No, she is not. The muscle of the uterine wall is smooth muscle, which we cannot voluntarily control. By pushing, she is using her abdominal wall skeletal muscles to help expel the baby.
Keratin defects could result in a fragile epidermis, a loss of the barrier to infection, deformed nails, and frayed hair, since the structures of the epidermis, nails, and hair are all highly dependent on keratin.
With lack of exercise, there is little of this periodic flushing of the cartilage with fresh tissue fluid. Chondrocytes die from lack of nutrition and oxygenation and from accumulation of metabolic wastes. Without chondrocytes, maintenance of the cartilage matrix cannot be sustained, and the cartilage degenerates.
The function of the alveoli is to allow O2 and CO2 to be exchanged quickly between the blood and inhaled air. Quick gas exchange requires a minimal barrier between the blood and air, which is why the alveolar epithelium is so thin. If it were as thick as the epithelium of the upper airway, gases would diffuse so slowly that blood would leave the alveoli without having discharged enough CO2 or picked up enough O2 to support the body’s needs.
Mast cells respond to injury by releasing histamine and heparin. Histamine dilates the nearby blood vessels and heparin inhibits blood clotting. Both of these effects promote increased blood flow to the area of injury, and with this come white blood cells, antibodies, oxygen, organic nutrients, and other agents that fight infection and promote tissue healing.
