Toll Free 1800 572 9282 
mailus@wbcsmadeeasy.in
The nuclei stain strongly, and the cytoplasm is less pale than that of the next zone, the zona fasciculata, as there are fewer lipid droplets in these cells.
W.B.C.S. Main 2018 Question Answer – Zoology – Histological Structure Of The Adrenal Cortex.
WBCS মেইনস ২০১৮ প্রশ্ন উত্তর – প্রাণীবিদ্যা – মাইটোকন্ড্রিয়া – অ্যাড্রিনাল কর্টেক্সের কাঠামো।
1)Describe
the histological structure of the adrenal cortex.
The structure of the adrenal gland was studied in 11 bottlenose dolphins (Tursiops truncatus), and five striped dolphins (Stenella coeruleoalba). These species are legally protected in Croatia. All examined animals died of natural causes and were found stranded along eastern Adriatic coast. In both species the adrenal gland consists of a cortex and a medulla; the cortex is divided into three zones. Whereas in the bottlenose dolphin, there is a zona arcuata which contains columnar cells arranged in the form of arches; in the striped dolphin this zone is replaced by zona glomerulosa containing rounded clusters of polygonal cells. In both species, the zona fasciculata consists of radially oriented cords of polygonal cells, whereas in zona reticularis cells are arranged in branching and anastomosing cords. The adrenal medulla in both species contains dark, epinephrine-secreting cells and light norepinephrine-secreting cells. Epinephrine-secreting cells are localized in the outer part of the medulla, whereas norepinephrine-secreting cells are found in the inner part, arranged in clusters and surrounded by septa of thin connective tissue. The gland is surrounded by a thick connective-tissue capsule, from where thick trabeculae extend towards the interior. In the bottlenose dolphin, group of cells resembling both medullar and cortical cells can be seen within the capsule; whereas only groups of cells resembling cortical cells are found within the capsule of the striped dolphin. In the bottlenose dolphin invagination of the adrenal cortex into the medulla is obvious as well as medullary protrusions extending through cortex to the connective tissue capsule.Continue Reading W.B.C.S. Main 2018 Question Answer – Zoology – Histological Structure Of The Adrenal Cortex.
All the hormones secreted by this region are steroid hormones, which are all based on cholesterol. Secretory cells, secrete steroid based hormones, and contain triglyceride droplets. The cortex can be divided into three regions:
- Zona glomerulosa
- Zona fasciculata
- Zona reticularis
Different hormones are secreted from each of these regions-
2. Zona fasciculata, the middle zone of the adrenal cortex secretes glucocorticoids which are important for carbohydrate, protein and lipid metabolism. An example is cortisol which raises blood glucose and cellular synthesis of glycogen. Its secretion is controlled by a hormone from the pituitary – ACTH.
The secretory cells are arranged in cords, often one cell thick, surrounded by fine strands of supporting tissue. Can you identify them?
The nuclei of these cells stain strongly, and the cytoplasm is rich in sER, mitochondria and lipid droplets. The cytoplasm looks pale and ‘foamy’ due to the presence of lipid droplets.
Some brown pigment is seen in some of these cells – this is lipofuscin, probably an insoluble degradation product of organelle turnover – an ‘age’ pigment. The cytoplasm of the cells in this region stains more darkly, and contains fewer lipid droplets.
Adrenal medulla:
This region of the adrenal glands contains basophilic staining cells, with a granular cytoplasm and no stored lipid. It also contains many venous channels which drain blood from the sinusoids of the cortex, pass through the medulla, and drain into the medullary vein.
This is because these cells are actively secreting the peptide based hormones – nor-adrenaline and adrenalin (catecholamines), which are stored in the granules.
Secretion of these hormones is controlled by the sympathetic nervous system. The targets of these hormones are the adrenergic receptors in the heart, blood vessels, bronchioles, visceral muscle, skeletal muscle, and in the liver, where they promote glycolysis (breakdown of glycogen).
Our own publications are available at our webstore (click here).
For Guidance of WBCS (Exe.) Etc. Preliminary , Main Exam and Interview, Study Mat, Mock Test, Guided by WBCS Gr A Officers , Online and Classroom, Call 9674493673, or mail us at – mailus@wbcsmadeeasy.in
Visit our you tube channel WBCSMadeEasy™ You tube Channel
Please subscribe here to get all future updates on this post/page/category/website
