What is rectal gland?

The rectal gland is a specialized salt secreting osmoregulatory organ found only. in chondrichtyhans and secretes a concentrated NaCl solution which is isos- motic to the plasma (Burger & Hess, 1960; Burger, 1965).

1. What is the function of the rectal glands?
2. Where is the rectal gland?
3. Who has rectal gland?
4. In which animal rectal gland is present?
5. What is the function of the rectal gland in sharks and rays?
6. Where are the salt glands located in seabirds?
7. What do shark kidneys do?
8. What is the function of the Digitiform gland?
9. What is the function of a shark's pancreas?
10. Do stingrays have skeletons?
11. Why is a Spiracle so important to skates?
12. Can seabirds drink salt water?
13. Do all crocodiles have salt glands?
14. Why do birds have salt glands?
15. Is urea a urine?
16. Which internal organ helps a shark float?
17. Do female dogfish sharks have Claspers?

What is the function of the rectal glands?

The rectal glands of elasmobranchs perform the function of salt-excreting organs. These glands are smaller and show regressive changes in specimens of the bull shark, Carcharhinus leucas found in fresh-water environment, compared with specimens of this and other species from a marine habitat.

Where is the rectal gland?

rectal gland A salt-secreting gland found in the cloaca of cartilaginous fishes.

Who has rectal gland?

Sharks are an amazing species. They are more than 400 million years old and have evolved an integrated osmoregulatory system that includes their gills, kidney, and rectal gland.

In which animal rectal gland is present?

The rectal gland of the spiny dogfish, Squalus acanthias, secretes a fluid which is essentially a sodium chloride solution with a concentration about twice that of the plasma and greater than that of sea water.

What is the function of the rectal gland in sharks and rays?

Rectal Gland

This organ is very important to elasmobranchs, whose livers produce large amounts of urea, thereby making these marine fishes slightly hyperosmotic to seawater (i.e. their internal solutes are greater than the surrounding seawater, so they are constantly gaining water and salt).

Where are the salt glands located in seabirds?

All seabirds and many shorebirds have a pair of supraorbital (above the eye) glands which perform one of the kidney's main functions: drawing salt ions out of the bloodstream. This salt gland allows these birds to drink the water they live in.

What do shark kidneys do?

For adaptation to high-salinity marine environments, cartilaginous fishes (sharks, skates, rays, and chimaeras) adopt a unique urea-based osmoregulation strategy. Their kidneys reabsorb nearly all filtered urea from the primary urine, and this is an essential component of urea retention in their body fluid.

What is the function of the Digitiform gland?

digitiform gland — rectal gland (an evagination of the terminal portion of the intestine of Elasmobranchii. Function formerly thought to be related to digestion or excretion, but now considered to secrete high concentrations of excess sodium chloride.

What is the function of a shark's pancreas?

The pancreas is both an exocrine gland, producing digestive enzymes and an endocrine gland regulating metabolism. The spleen, a lymphatic organ, lies to the left of the stomach.

Do stingrays have skeletons?

Stingrays are members of the group of fish that also includes sharks and skates. Sharks and rays have skeletons made of flexible cartilage instead of bone. What makes rays unusual is that their wing-like fins stretch out flat from their bodies, making them look like a disc with a tail.

Why is a Spiracle so important to skates?

Skates and rays respire primarily using their spiracles. Spiracles are small, round openings, located on top of and on either side of the head immediately posterior to the eye and anterior to the principal gill opening. These structures can be used in place of the mouth to actively draw water into the gill chambers.

Can seabirds drink salt water?

Seabirds have no problem drinking sea water. The salt they take in is absorbed and moves through their blood stream into a pair of salt glands above their eyes. The densely salty fluid is excreted from the nostrils and runs down grooves in the bill.

Do all crocodiles have salt glands?

In crocodiles, the salt-excreting glands are located on the tongue immediately below the lingual epithelium and are responsible for the excretion of sodium and chloride ions(Taplin and Grigg, 1981; Taplin et al., 1982). ... The salt glands appear as 20–40 distinct pores on the posterior half of the lingual surface.

Why do birds have salt glands?

Marine birds possess salt-secreting nasal glands which produce hypertonic solutions of sodium chloride in response to osmotic loads such as ingestion of sea water. ... The presence of this gland must be considered a necessary adaptation to marine life in animals whose kidney cannot excrete high salt concentrations.

Is urea a urine?

Urea (also known as carbamide) is a waste product of many living organisms, and is the major organic component of human urine. This is because it is at the end of chain of reactions which break down the amino acids that make up proteins.

Which internal organ helps a shark float?

Most bony fish have a swim bladder, an internal organ that can be filled with gas to help the fish float without swimming. Unfortunately, sharks do not have a swim bladder, but they have unique adaptations to survive in the oceans.

Do female dogfish sharks have Claspers?

Fertilization in the dogfish shark is internal. During copulation, one of the claspers is inserted into the oviduct orifice of the female. The sperm proceed from the cloaca of the male along the groove on the dorsal surface of the clasper into the female.