Table 1.
Measurements, and calculated volumes, surface areas, and ratios of surface area to volume (S:V) for head, midpiece, tail, and combined total of sperm cells from X. helleri (n = 6)
| Sperm cell geometry | Diameter (μm) | Length (μm) | Mean volume (V) (μm3) | Mean surface area (S) (μm2) | S:V (μm−1) |
|---|---|---|---|---|---|
| Heada | 1.28 ± 0.2 | 3.6 ± 0.4 | 4.6 | 14.70 | 3.07 |
| Mid-piecea | 0.68 ± 0.1 | 6.8 ± 0.5 | 2.5 | 14.53 | 5.88 |
| Taila | 0.24 ± 0.05 | 43.0 ± 2.2 | 1.95 | 32.42 | 16.62 |
| Totalb | 9.05 | 61.65 | 6.81 |
a
The volumes of the head, mid-piece and tail are all assumed to be cylinders.
b
Sum of the volumes and surface areas of the head, the mid-piece and the tail. Note that as long as the S:V is maintained as close to the original values as possible, any geometry can be assumed for the sperm cell—for simplicity we assumed the X. helleri can be modeled as a thin, long cylinder of length 33.3 μm and a diameter of 0.59 μm (which results in a surface area to volume ratio of 6.78 or within 0.4% of the calculated value). Also see Section 3.5.