What is dimorphism? How are zygotes produced? What are the two different gametes and where are they formed?
1. Dimoprhism: physically distinct males and females
2. when eggs and sperm fuse theyform zygotes
3. Male gonad: testes which form sperm
Female: ovaries which form eggs
How many chromosomes do humans have? How many are autosomal? How many are sex?
3. 1 pair: XX or XY
How many chromosomes are in each sperm and egg?
1. Sperm 23
2. Egg: 23
- Zygote has 46
What chromoeosmes do the sperm and egg have? How can they contribute to either a boy or girl?
1. Females only carry XX chromosomes in their eg
2. Men have either an X or Y chromosome in their sperm
*With this combination there can be either an XX or XY*
What are the male and female equivalent structures? What is the bipotential structure for each?
Male: Glans penis
Urethral folds and groove
Male: shaft of penis
Female: labia minora, opening of vagina and urethra
Male: penis shaft and scrotum
Female: labia majora
Male: epididymis, vas deferens, seminal vesicle
Female: fallopian tube, uterus, cervix, and upper vagina
What are the bipotential tissues?
The Sex-determining Region of Y chromosome (SRY) gene
Gonad: either testis or ovary
Ducts: wolffian or mullerian
Because of the SRY gene what happens to the medulla of the bipotential gonad? What are the two cells involved with the sperm? What three things does the wolffian duct develop into? What happens to the mullerian duct?
*This is essentially the development for a male*
1. The medulla develops into the testis
2. a. The sertoli cell: or nurse cell nourishes developing sperm cells
b. Leydig cell: make and secrete testosterone
3. Epididymis, vas deferens, and seminal vesicle
Because there is no SRY gene, what happens to the cortex of the bipotential gonad? What three thing are developed from the mullerian duct? What happens to the wolffian duct?
1. develops into ovary
2. Vagina, uterus, fallopian tubes
What is the overview for the internal development for females at ten weeks?
1. Gonadal cortex becomes ovary with absence of SRY protein
2. wolffian duct degenerates in absence of testosterone
3. mullerian duct becomes the fallopian tubes, uterus, and upper part of vagina. Because abscence of anti-mulllerian hormone
What is the overview for the internal development for males at ten weeks?
1. SRY protein directs the medulla of the bipotential gonad to develop into testis
2. anti mullerian hormone causes the mullerian duct to degenerate
3. testosterone converts wolffian duct into seminal vesicle, vas deferens, and epididymis
4. DHT controles prostate development
What is the development of the external genitalia of women?
At ten weeks
-Genital tubercle becomes clitoris
-Labioscrotal swelling becomes folds out
*in abscence of androgens, external genitalia are feminized*
-labioscrotal swelling is now labia majora
-urethral fold is now labia minora
WHat are the sex hormones for males and females?
-testosterone (95% testes/5% adrenal cortex)
What are the structures of the male reproductive system?
2. seminiferous tubule
3. External genitalia
4. Internal genitalia and glands/ducts
What is a vasectomy? How is it done? Does it have negative effects?
1. Vasectomy: common, reliable, permanent male contraception
2. the vas deferens is cut and tied to prevent sperm transport
3. No: it does not efefct testosterone, erections, or sexual pleasure
Where does spermatogenesis occur? How is this process done?
1. It occurs in the seminiferous tubule of the testes
2. a. has spermatogonia which are germ cells
b. sertoli cells nurish and regulate the development of sperm
What is the composition of sperm? What amount of sperm signals infertility? What causes infertility?
1. Sperm 1% (40-250million/ml) and accessory gland secretions 99% (1.5-5.0ml)
-secretions include water, buffers, nutrients and enzymes
2. less than 200million/ml
3. heat, drugs, or anabolic steroids
How do spermatozoa propell themselves? How do spermatozoa enter an ovum? what are the componets of spermatozoa?
1. Spermatozoa are propelled by flagella
2. The head of spermatozoa have an acrosome, which releases enzymes that digest the exterior ovum for entry
3. head with enzymes and DNA, long tail, and mitochondria
What are the female reproductive structures?
2. external genitalia
-labia majora and minora clitoris
3. Inner genitalia
Where are oocytes developed?