Pituitary Gland Histology L1 PDF

PITUITARY GLAND By Assist. Prof. Mona Farouk Dr. AHMED ABD EL-RAHMAN EL-MANSY  By the end of the lecture the student will be able to: Recognize the histological organization of the pituitary gland...

PITUITARY GLAND By Assist. Prof. Mona Farouk Dr. AHMED ABD EL-RAHMAN EL-MANSY  By the end of the lecture the student will be able to: Recognize the histological organization of the pituitary gland List the cells forming pars distalis Intended Learning Discuss the structure and function of acidophils and basophils Outcomes (ILOs) Describe the histological structure of pars tuberalis Describe the histological structure of pars intermedia Describe the histological structure of pars nervosa Describe the blood supply of the pituitary gland  PARS DISTALIS Stroma Parenchyma Reticular Cords Fenestrated Capsule Trabeculae network of cells capillaries Chromophils Chromophobes Acidophils Basophils Somatotrophs Mammotrophs Thyrotrophs Corticotrophs Gonadotrophs  PARS DISTALIS Stroma Parenchyma Reticular Cords Fenestrated Capsule Trabeculae network of cells capillaries Chromophils Chromophobes Acidophils Basophils Somatotrophs Mammotrophs Thyrotrophs Corticotrophs Gonadotrophs  Chromophils Chromophobes Number: 48% 52% Size: Larger Smaller Granules: Present Absent Function Hormone Undifferentiated (reserve) secretion or Exhausted chromophils  Acidophils Basophils Number: 37% 11% Site: Posterolateral Anteromedian Special stain: Orange G P.A.S. Acidophils  Acidophils Somatotrophs Mammotrophs Number: 50% of chromophils 15 – 20 % of chromophils Size: Medium-sized Large Functions: Growth hormone Prolactin: milk formation Pregnancy cells: ↑ size & number of cells and granules Control: GHRH PRH Basophils  Basophils Thyrotrophs Corticotrophs Gonadotrophs Number: 5% 15 - 20% 10% Size: Large Medium-sized Small Functions: TSH: stimulate 1. ACTH: adrenal 1. FSH thyroid cortex 2. ICSH (male) follicles 2. β lipotropin LH (female) 3. MSH Control: TRH CRH GnRH  PARS TUBERALIS  Highly vascular  Longitudinal cords Cells: Cuboidal basophilic undifferentiated Squamous Acidophils & basophils (gonadotrophs)  PARS INTERMEDIA  Poorly vascularized  Rathke’s cysts Cells: Corticotrophs (MSH)  PARS NERVOSA  Nerve fibers Unmyelinated Paraventricular & supraoptic  Herring bodies  Capillaries  Pituicytes  PARS NERVOSA  Nerve fibers Unmyelinated Paraventricular & supraoptic  Herring bodies  Capillaries  Pituicytes  PARS NERVOSA Functions:  Oxytocin (Paraventricular) Uterus Mammary gland  Vasopressin or ADH (Supraoptic)  PARS NERVOSA Functions:  Oxytocin (Paraventricular) Uterus Mammary gland  Vasopressin or ADH (Supraoptic)  PARS NERVOSA Functions:  Oxytocin (Paraventricular) Uterus Mammary gland  Vasopressin or ADH (Supraoptic)