Human Reproductive System

Gametes are the specialized reproductive cells (sperm and egg) involved in sexual reproduction. The zygote is formed after fertilization, embryo is a later developmental stage, and ovaries are organs that produce eggs.

Tubal ligation involves blocking or sealing the fallopian tubes to prevent the egg from meeting sperm, thus preventing fertilization.

The fusion of sperm and egg forms a zygote, which is the single diploid cell that results from fertilization and contains genetic material from both parents.

Seminal vesicles produce seminal fluid, which makes up about 60-70% of semen volume and provides lubrication for the male reproductive ducts. The testes produce sperm, vas deferens transports sperm, and scrotum protects the testes.

All three methods can prevent sperm entry: mechanical methods like condoms (physical barriers), surgical methods like vasectomy/tubectomy, and chemical barriers like spermicides. The question asks about preventing entry, and all these contraceptive methods achieve that.

The vagina is part of the female reproductive system, while vas deferens, seminal vesicle, and epididymis are all components of the male reproductive system that handle sperm production, maturation, and transport.

Fertilization occurs in the fallopian tube (specifically the ampulla region), where sperm meets the egg after ovulation. The uterus is where the fertilized egg implants, ovaries produce eggs, and vagina is the birth canal.

Spermatogenesis (sperm production) requires a temperature 2-3°C lower than normal core body temperature (37°C). The scrotum's location outside the abdominal cavity maintains this cooler temperature, which is essential for proper sperm development and viability.

The urethra is the common passage for both urine (from the urinary bladder) and semen (containing sperms) in males. During urination, only urine flows through the urethra, while during ejaculation, only semen is expelled - these processes cannot occur simultaneously due to sphincter control.

DNA is the genetic material that carries all hereditary information from one generation to the next. During reproduction, DNA is copied and passed to offspring, ensuring continuity of species characteristics.

The acrosome is the part of the sperm containing proteolytic enzymes to digest the zona pellucida. It is exposed by the process of capacitation. Then, under the influence of substances released by corona radiata cells, it releases its proteolytic enzymes and penetrates the oocyte.

The ampulla is the second portion of the fallopian tube. It is an intermediate dilated portion, which curves over the ovary. It is the most common site of mouse and human fertilisation.

penis

Orchitis is the medical term for inflammation of the testes. The suffix '-itis' indicates inflammation, while 'orch-' refers to the testis (from Greek 'orchis'). This condition can be caused by bacterial or viral infections, with mumps being a common viral cause. The other options refer to inflammation of different anatomical sites: peritoneum (peritonitis), skin (dermatitis), and cartilage (chondritis).

As a consequence of stimulation with luteinizing hormone the interstitial cells (Leydig) secrete testosterone into the intertubular tissue, where it is absorbed by blood vessels, lymphatics, and the seminiferous tubules.