</span>During erection, blood<span> flows into the spaces, causing distention and elevation of the penis. The amount of blood entering the penis can be increased by physical or psychological stimulation. As blood enters, there is a temporary reduction in the rate and volume of blood leaving the penis. The arteries carrying blood to the penis dilate; this, in turn, causes tissue expansion. The veins leading from the penis have funnel-shaped valves that reduce the outflow of blood. As the erectile tissue begins to enlarge, the additional pressure causes the veins to be squeezed against the surrounding fibrous tissue, and this further diminishes the outflow of blood. Essentially, blood becomes temporarily trapped in the organ.</span>
The penile shaft has 3 erectile columns. There are 2 corpus cavernosum and 1 corpus spongiosum. The skin is loose because those columns fill with blood and the skin will stretch and that's why it hardens. It is the changes in blood flow in the penis that results in an erection.
As a result of their surface area to volume ratio, smaller living cells are more active metabolically as transport through the cell organelles occur faster
A parasite is the one who feeds on the host and the host is the one who has to deal with the parasite. basically a parasite feeds on a animal or being so i can survive<span />
could use less heat and air conditioning, lighting, electronics in our homes. Drive gasoline cars less often, and walk more. stop buying new clothes as much, and recycling used. use renewable energy sources like wind and solar power.
