Grey matter is in the form of a longitudinal band surrounded by white matter, the two not sharply differentiated. Platyhelminthes Organ-system Bilateral Absent Absent Incomplete Absent Absent Flat body, suckers. They have their external features, which is their design, their clothes, what they look like. Other common features observed in the chordates are the dorsal, hollow nerve cord and paired pharyngeal gill slits. Locate the medulla caudal to the basilar pons.
In lamprey, the pineal eye is better developed than that in any other vertebrate. The specialised part of the oviduct where shell gland ducts and yolk duct open is called ootype. A ventral median depression called the basilar sulcus indicates the position occupied by the basilar artery. Radial symmetry is found in Asterias c. Pros encephalon : It consists of an anterior telencephalon made of two cerebral hemispheres, the two together is known as cerebrum, and a posterior diencephalon. The outer tube is formed by the body wall and the inner tube by the digestive canal. There is an scaling relationship between body mass of Lepidoptera and length of proboscis from which an interesting adaptive departure is the unusually long-tongued sphinx moth.
Posteriorly the branchial basket extends to form a cup-like pericardial cartilage accommodating the heart. These together form the hypobranchial nerve, innervating ventral part of the gill region. Remember that primary visual cortex resides along the banks of the calcarine sulcus. It is flattened, convex dorsally and concave ventrally. It swims head downward and burrows again rapidly. The peritoneum lies beneath the muscular layers.
This characteristic feature is named a. Excretory System of Lamprey : The excretory system consists of a pair of kidneys and their ducts. Swim bladder Teleosts have in their body-cavity a long air-filled bladder running just beneath the spinal column. Then it reaches the voluntary muscles or tongue or any other muscular tissue via heart and becomes encysted. The cerebellar surface is folded to form long, transverse convolutions called folia, separated by parallel sulci. The most abundant sense organs, tactile hairs, are scattered over the body.
In many species of fish, once the eggs are laid, there is no parental care, but if there is, it is usually carried out by the male. They occur in the head region, extend in a single line along the body on each side and consists of small patches of sensory cells innervated by branches of fifth and tenth nerves. Metamorphosis usually occurs in winter and the larva assumes the adult form. Organ systems in different groups of animals exhibit various patterns of complexities. With each breath, the nostrils let the cat inhale plenty of oxygen and exhale lots of carbon dioxide. Cerebellar lobules In the midsagittal view of the cerebellum, the vermis is divided into 10 lobules I-X.
The sensitivity of this system makes even a blind fish very difficult to catch by hand. In the stomach of the pig, as the egg-shell and embryophore get digested, the hexacanth embryo is released. An endolymphatic duct is present. Some of them have e. The embryo with the help of its hooks bores into the wall of the gut and reaches the blood stream. The body consists of head, thorax and abdomen.
The legs serve chiefly for locomotion but may be modified for serving as organs daddy longlegs , for capturing and immobilizing prey running spiders , and for producing sound daddy longlegs, spiders, sunspiders, and scorpions. It is followed by longitudinal and circular layers of muscles. Or Nemo, he's not just a fish, he's a young fish who craves independence from his father, but endangers himself in trying to achieve it. They have oral and aboral end. It is fused with the plexus over the fourth ventricle, the cavity of the medulla oblongata.
The coxal glands consist of three parts: a large excretory sac lying opposite the coxal segment of the first pair of legs, a long coiled tubule, and a short exit tube that opens to the exterior through orifices behind the first and third coxal leg segments. They are not connected with one another and sympathetic trunks are lacking. In coelenterates, the arrangement of cells is more complex. Provide appropriate technical term in the space provided. Two distinct phases are present in the life-history of lampreys. Rudimentary paired eyes are hidden below skin and muscles.
Small portion is formed by right atrium. Sort out the animals on the basis of their symmetry radial or bilateral coelenterates, ctenophores, annelids, arthropods, and echinoderms 3. All fish are aquatic and breathe by absorbing dissolved oxygen in the water using their gills. There are two main groups of fish, bony fish Teleosts and cartilaginous fish Elasmobranchs. Many areas will receive a more thorough examination in later laboratory exercises. The females of some moths have a scent-emitting organ located at the tip of the abdomen. The skin is tough, containing minute placoid scales.
Mention two similarities between a. The hypothalamus is located ventral to the hypothalamic sulcus and is important for visceral and endocrine regulation. The genitalia are complex and provide the basis for family identification and species discrimination. They manufacture useful fluids or secretions which pass out by narrow ducts and moisten the surface of the skin. Spinal cord : The spinal cord is tubular, of fairly uniform diameter throughout its length, tapering gradually towards the posterior, and encloses the central canal.