Veterinary Practical Biology/Zoology 2024 (AIN SHAMS UNIVERSITY) PDF

Biology/ Zoology Part 2024 ‘’ Practical Lessons ’’ Section: 5 6- Phylum: Cordata Sup-phylum: Vertebrata: 3- Class: Amphibia: Bufo regularis = Sclerophrys regularis (Reuss, 1833) = Amietophrynus regularis (Reuss, 1833): (The Egyptian Toad, African common toad, African toad, Af...

Biology/ Zoology Part 2024 ‘’ Practical Lessons ’’ Section: 5 6- Phylum: Cordata Sup-phylum: Vertebrata: 3- Class: Amphibia: Bufo regularis = Sclerophrys regularis (Reuss, 1833) = Amietophrynus regularis (Reuss, 1833): (The Egyptian Toad, African common toad, African toad, African bouncing toad (due to the bouncing motion)): Order: Anura. Family: Bufonidae. The external Morphology: - It is characterized by the absence of neck, absence of tail. - Eyes are bulging, and are guarded each by two eyelids, - an immovable upper, and a semi-transparent movable eyelid. - The color of the sub gular area is black in mature males, whitish in females and immature males. - The nostrils are two small openings lying near the anterior tip of the head. 3- Class: Amphibia: Bufo regularis The external Morphology: (continued): - The tympanic membrane is a circular area found posterior to each eye. - The parotoid gland is indicated by an elevated area of the skin found dorsal and posterior to each tympanic membrane. - The forelimbs are short, each hand has four digits and two horny pads on its ventral surface. - The hind-limbs are longer, and each has 5 digits - in addition to the prehallux or calcar. The Maculated Toad: The buccopharyngeal cavity: - Open the toad's mouth as much as you can and look up for the details in the following figure. - Note the following parts at the buccopharyngeal cavity: - Internal nares or nostrils - Anterior openings for the entry or exit of air; - Esophagus - tube that connects the mouth and the stomach in a frog; - Glottis - the opening from the mouth into the respiratory system; - Vocal Sacs - the vocal sac is the flexible membrane of skin possessed by male frogs; - Tongue - muscular structure attached to the front of the mouth which is extended to catch insects (its food); - Eustachian tube openings - openings in the mouth that lead to tubes that connect to the middle ear to equalize air pressure. Buccopharyngeal cavity, (Opened): Dissection Instructions: 1. Place frog in dissecting pan. The frog should be lying on its dorsal (back) side with the belly facing up. 2. Pins the frog for dissection by securing each of the four limbs to the pan. Place the pins through the hands and feet to secure them to the pan. 3. Begin the first skin incision once the legs of the frog are securely pinned to the dissection tray. Begin the first skin incision by using the forceps to lift the skin midway between the rear legs of the frog. Using the scalpel, make a cut along the center, or midline, of the frog, bisecting it equally. 4. Continue the skin incision continue the skin incision by using the scissors to cut all the way up the frog's body to the neck. Be very careful not to cut too deeply. 5. Make the leg incisions still using the scissors, make horizontal incisions just above the rear legs and between the front legs of the frog. How to cut the skin: Dissection Instructions: (continued): 6. Separate the skin & muscle once you have finished the incisions between the front and rear legs of the frog you need to separate the skin flaps from the muscle below. To do this: pick up the flap of skin with the forceps and use a scalpel to help separate the skin from the muscle below. 7. After checking the muscular system, use scissors to lift the abdominal muscles away from the body cavity. Cut along the midline of the body to the forelimbs. 8. Make transverse (horizontal) cuts near the arms and legs. 9. Lift the flaps of the body wall and pin back. How to open the abdominal cavity: The Digestive System: - The mouth opening leads to the buccal cavity which is edentulous and indistinct from the pharyngeal cavity; - both forming a single buccopharyngeal cavity which leads to the esophagus opening into the stomach. - The intestine is long and differentiated into the small intestine and the large one. The small intestine consists of the duodenum and the ileum. - The large intestine consists only of the rectum. - The accessory glands connected to the digestive system: (1) The liver is large, dark red in color, and consists of two lobes connected by an ithmus. The left lobe is cleft and larger than the right one; (2) The gall-bladder lies between the two lobes of the liver, posterior to the ithmus; (3) The spleen lies dorsally behind the stomach. (Part of the circulatory system, stores the blood); (4) The pancreas lies between the stomach and the duodenum. The general viscera: The general viscera: The Urinogenital System: The urinary (renal) system: - Consists of two kidneys. Each kidney is elongated and dark red in color. - There is a broad irregular yellow patch on the ventral surface of each kidney, this is the adrenal gland. - The Wolffian duct extends backwards from the lateral edge of the kidney, and finally opens on the dorsal side of the cloaca. - The urinary bladder is a thin walled bilobed sac which on the ventral side of the cloaca. The male genital system: Consists of: - two elongated testes, yellowish white in color. Each testis is connected to the median edge of the opposite kidney by a thin membrane called the mesorchium, where pass several fine tubes leading from the testis to the kidney. These are the vasa differentia. - The Wolffian duct is largely swollen to form the seminal vesicle. Thus, this duct acts as a urinary and at the same time as a genital duct. - Each of the two testes is connected anteriorly to a fat-body. - In between the two lies a small pale brown body, the Bidder's organ. The male genital system: urinary bladder The female genital system: Consists of: - two ovaries and two oviducts. The ovary is a large organ which occupies a considerable space in the coelom, particularly during the breeding season. It is granulated, lobulated and connected to the opposite kidney by a thin membrane called the mesovarium. - An oviduct is a long tube, opening into the body cavity by an internal opening near to the base of the lung of its side, it continues backwards as a convoluted tube where it swells up, opposite to the posterior third of the kidney, to form the ovisac. - The two ovisacs unite and open together by a common opening into the dorsal side of the cloaca. The two fat-bodies and the two Bidder's organ are present, each having the same relations with the ovary as with the testis The Urinogenital System of female: The circulatory system (The Heart): The heart consists of: - five chambers, only four of which are visible on either the ventral or the dorsal side. - On the ventral view: the ventricle, the two auricles (right and left), and the truncus arteriosus. - On the dorsal view: the ventricle, the two auricles, and the sinus venosus. - There is a girdle of fat between the auricles and the ventricle. The circulatory system (The Heart): The nervous system: The spinal nerves & sympathetic chain: - It consists of (10) pairs of spinal nerves. - The first spinal nerve, also called the hypoglossal nerve, ends in the muscles lying ventral to the tongue. - The second and third spinal nerves unite forming together the brachial plexus. - The fourth, fifth, and sixth spinal nerves are long nerves which pass obliquely backwards and outwards to supply the muscles of the side of the body and the abdomen. - The seventh, eighth, ninth and tenth spinal nerves extend alongside with the urostyle and unite to form the sacral plexus. The spinal nerves: The spinal nerves: