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:
The average distance is 16,000 km
Converging rate is 10 cm/year
1 km = 100,000 cm
= 16,000 × 100,000/10 cm/year
= 160,000,000 years
It will then take 160 Million years to collide.
Answer:
Microtubules have shapes like a spindle and are arranged to form centrosome and a cluster of such microtubules form centriole.
Explanation:
Microtubules are seen in eukaryotic cells to give shape and structure to the cells and they form part of the cytoskeleton. They are known to grow long and are dynamic. Centrosomes are known to be main microtubule that are found in animal cells. They are organelles that are made from the arrangement of clusters of microtubules. The centrioles are organized microtubules that actually help to serve as skeletal system of the cell. These centrioles help to determine the locations of the nucleus.
