excretion in unio and pila_poojasoni_new.pptx

The Bojanus organ and Keber’s organ are both part of the excretory system of Unio which belongs to the phylum Mollusca.
The organs of Bojanus or Bojanus organs are excretory glands that serve the function of kidneys in some of the molluscs. In other words, these are metanephridia that are found in some molluscs.
Keber's organ is a gland-like structure responsible for the removal of the nitrogenous wastes. It is also known as 'pericardial gland' and is a large, reddish-brown glandular mass.
Tissue-system grade
Triploblastic
Coelomate
Unsegmented
Bilaterally symmetrical
Body divisible into head,mantle,foot and visceral mass
Digestive system complete
Circulatory system closed type
Respiration direct by gills or lungs or both
Excretion by paired metanephridia
Terrestrial or aquatic
In Pila globosa, the excretory organ is a large kidney or renal organ or organ of Bojanus.
Like the gill, it is the organ of the left side, that of the right side having disappeared or modified into the gonoduct.
It communicates with the exterior on one hand and with the pericardial cavity representing coelom on the other; it is, thus, of the nature of a coelomoduct.
It consists of two chambers, a right anterior and a left situat posterior.
Anterior renal chamber :
It is more or less an oval organ, reddish in colour and lies anterior to the pericardium.
It opens into the branchial chamber of the mantle cavity through a slit- like opening near the epitaenia.
At the other end, it communicates with the posterior renal chamber through an internal opening.
Internal cavity of the anterior chamber is very much reduced due to the presence of many triangular leaf like processes or lamellae, those arising from the roof alternating with those from the floor.
Dorsal surface of the chamber is marked by numerous transverse grooves, corresponding to these internal lamellae.
Lamellae on the roof are arranged on either side of a median longitudinal axis, or the efferent renal sinus.
Lamellae on the floor are arranged on either side of a similar median axis, the afferent renal sinus, which is the right branch of the peri-intestinal sinus.
It breaks up into the numerous branches to supply the lamellae on both the sides.

Posterior renal chamber :
It is a broad, brownish to grey and hook-shaped chamber, situated behind the anterior renal chamber, in between the rectum on the right and the pericardium and the digestive gland on the left.
The ventral glandular portion of the kidney extracts guanin and other nitrogenous waste products of metabolism from the coelomic pericardial fluid as well as the blood supplied to the kidneys.
The walls of the pericardial sinus are also glandular, and supposed to secrete waste materials from the blood into the coelomic cavity.
The ciliated epithelial lining of the bladder produces an outgoing current, thus conveying excretory fluid from the glandular part of the kidney to the suprabranchial chamber which leads to the excurrent siphon.
There is reabsorptio

1. LACHOO MEMORIAL COLLEGE OF SCIENCE AND TECHNOLOGY TOPIC - KEBER’S AND BOJANUS ORGAN MSZO - 112 Submitted to : Submitted by : Dr. Ranjeeta Mathur Pooja soni (Associate Professor) MSc (Zoology)

2. INTRODUCTION: The Bojanus organ and Keber’s organ are both part of the excretory system of Unio which belongs to the phylum Mollusca. The organs of Bojanus or Bojanus organs are excretory glands that serve the function of kidneys in some of the molluscs. In other words, these are metanephridia that are found in some molluscs. Keber's organ is a gland-like structure responsible for the removal of the nitrogenous wastes. It is also known as 'pericardial gland' and is a large, reddish-brown glandular mass.

3. CHARACTERISTICS OF MOLLUSCA: Tissue-system grade Triploblastic Coelomate Unsegmented Bilaterally symmetrical Body divisible into head,mantle,foot and visceral mass Digestive system complete Circulatory system closed type Respiration direct by gills or lungs or both Excretion by paired metanephridia Terrestrial or aquatic

4. CLASSIFICATION OF Pila : Phylum : Mollusca Class : Gastropoda Subclass : Prosobranchia Order : Mesogastropoda Family : Pilidae Genus : Pila

5. EXCRETION IN Pila : In Pila globosa, the excretory organ is a large kidney or renal organ or organ of Bojanus. Like the gill, it is the organ of the left side, that of the right side having disappeared or modified into the gonoduct. It communicates with the exterior on one hand and with the pericardial cavity representing coelom on the other; it is, thus, of the nature of a coelomoduct. It consists of two chambers, a right anterior and a left situat posterior.

