An increase in volume DECREASES the pressure in the chest (pressure and volume vary inversely when temperature is held constant -- Boyle's law). Gas can only flow from an area of higher pressure to an area of lower pressure. It can't go uphill -- ever. It can only go from high to low pressure. When the diaphragm and intercostals contract, the diaphragm flattens and the rib cage rises. That increases the volume of the chest. That increase in volume decreases the pressure inside the chest (temperature is held constant -- because the temperature of the chest cavity does not change appreciably. It remains at body temp.). Air then flows from the area of higher pressure (atmospheric) to lower pressure (intrathoracic). That continues until the pressures are equal.
When the diaphragm and intercostals relax, the chest cavity decreases in size, the pressure increases to above atmospheric, and gas flows again from the area of higher pressure (intrathoracic) to lower pressure (atmospheric) until they are again equal.
It has nothing to do with the concentration of oxygen. You can ventilate a lung with ANY gas. It has to do with the change in pressure and only the change in pressure -- which is a function of the volume of the chest cavity.
I believe it is the ascending loop of henle. In the ascending portion, the loop becomes impermeable to water and instead the cells of the loop, actively reabsorb the solute; thus water is not reabsorbed but ions are readily reabsorbed. As the ions are reabsorbed the concentration becomes more and more hypotonic until it reaches 100-150 mOsm/L. Therefore, the ascending loop is called the diluting segment of the nephron due to its ability to dilute the fluid in the loop from 1200 to 100 mOsm/L.
Sex linkage genes are genes that are expressed together with sex genes, for example hemophilia which is linked on the X- gene. Genotype is the genetic make up of an individual. Females can be carriers, normal or have the disorder unlike males who cant be carriers since they there is no 2nd chromosomes to mask the first chromosome. The Genotype of career female will be XMXm
