What is the Difference Between Avian and Mammalian Reproductive System?

The avian and mammalian reproductive systems have several key differences. Some of the main distinctions include:

1. Fertilization and development: In the avian reproductive system, internal fertilization occurs, but the ovum develops and survives outside the mother's body. In contrast, mammals directly give birth to offspring, with the fertilization of the ovum and development of the embryo taking place inside the mother's body.
2. Ovaries and oviducts: Female birds have only a single left ovary and oviduct, while mammals have two ovaries and oviducts.
3. Yolk production: Birds produce large yolk-filled eggs, with the precursors of the yolk being synthesized by the liver. In mammals, nourishment of the embryo occurs through the placenta.
4. Post-birth care: Mammals usually feed their young with milk produced in the mammary glands, while birds feed their young through regurgitation.
5. Ovary structure: The avian ovary is not as compact as the mammalian ovary, but it does have a cortex and a poorly defined medulla.
6. Shell gland: In birds, the shell gland is essentially the avian uterus but does not allow for ova implantation.
7. Oviduct structure: The avian oviduct is divided into the infundibulum, the magnum, the isthmus, and the shell gland. The infundibulum is the extension of the oviduct with a vascularized mucosa lined by. The magnum deposits the egg white and is lined by ciliated and non-ciliated columnar cells. The lamina propria contains branched tubular glands. The isthmus is responsible for formation of the shell membranes and is similar in structure to the.

In summary, the avian and mammalian reproductive systems differ in terms of fertilization, development, ovary and oviduct structure, yolk production, post-birth care, and other reproductive organs.

Comparative Table: Avian vs Mammalian Reproductive System

The key difference between avian and mammalian reproductive systems lies in the development of the offspring. In avian reproduction, the ovum develops and survives outside the mother's body, whereas in mammalian reproduction, the fertilization of the ovum and development of the embryo take place inside the mother's body. Here is a table comparing the main differences between avian and mammalian reproductive systems:

Despite these differences, both avian and mammalian reproductive systems share some common features. For example, both systems have primary sex organs involved in sexual characteristics development, and both males and females possess testes and ovary, respectively.