1.Red blood cells carry nutrition and oxygen through the capillaries to the tissues. 2. Oxygen is inhaled from the atmosphere to alveoli. 3. Oxygen diffuses into the pulmonary capillaries carried by hemoglobin through the systemic capillaries to the cells. 4. Hemoglobin gives up oxygen and picks up carbon dioxide by diffusion.
Pre-menstrual symptoms (PMS) are the symptoms that a woman may experience one or two weeks before her period begins. PMS is more common in women of age group 30 to 40. About 80% of women experience mild or severe premenstrual symptoms before each period.
Before you have your period your body is secreting higher levels of the hormone progesterone. This hormone signals your body to start shedding some of the vaginal lining. It is possible that some amounts of tissue are shed before you experience your period, due to the high amount of progesterone that is in the body.