The gill is attached to the body about the middle of its length, and is highly vascular. 4. Draw a neatly labeled diagram of chloroplast found in leaf, and its role in photosynthesis? The dorsal branch sends an optic artery to the eye and then the two dorsal branches of the two antennaries unite with the median ophthalmic artery to run within the rostrum as paired rostral arteries. Chronic . 3. The inner wall of the cardiac stomach on the side of each comb-plate is folded to form a longitudinal channel, called the guiding ridge. 13 pairs of paired, biramous appendages are present in the cephalothorax. The green glands perform two important functions: 1. f Respiratory System of Prawn Prawn respires in the aquatic medium and it carries three sets of organs for the purpose lining of the branchiostegite, epipodites and gills. 1. The gonads are of different shapes and both occupy similar position. It is present on the base of each second antenna. 2. 18.16D). The body is elongated and divisible into an anterior cephalothorax and a posterior abdomen. The residue reaches the rectum and egested through the anus. The entire structure is enclosed within a haemocoelomic space, called pericardial sinus, the wall of which serves as pericardium. It is large, spacious and bag-like anterior part of the stomach. (iii) Pleuro-branch (Greek: Pleuros, side) attached with the outer border of the thorax and over the articulating surface of the walking legs. The anus opens on the ventral side near the base of the telson. It is colorless when de-oxygenated. The respiratory system works hand-in-hand with the nervous and cardiovascular systems to maintain homeostasis in blood gases and pH. Near the base of the rostrum and on each side of the carapace is placed an eye. TOS4. Respiratory system of prawn. It may attain a length up to seventy-five centimetres. 18.2). 18.3D) is placed slightly posterior to the mouth. The bladder occupies the innermost region and is drawn into a narrow tube to open to the exterior through the renal aperture on the inner side of the coxa. The female reproductive system consist of a pair of ovaries, a pair of oviducts and a pair of female gonopores (Fig 25.15B). The two guiding ridges posteriorly form the border of the cardio-pyloric opening. All these organs are enclosed within a special chamber on each side of the cephalothorax, which is called gill-chamber. Arising from the lower portion of the supraoesophageal ganglion and passing downwards and obliquely, curves forward to innervate the antenna. The entire outer surface of the body is covered by hard exoskeleton. 3). Delicate setae are present on both the upper and posterior surfaces of the plate. 18.13). Describe the respiratory system of prawn. Necessary cookies are absolutely essential for the website to function properly. The last part of the alimentary canal. Nervous System 10. This pigment is responsible for the blue colouration of the blood. 18.3A). Alimentary System 5. supraoesophageal ganglia is formed by the fusion of several pairs of ganglia. Second and eighth gills are arthrobranch. These images are called apposition images. It includes your airways, lungs and blood vessels. Haemolymph enters through the transverse channels and traverses other channels. The primary function of the respiratory system is to provide the body with oxygen. Of the three groups of respiratory organs, gills are referred to as primary respiratory organs. Such imbricately arranged sclerites are united with each other by thin un-calcified arthroidal membrane. Reproductive System 11. c. A rectangular filter plate bearing alternate ridges and grooves is present on the floor of the ventral chamber. This is called countercurrent flow and allows prawn's to obtain more oxygen from the water than if the blood and water flowed the same way. This cookie is set by GDPR Cookie Consent plugin. Content Guidelines 2. Breeding and Life History. The ventral branch supplies vessels to the first and second antennae. The two ventral sinuses are interconnected by several small slender channels. 2. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. It is a good swimmer but is also capable of crawling on the surface and at the time of danger can jump backwardly. 2. (iv) a single mid-posterior artery emerges from the posterior end (Fig. Necessary cookies are absolutely essential for the website to function properly. SINUSES are hollow spaces in the bones of your head above and below your eyes that are connected to your nose by small openings. The two lateral ducts are interconnected by a transverse connective. The body of Prawn is elongated, hemispherical and slightly tapering at the posterior end (Fig. This gives a backward thrust, which shifts the body to a considerable distance in backward direction. The nerves emanating from the central nervous system constitute peripheral nervous system: Arising from the outer side of each supraoesophageal ganglion it runs forward and outward and innervate the eye of the side. Feeding and Digestion 5. Each ommatidium is a complete visual unit, made up of cells arranged in end- to-end position along the long axis. This cookie is set by GDPR Cookie Consent plugin. Respiratory System 6. Does prawn use trachea as respiratory organ? Each gill consists of an axis or a slender base on which double rows of rhomboid branchial plates are arranged like the pages of a book. The free end of the distal segment is bluntly rounded and covered with a thin membrane (Fig 25. The cardiac stomach opens within th6 next part, pyloric stomach through a narrow, X-shaped cardio-pyloric opening. Histologically, the branchial base has three layers the outermost cuticle the medium epidermis, and the innermost connective tissue mass. Present one on the inner side of each third walking leg as a small aperture is called the female gonopre or reproductive opening. Each unit is called an ommatidium or ocellus. The flow of blood in the gills of a prawn travels in an opposite direction from the water when it passes over the gills. It is a small chamber, wider anteriorly and narrows down posteriorly to open on the ventral surface, at the base of the telson. Each group of parts has many separate components. hb```f``jf`a`cb@ !r4000| H`lr47bTda`'pY gallbladder color is black . Zoology Notes | Exclusive