In four-legged animals the weight of pregnancy is distributed over four legs, but in humans all the extra weight (the baby, the uterus and the breasts) is carried at the front of the body. Because there is more weight in front there is an increased tendency for the body to fall forwards. The muscles at the back of the body therefore have to work more to maintain the balance. From an Alexander perspective, misuse is when this increased muscular activity is concentrated in specific areas.

The way in which a pregnant woman compensates for the increased imbalance will reflect her habitual misuse. If she has a tendency to an over-tense posture, she will pull her head and upper back backwards, by over-contracting the muscles of the lower back. The woman with a more collapsed posture will give up all attempt to retain her uprightness. In both cases the deep muscles in the pelvis and the muscles of the legs have to work extremely hard to maintain the balance, and there will be excessive tension in the joints, which will restrict their range of movement. The ligaments are also put under a lot of strain, because instead of doing their normal job -which is to make the joints more stable - they have to do a great deal of the work of supporting the body (which should be done by the muscles).

Unfortunately, instead of stabilizing the balance, this way of compensating creates a vicious circle of misuse. In both the over-tense posture and the collapsed posture, the lower back is allowed to curve forwards excessively, which throws the weight of the baby even more forwards. The body then has to further compensate by contracting muscles in an attempt to bring the centre of gravity back. And so it goes on, made worse by the fact that the baby meanwhile is increasing in size. This gives us the commonly accepted image of the pregnant woman having a very hollow back with the pregnancy carried far out in front. Some pregnancy books even suggest this is a physiologically natural aspect of pregnancy!


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From one perspective, the egg is a highly specialized cell with a single function—namely, the generation of a new individual. From another perspective, the egg is developmentally the least restricted cell in an animal because, if fertilized, it can give rise to every cell type in the organism. Although it is barely visible with the naked eye, the egg is very large when compared to a typical body (somatic) cell. For example, a human egg is approximately 0.13 mm in diameter, a size 10 times the diameter and 1000 times the volume of most other human body cells. The egg is large so that it can adequately nourish the embryo until a connection is made between it and the mother.

In addition to its size, there are a number of structural features specific to the egg cell. Whereas most cells have an external surface called the plasma membrane, the egg has a special structure called the outer egg coat or zona pellucida. Consisting of a jellylike extracellular matrix composed mostly of glycoprotein molecules, the outer egg coat protects the egg from mechanical damage. It is also the site of specific receptors that enable same-species sperm (and only same-species sperm) to recognize the egg and, in the presence of certain conditions, to interact with it.

When such interaction does occur—that is, when a sperm cell actually does penetrate an egg cell—cortical granules, a set of specialized secretory vesicles located in the outer area of the egg's cytoplasm, release their contents and, in so doing, immediately alter the egg's outer coat so that no other sperm will be able to fuse with the egg.