FINAL: General Reproduction Flashcards
Is the reproductive system essential for life
No, it is the only body system that is not
What does sexual reproduction require
The union of egg and sperm (specialized cells called gametes)
What are gametes
Sex cells
Sperm for males
Oocyte (egg) for females
What are gametes produced by
Gonads
Female = ovary
Male = testis
What are chromosomes
Structures that organize DNA
How many chromosomes do humans have
23 pairs (46 individuals) in each cell
Each chromosome pair consists of…
One chromosome from maternal lineage
One chromosome from paternal lineage
When cells in our body divide what happens to chromosomes
The 46 are maintained through mitosis
Do gametes have chromosomes?
Yes, but they are unpaired
What is gametogenisis
The production of gametes
What is meiosis
The division of sex cells (gametes), where the pairs of chromosomes are separated
What happens to chromosomes in fertilization
Each chromosome pair is reestablished - the union of the sperm and egg (23 + 23 = 46)
What is formed at the end of fertilization
A zygote
What occurs during the acrosomal reaction in a sperm cell
- sperm releases enzymes from the acrosome to penetrate the outside layers of the egg
- 50% of the sperm will release enzymes before reaching zona pellicuda ( it takes a lot of sperm for fertilization )
What happens during cortical reaction
- this causes the prevention of fertilization by more than one sperm
- causes remaining proteins in zonal pellicuda to crosslink and become impernetrable
What are the steps of fertilization
Acrosomal reaction -> cortical reaction -> results in fertilization membrane -> other sperm are rejected
What is sex determined by
Chromosome pair #23 (individually called X or Y)
- after meiosis all eggs have one X chromosome while sperm have one y or one x
- after union of gametes, XX = female, XY = male
When are you able to differentiate the sex of a fetus
During development, fetus does not start to differentiate until about 6 weeks
- cannot tell via ultrasound until about 16 weeks
How do ovaries and testes develop in fetuses
They are both derived from same tissue, differentiates in the prescience of testosterone ( from Y chromosomes ) into the male structures
What are primary sex organs
Gonads, those that produce gametes
What are secondary sex organs
Other organs essential to reproduction
Help transport egg and sperm
What are secondary sex characteristics
They are not essential for reproduction
Physical characteristics that differentiate the sexes and help with mate attractions
Maintained by sex hormones (estrogen, progesterone and testosterone)
What structure is this
Acrosome (contains digestive enzymes)
What structure is this
Nucleus (contains 23 chromosomes)
