• Surrounds the ventral part of the third ventricle and comprises many nuclei that engages in autonomic activities and behavior

Produces: 

• Corticotropin-releasing hormone (CRH)

• Thyrotropin-releasing hormone (TRH)

• Gonadotropin-releasing hormone (GnRH)

• Prolactin-releasing factor (PRF)

• Dopamine

• Oxytocin

• Anti-Diuretic Hormone (ADH)

"Master Gland"

divides into Anterior Pituitary and Posterior Pituitary, both derived from different tissues during embryonic development. 

Anterior Pituitary 

• oral ectoderm

• glandular; produces own hormones 

• Growth Hormone (GH), Thyroid-Stimulating Hormone (TSH), Prolactin (PRL), Adrenocorticotropic Hormone (ACTH), Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH) 

• HOWEVER, no direct connection between the Hypothalamus, therefore the Hypothalamo-hypophyseal portal system is utilized

Posterior Pituitary

• nervous ectoderm

• non-glandular; axons from the hypothalamus terminates on blood vessles of Posterior Pituitary 

• Oxytocin and ADH enters blood in posterior lobe

• No portal system 

🙊 All pituitary hormones are proteinaceous!

• Receives information about dark-light cycles, indirectly detecting the photoperiod 

  • Light > Retina > Suprachiasmatic Nucleus (Hypothalamus) > Pineal Gland 

• Pinealocytes manufacture Serotonin into Melatonin through the enzyme (transferase) 

• Targets all cells in the body

• Increases basal metabolic rate (overall oxygen consumption, heart rate, ATP generation) 

• Increased metabolism of carbohydrates and lipids 

• Responsible for growth and development of young animals 

• Follicles 

  • Follicular Cells: produces Triiodothyronin (T3), Thyroxine (T4)

  • Colloid 

  • Thyroglobulin (precursors stored in Colloid) 

• C cells (Parafollicular cells) 

  • Produces calcitonin (peptide hormones that lowers blood levels of calcium) 

• Outside but adjacent to thyroid gland 

• Most mammals has 2 pairs 

  • External Parathyroid 

  • Internal Parathyroid 

    • *Porcine only has 1 pair of external and no internal

• produces Parathyroid Hormone (PTH) via Chief Cells 

  • Function: Increase blood calcium and decrease blood phosphate 

• Above but separate from the kidney 

• Cortex (Outer) 

  • Zona Glomerulosa (Superficial) 

    • Produces Aldosterone

  • Zona Fasciculata

    • Produces Cortisol and Corticosterone 

  • Zona Reticularis (Deep) 

    • Produces Cortisol and Corticosterone

    • Produces Androgen (e.g. Testosterone) 

• Medulla (Inner) 

  • Chromaffin Cells

  • Epinephrine

  • Norepinephrine 

• Located within Duodenal Loop 

• Exocrine Function 

  • Digestive enzymes, NaHCO3 (Sodium Bicarbonate) 

• Endocrine Function *

  • Pancreatic Islet Cells (Islets of Langerhans) 

    • Alpha Cells (Glucagon) 

      • Glucagon increases blood-glucose levels in blood

    • Beta Cells (Insulin) 

      • Insulin decreases blood-glucose levels in blood 

• Produces gametes (sperms) and hormones (testosterone/inhibin)

• Leydig Cells 

  • LH stimulates Leydig cells to produce Androgens (Testosterone)

• Sertoli Cells 

  • FSH stimulates Sertoli Cells ("nursing cells of sperms") to continue spermatogenesis 

    • Produces Estrogen, Inhibin

    • Tight Junctions establish blood-testis barrier 

• Seminiferous Tubules 

  • Site of sperm production 

• Located behind the Sternum 

• Produces: 

  • Thymopoietin (produces T cells) 

  • Thymosin/Thymulin (produce specialized T cells) 

  • Thymic Humeral Factor (maintain homeostasis of immune system)