erection

e·rec·tion   (ĭ-rěk'shən)    n.   The act of erecting. Something erected; a construction. Physiology The firm and enlarged condition of a body organ or part when the erectile tissue surrounding it becomes filled with blood, especially such a condition of the penis or clitoris. The process of filling with blood.

Main Entry: erec·tion
Pronunciation: i-'rek-sh&n
Function: noun
1 : the state marked by firm turgid form and erect position of apreviously flaccid bodily part containing cavernous tissue when that tissue becomes dilated with blood
2 : an occurrence of erection in the penis or clitoris

erection e·rec·tion (ĭ-rěk'shən)
n.

1. The firm and enlarged condition of a body organ or part when the erectile tissue surrounding it becomes filled with blood, especially such a condition of the penis or clitoris.

2. The process of filling with blood.

erection

enlargement, hardening, and elevation of the male reproductive organ, the penis. Internally, the penis has three long masses of cylindrical tissue, known as erectile tissue, that are bound together by fibrous tissue. The two identical areas running along the sides of the penis are termed corpora cavernosa; the third mass, known as the corpus spongiosum, lies below the corpora cavernosa, surrounds the urethra-(a tube that transports either urine or semen),-and extends forward to form the tip (or glans) of the penis. All three masses are spongelike; they contain large spaces between loose networks of tissue. When the penis is in a flaccid, or resting, state, the spaces are collapsed and the tissue is condensed. During erection, blood 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

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