Chapter 16 and 17 course packet Flashcards
The first 22 pairs of sex chromosomes are
Autosomes
Female sex chromosomes are truly what?
Homologous xx
What chromosomes do the males have?
X and a very short Y
What is Sry?
Sex-determining Region of the Y chromosome
One gene on the Y chromosome is called?
Sry
When does Sry become active?
When the embryo is about 6 weeks old
Up to about 6 weeks, both male and female embryos are what?
Anatomnically identical
If the Sry is present in only XY chromosomes what happens?
Germ cells and the cells immediately around them begin to develop into testes at about 7 weeks
If the Sry is absent then what?
Cells begin to develop into ovaries
The cells that become the male gonad (testes), begin to secrete and release what
Testosterone
What does the releasing of testosterone signal
The further developlment of the male sexual organs in the embryo & the male secondary sexual traits at puberty
The cells that become the female gonad (ovary), begin to secrete and release what
Estrogen & eventually progesterone
What does the releasing of estrogen and progesterone signal
The further development of the female sexual organs in the embryo & the female secondary sexual traits as puberty
What are the 5 male reproductive organs
1) 2 testes
2) 2 epididymis
3) 2 Vas deferens
4) 2 Ejaculatory ducts
5) Penis
3 Male accessory glands
1) 2 Seminal vesicle
2) Prostate gland
3) 2 Bulbourethral gland
Function of testes
Seminiferous tubules: sperm production; Leydig cells: sex hormones
Function of Epididymis
Sperm maturation site; & further from the testis, sperm storage
Function of Vas deferens
Rapid transport of sperm
Function of Ejaculatory duct
After seminal vesicle, conduction of sperm to the penis
Function of the penis
Organ of sexual intercourse
Function of the seminal vesicle
Secretion of fructose & prostaglandins, a large part of semen
Function of Prostate gland
Secretion of buffers and other substances that become part of semen
Function of the bulbourethral gland
Secretion of lubricating mucus
Where can the Leydig cells be found
Found between seminiferous tubules of the testes
Fertile males operate w/in what
A narrow range of circulating male hormones
The meiosis is easily seen when
Looking at a cross-section of a seminiferous tubule & moving from the outside in
What is the order of the cell (genome) for meiosis
1) Spermatogonium (2n)
2) Primary spermatocyte (2n)
3) Secondary spermatocyte (n, but still replicated DNA)
4) Early spermatids (n)
5) Late spermatids (n)
6) Immature sperm (n)
7) Mature sperm (n)
What is the meiotic stage for Spermatogonium
Mitosis
What is the meiotic stage for primary spermatocyte
Meiosis 1
What is the meiotic stage for Secondary spermatocyte
Meiosis 2
Location of Spermatogonium
Outermost cells within the tubule walls
Location of primary spermatocyte
Cells just inside the spermatogonia