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:
Moth Orchid
Explanation:
The Moth Orchid is the most common type of orchid and bears the name because of its supposed resemblance to a moth in flight. Native to Southeast Asia, the Philippines, and northern Australia, the Moth Orchid isn't exactly hard to find, and it comes in nearly every colour of the rainbow.
Answer:
Physical change
Any change to the physical properties of a substance is called a physical change.
Physical changes are usually reversible as no new substance is formed. It is the same substance but with changed physical properties.
Chemical change
A change in which one or more new substances are formed is called as a chemical change.
Usually a chemical change involves a chemical reaction, which forms new products.
Example : Rusting of Iron, or burning wood.
Explanation:
have a good day <3 sorry i could answer q1 only ill think baout the others..
<span>The major difference between viruses and living cells is that viruses do not have nuclei while living cells do. A second major difference is that viruses need a host cell to survive while living cells do not. For the most part, viruses just contain genetic material (typically in the form of RNA) inside of a capsid. Living cells have many more organelles, including ribosomes and cytoplasm, which viruses lack.</span>
