Untitled Quiz

Introduction to Pathophysiology

• Course taught by Dr. Mouadh Abdelkarim
• Covers endocrine system disorders, specifically
  • Insulin and Diabetes Mellitus
  • Parathyroid Hormone and Calcium Disorders
  • Pituitary Hormones Disorders
  • Thyroid Disorders
  • Adrenal Gland disorders

Major Endocrine Glands

• Hypothalamus
• Pituitary gland
• Pineal gland
• Thyroid
• Parathyroid glands
• Thymus
• Adrenal glands
• Pancreas
• Ovaries
• Testes

Location of Endocrine Glands

• Diagram showing locations of various endocrine glands in the body.
  • Parathyroid gland is located on the posterior side of the thyroid gland.
  • Other glands are depicted in their anatomical positions (e.g., pituitary, thyroid, adrenal, pancreas, ovaries, and testes).

Endocrine System

• Hormones function as chemical messengers
• Target receptors
• Negative feedback systems
• Chemical structure
  • Peptide
  • Steroid

Classification by Chemical Structure

• Steroids: Lipids that directly enter the cell nucleus to initiate transcription.
• Nonsteroids: Require a secondary messenger system to activate transcription in the nucleus.

Sources of Major Hormones and Their Primary Effects

• Table listing major hormones, their origin, and primary effects. (Specific hormone/effect details provided in the table.)

Control of the Endocrine System

• Endocrine and nervous systems regulate metabolic activities.
• Negative feedback
• Positive feedback (e.g., blood clotting, childbirth).
• Certain hormones act as antagonists (e.g., calcitonin and parathyroid hormone, insulin and glucagon).

Endocrine Disorders

• Disorders relate to impaired control or feedback.
• Excess hormone levels
  • Caused by tumor, impaired excretion by liver/kidney, or congenital factors
• Deficit of hormone or reduced effects
  • Caused by tumor, decreased tissue receptors, or increased antagonistic hormone production. Poor nutrition, atrophy, or surgical removal of the gland. Congenital factors

Diagnostic Tests

• Blood tests (e.g., checking serum hormone levels, radioimmunoassay, or immunochemical methods).
• Urine tests
• Stimulation or suppression tests
• Scanning, ultrasound, MRI
• Biopsy

Treatment

• Deficits treated with replacement therapy.
• Excessive secretions treated with medications, surgery, or radiation.

1- Insulin and Diabetes Mellitus

• Diabetes mellitus arises from inadequate insulin effects on receptor tissues
  • Deficit in insulin secretion
  • Production of insulin antagonists
• It leads to abnormal carbohydrate, protein, and fat metabolism.
• Some tissues can transport glucose without insulin
  • CNS, kidney, myocardium, gut, skeletal muscle
• Skeletal muscle can partially meet tissue needs without insulin

Types of Diabetes

• Type 1:
  • Autoimmune destruction of beta cells in pancreas.
  • Insulin replacement is required.
  • Acute onset in children/adolescents
  • Not linked to obesity.
  • Genetic factors may play a role.
  • Metabolic changes
    • Excessive amounts of fatty acids & metabolites
    • Ketones in the blood
• Type 2:
  • Noninsulin-dependent.
  • Oral hypoglycemic medications may be used.
  • Caused by decreased production of insulin and/or increased resistance by body cells to insulin.
  • Onset is slow and insidious, usually in older than 50 years.
  • Associated with obesity.
  • A component of metabolic syndrome.
  • Increasing incidence in teens and young adults.

A- Type 1 Diabetes

• Metabolic changes in catabolism of fats and proteins, producing ketones in the blood.

Diabetic Ketoacidosis (DKA)

• Occurs in insulin-dependent clients, commonly seen in type 1 diabetes.
• High blood glucose levels
• Mobilization and use of lipids to meet cellular needs result from production of ketoacids.
• May be initiated by infection or stress.
• May result from error in dosage, infection, change in diet, alcohol intake, or exercise.
• Signs/Symptoms
  • Kussmaul respirations (rapid, deep)
  • Acetone breath (sweet, fruity smell)
  • Lethargy and decreased responsiveness indicate central nervous system depression & decreased blood flow.
• Causes decreased serum bicarbonate and decreased serum pH.
• Complications lead to dehydration and electrolyte imbalances

2- Parathyroid Hormone and Calcium

• 4 parathyroid glands release PTH in response to a drop in serum calcium.
• Magnesium needed to activate PTH release.
• Effects of PTH on bone, kidney, and intestines.
• Actions of PTH on bone (osteoclastic activity)
• Mobilization of Ca+ from bone/demineralization which increases serum Ca++ levels.
• Hypoparathyroidism leads to hypocalcemia.
• Causes of Hypoparathyroidism: Tumor, congenital lack, surgery/radiation, autoimmune.
• Normal control & feedback of calcium- diagram included.
• Hyperparathyroidism leads to hypercalcemia.
• Causes of hyperparathyroidism: Tumor, secondary to renal failure, paraneoplastic syndrome.
• Common effects of parathyroid hormone imbalance- table included (hypo/hyper symptoms).

3- Pituitary Hormones

• Adenomas are the most common cause of pituitary disorders.
• Adenomas can affect the skull (headaches, seizures, drowsiness, visual deficits)
• Hormones secretion dependent on specific cells/location leading to excessive or decreased hormone release.
• Growth hormone (GH) control diagram provided.
  • Dwarfism (GH deficit before puberty)
  • Gigantism (excess GH before puberty/fusion of epiphysis)
  • Acromegaly (excess GH secretion in adults- often associated with adenomas)

Antidiuretic Hormone (ADH)

• Diabetes insipidus-deficit of ADH.
  • May originate in neurohypophysis
  • Possible genetic problems
  • Can be caused by head injury/surgery
  • Requires replacement treatment
• Inappropriate ADH syndrome (SIADH)
  • Excess ADH
  • May be temporary/triggered by stress; from an ectopic tumor
  • Treatment with diureics and sodium supplements

4- Thyroid Disorders

• Two thyroid hormones: T4 (thyroxine), T3 (triiodothyronine)
• Released in response to TSH.
• Hyperthyroidism (Graves' Disease), Hypothyroidism results from pituitary or thyroid malfunction.
• Goiter: enlarged thyroid gland
  • Endemic goiter (iodine deficiency)
  • Goitrogens (block synthesis of T3 & T4)
  • Toxic goiter (due to thyroid hyperactivity).
• Hypothyroidism (iodine deficit, Hashimoto's Thyroiditis, tumor, gland removal)
• Cretinism- results from untreated congenital hypothyroidism (during pregnancy)
• Hypothyroidism manifestations-symptoms listed.
• Comparison of Hypothyroidism and Hyperthyroidism-table included.

5- Adrenal Glands

• Adrenal medulla
  • Pheochromocytoma (neuroendocrine tumor, secretes epinephrine, norepinephrine)
• Adrenal cortex
  • Cushing syndrome (high glucocorticoid levels)
    • Causes: pituitary adenoma, adrenal adenoma, etc.
    • Symptoms: appearance change, high blood glucose, hypertension, muscle weakness
  • Addison disease (deficiency adrenocorticoid)
    • Causes: autoimmune reaction, hemorrhage, infection
    • Symptoms: low blood glucose, inadequate stress response, weight loss, low sodium, high potassium, hypertension