Pancreas– Sits between the stomach and spiral intestine. Produces digestive enzymes for release in the spiral intestine. 5. Liver– An enormous organ composed of three lobes. It is extremely oily – the oil helps the shark maintain buoyancy (float).
What is the structure of a shark's digestive system?
The Dogfish Shark—Structure and FUNction! Carefully open this portion of the digestive tube, called the valvular intestine, to expose the spiral valve inside. This structure provides maximum surface area over a relatively short distance for efficient absorption of nutrients from food.
What is the function of the rectal gland in shark?
This is the rectal gland. The rectal gland excretes sodium chloride solution, aiding in osmoregulation of the shark’s bodily fluids. Some other marine animals also have special organs for the elimination of excess salt. Enjoy using the spiny dogfish shark to put the fun into your study of structure and function!
What is the anatomy of a dogfish shark?
External Anatomy of the Dogfish Shark •Along the sides of the body is a light-colored horizontal stripe called the lateral line. The line is made up of a series of tiny pores that lead to receptors that are sensitive to the mechanical movement of water and sudden changes of pressure.
Where is the digestive system in a dogfish?
Cut across the posterior edge of the transverse septum avoiding the pericardial cavity. Like the dogfish, the main digestive tract is in the pleuroperitoneal cavity. The greater omentum extends from the dorsal wall to the stomach and the gastrosplenic ligament goes from the stomach to the spleen.
Do dogfish have pancreas?
Secretions of the exocrine pancreas contain digestive enzymes integral to the digestive process. The Pacific spiny dogfish (Squalus suckleyi) has a discrete pancreas, divided into two lobes termed the dorsal and ventral lobes. These lobes drain into the anterior intestine via a common duct to enable digestion.
Where is the pancreas in a shark?
The pancreas is located on the duodenum and the lower stomach. The secretions of the pancreas enter the duodenum by way of the pancreatic duct. The dark, triangular-shaped spleen is located near the posterior end of the stomach.
What does the intestine do in a dogfish shark?
The increased surface area of the intestines increases the food's transit time through the intestines, which increases the amount that can be absorbed. The spiral valve allows the food to be completely absorbed and digested. The more food that can be absorbed, the less a shark has to eat.
What is the function of pancreas?
The pancreas performs two main functions: Exocrine function: Produces substances (enzymes) that help with digestion. Endocrine function: Sends out hormones that control the amount of sugar in your bloodstream.
What does the pancreas do?
During digestion, your pancreas makes pancreatic juices called enzymes. These enzymes break down sugars, fats, and starches. Your pancreas also helps your digestive system by making hormones. These are chemical messengers that travel through your blood.
How do dogfish digest food?
The digestive tract is a tube, with coils and branches, which begins at the mouth and ends either at a cloaca or anus. It processes food, which moves by peristalsis through the process of digestion, absorption and elimination. The general pattern is to have an oral cavity, pharynx, esophagus, stomach and intestine.
What structure is unique to dogfish?
A feature peculiar to our specimen, the spiny dogfish, is the presence of two spines, one immediately anterior to each dorsal fin. When captured, these sharks will arch their backs and attempt to pierce their captor with these long sharp spines.
What sensory organs do dogfish sharks have?
eyes, snout, and nostrils are the openings of the ampullae of Lorenzini. These sense organs are sensitive to changes in temperature, water pressure, electrical fields, and salinity. organs called claspers on the inner side of their pelvic fins.
Do sharks have a pancreas?
Also easily found within the body cavity is the pancreas. The pancreas is a digestive gland with two pink lobes. Secretions pass from this organ to the duodenum from the ventral lobe through a small duct. There are two other organs that are visible but do not belong to the digestive system.
Do sharks have 2 stomachs?
Sharks have U-shaped stomachs that use very strong acids and enzymes to dissolve most of what is eaten. The stomach produces an easily absorbed, soupy mush. Only this liquid mush enters the intestines because the pyloric valve (the valve between the stomach and the intestines) is small.
What things have been found in sharks stomachs?
