BIOM1060 Lecture Notes - Male Reproductive System, Chromosome, Conceptus
BIOM1060 24/04/18
CONCEPTION AND FERTILISATION PHYSIOLOGY
Terms
- Pregnancy: period from fertilisation to birth
- Conceptus: developing offspring
- Gestation period: time from last menstrual period until birth (~280 days)
- Zygote: fertilised ovum (initial embryo)
- Embryo: conceptus from fertilisation to 8 weeks gestation
- Foetus: conceptus from 9 weeks to birth
Fertilisation
- Union of male and female gametes
- Involves fusion of genetic material contained within sperm and oocyte to form a zygote
- Conception normally takes place in ampulla of fallopian tube
- Fertilised ovum continues to uterus where implantation occurs and conceptus continues
Fertilisation vs conception
Conception: creation of a new human
Fertilisation: union of sperm and egg
Requirements for fertilisation
- Sperm must reach ovulated oocyte
o sperm viable for 24-48hrs after ejaculation, oocyte viable for 12-24hrs
- Coitus must occur no more than 2 days before or 24 days after ovulation
- Must be sufficient quality and quantity of sperm
- Sperm must be transported appropriately from male reproductive system and deposited
within female genital tract near cervix within appropriate time period
- Fallopian tube must be patent (open and unobstructed)
- Penetration of sperm into oocyte
Reproduction and conception
- Most cells in body have 46 chromosomes (23 pairs)
o diploid chromosomal number (2n): one maternal, one paternal (homologous
chromosomes)
- Gametes have only 23 chromosomes
o haploid chromosomal number (n): only one member of homologous pair
- Gamete formation involves meiosis (two consecutive cell divisions but only one round of
DNA replication - produces 4 daughter cells)
Spermatogenesis
- production and maturation of sperm
1. mitotic proliferation: produces large numbers of cells
2. meiotic division: generates genetic diversity and half chromosomes
3. cytodifferentitation (spermiogenesis): packages chromosomes for effective delivery to
oocyte
average number sperm produced = 300 million per day
find more resources at oneclass.com
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BIOM1060 24/04/18
Major regions of sperm
- Head: includes nucleus (DNA) and acrosome containing enzymes (allows to penetrate egg)
- Midpiece: metabolic region including mitochondria (produce ATP to move tail)
- Tail: locomotor region (includes flagellum)
Oogenesis
- Production of female gametes
- Takes years to complete (begins in foetal period)
- Oogonia (2n ovarian stem cells): multiply by mitosis and store nutrients
- Primary oocytes: develop in primordial follicles and become surrounded by follicle cells
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Gestation period: time from last menstrual period until birth (~280 days) Embryo: conceptus from fertilisation to 8 weeks gestation. Foetus: conceptus from 9 weeks to birth. Conception normally takes place in ampulla of fallopian tube. Fertilised ovum continues to uterus where implantation occurs and conceptus continues. Involves fusion of genetic material contained within sperm and oocyte to form a zygote. Sperm must reach ovulated oocyte: sperm viable for 24-48hrs after ejaculation, oocyte viable for 12-24hrs. Coitus must occur no more than 2 days before or 24 days after ovulation. Must be sufficient quality and quantity of sperm. Sperm must be transported appropriately from male reproductive system and deposited within female genital tract near cervix within appropriate time period. Fallopian tube must be patent (open and unobstructed) Most cells in body have 46 chromosomes (23 pairs: diploid chromosomal number (2n): one maternal, one paternal (homologous chromosomes) Gametes have only 23 chromosomes: haploid chromosomal number (n): only one member of homologous pair.
