Q.Describe the structure of the human ovum with a neat labelled diagram.

Step 1. The human ovum is microscopic but is the largest cell in the human body; it is alecithal (essentially no yolk) and non-cleidoic (no shell).

Step 2. At its centre is the ooplasm (the ovum's cytoplasm), containing a large nucleus called the germinal vesicle.

Step 3. Moving outward from the ooplasm, the ovum is wrapped by three coverings: first a thin, transparent inner vitelline membrane; then, separated from it by a narrow perivitelline space, a thick middle layer called the zona pellucida (the layer a fertilising sperm must digest through); and finally an outer thick coat of retained follicular cells called the corona radiata. …

Describe the ovum from the centre (ooplasm/nucleus) outward through i …

• Listing the coverings in the wrong inside-to-outside order (the zona pellucida is …