Male Repro

• The male reproductive system consists of the production of gametes, fertilization, development and nourishment of a new individual, and the production of reproductive hormones.
• Gametes are reproductive cells, with sperm from testes and oocytes from ovaries.
• Fertilization involves the transfer of sperm from the male reproductive tract to the female reproductive tract during intercourse, and the sperm fertilizes the oocyte and implants in the uterus to become a baby.
• The female uterus houses the fetus and nourishes it until the mother gives birth, and after birth, the female reproductive system feeds the baby with milk.
• The production of reproductive hormones triggers the development of secondary male and female characteristics as an individual matures.
• Meiosis is a special type of cell division that leads to the formation of sex cells, with each gamete containing a haploid number of chromosomes (23).
• Meiosis occurs in the testes (male) and ovaries (female), with the original cell having 23 chromosomes from the mother and 23 chromosomes from the father.
• During meiosis, the chromosomes are replicated creating chromatids, identical copies of each chromosome.
• During the first division of meiosis, the chromosomes are divided into 2 and are reduced to 23 chromosomes.
• During the second division of meiosis, the chromatids are separated and produces 4 cells with each cell having half of the original chromosome number.
• During sexual reproduction, 2 gametes (egg and sperm) merge and produces an offspring, with the merging of 2 gametes taking us back to the original number of chromosomes (46).
• Each division of meiosis has a prophase, metaphase, anaphase, and telophase.
• Meiosis I produces 2 cells, each having 23 chromosomes composed of 2 chromatids joined at the centromere.
• Sustentacular cells, also known as Sertocil cells, are large and extend from the periphery of the lumen of the seminiferous tubule, nourish the germ cells and produce hormones.
• Spermatogonia are most adjacent to the basement membrane of the seminiferous tubules, divide by mitosis, and the daughter cells either produce other spermatogonia or differentiate to become the primary spermatocytes.
• Spermatogenesis is the formation of sperm cells, which occurs in the seminiferous tubule, starting around puberty, around age 12-14, when the interstitial cells increase in number and size, a lumen develops in each seminiferous tubule, and sperm cell production begins.
• Spermatids undergo structural changes, most of the cytoplasm of the spermatid disappears and it develops a head, also have a midpiece (mitochondria) and flagellum (tail) to become a mature sperm cell or spermatozoa.
• Interstitial cells are endocrine cells that are located outside the seminiferous tubules and secrete testosterone.
• Inguinal hernia is a hernia where the intestines go through the dilated inguinal, causing pain and potentially impairing blood flow to the intestine.
• Cryptorchidism is the failure of one or both of the testes to descend into the scrotum, which can cause developmental concerns due to the unfavorable temperature of the body.
• Ducts are used to transport sperm cells from the seminiferous tubules to the exterior of the body.
• Acrosome is a vesicle that contains enzyme that act on the oocyte or the eggs so that they can penetrate the surface and fertilize it.
• Both secondary spermatocytes undergo meiosis II and become two spermatids, with a total of four spermatids.
• Primary spermatocytes have 46 chromosomes, and once they complete meiosis I, they produce two secondary spermatocytes having 23 chromosomes.
• Telophase II in meiosis is when each daughter cell receives one of the chromatids from each chromosome.
• Prophase II in meiosis is when the 23 chromosomes each consists of 2 chromatids.
• The tunica albuginea is the outer part of the testes which is a thick, white connective tissue capsule.
• The seminiferous tubules are the site of sperm cell development.
• Anaphase I in meiosis is when the pairs of chromosomes are separated to each pole of the cell.
• Germ cells divide and differentiate during spermatogenesis to form sperm cells.
• The zygote develops after fertilization and develops into an embryo 3 to 14 days after fertilization.
• Fertilization is the union of sperm and oocyte.
• Telophase I in meiosis is when each daughter cell receives one of the chromatids from each chromosome.
• The embryo is 14 to 56 days after fertilization.
• Anaphase II in meiosis is when the chromatid separates on the centromere and goes away from the middle towards 2 opposite poles.
• The fetus is 56 days after fertilization.
• The testes are the primary male reproductive organ, also called as male gonads, and are oval organs about 4-5cm long.
• Metaphase I in meiosis is when the chromosomes align along the center of the cell.
• Metaphase II in meiosis is when the chromosomes align along the center, but in a single pile and not in pairs.
• The testes normally develop in the abdominal pelvic cavity but eventually descend to the inguinal canal to the scrotum during the 7th-8th month of gestation.