HUMB1001 Lecture 11: 11. Male Reproductive Anatomy _ Physiology
Male Reproductive Anatomy & Physiology
Cell Replication and Gametogenesis
Mitosis
❖ Somatic cells of the body
❖ Exact genetic copy
❖ Must replicate DNA first
❖ Results in 2 diploid cells
o full genetic compliment
o 23prs (22prs Autosome, 1pr Sex)
❖ Divided into stages
o prophase, metaphase, anaphase, telophase
❖ Used for replacement, proliferation
Meiosis
❖ Two consecutive cell divisions with only one lot of DNA
replication
o Meiosis I and Meiosis II
❖ Produces 4 cells each with half the genetic material
o haploid cells – 23 chromosomes
o 22 autosomes
o 1 sex chromosomes (X or Y)
o Each cell is unique due to recombination of genetic
material
❖ For reproduction
o When 2 gametes (haploid) unite produce one diploid
cell
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Gametogenesis
❖ Process by which we produce haploid cells called gametes
o Ova – females
▪ Therefore, called Oogenesis
▪ before birth -> puberty to menopause
▪ Occurs in the ovaries
o Spermatozoa - males
▪ Therefore, called Spermatogenesis (total 74 days)
▪ Occurs in the testes (seminiferous tubules, 50 days)
▪ Includes Spermiogenesis (approximately 24 days)
❖ Uses both
o Mitotic divisions
▪ for replacement and proliferation
o Meiotic divisions
▪ to make haploid cells (cells with half the genetic content)
Spermatogenesis
• Spermatogenesis, or sperm formation, is the sequence of events that occur in the
seminiferous tubules (located inside the testes) to produce male gametes, sperm or
spermatozoa
• Process begins at ~14 years old and con3nues throughout life
• Males produce around about 400 million sperm per day
• Each sperm carries a haploid amount of genetic information containing both
maternal and paternally derived genes from the future grandparents of the offspring
• Spermatogenesis: production of fully functional sperm from stem cells
• Spermiogenesis: transforma3on of a spermatid into a sperm
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Spermatogenesis
• Stem cells, called Spermatogonia are the outermost cells in the seminiferous
tubules, in contact with the basal lamina
• The spermatogonia divide and form stem cells by mitosis up un3l puberty
• At puberty, each spermatogonium division results in two dis3nc3ve daughter cells,
Type A, and Type B
• Type A cells remain at the germinal layer to produce more stem cells
• Type B cells get pushed towards the lumen, where it becomes a primary
spermatocyte
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Results in 2 diploid cells full genetic compliment: 23prs (22prs autosome, 1pr sex) Divided into stages: prophase, metaphase, anaphase, telophase. Two consecutive cell divisions with only one lot of dna replication: meiosis i and meiosis ii. Produces 4 cells each with half the genetic material: haploid cells 23 chromosomes, 22 autosomes, 1 sex chromosomes (x or y, each cell is unique due to recombination of genetic material. For reproduction: when 2 gametes (haploid) unite produce one diploid cell. Uses both: mitotic divisions for replacement and proliferation, meiotic divisions to make haploid cells (cells with half the genetic content) Spermiogenesis: transforma3on of a spermatid into a sperm. Type a, and type b: type a cells remain at the germinal layer to produce more stem cells, type b cells get pushed towards the lumen, where it becomes a primary spermatocyte. We now enter the phase of spermiogenesis, forming functional sperm cells (spermatozoa) from spermatids.
