Endocrinology Module 1 Quiz

Module 1 - Key Topics

• Endocrinology glands provide basic functions like digestion, red blood cell production, reproduction, stress response, growth, autonomic nervous system (ANS) function, and homeostasis.
• Endocrine tissues secrete hormones:
  • Hydrophilic hormones (thyroid, catecholamines, amines, and peptides) are not bound to plasma proteins. They require transport proteins.
  • Lipophilic hormones (steroids) are bound to carrier proteins to travel in blood.
• Cyclic AMP (cAMP) is a second messenger system activated when a hormone binds to a cell-surface receptor.
• Hypothalamic-Pituitary Axis involves the hypothalamus and pituitary gland in regulating various bodily functions.
• Posterior pituitary releases ADH (antidiuretic hormone) and oxytocin.
• Anterior pituitary releases thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), growth hormone (GH), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin.
• Thyroid gland, located above the trachea, secretes thyroid hormones (T3 and T4). They regulate metabolism and other functions.

Thyroid Gland

• Located above the trachea, below the larynx.
• Made up of follicular cells (ring-like) that secrete calcitonin within a colloid (thyroglobulin).
• Two main hormones:
  • Tetraiodothyronine (T4): 90%, containing four iodine molecules.
  • Triiodothyronine (T3): 10%, containing three iodine molecules.
• Thyroid hormone synthesis occurs in the following steps:
  • Thyroglobulin production in the endoplasmic reticulum (ER).
  • Iodine trapping by follicular cells from the blood.
  • Iodine is moved into follicular lumen.
  • Iodine organification, where iodine is added to thyroglobulin.
  • Coupling of MIT and DIT to form T3 and T4.
• Thyroid hormone is released by follicular cells via phagocytosis/digestion of thyroglobulin by lysosomes, releasing free T3 and T4.

Release of Thyroid Hormone

• Follicular cells engulf colloid via phagocytosis.
• Lysosomes digest thyroglobulin, releasing T3, T4, MIT, and DIT.
• Free T3 and T4 enter the bloodstream and bind to transport proteins (thyroid-binding globulin).

Actions

• Metabolic processes
• Growth development
• Cardiovascular function
• Intermediary metabolism
• Sympathomimetic.

Hypothyroidism vs Hyperthyroidism

• Hypothyroidism: Low thyroid hormone levels, leading to symptoms like cold intolerance, weakness, weight gain, slow heart rate, and a larger thyroid gland.
• Hyperthyroidism: High thyroid hormone levels, leading to symptoms such as high heart rate, muscle weakness, mood swings, and weight loss

Adrenal Glands

• Respond to both acute and chronic stress.
• Located on top of each kidney.
• Cortex: Produces steroid hormones like mineralocorticoids (aldosterone), glucocorticoids, and androgens.
• Medulla: Produces catecholamines such as adrenaline (epinephrine) and norepinephrine.

Module 2 - Growth and Calcium Metabolism

• Growth Hormone (GH): Secreted by the anterior pituitary, stimulating protein synthesis, cell division, fat breakdown, and chondrocyte activity.
• Controlled by GHRH (growth hormone releasing hormone) and GHIH (somatostatin).
• Hypothalamus: Monitors and regulates internal environment. Releases peptides that affect pituitary hormones.
• Thyroid hormone (TH): Promotes growth.
• Calcitonin: secreted by thyroid's C cells, lowers blood calcium.
• Parathyroid hormone (PTH): secreted by para glands, raises blood calcium.
• Vitamin D: converted to calcitriol, increases calcium absorption.
• Hypocalcemia: low blood calcium, causes spasms, tingling, and cardiac issues.
• Hypercalcemia: high blood calcium, causes fatigue, confusion, and kidney stones.

Pineal Gland's Role in Reproductive Hormones

• Melatonin affects GnRH secretion, linking light exposure to reproductive cycles (e.g., seasonal breeding in animals and circadian effects in humans).
• Steroid hormones (e.g., testosterone and estrogen) bind to proteins like sex hormone-binding globulin (SHBG).

Male Reproductive System

• Tests: Produce sperm.
• Sperm production (spermatogenesis) is affected by follicle-stimulating hormone (FSH) and testosterone.

Female Reproductive System

• Oogenesis (ova production).
• Cycle: Follicular phase (estrogen secretion), ovulation (LH surge), and luteal phase (progesterone secretion).
• Uterine cycle: Endometrial changes during menstrual cycle.

Module 2- Fetal Development & Maternal

• Placental functions: Interface gases exchange/nutrient delivery, and waste elimination.
• Passive immunity, maternal antibodies transfer to fetus.
• Maternal physiological changes (cardiovascular, respiratory, renal).
• Parturition (childbirth): Hormone regulation (estrogen, oxytocin, prostaglandins), stages of labor (dilation, expulsion, placental), and uterine involution.

Module 2- Lactation

• Preparation during pregnancy: Estrogen stimulates milk duct growth, progesterone inhibits milk secretion.
• Milk secretion post-birth: prolactin stimulates milk production.
• Let-down reflex: oxytocin, released in response to suckling, causes myoepithelial cell contraction, ejecting milk.
• Milk composition: Contains essential nutrients, and immune components, like antibodies and lysozymes, and colostrum.

Clinical Considerations

• Complications in fertilization, including ectopic pregnancy.
• Gestational complications, such as pre-eclampsia.
• Postpartum complications, including postpartum hemorrhage.

Module 3- Introduction into Respiratory System

• Respiratory system is crucial for gas exchange, allowing oxygen uptake and carbon dioxide expulsion.
• Two types of respiration: internal (oxygen use and carbon dioxide production) and external (bringing oxygen into the body and removing carbon dioxide).
• Ventilation involves air movement in and out of lungs.

Anatomy of the Respiratory System

• Upper respiratory tract: nose, nasal cavity, pharynx, and larynx.
• Lower respiratory tract: trachea, bronchi, bronchioles, and alveoli.

Module 3- Lung Volumes and Respiratory Dysfunction

• Lung volumes include tidal volume (VT), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), and residual volume (RV).
• Lung capacities incorporate combinations of lung volumes (e.g., inspiratory capacity, functional residual capacity, vital capacity, total lung capacity).
• Obstructive lung disease: increased airway resistance and difficulty exhaling (e.g., asthma, chronic bronchitis, emphysema)
• Restrictive lung disease: reduced lung volumes (e.g., pulmonary fibrosis).

Module 3- Ventilation

• Minute ventilation: total amount of air inhaled per minute
• Expiratory flow (pulmonary function) testing.
• Work of breathing: overcoming elastic forces and airway resistance
• Gas exchange in lungs and tissues (process and driving forces)
• Partial pressures of gases (important for gas exchange)
• Factors affecting oxygen dissociation curve
• Mechanism of carbon dioxide transport

Module 3 - Control of Ventilation

• Peripheral chemoreceptors
• Central chemoreceptors
• Chemical and mechanical factors affecting ventilation.