ex. 43 [reproduction physiology]

• meiosis: a type of cell division that produces four haploid daughter cells from one diploid parent cell
• gametogenesis: the process of producing gametes (sex cells)
• oogenesis: female gamete formation
• spermatogenesis: human sperm production
• synapsis: the joining of homologous chromosomes during meiosis
• haploid: a cell that contains only one set of chromosomes (23 chromosomes)
• zygote: fertilized egg that has not yet undergone mitosis
• diploid: 2 sets of chromosomes, one from each parent (46 chromosomes)
• Spermiogenesis: process of excess cytoplasm being striped away from spermatid to create motile sperm
• luteinizing hormone prompts Leydig cells to produce testosterone, which acts with FSH to stimulate sperm production
• similarities between mitosis and meiosis

  • chromosomes are replicated before division process
  • prophase, metaphase, anaphase, telophase
  • dyads are visible
• meiosis

  • tetrads are visible
  • four haploid daughter cells genetically different from mother cell
  • only in ovaries and testes
  • homologues synapse; chiasmata seen
  • provides cells for production of offspring
  • two nuclear division w/o chromosomal replication before second division
• mitosis

  • two haploid daughter cells genetically identical to mother cell
  • throughout the body (somatic cells: growth and repair)
• spermatogonia: primitive stem cells that undergo mitosis to form two daughter cells (diploid cell)

  • type a continues stem cell line
  • type b differentiates
• primary spermatocyte: spermatogonium that has yet to complete meiosis I (diploid cell)
• secondary spermatocyte: spermatocyte about to enter meiosis II (haploid cell)
• sustentocyte: nourish spermatids as they begin their transformation into sperm (Sertoli cell)
• spermatid?


  product of meiosis II
• sperm?


  product of spermiogenesis
• follicles release estrogen, small amounts of progesterone, and inhibin
• corpus luteum releases progesterone, estrogen and inhibin
• spermatogenesis: four spermatids vs. oogenesis: one ovum and three polar bodies
• spermatogenesis begins at puberty whereas oogenesis begins during fetal stage
• spermatogenesis is lifelong but oogenesis ends with menopause
• effect of FSH on ovary?

  ovulation; during puberty follicles begin to mature every 28 days
• LH effect on ovaries?

  ovulation
• GnRh from hypothalamus triggers FSH and LH release from anterior pituitary which stimulate follicle maturation and trigger ovulation; estrogen peaks during proliferative uterine phase contributing to FSH and LH surge
• menstrual stage: functional layer of endometrium shed
• proliferative stage: functional layer of endometrium rebuilt
• secretory stage: immediately after ovulation; blood supply and glandular secretion of nutrients increases to prepare for implantation on endometrium
• during menstrual phase LH, FSH, estrogen, and progesterone low
• during proliferative phase estrogen (thickens endometrium), FSH, and LH start to increase
• during secretory phase progesterone spikes while FSH, LH and estrogen gradually decline
• seminiferous tubule cross-section

  A) spermatogonia

  B) primary spermatocytes

  C) spermatids

  D) immature sperm in lumen

  E) sustenocytes (Leydig cells)

  
• sperm anatomy

  A) acrosome

  B) nucleus (genetic region)

  C) mitochondrion (ATP production)

  D) locomotion

  
• microscopic ovary and follicles

  A) primary follicle

  B) corpus albicans

  C) secondary follicle

  D) vesicular (antral) follicle

  E) antrum

  F) secondary oocyte

  G) zona pellucida

  H) ovulated oocyte

  I) corona radiata

  J) corpus luteum