Question

1. Discuss the chemical constituency of the seminal plasma and the role each component plays in supporting successful fertilization.

2. What barriers are faced by sperm in the female reproductive tract?

3. Describe the process of capacitation – what changes are made to the sperm during this period and what substances contribute to these changes?

4. During fertilization, changes are made to the sperm and to the oocyte; describe these changes and their consequences

Answer 1

1.Seminalplasma contains secretion of Seminal vesicles , prostate ,bulbourethral glands.

- The major portion of seminal secretion contains fructose. Fructose constitute the main energy sources of sperm cells.

- Prostatic secretion contains acid phosphatase, fibrinolysin, zink. Zink help to stabilize the DNA-containing chromatin in the sperm cells.

- Secretion of bulbourethral glands include galactose and mucus. Mucus serve to increase the mobility of sperm cells in the vagina and cervix.

2. Sperms are deposited in the anterior vaginal wall. They have to face the immune response and vaginal acidity First.

- cervical mucus then filters out sperm with poor morphology and motility. Hence minority of the ejaculated sperms eter the cervix. Then these sperm swim through the utero tubal junction to reach the fallopian tube.

3. Mammalian sperm must undergo a series of biochemical and physiological modification, collectively called capacitation, in the female reproductive tract prior the acrosome reaction. A series of signalling event causes actin polymerization an essential process for the development of hyperactivated motility which is a necessary for successful fertilization. These signalling event include protein kinase mediated regulation of intracellular Ca+ during capacitation.

4. During fertilization , a sperm come in contact with the Zona pellucida layer of ovum and induce changes in the membrane that block entry of other sperms. Thus this ensures that only one sperm can fertilize an ovum.

- The secretion of the Acrosome help the sperm enter into the cytoplasm of the ovum through zona pellucida and plasma membrane. This induces the completion of the meiotic division of secondary oocyte. Soon the haploid nucleus of sperm and ovum are fused and form a diploid zygote.

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