Introduction and Human Systems

Microbes

Microbes: This includes bacteria, viruses, fungi and parasites. They can be bad when entering our body.

　　　　　They are very small! Yeast, a kind of fungi and bacteria is smaller than red blood cells (a very small cell which exists in your blood, and we can’t see it). Viruses are even smaller than bacteria.

Size Comparison: human＞organs>Fruit flies>Human egg> red blood cell> yeast>bacteria>viruses

  • Parasites(tapeworm, roundworm, hookworm, malaria, paramecium, amoeba and pubic lice) A kind of small worms or insects which live in a living body. Pubic lice are regarded as a sexual disease because people get them most during sex.
  •  Fungi (ringworm, mushrooms) Mushrooms are actually one kind of fungi. Another kind of fungi is ringworm. And, fungi cause vaginal yeast infections. 
  •  Bacteria(Cholera, syphilis, gonorrhea, chancroid) Cholera is one kind of bacteria. Cholera causes vomiting and bacterial dysentery, which is bad diarrhea. In addition, there are some sexual diseases caused by bacteria, such as syphilis, and gonorrhea.
  •  Viruses(Covid-19,HIV) Viruses cause many infections such as the common cold, Covid-19 and AIDS. HIV stands for Human Immunodeficiency Virus. You can get HIV if you have sex with someone who has HIV without using protection. To reduce transmission of HIV, we should always use protection such as condoms.