Physical Protection:
* Amniotic sac: The fetus develops inside a fluid-filled sac called the amnion, which cushions and protects it from shocks and bumps.
* Placenta: The placenta acts as a barrier between the mother's blood and the fetus's blood, preventing harmful substances from crossing over. It also provides nutrients and oxygen to the fetus and removes waste products.
* Uterine wall: The uterine wall is a strong, muscular structure that protects the fetus from external pressures and injuries.
Immune Protection:
* Maternal antibodies: Antibodies from the mother's immune system cross the placenta and enter the fetal bloodstream, providing passive immunity to the fetus. This means the fetus is protected from some diseases the mother has been exposed to.
* Fetal immune system: The fetus develops its own immune system, which becomes more mature as the pregnancy progresses.
Other Protections:
* Hormonal regulation: Hormones produced by the mother and fetus help regulate the development and growth of the fetus and maintain a healthy pregnancy.
* Nutrient and oxygen supply: The placenta ensures a constant supply of nutrients and oxygen to the fetus, vital for its growth and development.
Important Note: While the uterus provides a safe haven for the developing fetus, it's not completely immune to threats. Factors like maternal health, nutrition, and exposure to toxins can affect the well-being of the fetus.
It's also important to remember that the level of protection varies between different species of mammals. For example, marsupials like kangaroos give birth to relatively undeveloped young, who then complete their development in a pouch.