AN OUTLINE OF ENDOCRINE SYSTEM Presented by Dr

AN OUTLINE OF ENDOCRINE SYSTEM Presented by: Dr. Indraneel Saha Assistant Professor in Z Sarsuna College

ANTERIOR PITUITARY AND ITS SECRETIONS:

POSTERIOR PITUITARY: HORMONES OXYTOCIN VASOPRESSIN/ ADH FUNCTIONS CHILD BIRTH/PARTURITION, MILK LET DOWN EJACULATION IN MALES PRESSOR EFFECT TUBULAR REABSORBTION OF WATER THESE HORMONES ARE CALLED NEUROHORMONES

HYPOTHALAMO- HYPOPHYSEAL AXIS:

THYROID GLANDS:

Histological features: Glandular portion is represented by numerous round, oval shaped thyroid follicles. Each follicle is lined with cuboidal epithelial cells with a prominent nucleus resting on the basement membrane. Each follicle has a large lumen filled with eosinophilic colloid material. Presence of blood vessels in connective tissue stroma. Hormones: Thyroxine (T 4 = Tetra Iodo Thyronine) T 3 = Tri Iodo Thyronine T 3 is more potent than T 4 Functions: Calorigenesis Regulates body temperature Regulates BMR Regulates metamorphosis in tadpole of frog

ADRENAL GLANDS: • ZONES OF CORTEX ZONA GLOMERULOSA ZONA FASCICULATA ZONA RETICULARIS • MEDULLA IS MADE UP OF CHROMAFFIN CELLS WITH E AND NE GRANULES

Histological features: Presence of connective tissue capsule covering the glandular parenchyma. Glandular parenchyma is distinctly demarcated into peripheral cortex and centric medulla. The cortical region appears to made up of three regionsa. Zona glomerulosa- outer most zone, immediately beneath the capsule containing closely packed, slightly dense strain group of cells. b. Zona fasciculata- middle portion and widest zone, polyhedral cells are arranged in straight cord which are dispersed at right angles to surface. Cells are pale strain and appear to be vacuolated. Sinusoids are present. c. Zona reticularis- inner zone resting on medullary region. The cells are in the form of anastomosing network like. Central portion of medulla appears to be comprised of more loosely arranged chromaffin cells which are basophilic and has nerves and blood capillaries. Hormones: ZG produces Aldosterone ZF produces Corticosterone ZR produces Adrenal androgens (DHEA, Androstenedione) Medulla produces Epinephrine and Nor epinephrine

Epinephrine and Nor Epinephrine are antagonistic in functions