Let´s start to study reproduction.
Living organisms reproduce sexualy or asexualy. Therefore, we say that there are two types of reproduction.
- Act: Use information from the text book to build a comparison table between sexual and asexual reproduction.
Humans reproduce sexualy.
2. Watch this video to learn about the MALE REPRODUCTIVE SYSTEM.
3. Act: Summarize the functions of each of the organs which are part of the male reproductive system. Take a look at THESE SLIDES !
Penis: This is the male organ used in sexual intercourse. It has three parts: the root, which attaches to the wall of the abdomen; the body, or shaft; and the glans, which is the cone-shaped part at the end of the penis. The glans, also called the head of the penis, is covered with a loose layer of skin called foreskin. The opening of the urethra is at the tip of the penis. The glans of the penis also contains a number of sensitive nerve endings. The penis delivers semen to the female during intercourse and has the urethra, which is used to transport semen and urine.
Testicles: these are oval organs that lie in the scrotum Men have two testes. The testes are responsible for making testosterone and for generating sperm.
Scrotum: This is the sac of skin that hangs behind and below the penis. It contains the testicles (also called testes), as well as many nerves and blood vessels. The scrotum acts as a climate control system for the testes. For normal sperm development, the testes must be at a temperature slightly cooler than body temperature.
Urethra: the tube that carries urine from the bladder to outside of the body. It has the additional function of ejaculating semen when the man reaches orgasm.
Bulbourethral glands: pea-sized structures located on the sides of the urethra just below the prostate gland. These glands produce a slippery fluid that serves to lubricate the urethra and to neutralize any acidity that may be present due to residual drops of urine in the urethra.
Prostate gland: The prostate gland is a structure that is located below the urinary bladder in front of the rectum. The prostate gland contributes additional fluid to the ejaculate. Prostate fluids also help to nourish the sperm. The urethra runs through the center of the prostate gland.
Epididymis: a long tube that rests on the backside of each testicle. It transports and stores sperm cells that are produced in the testes. It also is the job of the epididymis to bring the sperm to maturity, since the sperm that emerge from the testes are immature and incapable of fertilization.
Seminal vesicles: pouches that attach to the vas deferens near the base of the bladder. The seminal vesicles produce a sugar-rich fluid (fructose) that provides sperm with a source of energy to help them move. The fluid of the seminal vesicles makes up most of the volume of a man’s ejaculatory fluid, or ejaculate.
Ejaculatory ducts: These are formed by the fusion of the vas deferens and the seminal vesicles. The ejaculatory ducts empty into the urethra.
4. State the components and the function of semen.
Semen is a greyish white bodily fluid that is secreted by the gonads of male animals. It carries sperm or the spermatozoa and fructose and other enzymes that help the sperm to survive to facilitate successful fertilization.
The semen has:
- ascorbic acid
- blood group antigens
- citric acid
- vitamin B12
- uric acid
- lactic acid
- other nutrients
Its function is to unite one half of the man’s DNA with one half of the woman’s, creating a complete set of DNA in the fertilized egg, which grows into a human fetus.
5. Make a large labelled drawing of a sperm cell and state how the structure is adapted to its function. (Do not add a picture).