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Unformatted text preview: he general transport process involved in dialysis is
diffusion; the movement of molecules from a region of
high concentration to a region of low concentration. 5. The dialysing solution runs in the opposite direction
to that of the blood (similar to countercurrent heat
exchangers) because in this way almost all of the
urea can be removed from the blood in the shortest
possible time. Further explanation: The blood at
the beginning of the dialysis column (high urea)
encounters dialysate that already contains some
urea, but there is still a concentration gradient from
blood to dialysate. By the time the blood reaches the
end of the dialysis column most of the urea has been
removed, but it encounters fresh dialysing solution
(no urea) and there is still a concentration gradient.
Having blood and dialysate running in opposite
direction maintains the concentration gradient for a
longer time. If the two fluids ran in the same direction
the concentrations would quickly equilibrate, and urea
would cease to pass into the dialysate. Female Reproductive System (page 212)
1. (a) Uterus
(b) Fallopian tube (oviduct) (e) Vagina
(f) Clitoris 2. (a) Houses developing embryo, establishes placenta.
(b) The usual place of fertilization and also conducts
the egg to the uterus.
(c) Produces ova (eggs) and female reproductive
hormones (estrogen and progesterone).
(d) Entry to uterus. Its mucus protects the uterus
from invasion by microorganisms. It is a powerful
muscle that prevents the loss of the fetus in
pregnancy. 3. (a) A = Ovary.
(c) Oogenesis (gametogenesis is also correct). 4. (a) Oocyte released: Metaphase of meiosis II.
(b) Meiosis II completed: After fertilization. The urea passes into the dialysate because there is
always less urea present in dialysate than in blood.
Therefore there is a concentration gradient for urea
between the blood and the dialysate. 4. Anatomy and Physiology 3. donor will not be avaiable when required. Life-time
dialysis is expensive, time consuming an...
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- Winter '13