Question

5) What is the path that a typical spermatogonium would take to fertilize an oocyte? Include at least 4 structures for the male and at least 4 structures for the female. Name each step like you would give someone directions (College Drive, to Atlanta street, through downtown, to Highway 41…) (organs, openings, regions of the organ, etc) 8pts n

Answer 1

Answer:

Path followed by spermatogonium to fertilize an oocyte is listed below:

1. Capacitation of Sperm: The sperm which is ejaculated will not be able to fertlize the oocyte. In order to fertilize the oocyte, they will go a set of changes which is known as capacitation. Process of capacitation involves the adherent seminal plasma protein removal and reorganizing the proteins and lipids present in the plasma membrane. This process also involves extracelular Calcium influx with increased cyclic AMP and decreased intracellular pH. This process basically occurs when the sperm is present in the female reproductive tract for sometime (which they usually do during gamate transport).

2. Binding of Sperm to Zona Pellucida: After the sperm undergoes the process of capacitation, it binds to zona pellucida. Binding is a ligand receptor interaction where carbohudrate groups which is present on zona pellucida glycoproteins functions as receptor for sperm.

3. The Acrosome Reaction: This reaction helps the sperm to pass through zona pellucida layer. The protein which acted as a sperm receptor lead to various changes which causes fusion between the plasma membrane and acrosomal membrane. This fusion of me membrane leads to release of acrosomal enzyme from sperm head. As this reaction progresses, the more of plasma membrane and acrosomal membarne gets fused. When sperm crosses zona pellucida, the entire head of sperm till acrrosomal membrane is stripped off.

4. Penetration of the Zona Pellucida: The two factors which helps sperm to cross the layer of zona pellucida are :

• Enzymes which digests zona pellucida
• Motility of sperm

5. Binding of Sperm to Oocyte: After the sperm enters zona pellucida, it binds to the plasma membrane of the oocyte and leads to fusion with plasma membrane. A type of protein called fertilin, present in the sperm, binds with the protein present in the plasma membrane of oocyte and that leads to initiation of fusion.

6. Activation of Egg and the Cortical Reaction: when sperm binds to oocyte, a number of physical and metabolic changes occurs in the oocyte which is called egg activation.During cortisol reaction, Cortisol granules which contains various enzymes and proteases diffuses in zona pellucida layer which leads to egg exocytosis.

Structures of male reproductive system are:

1. Testes
2. S crotum
3. P enis
4. Epididymis
5. Vas deferens
6. Prostate
7. Seminal vesicles.

Structures of female reproductive system are:

1. Uterus
2. V agina
3. Fallopian tubes
4. Ovaries.