4 is the correct answer hope you get it right!!!
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:
1/2 of a radioactive substance will remain after 3 half lives.
Answer:
Explanation: Collenchyma cells are elongated cells with unevenly-thickened walls. They provide structural support, mainly to the stem and leaves.
Answer:
B. analyzes sensory information, stores information, makes decisions
Explanation:
The receptors sense the changes or stimuli. The sensory neurons of the nervous system deliver this sensory information to the processing center, that is, to the central nervous system. The central nervous system serves to store the information and analyze it to determine the best suitable response. The ability of the nervous system to the store and process of sensory information to make the effector organs to exhibit the best response represents its integrative function.
