Adenohypophysis Structure and Function
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Questions and Answers

What are the primary cell types present in the pars distalis of the adenohypophysis?

  • Follicular cells and C cells
  • Chromophobes and chromophils (correct)
  • Neuron cells and glial cells
  • Erythrocytes and leukocytes
  • What distinguishes acidophils from basophils in the pars distalis?

  • Acidophils are found in clusters
  • Acidophils secrete growth hormone (correct)
  • Acidophils have a high granule content
  • Acidophils stain poorly
  • Which type of chromophil is primarily responsible for the secretion of growth hormone?

  • Chromophobes
  • Basophils
  • Somatotrophs (correct)
  • Mammotrophs
  • Which staining technique can be used for accurate identification of different chromophils?

    <p>Immunohistochemistry</p> Signup and view all the answers

    In what percentage do mammotrophs constitute the cell population in multiparous females?

    <p>31%</p> Signup and view all the answers

    What is the main role of chromophobes in the adenohypophysis?

    <p>Differentiating into other types of chromophils</p> Signup and view all the answers

    Which cell type makes up approximately 50% of the epithelial cells in the pars distalis?

    <p>Chromophobes</p> Signup and view all the answers

    What is the main structural difference between the two types of acidophils, somatotrophs and mammotrophs?

    <p>Somatotrophs have more pronounced Golgi apparatus</p> Signup and view all the answers

    What is a characteristic feature of somatotrophs observed under an electron microscope?

    <p>Numerous electron dense granules</p> Signup and view all the answers

    Which part of the adenohypophysis is the largest?

    <p>Pars distalis</p> Signup and view all the answers

    Study Notes

    Adenohypophysis Overview

    • Glandular epithelial part of the pituitary gland, stained deeply with H&E.
    • Divided into three parts: Pars distalis, Pars tuberalis, Pars intermedia.

    Pars Distalis

    • Largest portion of the adenohypophysis.
    • Contains stroma and parenchyma components.
    • Stroma has a thin connective tissue capsule with delicate reticular fibers supporting blood sinusoids.
    • Parenchyma consists of irregular cords or clusters of secretory endocrine cells along with blood sinusoids.

    Cell Types in Pars Distalis

    • Classified based on staining affinity into Chromophobes and Chromophils.
    • Chromophobes:
      • Constitute 50% of epithelial cells, poor affinity for staining due to fewer granules.
      • Serve as reserve cells, capable of differentiating into Chromophils.
    • Chromophils:
      • Comprise the other 50% of epithelial cells, high staining affinity due to abundant hormone granules.

    Chromophil Subtypes

    • Further divided into Acidophils and Basophils based on staining characteristics.

    Acidophils

    • Two types present: Somatotrophs and Mammotrophs.

    Somatotrophs

    • Most numerous acidophil subtype, responsible for secretion of somatotropin (growth hormone).
    • Identified by large euchromatic nucleus with prominent nucleoli and well-developed Golgi apparatus.

    Mammotrophs (Lactotrophs)

    • Constitute approximately 9% of the cell population in males and nulliparous females, and up to 31% in multiparous females.
    • Secrete prolactin and distributed individually, not in clusters.
    • Cytological features similar to somatotrophs but have fewer elongated cisternae of rough endoplasmic reticulum (RER) when compared.

    Acidophil Characteristics

    • Both types are large rounded cells with central rounded nuclei and acidophilic cytoplasm.
    • Exhibits negative PAS reaction and positive orange G stain, helping in identification.
    • Somatotrophs have numerous electron-dense granules (300-350 nm) while mammotrophs exhibit larger granules (500-900 nm) during pregnancy.

    Ultrastructural Features

    • Somatotrophs possess small rod-shaped mitochondria and a well-developed Golgi apparatus with parallel RER.
    • Mammotrophs have a highly developed RER during pregnancy, with Golgi apparatus reaching near nuclear size and abundant lysosomes present.

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    Description

    This quiz covers the adenohypophysis, the glandular part of the pituitary gland. You'll explore its three parts: pars distalis, pars tuberalis, and pars intermedia. Learn about the structure, function, and cell types found in the pars distalis.

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