Human Reproductive System Quiz

The morula, a solid ball of cells, receives nutrients through diffusion from the surrounding fluids in the oviduct.

Capacitation is a process that allows the sperm to be ready for fertilization. It involves changes to the sperm's surface, including the removal of a protective coating and changes in the membrane that enable the sperm to bind to the egg.

Human chorionic gonadotropin (hCG) is a hormone produced by the developing placenta. It maintains the corpus luteum, ensuring a continued production of progesterone, which is crucial for sustaining the pregnancy in the early stages.

Placenta previa is a condition where the placenta is located low in the uterus, partially or completely covering the cervix.

The umbilical cord contains two arteries and one vein.

The most common site for ectopic pregnancy is the ampulla, the widest part of the fallopian tube.

The acrosome is a cap-like structure at the head of the sperm. It contains enzymes such as hyaluronidase and acrosin, which are essential for breaking down the layers surrounding the egg (corona radiata and zona pellucida).

The slow block to polyspermy involves a series of events that occur in the egg after fertilization. It begins with the entry of the sperm, followed by calcium release from the smooth endoplasmic reticulum, leading to fusion of lysosomes with the oocyte membrane. Hydrolytic enzymes are then released, breaking down the zona pellucida and ZP3 receptors to prevent further sperm penetration.

Cilia and flagella have a 9 + 2 arrangement of microtubules, which are responsible for their movement.

The corona radiata is a layer of cells that surrounds the egg. It originates from the Graafian follicle, which is a mature ovarian follicle that releases the egg during ovulation.

The outer cell mass of the blastocyst develops into the trophoblast, which will eventually form the placenta. The inner cell mass will develop into the embryoblast, which will form the embryo.

The nervous system, heart, and eyes develop first during organogenesis.

In the umbilical cord, the arteries carry deoxygenated blood from the fetus to the placenta, while the veins carry oxygenated blood from the placenta to the fetus.

The fast block to polyspermy involves a rapid depolarization of the egg's membrane, caused by the release of sodium ions (Na^+) from the rough endoplasmic reticulum. This change in membrane potential prevents further sperm from binding to the egg.

Teratogens are substances or agents that can cause birth defects. Examples include vitamin A, radiation, nicotine, cocaine, herpes virus, and thalidomide.

Elevated levels of estrogen in the mother's blood cause an increased sensitivity of the smooth muscle in the uterus to oxytocin. Estrogen also antagonizes the inhibitory effect of progesterone on uterine contractions, leading to increased uterine contractions and labor.

Mixing of maternal and fetal blood can lead to several complications, including:

1. Exchange of pathogens: This can be fatal for the fetus due to the risk of infection.

2. Rh incompatibility: If the mother is Rh-negative and the fetus is Rh-positive, maternal antibodies can attack fetal red blood cells, leading to hemolytic disease of the newborn.

3. ABO incompatibility: Although less severe than Rh incompatibility, it can cause mild problems such as jaundice.

Therefore, the correct answer is options 1 and 2.

A fertilized egg implants in the uterus and starts to develop into a blastocyst, which further differentiates into the embryo and placenta.

The zona pellucida is a glycoprotein layer surrounding the egg. It plays a crucial role in fertilization, ensuring that only one sperm fertilizes the egg, by acting as a barrier against additional sperm. It breaks down during implantation, allowing the blastocyst to attach to the uterine wall.

The germ layers are formed during gastrulation, a crucial stage in embryonic development. These layers are responsible for the formation of different tissues and organs in the body. The three germ layers are:

1. Ectoderm: Forms skin, nervous system, and some other tissues.

2. Mesoderm: Forms muscles, bones, circulatory system, excretory system, and others.

3. Endoderm: Forms digestive system, respiratory system, liver, and pancreas.

The process of differentiation is critical during embryonic development. It involves cells becoming more specialized in structure and function, giving rise to various tissues and organs. This process is regulated by a complex interplay of genetic factors and environmental cues.

Organogenesis is the process by which organs develop from the three germ layers. It is a complex and highly orchestrated process, regulated by genes and signaling molecules that work in concert to direct the development of specific tissues and organs.

The process of fertilization begins with the sperm's journey through the female reproductive tract. It involves a series of steps that include:

1. Capacitation: The sperm undergoes changes in its membrane to become capable of fertilizing the egg.

2. Acrosome Reaction: The acrosome releases enzymes that break down the layers surrounding the egg.

3. Penetration of the Egg: The sperm's head penetrates the outermost layer (corona radiata) and then the zona pellucida.

4. Fusion of Gametes: The sperm's nucleus fuses with the egg's nucleus, creating a zygote.