Endocrine System Flashcards
(20 cards)
Overview of the Endocrine System
Definition: A system of glands that secrete hormones to regulate bodily functions.
Key Functions: Metabolism, growth, development, reproduction, and mood regulation.
Major Glands: Pituitary, thyroid, adrenal, pancreas, gonads (ovaries and testes).
Hormones and Their Functions
Definition: Chemical messengers released into the bloodstream.
Examples:
Insulin: Regulates blood glucose levels.
Thyroid Hormones (T3, T4): Regulate metabolism and energy levels.
Cortisol: Manages stress response and metabolism.
Estrogen & Testosterone: Control reproductive functions and secondary sexual characteristics.
Pituitary Gland
Location: Base of the brain, often referred to as the “master gland.”
Divisions:
Anterior Pituitary: Produces hormones like GH (growth hormone), ACTH, TSH, LH, FSH, and PRL (prolactin).
Posterior Pituitary: Stores and releases ADH (antidiuretic hormone) and oxytocin.
Functions: Regulates other endocrine glands and bodily function
Thyroid Gland
Location: Anterior neck, below the larynx.
Hormones Produced:
Thyroxine (T4) and Triiodothyronine (T3): Regulate metabolism, energy, and growth.
Calcitonin: Lowers blood calcium levels by inhibiting osteoclast activity.
Clinical Relevance: Disorders include hypothyroidism and hyperthyroidism.
Adrenal Glands
Location: Sit on top of each kidney.
Divisions:
Adrenal Cortex: Produces corticosteroids (cortisol, aldosterone) and androgens.
Adrenal Medulla: Produces catecholamines (epinephrine, norepinephrine) for the “fight or flight” response.
Functions: Stress response, blood pressure regulation, and metabolism
Pancreas
Location: Behind the stomach, part of both the endocrine and digestive systems.
Hormones Produced:
Insulin: Lowers blood glucose levels.
Glucagon: Raises blood glucose levels.
Clinical Relevance: Dysregulation leads to diabetes mellitus.
Gonads (Ovaries and Testes)
Ovaries: Produce estrogen and progesterone; regulate menstrual cycle and pregnancy.
Testes: Produce testosterone; control sperm production and male characteristics.
Clinical Relevance: Hormonal imbalances can affect fertility and sexual development.
Feedback Mechanisms in the Endocrine System
Negative Feedback: Most common mechanism; inhibits hormone release to maintain homeostasis (e.g., thyroid hormone regulation).
Positive Feedback: Stimulates hormone release to enhance the effect (e.g., oxytocin during childbirth).
Endocrine Disorders
Diabetes Mellitus: Impaired insulin production or action; types include Type 1 and Type 2.
Thyroid Disorders: Hypothyroidism (low hormone levels) vs. hyperthyroidism (high hormone levels).
Cushing’s Syndrome: Excess cortisol production leading to weight gain and hypertension.
Addison’s Disease: Insufficient cortisol and aldosterone production.
Assessment of Endocrine Function
History Taking: Inquire about symptoms (e.g., weight changes, energy levels, mood swings).
Physical Examination: Look for signs like skin changes, hair distribution, and thyroid enlargement.
Diagnostic Tests: Blood tests for hormone levels, imaging studies (e.g., CT, MRI) for gland abnormalities.
Diabetes Management
Type 1 Diabetes: Insulin therapy required; regular blood glucose monitoring.
Type 2 Diabetes: Lifestyle changes (diet, exercise), oral medications, and possible insulin therapy.
Patient Education: Importance of glucose monitoring, recognizing hypoglycemia and hyperglycemia symptoms.
Thyroid Function Tests
TSH (Thyroid Stimulating Hormone): First-line test; high levels indicate hypothyroidism, low levels indicate hyperthyroidism.
T3 and T4 Levels: Direct assessment of thyroid hormone production.
Thyroid Antibodies: Helps diagnose autoimmune thyroid disorders (e.g., Hashimoto’s thyroiditis, Graves’ disease).
Hormonal Regulation of Metabolism
Insulin: Promotes glucose uptake and storage; regulates fat and protein metabolism.
Glucagon: Stimulates glycogen breakdown and glucose release from the liver.
Thyroid Hormones: Increase basal metabolic rate and influence growth and development.
Stress and the Endocrine System
Stress Response: Activation of the hypothalamus-pituitary-adrenal (HPA) axis.
Cortisol Release: Increases glucose availability, suppresses immune response.
Long-term Stress: Can lead to chronic conditions like hypertension and diabetes.
Hormonal Effects on Mood
Estrogen: Fluctuations can affect mood; linked to premenstrual syndrome (PMS) and postpartum depression.
Testosterone: Low levels can lead to depression and fatigue in men.
Thyroid Hormones: Imbalances can lead to mood disorders (e.g., depression in hypothyroidism).
Role of the Hypothalamus
Location: Below the thalamus; connects the nervous system to the endocrine system.
Functions: Regulates body temperature, hunger, thirst, sleep, and circadian rhythms.
Hormonal Control: Produces releasing and inhibiting hormones that regulate the pituitary gland.
Hormonal Changes with Aging
Menopause: Decrease in estrogen and progesterone; leads to symptoms like hot flashes and osteoporosis.
Andropause: Gradual decline in testosterone in men; affects energy, mood, and muscle mass.
Thyroid Changes: Risk of hypothyroidism increases with age.
Patient Education on Endocrine Health
Balanced Diet: Importance of nutrition for hormonal balance (e.g., fiber, healthy fats).
Regular Exercise: Helps regulate insulin and manage weight.
Stress Management: Techniques such as mindfulness, yoga, and deep breathing.
Pharmacological Treatments in Endocrinology
Insulin Therapy: For Type 1 and some Type 2 diabetes patients.
Thyroid Hormone Replacement: Levothyroxine for hypothyroidism.
Hormonal Contraceptives: Regulate menstrual cycle and alleviate symptoms of PMS.
Corticosteroids: For conditions like Addison’s disease and inflammatory disorders.
Endocrine Emergencies
Diabetic Ketoacidosis (DKA): Life-threatening complication of diabetes; requires immediate insulin therapy and fluid replacement.
Thyroid Storm: Severe hyperthyroidism leading to fever, tachycardia, and confusion; needs rapid treatment.
Adrenal Crisis: Life-threatening adrenal insufficiency; requires IV hydrocortisone administration.
