Reproduction

• Gametogenesis in males begins at the progenitor cell called spermatogonium
• Spermatogonium undergoes mitosis and produces 2 diploid cells also called primary spermatocytes
• Primary spermatocytes first undergo meiosis 1 and become secondary spematocytes and then after meiosis 2 become spermatids
• Spermatids need to lose cytoplasm and gain tail to become sperm
• A progenitor cell for gamtogenesis in females is oogonium
• When oogonium undergoes mitosis, it produces primary oocytes
• Primary oocytes arrest in prophase 1 until puberty happens in girls
• Out of 1 diploid female ooginium, 1 haploid secondary oocytes is produced as a result of meiosis 1 because it gets all cytoplasm and another one (called polar body) degrades
• Secondary oocytes get arrested in metaphase 2 and travel to Fallopian tubes until sperm fertilizes them
• Fertilized secondary oocyte undergoes meiosis 2, polar body degrades again and ootid is produced
• Ootid matures to ovum, and then to zygote
• This is a process of sperm production

  A) spermatogonium

  B) primary spermatocyte

  C) secondary spermatocyte

  D) spermatid

  E) sperm

  
• This is the process of ovum production

  A) oogonium

  B) primary oocyte

  C) secondary oocyte

  D) polar body

  E) polar bodies

  F) ovum

  
• Spermatogonium and oogonium are diploid
• Primary spermatocytes and primary oocytes are diploid
• Secondary spermatocyte and secondary oocyte are haploid
• Spermatid and sperm are haploid
• Ootid and ovum itself are haploid, but since they are joined with sperm at this stage, they are diploid
• The other name for sperm is spermatozoa
• Spermiogenesis is the process of maturation of sperm
• Follicle is a multilayer sac of cells that contains, nourishes and protects immature primary oocyte
• Oogonium undergoes mitosis in girls before they are born
• Ovum is a secondary oocyte that has been fertilized
• Fertilization by sperm in women happens in fallopian tube
• Ovum + sperm = zygote
• By the time zygote travels from fallopian tubes to uterus, it divides and in uterus it is called blastocyst
• When ovulation happens, 1 follicle gets destroyed and 2d oocyte just chills in the fallopean tube until sperm comes, but what is left from that follicle is called corpus luteum and it secretes estrogen and progesteron
• This is a menstrual cycle

  A) corpus luteum

  B) ovulation

  C) estrogen

  D) progesterone

  E) follicular phase

  F) luteal phase

  
• Menses begin when corpus luteum is degraded and progesterone levels drop
• Outer layer of secondary oocyte in the fallopian tube is called corona radiata and inner layer is zona pellucida
• Sperm enters 2dary oocyte through the tube-like structure called acrosomal process which has enzymes digesting a path through membranes
• Cortical reaction occurs when 1 sperm enters ovum so polyspermia does not occur
• Totipotent are stem cells that can become any cell, placenta or embryo
• Pluripotent stem cells can become any one of the 3 germ layers
• Multipotent stem cells can replace cells of a particular lineage
• Morula is a zygote compromised of 16 or more cells
• This is blastocyst

  A) internal cell mass

  B) trophoblast

  C) zona pellucida

  
• Blastocyst is not implanted in the endometrium and does not grow in size until zona pellucida is shed
• Inner cell mass of blastocyst has pluripotent cells that can develop into any cell type in the body
• During first trimester, blastocyst produces HCG hormone which helps to maintain estrogen and progesterone levels high, preventing menstruation and corpus luteum degradation