Notes on Zoology for Students, Earthworm: Digestive and Reproductive System | Zoology, Invertebrate Nervous System (With Diagram) | Zoology, Respiration in Prawn | Crustacean Anthrapods, Essay on Earthworm: Feeding and Digestion, Animal Cell and Cell Culture Notes: Introduction, Substrates, Isolation, Types and Techniques, Gastrulation and Primary Organ Formation in Fishes | Embryology, Gastrulation in Amphioxus and Amphibians | Embryology, Parental Genes and Embryos | Gastrulation | Embryology, Fate Maps of an Embryo | Animals | Embryology. Respiration is a mechanism by which gaseous exchange takes place between the organism and the environment, in which oxygen is taken in and carbon dioxide is given out. The single ophthalmic or cephalic artery originates from the apex of the heart and runs anteriorly along the mid-dorsal line up to the base of the rostrum and unites with the branches of two antennary arteries. Each eye is a collection of a large number of visual elements called ommatidia and is borne on a movable stalk. The mouth is a slit-like aperture situated on the ventral surface of the head. When light is dim, ommatidia work together to form a single but blurred image. This cookie is set by GDPR Cookie Consent plugin. Such an image is known as apposition image. Beneath the corneal facet is a pair of flat corneagen cells of epidermal origin which secrete a new cornea when the old one is lost during moulting. It also performs the function of osmoregulation (Fig. This system also removes waste gases . The gonopore is guarded by a small cuticular lid. The position of these paired openings depends upon the sex of the individual. Anterior ends of the two testes are united but the posterior ends are free. _4--a`(/>K:9lgU ? Movement 4. Heart is united with the pyloric stomach by a cardio-pyloric strand. Before giving off the optic artery, the antennary artery sends a common artery, which divides into renal, antennal and antennular branches and supply the respective organs. Name the types of nitrogenous bases present in the RNA. Inside the base (pre-coxa) of each antennule, the statocyst is present as a small, white and spherical cuticular sac. Two lateral blood channels and a median longitudinal channel pass along the entire length of the gills base. The cephalothorax is formed by the fusion of 5 cephalic and 8 thoracic segments, and covered externally by a hard cephalothoracic shield, the carapace, anteriorly drawn into a serrated and pointed rostrum. The gills are crescent-shaped and increase in size anteroposteriorly (Fig. Locomotion 4. The renal sac is a thin-walled median structure lying just above the stomach. The gill chamber is covered by the lateral extension of carapace called gill-cover or branchiostegite. At the same time, excess salts are discharged from the blood into the water and necessary salts are absorbed from the water into the blood. 3. In order to pass a constant supply of oxygenated It performs respiration by 3 organs. endstream endobj 97 0 obj <. Each abdominal segment is laterally compressed and is bounded by a ring-like exoskeletal piece, called the sclerite. After covering the entire margin of the plate, the marginal channel opens within the median channel. It is fan-shaped (Fig. All these organs are enclosed within a special chamber on each side of the cephalothorax, which is called gill-chamber. Both the upper and posterior surfaces have delicate setae. Disclaimer Copyright. 25.8) is a hollow organ, somewhat triangular in outline, and with thick muscular walls. The second maxilla serves double functionsjaws are for food-getting and the scaphognathite is for producing constant water current within the gill chambers. The close apposition of these appendages speaks about the fusion of cephalothoracic segments. ii. 1. The renal sac acts as a temporary reservoir for waste products. iii. By the apposition-of those points of images in a number of ommatidia an erect image of the object is formed. Change of place in prawn takes place in three ways: The body is kept straight in a horizontal position. The first two legs end in chela and the second is the largest. Excretory System 8. Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features. These organs are enclosed within a special chamber, the gill chamber, lying on each side of the cephalothorax. It divides immediately into a supraintestinal and a sternal artery. During the flow of water currents, the vascularized surface of branchiostegites, gills and epipodites are bathed in water and gaseous exchange occurs through these areas, that is dissolved oxygen is taken in and carbon-dioxide passes out. From the posterior end of the thoracic ganglionic mass originates ventral nerve cord which runs up to the posterior-most segment. Both the exo and endopodites bear tactile setae but the former is larger. Maxillipeds, maxillulae and maxillae help in tearing it into pieces. The inner margin is lined with numerous setae. In the second pleopod of male, an appendix masculine, concerned with reproduction is found. (c) Mandibular artery to the muscle of the mandible. Gills or Branchiae. The ommatidia of a compound eye may work singly or collectively. It is a bilobed structure formed by the fusion of the right and left ganglia and is situated beneath the base of the rostrum just in front of the junction of the oesophagus with the cardiac stomach. Prawn stomach located on the Head of a prawn , looks like a The beating of a leaf-like flap, the scaphognathite, causes water to enter the branchial chamber from below and behind that is, through an opening between the thoracic legs and in front of the abdomen. The cornea is divided into a large number of square facets, each corresponding to a single ommatidium. 3. It is more or less a triangular organ with inner spongy cavity. It has an irregularly folded lining of cuticle. It runs anteriorly along the outer border of the mandibular muscle. Save my name, email, and website in this browser for the next time I comment. In each pleopod the protopodite has a longer basis than the coxa (Fig. At the end of the abdomen a median triangular piece called telson is present. Symptoms of the common cold include runny or stuffy nose, congestion, pressure in the sinuses .

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