We all know the ancestors of whales are small land mammals, after starting to live in the ocean, they went through more than 50 million years of evolution and eventually became a family of marine mammals. have the most diverse and popular breasts today. The whale suborder includes not only giant blue whales, sperm whales, and bowhead whales, but also many different species of dolphins. Species in the suborder whales still exist on Earth today. The “whale” Pakicetus is one of the earliest known ancient whales, this animal that lived 50 million years ago looked like a dog with long limbs and fur. If you look closely at the Pakicetus whale, you will see that its nose is located in the front of the head, like today’s mammals. Because the nostrils of Pakicetus whales are located in front of the mouth, when swimming they will look like dogs today because underwater, they have to almost raise their heads out of the water when swimming. Pakicetus is an extinct genus of cetacea, found in Pre-Eocene rocks in Pakistan. The strata where the fossils were found were then part of the coastal Tethys Sea. .As the ancient whales gradually entered the ocean, their body structure began to evolve in a way that was adapted to aquatic life, including the position of the neck, the nostrils gradually moving to the top of the head, Below are pictures of the primitive whale (Protocetus) and a restored image of the Basilosaurus whale, both of which show their nostrils gradually turning upward. Protocetus is one of the most ancient whale genera, which lived in the middle of the Meridian period 45 million years ago near Cairo, Egypt. It was one of the first genera of whales to have fully adapted to aquatic habitats. They are quite small, only about 2.5 m long, on the body still keep the traces of limbs with fingers connected by swimming membranes with the hind limbs smaller than the front limbs. Jaws long, with sharp teeth. The front teeth are used to catch prey and the back teeth are used to cut meat. Unlike the older predecessor Pakicetus, which lived a semi-aquatic lifestyle, Protocetus was able to develop ear canals and hear underwater sounds (but it is unclear whether they developed sonar or sonar). not yet) and developed a flattened tail like today’s whales. Their nostrils are still located on the head, they still do not have a stoma on the top of the head and rely more on eyesight for food. Basilosaurus is one of the primitive whales that evolved from land mammals and later evolved into modern day whales. Basilosaurus averaged about 18 – 20 m long and weighed about 15 tons, once distributed in North America, North Africa and Central Asia and was considered the largest animal that ever lived in its time. The ancient whale species mentioned above all belong to the ancient whale suborder, the baleen whales and the toothed whales in the ocean today all evolved from the ancient whale suborder. They appeared in the middle Oligocene, about 30 million years ago. Compared to today’s whales, their appearance is quite similar to ancient whales, but the evolution to change the position of the nostrils took quite a long time – about 20 million years. Diagram of the evolution of ancient whales. Schematic diagram of the evolution of modern whales. Modern whales have evolved to move the nostrils from the front of the mouth to the top of the head. It’s not just a change of location. The esophagus and trachea of ​​today’s terrestrial mammals are interconnected, so if our noses are blocked by a cold, we can still use our mouths to breathe instead of our nostrils. In addition to breathing, our nose also has the function of smelling. But modern whales are different, and the changes in the position of the nostrils and the changes they made to aquatic life have caused the trachea and esophagus to separate. The nostrils connect to the lungs and the esophagus connects to the digestive system, so their noses are only used for breathing, not for smelling. The nostrils of modern whales located at the top of the head actually help them survive more effectively and safely than the holes in the front of the mouth when in the ocean. But even if their nostrils are at the top of their heads, when they dive into the ocean, their noses are still underwater, how can modern whales ensure that they won’t choke? In fact, under the nostrils of whales have a very strong muscle group, they can completely close their nostrils when diving, avoiding the risk of choking on water. The separation of the esophagus and trachea also ensures that modern whales will not choke on water while hunting in the ocean. Large nostrils of baleen whales. The nostrils of a blue whale when diving into the water. In fact, all baleen whales still have two nostrils, while toothed whales have only one. The jets that whales spit out of the water are not water in their noses, but rather accumulations of water remaining in the “pits” of the nostrils, which are formed under the action of sub-lower pressure. Ocean. This prevents water from entering the nostrils, improving the safety and efficiency of breathing. However, the water column due to the whale’s breathing process once brought them great danger. In the era of whaling, sailors often relied on these water columns to locate the schools of fish. elephants. Killer whales belong to the toothed whale subspecies with only one nostril. Gray whales belong to the subspecies of baleen whales that spray water with a pair of nostrils.

About a month earlier, while working in the field, Mr. S. washed his face and drank from the stream near his house. After a while, he found that he was coughing, spitting blood and having difficulty breathing, so he went to Ham Yen hospital for medical examination, then he was transferred to the General Hospital of Tuyen Quang province.

As the person directly endoscopically picking up the leeches for the patient, MSc.BS. Vu Dang Khoa, Head of Department of Ear, Nose and Throat, said that Mr. S. was under general anesthesia, then performed a tracheostomy, anesthesia for resuscitation. When the laparoscopy revealed that the larynx showed a foreign body under the hypopharynx, the upper part of the trachea, the doctors carried out the removal of the foreign body as a stream leech.

According to Dr. Khoa, leeches are living things that can move from the nose, mouth to the larynx – the patient’s trachea becomes a foreign object. Leeches live in the airways of the patient for a long time, can move up the larynx or down the bronchial gas, causing symptoms of coughing attacks, hoarseness, spitting up blood, difficulty breathing. At the location where the animal sucks, causing prolonged bleeding, difficult blood clotting is life-threatening.

Although it has been warned much, but leeches and parasitic squeezing still occur continuously. The reason is due to the habit of using water in streams and streams when going to the forest.

Scary is when the leeches, the new squeezed into the body through the water into the nose, throat, the small size, but after they suck blood and grow very quickly in a short time.

Symptoms of bleeding are detected in the form of hemoptysis, vomiting of blood, hematuria. The blood-absorbing leeches have symptoms such as increased pressure, discomfort, pain, nerve stimulation originating from the parasitic location, dysfunction of parasitic leeches, superinfection of bacteria causing inflammation in the area. leeches absorb blood, causing an abscess under the mucosa.

If the bleeding persists, the patient will experience anemia. If not examined and handled in time, leeches are getting bigger and bigger, causing obstruction of the trachea, respiratory failure … for a long time, it can lead to death.

According to experts, when leeches penetrate the natural cavities of the body, you should rinse your mouth with high concentration of salt water or inhale substances that have a spicy, pungent odor.

If the leeches are in a shallow area, the doctor may use a scope to remove them; If sticking deeply, it is necessary to anesthetize and use specialized equipment; If it is too deep, they must be operated on to remove leeches. If the leech enters the genital tract, soaking or injecting it with concentrated salt water can also cause the leech to die, or the leech to come out on its own.

Minh Hoa (th)