LC-Article

Sperm Article (1) What is a germ cell? (male germ cell and female germ cell) Germ cells are all reproductive cells with 23 chromosomes produced through the process of meiosis. (2) Compare the size of a sperm to an egg. Sperm: 5 microns, or two ten-thousandths of an inch Egg: 30 times the width of the sperm's head (3) Compare the number of eggs produced by human females to the number sperm produced by human males. Eggs Produced: 1 million: 500 ripen Sperm Produced: 12 trillion in a life time; 4 million per hour (4) Describe semen. What is the purpose of semen? Semen is a "viscous mix of sugars, citric acid and other ingredients designed to pamper and power the sperm cells and prepare them for difficult times ahead." (Angier) (5) What can be wrong with sperm? What percentage of sperm are usually normal? Sperm often have two heads or two tails, or no tails at all. Only 15% of an average man's sperm is usable. (6) Where do sperm develop? Why could a fever disrupt sperm production for months? Sperm develop in the testicles that are outside of the body cooling to 2 degrees cooler than the rest of the body. A fever can heat even the testicles making sperm production difficult. (7) Describe in detail the three parts of a sperm cell. The sperm cell consists of: - Head containing the 23 chromosomes and the enzymes to enter the egg - Mid piece containing the mitochondria to propel the sperm through the fallopian tubes. - Tail moving the head one twelfth of an inch per minute (8) How do the sperm react to being in the female reproductive tract? How do they know where to go? The sperm swim straight ahead until the sense signals from the vaginal and cervical mucus. They then follow these signals to the main egg. (9) How is the egg only fertilized by one sperm? Only a dozen or so sperm reach the outer layer of the egg and their proteins have to match up perfectly to succeed. The egg only chooses the one perfect sperm.