The contraction produced can be described as a twitch, summation, or tetanus, depending on the frequency of action potentials. In skeletal muscles, muscle tension is at its greatest when the muscle is stretched to an intermediate length as described by the length-tension relationship. Smooth and cardiac muscle contractions are myogenic and can be modulated by the autonomic nervous system.
Citation: Pray, L. (2008) Sex-linked diseases: the case of Duchenne muscular dystrophy (DMD). Nature Education 1(1):132. Prenatal diagnostic testing can now determine whether a fetus carries a debilitating or fatal sex-linked mutation.
Sexually transmitted diseases (STDs) are diseases that are mainly passed from one person to another during sex. There are at least 25 different sexually transmitted diseases with a range of different symptoms. These diseases may be spread through vaginal, anal and oral sex.ost sexually transmitted diseases will only affect you if you have sexual contact with someone who has an STD. However there are some infections, for example scabies, which are referred to as STDs because they are most commonly transmitted sexually, but which can also be passed on in other ways.