Answer:
When you sit on a plane for 6 hours without moving, blood accumulates in your veins, and the moment you get up, gravitational forces affect venous return, cardiac output, blood pressure, and venous pressure. That way, when you're sitting on a plane, the gravitational force is the same at the upper and lower extremities, such as the chest, abdomen, and legs, causing venous blood pressure and volume to be evenly distributed throughout the body. However, when one gets up, one becomes dizzy because of abnormal regulation of blood pressure. This is because gravity causes blood to accumulate in the lower extremities (veins of the legs and trunk). This lowers the blood pressure and the blood that the heart pumps. By causing blood to accumulate in the lower extremities, and as venous compliance increases, the veins expand with blood that causes the volume of blood to shift in the veins. This increases the volume and venous pressure in the lower extremities when standing. And the volume of thoracic venous blood is less and less central venous pressure. This leads to a decline in stroke volume. Cardiac output and mean arterial pressure also decrease as left ventricular stroke volume decreases, reducing pulmonary venous return. Decreased standing blood pressure, referred to as orthostatic or postural hypotension. Thus, lowering blood pressure decreases cerebral blood flow, which means less range of blood in the brain causing dizziness.
Explanation:
Answer:
Homeostasis is the ability to maintain a relatively stable internal state that persists despite changes in the world outside. All living organisms, from plants to puppies to people, must regulate their internal environment to process energy and ultimately survive.
Answer:
Iraq will have to massively reduce the birth rate to achieve a zero growth rate. In the middle east, there is more sexual freedom which may cause sexual education to be useless. Iraqi government would most likely have to give widespread contraception to its citizens.They would either have to lower birth rates or increase death rates. It would be more practical for the Iraqi government to provide contraception's and sexual education among its citizens to decrease birth rates.
Explanation:
Between 15,000 and 25,000 years ago.
