动物疾病模型,蛙或蟾蜍坐骨神经－腓肠肌标本 z-bio 2021-03-08 381

　　Principle of the experiment

　　Amphibians such as frogs and toads have the same basic living activities and physiological functions as warm-blooded animals, and can easily understand the living conditions of isolated tissues. Neuromuscular specimens can be maintained by the penetration of len solution. Therefore, for a long time, in physiological activities, frog or toad psoriasis neurogastric membrane isolated specimens are often used in physiological experiments to observe the excitability, excitability process and contraction characteristics of skeletal muscle.

　　experiment apparatus

　　1 set of beaker surgical instruments and medicines: 1 frog plate, 1 small glass plate, 1 coarse scissors, 1 straight scissors, 1 large tweezers, 1 small tweezers, 1 scissors for eyes, 1 probe, 2 glass minute hands, 1 large beaker, 1 small beaker, 1 dropper, 1 petri dish, cotton thread, len solution, zinc copper fork.

　　Experimental steps

　　1. Destroy the brain and spinal cord: Take out the toad and rinse it with tap water. Hold the toad with your left hand, use your index finger to push the head forward and bend the head, then use your right hand to hold the frog's needle through the large hole, pierce the cranial cavity forward, and stir left and right. Destroy the brain tissue and pull the needle of the frog into the large hole. After pulling out, the tip is rotated and inserted into the cranial cavity to destroy the spinal cord. After insertion into the spinal canal, the hind limbs of the toad almost always lose tension and develop urinary incontinence. When the brain and spinal cord were completely destroyed, the toad's limbs drooped and his breathing disappeared.

　　2. Cut the upper limbs and internal organs: Use coarse scissors to cut the spine of the joint joint into 0.5-1.0 cm pieces. Fix the posterior spine with forceps, and use scissors to cut all internal organs along both sides of the spine, as well as the head and chest, so that the hind limbs, ac bone, posterior spine and sciatic nerve are close to both sides of the spine.

　　3. Peeling: Use tweezers or use your left hand to directly pinch the spine stump (be careful not to press the nerve), use your right hand, hind limbs and a petri dish to pinch the skin specimen of the stump and place it in the tweezers solution. Before proceeding to the next step, please wash your hands and used utensils.

　　4. Separate legs: Use thin glass needles to loosen the two sciatic nerves on both sides of the spine, tie a thin thread near the spine, and then tie the nerves between the tie and the spine. Place a thin line on the nerve, place two sciatic nerves on each of the two thighs, hold the spine with your left hand, tilt the bone, and cut off the entire lower spine. Pinch the i bones on both sides and separate them in opposite directions to dislocate the symphysis pubis. Cut the two lower limbs along the center of the symphysis pubis. Soak one leg in the len solution for later use, and then place the other leg. Plate in immersed glass. There is Ren's solution above.

　　5. Separate the sciatic nerve and incise the femur. Identify the location of the sciatic nerve groove and gastrocnemius muscle, cut open the piriformis and surrounding connective tissue with scissors, and hold a thin nerve with your left hand. Hold the scissors or glass minute needle along the sciatic nerve groove in your right hand. Carefully remove the sciatic nerve until it escapes into the lite socket. Place a clean sciatic nerve on the calf, cut all the tendons of the femur along the knee joint, wipe the attached muscles of the calf with scissors, cut the upper thigh of the femur and 1/3 of the muscles of the upper thigh, a kind called sciatic nerve Calf specimen.

　　6. Free gastrocnemius: Based on the calf specimen of the sciatic nerve, cut the lower end of the Achilles tendon with scissors, draw a thin line at the junction of the Achilles tendon and the muscle, and hold the line. The gastrocnemius muscle to the knee joint. Finally, cut off the calf under the knee joint with coarse scissors, leaving specimens of the sciatic nerve and gastrocnemius muscle. The prepared specimen gently touches the sciatic nerve with the poles of the zinc-copper fork. The immediate contraction of the gastrocnemius muscle indicates that the specimen has good excitability. Then place the sample in the Len solution and wait for the excitability to stabilize. Before proceeding with the experiment.

　　Note

　　1. Avoid contact with skin poisoning and other impurities in the peeled tissue.

　　2. When separating nerves, be sure to use a glass minute hand, do not use knives or scissors.

　　3. Don't pull the nerves too hard, so as not to damage them.

　　4. During the sample preparation process, the kernel solution should be used to properly wet the sample.

　　5. Do not touch or hold the nerve muscles of the specimen with your fingers or metal equipment.