Endocrine system of fishes ppt

Fishes, amphibians, reptiles, and birds have paired pharyngeal ultimobranchial glands that secrete the hypocalcemic hormone calcitonin. The corpuscles of Stannius, unique glandular islets found only in the kidneys of bony fishes, secrete a peptide called hypocalcin.

1. ENDOCRINE SYSTEM of fishes Ashish sahu

2. INDEX : ENDOCRINE GLAND. MAJOR ENDOCRINE GLAND. DETAILED STUDY OF EACH ENDOCRINE GLAND.

3. ENDOCRINE GLAND : The gland which secrete their product HORMONE directly into the blood rather than through a duct .   MAJOR GLANDS OF ENDOCRINE SYSTEM OF FISHES :- The pituitary gland or hypophysis Thyroid gland Adrenal gland The corpuscles of stannius The ultimobranchial gland Urohypophysis Pancreatic islet Pineal organ

4. PITUITARY GLAND OR HYPOPHYSIS : LOCATION :- Ventral surface of brain below optic chiasma DERIVATION :- Pituitary gland derived from two different components:- Adenohypophysis : It is derived from the dorsal evagination of the ectodermal part of buccal cavity called RATHEK’S POUCH . Neurohypophysis : The neurohypophysis develop from the floor of embryonic diencephlon .

5. ADENOHYPOPHYSIS DIVIDED INTO THREE SUB DIVISION :- Rostral pars distalis Proximal pars distalis Pars intermedia

6. ROSTRAL PARS DISTALIS OR PROADENOHYPOPHYSIS ; Most smallest part of the adenohypophysis . Chief cell of proadenohypophysis is Prolactin . Populated by the Acidophill cells, Cynophill , Chromophobes . Acidophill cells are stained by Azocarmine (A-C) or Orange (O-C) stain. Cynophill stain with Aniline blue (AB) Aldehyde fuschin (AF) Aldehyde thionine (AT). Chromophobes have non granular cytoplasm, do not take any stain.

7. PROXIMAL PARS DISTALIS OR MESOADENOHYPOPHYSIS It lies in middle. Largest part of the hypophysis . Consist Acidophilic, Cynophillic and Chromophobic cells. Acidophillic cells include Erythrosinophilic and Orangeophillic cells. Cynophills are principal cell type of PPD. Chromophobes are fewer in number and distributed among Acidophills , Cynophiles . Chromophobes are easily identified due to very poor staining property.  

8. PARS INTERMEDIA Lies in posterioror posterioventral end of the hypophysis . Consist of Acidophills , cynophiles and chromophobes cells. Cyanophiles are much reduced in size and no.and get degranulated during the post spawning phase of reproductive cycle. Chromophobes are fewer in number . Amphiphillic cells which which stain both with Aniline blue and the Alcian blue and Orange G.

9. NEUROHYPOPHYSIS : Composed of Axonal nerve fibre . Mostly non – myelinated . Originating from natural cells bodies in the Hypothalmus . Many fibre terminate in the neurohypophyseal core in close relationship to blodd vessel. An arrangement peculiar to Teleost. A SPECIAL FEATURE OF THE FISH PITUITARY IS THE EXTENSIVE ORBORIZATION OF PARS INTERMEDIA BY NEUROHYPOPHYSIS. Neurohypophysis some time in large masses termed as “HERRING BODIES”.

10. PITUITARY PARTS DIVISION CELL TYPES SECRETION FUNCTION A.Proximal pars distalis (i) Thyrotophs Thyrotropins Eg. TSH Regulates the growth and secretion from thyroid. (ii) Gonadotrophs Gonadotropin Eg.FSH(follicular stimulating hormone) and LH (leutenizing hormone) Regulates the secretion of gonadal hormone, spermatogenesis and oogenesis. 1.Adenohypophysis (iii) Somatotroph Somatotropins Eg.GH (growth hormone) Increases growth and BMR of fish body.

11. B.Rostral pars intermedia (i) Lactotroph Prolactin Regulation of Osmoregulation and melenogenesis. C.Pars intermedia ------------- MSH and MCH (melanophore dispersing and melenophore contracting hormone) Regulates the concentration and dispersion of pigments within melanophores. 2.Neurohypophysis Pars –nervosa ------------ Vasopressin and Oxytocin Regulates Osmoregulation ,salt-water balance, mating and egg laying.

