(ii) It is the centre of spinal reflex action. On stimulation the sympathetic nerve fibres secrete a chemical sympathin, which stimulates the organs to function. Frogs are classified as amphibians. There is also present a pair of elastic bands, the vocal cords which extend longitudinally across the laryngotracheal chamber. The nictitating membrane is movable, semitransparent and can be drawn over the eye when animal is inside water where it prevents aquatic infection and also enables the frog to see under water. The rate of heart beat is controlled by the medulla oblongata of the brain and by certain hormones such as adrenalin and thyroxine. They increase in size during summer. In female ureters carry urine alone, while in male both sperms and urine are carried from kidney to cloacal chamber, hence called urinogenital ducts. Since the urinogenital system comprises two closely associated urinary (excretory) and the genital (reproductive) system, it is collectively called as the urinogenital system. Required fields are marked *, All Rights Reserved Copyrights @ 2020 StudyToday.net. It comprises the following structures. It is much smaller in the adult than in the tadpole. The contraction of heart (systole) and the relaxation of heart (diastole) constitute the heart beat. When the two auricles are full of blood, they contract simultaneously. From the brachial plexus, the second nerve continues as a brachial nerve to the skin and muscles of fore-limb. Increase in carbon dioxide and temperature also affects the sinus venosus and thereby it increases the rate of heart beat. The lobules produce pancreatic juice which is poured into the bile duct through many pancreatic ducts and finally reaches the duodenum via common hepatopancreatic duct. Yes, frogs are endangered. The free bilobed posterior end can be thrown out and retracted backward with a great speed after catching the prey. The neck being absent in frog, the head is directly continued into the trunk. The heart is a modified blood vessel to receive and distribute the blood. The fat bodies are attached anteriorly. There are different genus and species amongst the different families which contribute to this large class of Amphibia. It supplies the ear and carries impulses from the ear to the brain, thus helps in hearing and balancing the organs. This phenomenon, known as ecdysis, is affected by the secretions (hormones) of two ductless glands, the pituitary and thyroid. It only allows the blood to flow towards the right auricle. Princess and the Frog - essay example for free Newyorkessays - database with more than 65000 college essays for studying 】 It is a transparent, highly distensible bilobed sac, attached to the ventral side of the cloaca, below the opening of the ureters urinogenital ducts. The Cricket frog (4cm or 1.5 inches long) can leap 40 times its length in one jump! This opening is guarded by a small valve. The myelocoel communicates with the central canal of spinal cord. The pituitary gland is also called ‘master endocrine gland’ because some of its hormones influence other endocrine glands. When an individual feels deficiency of food, the glycogen is converted into glucose and is transferred to the blood stream via hepatic veins. Each oviduct consists of ovarian funnel, ovarian tubule and ovisac. There is no such cord or ganglia as found in the sympathetic nervous system. The Frog Life Cycle Process Essay...The Frog Life Cycle In Biology, we know the term metamorphosis which is the transformation process of animal’s body structure from the immature one to the adult form. When it is completely empty, it shrinks. What are the general characters of bryophytes? Externally, it bears a rounded patch, the tympanum or tympanic membrane, which is tightly mounted on a cartilaginous ring, the tympanic ring. The heart is protected by the pectoral girdle ventrolaterally and by vertebral column dorsally. February 16, 2018 by Manasi Shewale Leave a Comment. Whenever we think about a frog, we think about colorful little tail-less organisms which hop to move from one place to another. Posteriorly each sympathetic cord joins the 9th spinal nerve and later on ends there. The outer layer of the sac is called parietal pericardium and inner layer is known as visceral pericardium. It innervates the muscles of hyoid apparatus, muscles and skin of lower jaw. Seminal vesicles are not well-developed in Rana tigrina. It supplies the taste buds of tongue and muscles of the pharynx. They run backwards from the kidneys and open into the cloaca, and carry urine from the kidneys to cloacal chamber. This is what makes it different from the rest of the animals. It also takes part in the formation of brachial plexus. In higher vertebrates like mammals, the adrenal gland consists of distinct outer cortex and inner medulla. The left lobe is larger and divided into two smaller lobes. (ii) Pyloric stomach is a posterior narrow tapering part, which is separated from the duodenum by a muscular constriction, the pyloric constriction externally, which indicates the position of pyloric sphincter and controls the entry of food into duodenum. Frog is useful animal for human being because it eats up insects which are harmful for the crops. The adult frog is carnivorous and mostly feeds on insects and their larvae, spiders, earthworms and in some cases evens their own larvae. Each thyroid gland is situated behind the hyoid apparatus. Development is indirect involving a larval stage called tadpole. The space between the seminiferous tubules is filled with the connective tissue, blood capillaries, nerve fibres and interstitial cells. It can be represented by the following graphical sketch. The olive greenish colour is due to the combined effect of these three pigments. It produces RBCs and WBCs in adult too. They secrete thyroxine. (3) The diencephalon acts as a relay centre, because it conveys the impulses to cerebral hemispheres. Thus the blood is detoxified (purified) of harmful nitrogenous waste; (iii) Liver produces blood proteins which are put into blood circulation. The lower eye lid is vestigial and immovable. The teeth help the frog hold on to the prey to stop the prey from escaping. The adult frog is carnivorous, eating insects, spiders, earthworms etc. There is a foramen magnum through which brain joins the spinal cord. (ii) Guanophores are specialized cells which contain white pigment called guanine. The nerves arising from the sympathetic ganglia supply the respective visceral organs, such as heart, liver, stomach, intestine, kidneys, gonads, blood vessels, urinary bladder, etc. Spinal cord in frog extends up to the anterior part of the urostyle. The outer tough, thick membrane is duramater, and the inner thin, more delicate and vascular membrane is pia arachnoid membrane. The auriculoventricular node is stimulated by the auricular contraction and passes a fresh wave of the contraction over the wall of the ventricle. Essay On The Frog And The Toad 971 Words | 4 Pages. The epidermis is non-vascular layer. Pectoral girdle (shoulder girdle) is made up of similar right and left halves. It lies in the neural canal of vertebral column and extends from the medulla oblongata of the brain to almost the end of back-bone. Lagena is the forerunner of the cochlear duct of higher vertebrates. Golden Frog Classification 1297 Words | 6 Pages. Vagus is mixed in nature because it carries both motor and sensory fibres. The anterior and posterior semicircular canals are united at their origin. The brain is covered by two membranes or meanings (sing meninx). (ii) Posterior spacious abdominal (pleuroperitoneal) coelom in which the rest of the internal organs lying in the trunk are lodged. The finger corresponding to our thumb or pollex is rudimentary and invisible externally. The muscles controlling the movement of eye ball are attached on it. These sacs are the pouches of the skin on the throat, opening into the buccopharyngeal cavity and acting as resonators. Cortisol regulates the metabolism of carbohydrates, proteins and fats. These glands are present in the small intestine which secretes the intestinal juice. The act of taking the food material into the buccopharyngeal cavity is called ingestion. Whatever little energy required during this period is obtained from the fat-bodies and from the stored glycogen of the liver, which had been stored in sufficient quantity earlier. Frog also eats mosquitoes which act as vectors for parasites (e.g., malarial parasite) of man. The position of pineal body is indicated externally by the brow spot. So each eye of this animal forms a separate image of the object. It is sword like. It is the innermost layer of the eye on which the image is formed, that is why it is nervous and perceptive layer. From the Bidder’s canal, the sperms are carried to the transverse collecting tubules, longitudinal collecting tubule and then to the urinogenital duct. 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