Everything from license plates to boots and fur coats have been found in the bellies of Tiger sharks, yet scientists at the Gulf Coast Research Laboratory were still shocked when they discovered the bones of an adult, 7ft long dolphin in the stomach of a massive 9ft long Tiger shark.
How do sharks digest their food?
Shark intestines are short and compact. The surface area of the intestine is increased by internal valves, or coils, that can take any of several forms. The increased surface area slows food passage through the intestine, and speeds up the rate at which it can be digested and absorbed into the blood.
What is the alimentary canal of a dogfish?
The alimentary canal of Dogfish (Scoliodon) comprises the mouth, buccal cavity, pharynx, oesophagus, stomach, intestine and rectum opening in the cloaca through anus. a. Mouth: It is a ventral crescentic opening guarded by upper and lower lips which are folds of integument.
Where is the pancreas located?
The pancreas is a compact bilobed gland situated in the angle between the cardiac and pyloric stomach. It comprises a longer dorsal lobe running parallel to the posterior part of the cardiac stomach and a smaller ventral lobe lying closely applied to the pyloric stomach.
What is the blind sac in the pyloric limb?
At the junction of cardiac and pyloric limbs there is a blind outgrowth, the blind sac and sphincter valve. The oesophageal opening into the cardiac stomach is guarded by an oesophageal valve developed from a circular fold of mucous membrane. Like oesophagus, the inner mucous lining of the cardiac stomach is also thrown into prominent longitudinal ...
What enzyme converts starch into sugar?
The trypsin acts on the remaining proteins, the amylopsin converts starch into sugar and lipase turns fats into fatty acids. The digested food is absorbed into the blood over the extensive surfaces of the intestine and scroll-valve. Chondrichthyes, Chordata, Digestive System of Dogfish, Dogfish, Vertebrates, Zoology.
Where are the teeth of a squid borne?
They are all alike in shape, homodont, and are borne in several parallel rows on the inner margin of the upper and lower jaws. They are not attached to the jaw cartilages and are simply embedded in the skin like scales. The teeth are used to catch the prey and prevent its escape but not to crush or masticate it.
What is the behavior of a dogfish?
Along with lemon sharks, blue sharks, and hammerheads, dogfish will congregate and even hunt in packs. Their behavior is voracious, and the group will eat just about anything they can catch.
What is a dogfish?
Dogfish. Dogfish are a number of species of sharks in the Squalidae family. They have venomous spines, something that no other shark species have. While there are quite a few different species of this shark, the most well-known species is the spiny dogfish. Because of this, we will focus this article upon this species, ...
How old are dogfish when they reproduce?
Male dogfish begin to reproduce at around 11 years old, and females at around 20 years old. They are ovoviviparous, which means that they develop the eggs within their uterus, and give live birth. This species has possibly the longest gestation period of any vertebrate animal.
Why is the dogfish species considered vulnerable?
This means that the number of animals reaching adulthood to replenish the population is drastically low. Because of this, the IUCN lists this species as Vulnerable. A number of initiatives have begun to control the harvest of dogfish in an attempt to reduce the population loss.
Why is a dogfish called a spiny fish?
It gets the name “spiny” because it has sharp spines in front of each dorsal fin. If a predator grabs it, it arches its back, pushing the spines into the predator’s skin or mouth. “Dogfish” – The term “dogfish” comes from the behavior of this species.
How long do dogfish live?
Learn more about these little sharks below. Long Lived – Researchers believe this species may be capable of living up to 100 years or more! Female dogfish do not reach sexual maturity until about 20 years of age, suggesting that they have a long lifespan.
What do sharks eat?
They are notoriously aggressive and relentless predators. Newborns are even known to pursue prey several times their own size. They eat fish, squid, crabs, other crustaceans, and invertebrates.
Where is the digestive tract in a dogfish?
Cut across the posterior edge of the transverse septum avoiding the pericardial cavity. Like the dogfish, the main digestive tract is in the pleuroperitoneal cavity. The greater omentum extends from the dorsal wall to the stomach and the gastrosplenic ligament goes from the stomach to the spleen.
Where is the pharynx of a dogfish?
