In most living animals, egg cells are vastly larger than sperm cells. In humans, for example, a single egg is 10 million times the volume of a sperm cell.
In humans, they are several times larger than a typical body cell and about 10,000 times larger than sperm cells. There's a reason why egg cells, or oocytes, are so big: They need to accumulate enough nutrients to support a growing embryo after fertilization, plus mitochondria to power all of that growth.
The egg is among the largest cells in an organism, while the sperm (spermatozoon, plural spermatozoa) is often the smallest.
The female egg cell is bigger than you think
Compared to the other human cells, egg cells are huge. They are 100 microns in diameter (that's a millionth of a metre) and are about as wide of a strand of hair. That may sound small, but no other cell comes close to being that large.
In general, eggs are typically spherical or ovoid, with a diameter of about 0.1 mm in humans and sea urchins (whose feeding larvae are tiny), 1 mm to 2 mm in frogs and fishes, and many centimeters in birds and reptiles (Figure 20-19).
The fact is that egg cells are about 4 times the size of skin cells—and about 20 times the size of sperm!
When your follicles have reached around 18-20mm in diameter they are deemed ready for egg collection. You'll be given a hormone trigger injection to stimulate your follicles to release the mature eggs that have been prepared in your follicles.
The embryo is about 1/2-inch and has a four-chambered heart and nostrils. Electrical activity begins in the developing brain and nervous system. The brain continues to form.
Egg size matters more in some baking recipes than others. One good rule of thumb to keep in mind: The more eggs in a recipe, the more size will have a significant impact. As you add more eggs, that difference in weight—~2 ounces for a large compared to ~2 ¼ ounces for an XL and ~2 ½ for a jumbo—is amplified.
Jumbo: Jumbo eggs refer to especially large eggs that measure 30 ounces per dozen or 2.5 ounces per egg. These are relatively rare, but not as unusual as peewee eggs.
The basis for the Shettles method starts with the fact that X-chromosome sperm (female) are on average slightly larger and thus slower moving than Y-chromosome sperm (male).
If two sperms fertilize an egg, things go wildly wrong, yielding a triploid offspring with 69 chromosomes with an extra set in addition to the normal maternal/paternal pair. An egg fertilized by three sperms receives two extra chromosome sets, resulting in a quadruploid individual with 92 chromosomes.
Occasionally, two sperm are known to fertilize a single egg; this 'double fertilization' is thought to happen in about 1% of human conceptions. An embryo created this way doesn't usually survive, but a few cases are known to have made it — these children are chimaeras of cells with X and Y chromosomes.
In a healthy and normal-sized ovary, the number of egg reserves are likely sufficient. However, the egg size also matters in conceiving because it has to be of the right size for fertility. The minimum egg size to get pregnant is 18-20mm (1.8 – 2.0cm), otherwise, the normal egg size is 22 to 24mm (2.2 – 2.4cm).
Usually once the follicle is greater than 24 mms, the egg within is overmature and therefore no longer viable. Ovulation may occur but that is the main problem. Also, it is highly likely that these follicles will turn cystic (persist) and have to be suppressed with birth control pills.
In animals, female gametes are called ova or egg cells, and male gametes are called sperm. Ova and sperm are haploid cells, with each cell carrying only one copy of each chromosome.
Two large eggs: If your recipe requires two large eggs, you can substitute two eggs of either medium, extra-large or jumbo size. The only amount adjustment necessary is if you have small eggs instead, in which case, you should use three.
Hen body weight is the key to increased egg size. Bigger hens produce larger eggs than smaller hens and bigger breeders produce larger eggs than smaller breeders. For modern White Leghorns, rearing pullets that weigh at least 1.35 kg (3.0 lbs.) at the start of egg production will increase both hen weight and egg size.
Large: 25.5 ounces (about 2.125 ounces per egg) Extra-Large: 26.5 ounces (about 2.20 ounce per egg) Jumbo: 30 ounces (about 2.5 ounce per egg)
If she has sex five days before she ovulates, her probability of pregnancy is about 10 percent. If she has sex on the day of ovulation, or the two days before, the chance of getting pregnant is around 30 percent. These are average figures and depend on a woman's age.
Of those fertilised eggs, around 15% will be lost before implantation begins. Of those which begin to implant, only about half will implant successfully. Of the half which do implant successfully (as shown by detectable HCG in the woman's urine), between one third and one half will be lost at the time of the menses.
There are two good ways to measure egg count: an antral follicle count and an AMH (anti-Müllerian hormone) test. During an antral follicle count, a doctor uses ultrasound to count the visible follicles. Each follicle contains an immature egg that could potentially mature and ovulate.
Symptoms and signs of hyperovulation
Hyperovulation can't be easily detected using ovulation kits. The only way to tell for sure if you're hyperovulating is through an ultrasound. A sign of hyperovulation could also be more white, stretchy vaginal discharge.
Because many eggs start to develop but die off before being ovulated, a woman goes through roughly 300,000-400,000 eggs in their reproductive years, but only ovulates 300-400 eggs. The average woman runs out of eggs and starts menopause around the egg of 52.