CBSE Class 10 Answered
Sex is the phenomenon by which whether the newly born is a male or female is identified.
Uterus
- Uterus is a part of female reproductive system. It is a hollow pear-shaped, muscular organ.
- It is situated in the pelvic cavity between the urinary bladder and the rectum.
- The lower narrow part is of the uterus is the cervix.
- The internal wall of the uterus is lined by tissue layers. The innermost layer is called endothelium which is lined by the ciliated epithelium.
- It protects and nourishes the developing embryo.
Sperm:
Sperm male reproductive cell or male gamete.
Structure of sperm:
A. Acrosome:
- It is located in the head region of the sperm.
- It contains an enzyme ‘hyaluronidase’.
- This enzyme facilitates entry of the sperm into the egg by dissolving the wall of the ovum.
B. Nucleus:
- Nucleus of the sperms contains genetic material (22 + X/22 + Y chromosomes).
- During fertilization, the nucleus combines with the ovum containing 22 + X chromosome, thus restoring the normal number of 23 pairs.
C. Mitochondria:
- The mitochondria contained in the middle piece.
- It provides energy (ATP) for the activity of the sperm to swim.
D. Tail:
- The tail part helps the sperm for its forwards movement to cross the passage of the cervix