Endocrine glands in fishes by Uday M.Sc. II year.pptx

different endocrine glands in fishes are discussed.

1. ENDROCRINE GLANDS OF FISHES UDAYA PRATAP GAUTAM M.Sc. (Final) Zoology

2. Introduction The glands that secrete their product into the bloodstream and body tissue along with the central nervous system to control and regulate many kinds of body functions are known as Endocrine Gland. In fishes various endocrine gland has been found associated with different tasks and functions.

3. Different type of endocrine glands are found in fishes, Such as – 1- The pituitary Gland or Hypophysis 2- Thyroid gland 3 - Adrenal gland 4- Corpuscles of Stannius 5- Ultimobranchial Gland 6- Urohypophysis Gland 7- Pancreatic Gland 8- Pineal Gland Endocrine glands of fishes

4. Endocrine Gland of fishes

5. 1-The Pituitary Gland or Hypophysis Location:- Ventral surface of brain below optic chiasma . . Origin:- Two part of pituitary gland are derived from two different components. Neurohypophysis develops from the floor of the embryonic diencephalon . Adenohypophysis develops from the dorsal evagination of the ectodermal part of buccal cavity called Rathke’s pouch . Part and division of pituitary, their cell types, secretions and action of their hormones: The part of this gland their division, cell types, secretion and functions are given in a tubular form- 2- Thyroid Gland :- Origin: The thyroid gland in fishes arises from the floor of the pharynx as a median evagination . Location: The location of thyroid gland varies considerably in different fish species , such as – .

6. Location of pituitary gland or Hypophysis

7. 2- Thyroid Gland . Origin:- The thyroid gland in fishes arises from the floor of the pharynx as a median evagination . . Location:- The location of thyroid gland varies considerably in different fish species, such as – In cyclostomes, follicles of thyroid are dispersed around the ventral aorta. In bony fishes, it may lie under the 1 st branchial arch on each side. Shape:- The shape of the gland is also variable depending on various fishes group, such as- In cyclostomes, the thyroid is in the form of follicles.

8. In many teleosts, thyroid becomes a diffused structure as small masses of follicles. In elasmobranches and bony fishes , thyroid is compact structure. In dipnoi , thyroid comprises a pair of interconnect lobes. HISTOLOGY:- The thyroid gland is composed of a large number of follicles forming a shape of a hollow ball and consisting of a single layer of epithelial cells that encloses a fluid filled space. These follicles are bounded together by connective tissue. The gland is highly vascular and the epithelium surrounding the follicle may be thick or thin and height of the cells depends upon its secretory activity. The epithelium mainly composed of two types of cells - the chief cells are cuboidal or columnar in shape with clear cytoplasm and colloid cells , contain droplets of secretory material. SECRETION:- Chiefly thyroxine

9. FUNCTION Of thyroid Gland :- . The thyroid hormone’s role in oxygen consumption in fishes have been pointed out though it lacks cosistency . . Thyroid hormone influences osmoregulation in salmon and gastroteus . . Thyroid along with other endocrine glands also influences migration in fishes. . It is also known to effect growth and nitrogen metabolism in gold fishes. . Thyroxin b rings about maturation in fishes. . Scale and bone formation in fishes is also influences by thyroxin.

10. Location of thyroid gland

11. 3. ADRENAL GLAND :- Adrenal gland in fishes is quite different from that of mammals. The two components of adrenal gland i.e , cortex and medulla are separately found. LOCATION:- One of three layers of cells lying along cardinal veins in the region of the hemopoietic head kidney . ORIGIN:- Mesodermal layer of embryo SECRETION:- Adrenaline , Cortisol

12. Function of Adrenal Gland :- Promote utilization of steroid fat Carbohydrate metabolism Protein catabolism Sodium retention Electrolyte metabolism

13. 4. THE CORPUSCLES OF STANNIUS:- LOCATION:- Attached to or embedded in kidneys of holosteans and teleolsts ORIGIN :- The corpuscles of stannius orginate as outgrowths from the pronephric or the mesonephric duct of kidney. NATURE:- Proteinous SECRETION: - Hypocalcin COLOUR:- Pink or White FUNCTION :- Regulates calcium balance

14. Location of corpuscles of stannius gland

15. 5. THE ULTIMOBRANCHIAL GLANDS It is also known as post branchial bodies or supra-pericardial bodies or ultimobranchial bodies. LOCATION :- Sac-like structures between ventral wall of esophagus and sinus venosus . ORIGIN:- Ultimobranchial gland develop embryologically from the epithelium of the last or ultimate gill pouch. SECRETION:- Calcitonin FUNCTION:- Regulates calcium level in blood

16. Ultimo-branchial gland

17. 6. UROHYPOPHYSIS :- It is also known as Ureophysis or caudal Neusecretory organ LOCATION:- This gland is in the form of swelling at the posterior end of the caudal spinal cord i.e. in the tail of the teleosts . SECRETION:- Urotensins FUNCTION:- Metabolic regulations.

18. Location of Ureophysis gland:-

19. 7. PANCREATIC ISLETS LOCATION:- Gut walls in larval Lampreys; Hepato-pancreas , most bony fishes EMBRYONIC ORIGIN:- Mesoderm SECREATION:- Insulin FUNCTION:- Carbohydrates metabolism

20. 8. PINEAL GLAND:- LOCATION/ORIGIN:- The pineal organ of the fish arises as a postero -mid dorsal evagination of the epithalamus . SECRETION:- Melatonin FUNCTION:- Photosensory and secretory functions

21. Bibliography I have collect all the data from the online with the help of internet and also with the help of some reference books like TEXT BOOK OF FISH BIOLOGY AND FISHERIES, written by S.S KHANNA and H.R SINGH .

22. Thank You……