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:
<span>Epithelial and connective tissues combine to form four types of membranes: mucous membranes (epithelial tissues are moist), serous membranes (line cavities that are not open to the outside environment), cutaneous membranes (skin that covers the surface of the body), and synovial membranes (produce synovial fluid).</span>
Answer:
recombinant DNA
Explanation:
In molecular biology, recombinant DNA molecules are genetic sequences formed by combining DNA material from different sources (i.e., organisms, populations, species, etc). Proteins produced from DNA recombinant molecules are known as recombinant proteins. Molecular cloning is the most widely used technique in molecular biology in order to produce recombinant DNA molecules. In this technique, a cloning vector such as, for example, a plasmid of a bacterium, is used to insert a foreign DNA fragment into another cell which is then expressed in the host cell.
Gulls, crows and herons are all opportunists. They'll eat just about anything that they can get their beaks on. That includes fiddler crabs.
