How long does it take for the development of a mature spermatid?
Where does spermatogenesis occur in the testis?
In the seminiferous tubules
Put the following in order of their development during spermatogenesis: spermatozoan, primary spermatocyte, secondary spermatocyte, spermatid, and spermatogonium.
Spermatogonium, primary spermatocyte, secondary spermatocyte, spermatid then spermatozoan
In spermatogenesis, what is the immature form of sperm called? What is the mature form called?
Spermatogonium; spermatozoan (remember: Gonium is going to be a sperm; Zoan is Zooming out of testis)
A spermatogonium has _____ (number) _____ (single chromosomes/sister chromatids), is _____ (diploid/haploid), and is _____ (4N/2N/N).
46; single chromosomes; diploid; 2N
A primary spermatocyte has _____ (number) _____ (single chromosomes/sister chromatids), is _____ (diploid/haploid), and is _____ (4N/2N/N).
46; sister chromatids; diploid; 4N
A secondary spermatocyte has _____ (number) _____ (single chromosomes/sister chromatids), is _____ (diploid/haploid), and is _____ (4N/2N/N).
23; sister chromatids; haploid; 2N
A spermatid has _____ (number) _____ (single chromosomes/sister chromatids), is _____ (diploid/haploid), and is _____ (4N/2N/N).
23; single chromosomes; haploid; N
What events define the process known as spermiogenesis?
The spermatid becomes a spermatozoan by losing cytoplasmic contents and gaining an acrosomal cap
During spermatogenesis, _____ undergoes meiosis I to form _____, whereas _____ undergoes meiosis II to form _____.
Primary spermatocyte; secondary spermatocyte; sperm
In males, follicle-stimulating hormone stimulates which cells? What is the resulting secretion?
Follicle-stimulating hormone stimulates Sertoli cells to produce androgen-binding protein and inhibin
In males, luteinizing hormone stimulates which cells? What is the resulting secretion?
Luteinizing hormone stimulates Leydig cells to produce testosterone
In male spermatogenesis, what is the effect of inhibin released by Sertoli cells?
Inhibin provides negative feedback of follicle-stimulating hormone release by the anterior pituitary
How does testosterone affect the hypothalamus-pituitary axis in the regulation of spermatogenesis?
Testosterone is necessary for sperm production in the testes but provides negative feedback on gonadotropin-releasing hormone and luteinizing hormone secretion in the hypothalamus and pituitary
Gonadotropin-releasing hormone from the hypothalamus stimulates the release of what two hormones from the anterior pituitary?
Luteinizing hormone and follicle-stimulating hormone
What are the functions of luteinizing hormone and follicle-stimulating hormone?
Follicle-stimulating hormone causes Sertoli cells to aid in Sperm production, whereas LH causes Leydig cells to release testosterone (also aiding sperm production)
Rank the following three androgens in order of potency: androstenedione, dihydrotestosterone, and testosterone.
Dihydrotestosterone > testosterone > androstenedione
What is the major source of dihydrotestosterone and testosterone in men?
What is the major source of androstenedione in men?
What enzyme converts testosterone to dihydrotestosterone?
What medication inhibits 5α-reductase?
What enzyme converts testosterone and dihydrotestosterone to estrogen in men? Where is this enzyme found?
Aromatase, which is found in adipose tissue and Sertoli cells
What effects does testosterone have during puberty?
Testosterone is responsible for the growth spurt (affecting the penis, seminal vesicles, sperm, muscle, and red blood cell development), deepening of the voice, increased libido, and closure of epiphyseal plates (ending linear growth)
Name three structures in which differentiation depends on testosterone during embryogenesis.
The epididymis, the vas deferens, and the seminal vesicles
How does testosterone cause epiphyseal plate closure in men?
Testosterone is converted to estrogen, which closes epiphyseal plates
What are the effects of dihydrotestosterone during male embryogenesis?
Differentiation of the penis, scrotum, and prostate
What are the effects of dihydrotestosterone on adult males?
Balding, prostate growth, and sebaceous gland activity
A bodybuilder comes to your office for infertility, and on exam you note small testicles; what is a likely cause of his infertility?
Azoospermia, caused by exogenous testosterone use resulting in hypothalamic-pituitary-gonadal axis inhibition and low intratesticular testosterone
Name four places in female body where estrogen is produced.
The ovaries (17β-estradiol), the placenta (estriol), the blood (aromatization), and the adipose tissue
Rank the following three forms of estrogen in order of potency: estradiol, estriol, and estrone.
Estradiol > estrone > estriol