Reproduction & Cell Growth Flashcards
Female sex changes after menopause
- Vaginal epithelium dehydrates
- Changes in mood
- Breasts and reproductive organs shrink
- would also occur if ovaries were removed*
Vagina
Endometrial implants within the vagina may impair the passage of sperm and decrease the likelihood that an ovulated oocyte will be fertilized
Ovaries
Female gonads that produce gametes (oocytes) and secrete female sex hormones; endometrial implants attached to the ovary may cause infertility by impairing follicular maturation or ovulation
Fallopian tubes
Duct structures lined with motile cilia that transfer the ovulated oocyte from the abdominal cavity toward the uterus; implants would prevent a fertilized oocyte from reaching the uterus for implantation
Cervix
Barrier separating vagina and uterus; implants may impair the passage of sperm and decrease chance of fertilization
Female puberty effects
- Growth and maturation of female sexual organs (fallopian tubes, uterus)
- Development of sex-specific traits (widening of pelvis, breast development)
- Initiation of the menstrual cycle through stimulation of oogenesis and ovulation
Female menopause
Production of estrogen and progesterone within the ovaries declines (opposite of what happens during female puberty; breasts shrink, vaginal epithelium dehydrates, etc)
Head (sperm)
Contains an acrosome and the nucleus; rich in specialized lysosome-like enzymes for piercing the outer shell of an oocyte during fertilization
Midpiece (sperm)
Section packed with mitochondria, essential organelles that produce the ATP required for flagellum-driven sperm motility; also contains a pair of central MTs that are anchored to the cytoskeleton and extend down the length of the flagellum (tail region)
Flagellum (sperm)
Specialized for wavelike movements to propel sperm through a fluid environment; this is derived from the action of ATP-dependent motor proteins that act on the central MTs
Spermatogenesis
Male gametes are produced in the seminiferous tubules of the testes
- Pathway: spermatogonium (stem cells that undergo cell division), spermatocyte, spermatid, and spermatozoon (mature sperm, through the loss of most of their cytoplasm, acrosome formation around the nucleus, and mitochondrial concentration round the midpiece, and development of a tail)
Spermatogenesis
Male gametes are produced in the seminiferous tubules of the testes
- Pathway: spermatogonium (stem cells that undergo cell division), spermatocyte, spermatid, and spermatozoon (mature sperm, through the loss of most of their cytoplasm, acrosome formation around the nucleus, and mitochondrial concentration round the midpiece, and development of a tail)
Oogenesis
(Starts at 4 weeks gestation) Oogonia (germ cells) are diploid stem cells that first multiply via mitosis and become primary oocytes
Primary oocytes
They commence the first meiotic division but become arrested in prophase I (this is from infancy to puberty)
Female puberty (body effects)
- Stimulation by follicle-stimulating hormone (FSH) followed by a surge in luteinizing hormone (LH) causes some primary oocytes to resume meiosis I
- The last stage of meiosis I (telophase I) yields two unevenly divided haploid cells (one is the secondary oocyte, while the other is the first polar body (does not develop into a mature oocyte))
- Secondary oocyte begins meiosis II but halts in metaphase II, and the polar body degenerates
- SO remains frozen in metaphase II until fertilization occurs, at which point it completes its second meiotic division (telophase II) to an ootid and second polar body
- The zygote that results is diploid due to genetic contribution from both the ovum and sperm nuclei
Human sperm and oocytes are substantially different in the following:
Maturation stage at birth, cell volume, and the rate at which they are produced
Human sperm and oocytes are substantially different in the following:
Maturation stage at birth, cell volume, and the rate at which they are produced
Cell cycle
G0: Cell cycle arrest, resting phase
G1 phase: Presynthetic growth, organelle duplication
S phase: DNA replication
G2 phase: Premitotic growth, DNA damage repair
M phase: Cell division
Kinesin
Moves intracellular cargo along MTs in anterograde axonal transport (away from the nucleus and toward distal sites)
Dynein
Participates in retrograde axonal transport of intracellular cargo (from distal sites toward the nucleus)
Reduced number of fallopian cilia
Cause an embryo to implant in a location other than the uterine lining
Pluripotent cells
Are very undifferentiated cells and can develop into virtually all adult cells
Frequency of recombination
Genes that are situated physically closer together on the chromosome have a lower probability of being separated during meiosis I. Therefore, the greater the physical distance between genes, the higher the frequency of recombination
Eukaryotes
Have nuclei, and other membrane-bound organelles
