|
|
After a vasectomy, it takes about 12 ejaculations to clear out sperm that were already beyond the blocked area.
The first-known contraceptive was crocodile dung, used in Egypt in 2000 BC. Condoms were also reportedly used, made of animal bladders or intestines.
Vampire bats have a natural anticoagulant in their saliva that permits continuous bleeding after they painlessly open a wound with their incisors. This capillary blood does not cause any significant blood loss to their victims.
Hypertension is a silent killer because it is deadly and has no significant early symptoms. The danger from hypertension is the extra load on the heart, which can lead to hypertensive heart disease and kidney damage. This occurs without any major symptoms until the high blood pressure becomes extreme. Regular blood pressure checks are an important method of catching hypertension before it can kill you.
The first successful kidney transplant was performed in 1954 and occurred in Boston. A kidney from an identical twin was transplanted into his dying brother's body and was not rejected because it did not appear foreign to his body.
![In 1885 masked Nebraskans seeking access to water posed for photographer S. D. Butcher, who captione](https://biology-forums.com/gallery/47/medium_376063_22_08_15_11_31_04_223822138.jpeg)
![It is important for new employees to know the location of all fire extinguishers. (B) Aim low toward ...](https://biology-forums.com/gallery/47/medium_665046_01_03_17_9_46_55_261151227.jpeg)