Reproduction 1

Question 1

What chromosome pair are the sex chromosomes?

Answer 1

23rd Pair

X and Y

Question 2

What chromosomes are male and female?

Answer 2

XX = female
XY = male

The Y Chromosome has essential genes for developing into male

Question 3

What is the reproductive system?

Answer 3

All the organs involved in mating, gametogenesis and other functions involved in producing offspring

Organs:

• Gonads
• Accessory reproductive organs

Question 4

What are the male gonads and gametes?

Answer 4

Male gonads: testes

Male gametes: spermatozoa

Question 5

What are the female gonads and gametes?

Answer 5

Female gonads: ovaries

Female gametes: ova

Question 6

What is the difference between haploid and diploid?

Answer 6

Haploid = n chromosomes
Diploid = 2n chromosomes

Gametes are haploid

Question 7

What are the functions of gonads?

Answer 7

• Produce gametes

- Secrete sex hormones

Question 8

What is gametogenesis?

Answer 8

Production of gametes from undifferentiated germ cells by meiosis

Question 9

What is the role of Chromosomes in Sex Determination?

Answer 9

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

Question 10

What does the srY gene doing?

Answer 10

sex determining region on the Y Chromosomes

-codes for testis-determining factor

Question 11

What is sex differentiation controlled by?

Answer 11

Hormones
-first two weeks: embryo sexually indifferent

Wolffian ducts (precursor to the male tract)
Mullerian ducts (precursor to female tract)

Question 12

What occurs during sex differentiation if testes present?

Answer 12

testes secrete:
-testosterone
-Mullerian-inhibiting substance
these hormones stimulate development of Wolffian ducts and degeneration of Mullerian ducts

Question 13

What occurs during sex differentiation if no testes present?

Answer 13

Hormones absent -> Wolffian ducts regress, Mullerian ducts develop

Question 14

What are the patterns of reproductive activity over the human lifespan?

Answer 14

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

Question 15

What are the secondary sexual characteristics?

Answer 15

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

Question 16

What are the need for secondary sexual characteristics?

Answer 16

-do attract opposite sex however they are strongly influenced by society and cultural behaviour

Question 17

What is the difference between genotypic, gonadic and phenotypic?

Answer 17

Genotypic (determined by XY or XX)
Gonadic (determined by presence of testes/ovaries)
Phenotypic (the apparent anatomic sex of an individual)

Question 18

What are the cells of the testis?

Answer 18

• 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)

Question 19

What are the effects of testosterone?

Answer 19

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

Question 20

What are the functions of Sertoli Cells?

Answer 20

• 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

Question 21

What occurs to the penis during sexual arousal?

Answer 21

• Blood flow to the penis increases
• engorges erectile tissue
• penis swells and elongates

Question 22

What are the blood levels of Sex Hormones in Males?

Answer 22

Fairly constant on short term basis

Prepubescent
-Low blood levels

Puberty and adulthood
-High blood levels