Are there differences between the male and female skeletons?

Several general differences exist between the male and female skeletons. The male skeleton is generally larger and heavier than the female skeleton. The bones of the skull are generally more graceful and less angular in the female skeleton. A female also has a wider, shorter breastbone and slimmer wrists. There are significant differences between the pelvis of a female and a male, which are related to pregnancy and childbirth. The female pelvis is wider and shallower than the male pelvis. Females have an enlarged pelvic outlet and a wider, more circular pelvic inlet. The angle between the pubic bones is much sharper in males, resulting in a more circular, narrower, almost heart-shaped pelvis

How does blood circulate in the fetus?

Fetal circulation differs from circulation after birth because the lungs of the fetus are nonfunctional. Therefore, blood circulation essentially bypasses the lungs in the fetus. The umbilical vein carries oxygenated blood from the placenta to the fetus. About half of the blood from the umbilical vein enters the liver, while the rest of the blood bypasses the liver and enters the ductus venosus. The ductus venosus joins the inferior vena cava. Blood enters the right atrium of the heart and then flows through the foramen ovale to the left atrium. Blood then passes into the left ventricle (lower portion of the heart) and then to the aorta. From the aorta, blood is sent to the head and upper extremities. It returns to the right atrium of the heart through the superior vena cava. Some blood stays in the pulmonary trunk to reach the developing lung tissues.

What is the general course of development for cases of syphilis?

The etiologic agent of syphilis is the spirochete Treponema pallidum. The organism is motile and can be observed moving about under the dark- field microscope. It is extremely difficult to cultivate in the laboratory, and direct observation is usually required for diagnosis. The organism is transmitted among humans by sexual contact, such as during sexual intercourse.

The development of syphilis is generally an involved series of events. The primary stage consists of a painless, hard sore called a chancre at the site where spirochetes have entered the body(usually on the external or internal genital organs). After several weeks, the chancre disappears and a latent period ensues. The secondary stage appears many weeks or months later. The secondary stage is accompanied by a skin rash with pustular lesions and skin eruptions. The hair on the head and eyebrows is often lost. Liver inflammation is common, and an influenza like syndrome may appear. The person is highly contagious at this point. After some time, the lesions heal and another latent stage develops. A tertiary stage may appear years later. This stage is characterized by the formation of gummas, which are gummy, granular lesions that form in the brain and major blood vessels. The patient often becomes paralyzed and usually suffers permanent damage to the blood vessels. In addition, the symptoms of dementia may occur. Death usually accompanies destruction of the heart and blood vessel tissues.

One of the dangers of syphilis is the possible development of congenital syphilis. In this instance, the spirochetes cross the placenta and enter the fetal blood from the mother’s blood. Newborns show signs such as notched incisors (Hutchinson’s teeth), a perforated palate, an aged- looking face, and damage to the nose. Congenital syphilis may also result in stillbirth.