The pharynx is the portion leading past the spiracle and five gill slits and also contains the tongue in dogfish. Note the taste buds on the tongue. To view this area, cut through the left jaw of the dogfish and perpendicularly through the center of the gills to the pectoral fin.
How to cut a shark's mouth?
Use your scissors to cut through the left jaw and ventral to the gills to the pectoral girdle. Cut horizontally through the esophagus to open up the mouth. Be sure to avoid the pericardial area and any blood vessels. In the oral cavity are teeth, two rows in the upper jaw, and one in the lower. The tongue is better developed than that of the shark. The pharynx has two pairs of gill slits. On the posterior floor of the pharynx lies the glottis, a slit that leads into the trachea. From the pharynx to the stomach is a short, poorly defined esophagus. The straight stomach has internal rugae and ends with a muscular pyloric sphincter. The small intestine is the duodenum anteriorly, and then a long coiled portion with internal small folds called plicae, which increase the surface area. There is a short large intestine, which enters the cloaca via the anus.
What is the function of fluid in the body?
The fluid serves as a lubricant to allow frictionless movement of the organs. The primary mesenteries are dorsal and ventral, although the dorsal mesentery is often interrupted and moved to one side or the other with the organs and the ventral mesentery is reduced to the membranes of the liver and bladder.
What is the visceral cavity?
The visceral cavity is lined on the inside with a transparent parietal (somatic) peritoneum. It is attached to the muscles of the body wall but it also overlies the urogenital system, which is retroperitoneal. The parietal peritoneum from each side meet dorsally and ventrally to form a double walled mesentery.
Where does the pancreas extend?
Pancreas, consisting of two lobes; a ventral lobe overlying the duodenum, and a dorsal lobe, in the curve between pyloric stomach and duodenum.
Which organs excrete salt?
The rectal gland is for salt excretion for osmoregulation. The rectum, the most posterior portion, ends in the anus which projects into the cloaca, a common opening with the urogenital ducts. Digestive Organs. Liver, composed of three lobes, and a greenish gall bladder.
What is the digestive organ of a dogfish shark?
Digestive Anatomy of the Dogfish Shark . •A smooth, shiny membrane called peritoneumcan be seen lining the inside of the body wall. The visceral organs are suspended dorsally by a double membrane of peritoneum know as mesentery. •The liveris the largest organ Iying within the body cavity.
What is the lateral line on a dogfish shark?
External Anatomy of the Dogfish Shark . •Along the sides of the body is a light-colored horizontal stripe called the lateral line. The line is made up of a series of tiny pores that lead to receptors that are sensitive to the mechanical movement of water and sudden changes of pressure. •The spiny dogfish has a double dorsal fin.
How many spines does a dogfish have?
The spiny dogfish has the presence two spines, one immediately in front of each dorsal fin. The spines carry a poison secreted by glands at their base. •The caudal finis divided into two lobes: a larger dorsal lobe and a smaller ventral lobe. This type of tail is known as a heterocercal tail.
Where is the spiracle in a shark?
The spiracle is an incurrent water passageway leading into the mouth for respiration. •Most sharks have five external gill slitslocated on thire sides behind the mouth and in front of the pectoral fins. Water taken in by the mouth and spiracles is passed over the internal gills and forced out by way of the gill slits.
What is a shark's tail called?
This type of tail is known as a heterocercal tail. •The eyesare prominent in sharks and are very similar to the eyes of man. A transparent cornea covers and protects the eye. A darkly pigmented iris can be seen below the cornea with the pupil at its center. Upper and lower eyelids protect the eye.
Which part of the body is the thick muscular tube that connects the oral cavity and pharynx?
along its right edge. •The esophagusis the thick muscular tube extending from the top of the cavity connecting the oral cavity and pharynx with the stomach. •The esophagus leads into the "J"-shaped . stomach. The upper portion, the cardiac region, continues as the main body, and ends at the duodenal end.
Is shark kidney a single system?
However, due to their similar developmental origins and the sharing of common structures, they are usually considered as a single system. •The shark kidney and its ducts are quite different from those in higher vertebrates. The relationship between the urinary and genital structures is also quite different.