12. THYROID GLAND : ORIGIN: Arises as a median evagination from the floor of Pharynx . LOCATION: In Cyclostomes : Thyroid dispersed around the ventral aorta. In Elasmobranchs : Gland is located ventrally at bifurcation of ventral aorta. In Bony fishes : It lies under the 1 st branchial arch on each side. In Teleost : found along the ventral aorta and along the afferent Branchial artries of gills.  

13. SHAPE : In Cyclostomes : Thyroid is in the form of follicles. In Elasmobranchs and Bony fishes : Thyroid is a compact structure. In Teleost: Thyroid become diffused structure as small masses of follicles. In Dipnoi : Thyroid comprises a pair of interconnected lobe.   HORMONE OF THYROID GLAND: Chiefly THYROXINE.

14.   CHEMISTRY OF THYROID HORMONE : The Thyroid hormone is the Iodinated derivative of THYROSINE (TYROSINE) which is an Amino acid .   REGULATION OF THYROXINE SECRETION FROM THYROID : The production of THYROXINE hormone is under the control of THYROTROPIN (TSH) secreted from Adenohypophysis . Increase in humidity activates the Thyroid activity.          

15. ADRENAL GLAND : The two components of adrenal gland are: Cortex Medulla In Cyclostomes ,presumptive Adrenocortical cells occur in scattered group on the wall of cardinal vein. In Elasmobranchs : The Adrenal gland does not contain Chromaffin tissue. In Chondrichthys : The steroidogenic cells form internal bodies at the caudal end of kidney and chromaffin cells lies embedded within the tissue of both kidney near posterior ends.        

16. FUNCTION OF ADRENAL GLAND: Hormone of steroidogenic tissue are collectively called as ADRENOCORTICOSTEROIDS which act upon the following process:- Osmoregulation ,protein and carbohydrate metabolism. Blood cells movement from Hematopoietic and Lymphoid tissue .    

17. Growth,regeneration and anti-inflammatory reaction. In Teleost fishes ,injection of high dises of adrenocorticosteroid often cause effect which disturb the Electrolyte balance. High doses in Anguilla anguilla increase muscle water content while muscle sodium concentration declines.

18. THE CORPUSCLES OF STANNIUS LOCATION : The corpuscles of stannius are generally small nodular bodies lying partly or completely embedded on dorsal or dorso -lateral ventro -lateral sides of kidney of bony fishes . EXACT LOCATION IS MEASURED FROM THE URINOGENITAL APERTURE. SHAPE : Oval and round but in Gold fish and Salmon it is flat white structure on peritoneal surface of the kidney SIZE : Corpuscles of stannius varies from 0.15-6.0 mm .

19. NUMBER : 1 to 10 in no. COLOUR : Pink or white ORIGIN : Originated as outgrowth from the pronephric or the mesonephric duct of kidney. NATURE : Corpuscles of stannius are steridogenic .  

20. FUNCTION :   PRESENCE OF RENIN ACTIVITY Extract of corpuscles of stannius of the Eel caused a rise blood pressure in which resembled to that evoked by rennin.   OSMOREGULATORY FUNCTION REMOVAL OF CORPUSCLES OF STANNIUS CAUSED REDUCTION IN PLASMA SODIUM AND INCREASE IN POTTASIUM AND CALCIUM CONCENTRATION WHICH MAY EVEN RESULT TO DEATH.                                                              

21. NUMBER : 1 to 10 in no. COLOUR : Pink or white ORIGIN : Originated as outgrowth from the pronephric or the mesonephric duct of kidney. NATURE : Corpuscles of stannius are steridogenic .  

22. THE ULTIMOBRANCHIAL GLAND OTHER NAME : POST BRANCHIAL BODIES OR SUPRAPERICARDINAL BODIES OR ULTIMOBRACHIAL BODIES   OCCURRENCE : It is not found in cyclostomes but reported in almost all group of fishes.

23.   ORIGIN: Develop embryologically from the epithelium of last or ultimate gill pouch.   LOCATION : In Elasmobranchs gland is found on the left side only between the pericardium and ventral surface of pharynx just anterior to its junction with the oesophagus

24. In T eleost the gland is bilateral and is located in the tranverse septum between the abdominal cavity and sinus venosus just ventral to the oesophagus .   HORMONE : Gland has been found to secrete CALCITONIN hormone which in mammals oppose the action of PARATHHORMONE.   CHEMISTY OF CALCITONIN: It is a straight chain peptide containing 32 amino acid residue with a molecular weight of approximately 3600-4500.    

25. FUNCTION : It is a source of calcium regulating hormone – CALCITONIN ,which control Hypercalcimia and lower plasma by inhibiting bone resorbtion in mammals. The concentration of CACITONIN is high in Chimaeroids , Elasmobranch and Teleosts .

26. UROHYPOPHYSIS :   OTHER NAME : Caudal Neurosecretory Organ OCCURRENC E : Absence in Teleostean and identified in Agnathas .   LOCATION : Posterior end of caudal spinal cord ie in tail of teleosts .  

27. STRUCTURE : Cells are large and have enlarge axon of neurosecretory fibre,also called DAHLGREN CELLS lies in grey matter of cord.

28. UROHYPOPHYSIS HAVE MANY CHEMICAL ACTION. THEIR PROTEIN AND POLYPEPTIDE CASSIFIED AS : - UROTENSIN I : Decrease blood pressure when injected to rat. UROTENSIN II :- Control smooth muscles including urinary bladder in Trout Increase the blood preesure and urine flow in Eels.

29. UROTENSIN III :- Enhance sodium uptake across the gill of Gold fish .   UROTENSIN IV :- Increase water transfer and shows other similarities to VASOPRESSIN .  

30.   FUNCTION : Increase sodium influx in fresh water fishes. Diuresis and decreased Na excretion in Gold fish. Sodium regulation. Increased blood pressure in Eels. Increase bladder contraction in Teleost. Caudal fish locomotion. Contract smooth muscles of urinogenital tract including sperm duct.

31.   PANCREATIC ISLET : Pancreas comprises both exocrine and e ndocrine parts. Endocrinal part is represented by islet of Langerhans .   Fish islet are fairly large in size ,and composed of three type of cells :- BETA CELLS (B CELLS) - which secrete insulin . ALPHA CELLS (A CELLS ) - which secrete glucagon. D CELLS – Function is unknown . 

32. PINEAL ORGAN : Pineal organ arises postermiddorsal evagination of the epithalmus .   PINEAL ORGAN CONSIST : Pineal sac. Pineal thalmus . Pineal stalk.   Pineal sac considered as photoreceptive organ in fishes . Also consider to be an endocrine gland.   PINEALECTOMY IS LEBISTER RESULT IN REDUCED GROWTH RATE,ABNORMALITIES IS THE SKELETON AND STIMULATION OF THYROID HYPOPHYSIS AND CORPUSCLES OF STANNIUS

33. GLAND HORMONE NATURE FUNCTIONS 1.Hypothalamus Releasing hormone Peptides Regulates the secretion of hypophysis 2.Thyroid gland Thyroxine (T4), Tridothyronin (T3) Amino acids Reproduction, migratory behavior, scale and bone formation,electrolytic movements,metabolism,and nutrients assimilation. 3.Interrenal (adrenal gland) Adrenaline ,cortisol Amino acid,steroid Counteracts stress 4.Testis Testosterone, 11-ketotestosterone Steroids Metabolic effect, controls secondary sexual characters, sperm production

34. 5.Ovary 17B-ostradiol oestrone, progestagens Steroids Metabolic effect ,yolk and egg production. 6.Pancreas Insulin , glucagon, somatostatin Peptides Regulation of carbohydrate metabolism as in vertebrates. 7.Pineal gland Melatonin Peptides Photosensory and secretory function. 8.Ultimobranchial gland Calcitonin Peptides Regulates calcium level in blood. 9.Stannius corpuscles Hypocalcin Protein Regulates cacium balance. 10.Urohypophysis Urotensins Polypeptide Metabolic regulation.

35. Reference : A textbook of fish and fisheries …s. s. khanna & h. r. singh . Fish & fisheries … Pandey & shukla .   Pdf of endocrine gland of fish.     Handbook of fisheries and aquaculture.     E- course of icar .   Wikipedia, endocrine system of fishes.  

36. Thank you !