Male Reproductive Physiology: Questions and Answers, Lecture notes of Medicine

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Male reproductive

physiology

Gachuki maina

Questions

Questions True or false

• HCG is
  • A steroid
  • Acts directly on the uterus to maintain the endometrium
  • Is formed in the anterior pituitary
  • Blood levels rise steadily through pregnancy
  • Can be detected in the urine as an early sign of pregnancy.
• The corpus luteum
  • Is essential for the secretory phase of the menstrual cycle
  • Development is controlled by the pituitary gland
  • Secrets hormones in early pregnancy when stimulated by the pituitary
  • Is greyish-white in color
  • Begins to atrophy in the second month of pregnancy

Question True or false

• The ovaries
  • Begin to develop ova at puberty when acted on by FSH
  • Are required for cyclical menstrual activity
  • Must have double follicular rupture if identical twins are conceived
  • Cease to respond to FSH after the menopause
  • Secrete hormones which constrict uterine vessels
• The 21 st

day of the menstrual cycle differs from the seventh in that the

• Endometrium is thicker and contains glands
• Blood level of progesterone is higher
• Blood is estrogen-free
• Blood level of FSH is at a maximum
• Endometrial glycogen content is higher

Introduction to the male reproductive system

• The male reproductive system is composed of - Gonads - testes - Reproductive tract :- epididymis, ductus (vas) deferens, urethra. - External genitalia :- penis ( composed of corpora cavernosa and corpus spongiousum) - Accessory glands :- prostate, seminal vesicles, and bulbourethral glands.

Function of the male reproductive

system

• Production of sperm
• Delivery of sperm to the female

GAMETES

• Gametes are haploid reproductive

cells with half the normal

complement of chromosomes

• Haploid=23 chromosomes
• Gametes- male gamete is the

sperm(spermatozoa) and female

game is the ova (egg)

• Gametes are produced by meiosis
• Gametes are genetically unique ,

producing genetically unique

offspring.

23 pairs of human chromosomes

• Body cells –
  • have 23 types of chromosomes- 2 pairs each, making a total of 48 chromosomes in human cells
• Gametes
  • 23 types of 1 copy in each gamete

Meiosis

• Meiosis is a specialized form of cell division that begins with a reproductive stem cell ( 2n=46) and goes through 2 nuclear divisions to produce 4 ( 1n=23) gamete daughter cells.

Meiosis I-II

• Crossover during prophase

Independent assortment during

metaphase 1

Sex determination

• Whether an individual matures into a male or female is determined by the combination of sex chromosomes they inherit - 22 autosomal chromosomes - 2 sex chromosomes (X and Y) - XY= genetic male - XX= genetic female

Males can contribute X or Y

• Sex chromosomes are split during meiosis along with the autosomal chromosomes
• Males (father) have X and Y, their haploid gametes, then can have either X or Y
• Females (mother) have X and X, their haploid gametes can only have X.
• Genetic sex determination, then is determined by males