Sexually transmitted diseases (STDs) are infections that are passed from one person to another through sexual contact. The causes of STDs are bacteria, parasites, yeast, and viruses. There are more than 20 types of STDs, including. Chlamydia. Genital herpes. Gonorrhea.
Society for Endocrinology. Hormones. Oxytocin is a hormone that acts on organs in the body (including the breast and uterus) and as a chemical messenger in the brain controlling key aspects of the reproductive system including childbirth and lactation, and aspects of human behaviour.
Sensory Organs and How They Function. First, Amy touched a cold door knob. There are receptors in her skin responsible for gathering the signals to be sent to her brain. Two layers of the skin, the dermis (inner layer of skin) and epidermis (outer layer of skin), contain receptors.