Reproduction 1 Flashcards
What chromosome pair are the sex chromosomes?
23rd Pair
X and Y
What chromosomes are male and female?
XX = female XY = male
The Y Chromosome has essential genes for developing into male
What is the reproductive system?
All the organs involved in mating, gametogenesis and other functions involved in producing offspring
Organs:
- Gonads
- Accessory reproductive organs
What are the male gonads and gametes?
Male gonads: testes
Male gametes: spermatozoa
What are the female gonads and gametes?
Female gonads: ovaries
Female gametes: ova
What is the difference between haploid and diploid?
Haploid = n chromosomes Diploid = 2n chromosomes
Gametes are haploid
What are the functions of gonads?
- Produce gametes
- Secrete sex hormones
What is gametogenesis?
Production of gametes from undifferentiated germ cells by meiosis
What is the role of Chromosomes in Sex Determination?
Chromosomes determine whether fetus develops ovaries or testes
Y chromosome contains srY gene:
-If srY gene present -testes form
If srY gene absent - ovaries form
What does the srY gene doing?
sex determining region on the Y Chromosomes
-codes for testis-determining factor
What is sex differentiation controlled by?
Hormones
-first two weeks: embryo sexually indifferent
Wolffian ducts (precursor to the male tract) Mullerian ducts (precursor to female tract)
What occurs during sex differentiation if testes present?
testes secrete:
-testosterone
-Mullerian-inhibiting substance
these hormones stimulate development of Wolffian ducts and degeneration of Mullerian ducts
What occurs during sex differentiation if no testes present?
Hormones absent -> Wolffian ducts regress, Mullerian ducts develop
What are the patterns of reproductive activity over the human lifespan?
1) Adolescence (up to 10-14years) -inability to reproduce
2) Puberty (starts at 10-14) -sexual maturation
- reproductive organs mature
- secondary sexual characteristics develop
3) Females lose ability to reproduce around 45-50
- Menopause: loss of female reproductive capacity
- Male retains ability to produce sperm
What are the secondary sexual characteristics?
External characteristics not directly involved in reproduction
Males: -Broad Shoulder -Presence of Facial Hair Females: -Curvier Hips -Absence of Facial Hair
- Testosterone in males
- Estrogen in female
What are the need for secondary sexual characteristics?
-do attract opposite sex however they are strongly influenced by society and cultural behaviour
What is the difference between genotypic, gonadic and phenotypic?
Genotypic (determined by XY or XX)
Gonadic (determined by presence of testes/ovaries)
Phenotypic (the apparent anatomic sex of an individual)
What are the cells of the testis?
- Leydig cells (interstitial cells that secrete testosterone)
- Sertoli cells (epithelial cells that support sperm development)
- Smooth muscle (peristalsis to propel sperm)
- Blood-testis barrier (tight junctions with luminal or basal compartments)
What are the effects of testosterone?
Before birth:
- Masculinizes reproductive tract and external genetalia
- Promotes descent of testes into scrotum
After Birth:
- Promotes growth and maturation of the reproductive system at puberty
- Is essential for spermatogenesis
- maintains the reproductive tract throughout adulthood
What are the functions of Sertoli Cells?
- Support sperm development
- Secrete luminal fluid in which sperm develops
- Secrete androgen-binding protein
- Androgen buffer
- Helps maintain steady androgens in lumen
- Target cells to testosterone and FSH
- Secrete inhibin
- Secrete MIS
What occurs to the penis during sexual arousal?
- Blood flow to the penis increases
- engorges erectile tissue
- penis swells and elongates
What are the blood levels of Sex Hormones in Males?
Fairly constant on short term basis
Prepubescent
-Low blood levels
Puberty and adulthood
-High blood levels
