
  • Diagnose with imaging study (CT or scans)

Nephrocalcinosis

• Nephrocalcinosis is the deposition of calcium phosphate in the kidney's renal parenchyma
• Diagnose with imaging studies like Intravenous urograms and abdominal radiographs.
• Treatment addresses the underlying metabolic condition.