6. Anterior renal chamber : It is more or less an oval organ, reddish in colour and lies anterior to the pericardium. It opens into the branchial chamber of the mantle cavity through a slit- like opening near the epitaenia. At the other end, it communicates with the posterior renal chamber through an internal opening. Internal cavity of the anterior chamber is very much reduced due to the presence of many triangular leaf like processes or lamellae, those arising from the roof alternating with those from the floor. Dorsal surface of the chamber is marked by numerous transverse grooves, corresponding to these internal lamellae.

7. Lamellae on the roof are arranged on either side of a median longitudinal axis, or the efferent renal sinus. Lamellae on the floor are arranged on either side of a similar median axis, the afferent renal sinus, which is the right branch of the peri-intestinal sinus. It breaks up into the numerous branches to supply the lamellae on both the sides. Posterior renal chamber : It is a broad, brownish to grey and hook-shaped chamber, situated behind the anterior renal chamber, in between the rectum on the right and the pericardium and the digestive gland on the left.

8. Its large internal cavity encloses a part of the genital duct and a few coils of the intestine. At one end, it communicates with the anterior renal chamber through an aperture, and at the other with the pericardium through an elongated slit-like reno-pericardial aperture, perforating a thin vertical reno-pericardial septum, separating the two afferent and efferent renal vessels profusely branch in the roof of this chamber.

9. PHYSIOLOGY OF EXCRETION : Two renal chambers are richly supplied with blood from which the nitrogenous waste products are separated. Excretory fluid from the posterior chamber is also transferred to the anterior chamber, from where it is discharged through the external renal aperture into the mantle cavity and finally passed out of the body through the right nuchal lobe along with the outflowing water. Excretory fluid contains mostly ammonia and some ammonium compounds, urea and uric acid. Pila shows an adaptation for water conservation during terrestrial phase by converting ammonia into the insoluble uric acid.

10. During aquatic phase, Pila excretes ammonia, but during terrestrial phase, it excretes uric acid. So it is both ammonotelic as well as uricotelic. Digestive gland of most gastropods also forms an organ of excretion. It contains some excretory cells which engulf and store the excretory wastes and later pass out through the stomach and intestine .

11. CLASSIFICATION OF Unio : Phylum : Mollusca Class : Pelecypoda Order : Eulamellibranchia Family : Unionidae Genus : Unio

12. EXCRETION IN Unio : Excretion is taken care of by- (i) a pair of kidneys or organs of Bojanus, and (ii) the Keber's organs. Organs of Bojanus : The two kidneys or nephridia are often termed the organs of Bojanus after the name of their on by discoverer. They are situated beneath the floor of the pericardial cavity, one on each side of the vena cava. They are derived from the true coelom (urocoels).

13. Each kidney is a long, dark and glandular tube open at both ends. It is bent upon itself like a broad U-shaped tube, with the loop posterior, the two ends anterior and the two limbs lying parallel and one above the other. The lower arm is brown, spongy, glandular and thick-walled, forming the kidney proper, which opens anteriorly into the fluid-filled pericardial cavity by a small ciliated renopericardial aperture. The dorsal arm is small, non-glandular, lined by ciliated epithelium and thin-walled known as the ureter or urinary bladder, which opens anteriorly into the supra-branchial chamber of the inner gill-lamina by a small renal aperture.

14. The bladders of both the kidneys intercommunicate by an aperture.

15. Keber's organ : The Keber's organ or the pericardial gland is a large reddish-brown, glandular mass situated in front of the pericardium. It probably helps in excretion, discharging waste products into the pericardial cavity to be finally eliminated through the kidneys.

16. PHYSIOLOGY OF EXCRETION : The ventral glandular portion of the kidney extracts guanin and other nitrogenous waste products of metabolism from the coelomic pericardial fluid as well as the blood supplied to the kidneys. The walls of the pericardial sinus are also glandular, and suppossed to secrete waste materials from the blood into the coelomic cavity. The ciliated epithelial lining of the bladder produces an outgoing current, thus coveying excretory fluid from the glandular part of the kidney to the supra-branchial chamber which leads to the excurrent siphon.

17. There is reabsorption of salts in the two kidneys which also serves for maintaining the blood concentration level by removing excessive water from it.

18. THANK YOU