# Surface area and volume of spermatozoa

Range | 106 μm^2 surface area: 22.2 μm^3 volume |
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Organism | Human Homo sapiens |

Reference | Curry MR, Millar JD, Tamuli SM, Watson PF. Surface area and volume measurements for ram and human spermatozoa. Biol Reprod. 1996 Dec55(6):1325-32. link p.1327 right column top, 2nd and bottom paragraphs PubMed ID8949890 |

Method | Spermatozoon surface area was measured by micrometric methods and was also measured from electron micrographs using a stereological method. Micrometric methods gave surface area above. Stereology methods gave surface area of 106.5µm^2. Sperm volumes were estimated by stereology and by radiolabel volume exclusion methods. |

Comments | P.1327 left column bottom paragraph to right column bottom paragraph: "Human spermatozoa: Ten measurements were made from single ejaculates for each of seven different donors, and areas were calculated using van Duijn's formula [ref 8] (Table 2). The overall mean value for projected head area was 20.5±2.3µm^2. If the flagellar area is modeled as above using published values for midpiece and principle piece dimensions [ref 4], an estimate of 65µm^2 for flagellar area is obtained, giving a total surface area of 106µm^2 using the above model. Stereology: Surface Area-Estimation of surface density requires that sperm profiles are randomly arranged in each electron micrograph. However, for spermatozoa pelleted in the capillary tubes there was a tendency for the long axes of the sperm heads to align parallel to each other (Fig. 2), which would, for instance, result in a greater number of interceptions being recorded with use of a grid with vertical lines than with one with horizontal lines. To overcome this problem it is necessary to use isotropic probes. For this study, counts were made using a test grid consisting of a series of semicircular test lines (Fig. 3a). With use of this grid, the mean (±SEM, n = 6) ram sperm surface area was calculated as 142.3±10.8µm^2 (Table 3). For human spermatozoa, the equivalent estimate was 106.5 ± 6.2µm^2 (Table 3). Volume: Volume density was calculated from point counts using either the ends of the semicircular test lines (Fig. 3a) or a grid composed of squares with intersections used as test points (Fig. 3b), resulting in grids with either 84 or 1271 test points, respectively. For ram spermatozoa, mean sperm volume (±SEM, n = 6) using the 84-point grid was 30.9±2.2µm^3 and using the 1271 point grid was 31.7±2.2µm^3 (Table 4). A paired t-test showed these values to be not significantly different (t(5) = 1.01, p = 0.357), and the overall mean value was 31.3±3.5µm^3. For human spermatozoa, the respective values were 24.2±0.9µm^3 and 20.1±1.3µm^3 (Table 4). Because of the small sample size, these results were tested by the nonparametric Wilcoxon test and found to be not significantly different, the overall mean value was 22.2±1.2µm^3." |

Entered by | Uri M |

ID | 106852 |