Download presentation
Presentation is loading. Please wait.
Published byBeverly Simpson Modified over 8 years ago
2
ENDOCRINE GLANDS Dr Iram Tassaduq
3
ENDOCRINE GLANDS An “endocrine gland” is one whose product passes by way of the blood vascular system to other cells in the body, where it elicits a specific response.
4
COMPONENTS OF THE ENDOCRINE SYSTEM Discrete endocrine glands The endocrine components of the glands with both exocrine & endocrine functions Scattered cells with endocrine functions
6
FEATURES OF ENDOCRINE GLANDS Endocrine glands vary greatly in size. The cells secreting the hormones (parenchyma) are epithelial, epithelioid, or neuronal. The glands are richly vascularized by highly permeable capillaries.
7
HYPOPHYSIS Located in SELLA TURCICA 1cm in length 1-1.3cm in width Weigh s 0.5-0.6 gm
9
ORGANIZATIONADENOHYPOPHYSIS Pars tuberalis Pars distalis- Pars intermediaNEUROHYPOPHYSIS Pars nervosa Infundibulum (infundibular stem & median eminence )
13
ADENOHYPOPHYSIS
14
PARS DISTALIS 75% of the mass of the hypophysis Common stains allow recognition of 3 cell types o Chromophobes o2 types of chromophils Acidophils Basophils
15
PARS DISTALIS At higher magnifications the dark staining chromophils ( A) and the very light staining chromophobes (B) are easily distinguished.
18
ACIDOPHILS Larger than chromophobes Cells taking OrangeG stain are alpha acidophils Also called somatotrophs Contain extensive RER
19
ACIDOPHILS Carminophils stain intensely with azocarmine Also called mamotrophs Cytoplasmic granules are larger in size and are scattered
20
BASOPHILS Larger than acidophils Best stained with PAS beta Subdivided into beta and delta cells
21
BASOPHILS Beta cells secrete TSH Larger in size Granules concentrated at periphery Delta cells include Gonadotrophs and coticotrophs
23
CHROMOPHOBES Small rounded polygonal cells Have little cytoplasm devoid of granules Appear in groups They were called reserve cells in past
25
PARS TUBERALIS Funnel shaped region Surrounding the infundibulum. Most of the cells secrete gonadotropins and are arranged in cords along blood vessels
26
PARS INTERMEDIA Surrounds a series of small cavities Parenchyma surround colloid filled follicles Pars intermedia contains basophils and chromophobes Basophils secrete MSH Poorly developed in humans
27
PARS INTERMEDIA
29
PARS NERVOSA Extension of CNS that stores and releases secretory products from hypothalamus Three types of neurosecretory vesicles
30
NEUROHYPOPHYSIS - PARS NERVOSA This region of the pituitary is non secretory Its cells are neuroglial-like pituicytes (C).
32
NEURO SECRETORY VESICLES Herring bodies ranging 10-30nm contain oxytocin or ADH Vesicles containing acetylcholine approx 30nm in size Vesicles ranging 50-80nm resembling vesicles of adrenal medulla containing adrenergic nerve endings
34
THYROID GLAND
35
C.T. sheath formed by deep cervical fascia Extremely labile gland & varies in size & structure
36
Three dimensional view of thyroid follicles
37
DEVELOPMENT OF THYROID GLAND Begins to develop during 4 th week of gestation from a primordium originating as an endodermal thickening of floor of primitive pharynx
38
STRUCTURAL UNIT OF THYROID GLAND ----- THYROID FOLLICLE
39
FOLLICULAR EPITHELIUM Follicular cells Para follicular cells
40
FOLLICULAR CELLS PRINCIPAL/ CHIEF CELLS Responsible for the production of T3 & T4 Vary in size & shape Slightly basophilic in H & E stained slides Lipid droplets & PAS positive droplets
41
COLLOID Inactive storage form of thyroid hormone Constituents Principal component is thyroglobulin (large iodinated glycoprotein) Enzymes Glycoproteins Staining with both acidic & basic dyes. Strongly with PAS
42
FUNCTION OF THYROID GLAND
43
PARAFOLLICULAR CELLS C CELLS/ CALCITONIN CELLS Located in periphery of follicular epithelium No exposure to lumen In H & E stained slides appear as pale staining cells Secrete calcitonin
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.