Male reproduction

Question 1

Identify the major male reproductive organs

Answer 1

Testes, epididymus, ductus deferens, prostate, seminal vesicles, BUGs, penis

Question 2

List the major actions of androgens during fetal development of the male reproductive tract

Answer 2

release of MIS causing the degeneration of Mullerian ducts; contribute to development of secondary sex characteristics and masculinization of urogenital tract and external genitalia

Question 3

Describe the role of MIS in male reproductive tract development

Answer 3

degeneration of Mullerian ducts

Question 4

Describe the function of germ cells and Sertoli cells

Answer 4

Sertoli cells: regulate maturation and provide a source of nutrition; regulate germ cell development germ cells: spermatogonia to spermatozoa

Question 5

Describe the function of LH and FSH in the testis

Answer 5

LH- acts on Leydig cells, stimulates secretion of testosterone FSH- acts on Sertoli cells, acts indirectly on spermatogenesis

Question 6

Describe with diagrams the regulatory system that controls the secretion of testosterone by Leydig cells

Answer 6

Question 7

Describe with diagrams the feedback system that controls the secretion of testerone

Answer 7

Question 8

Describe whether the major effects of testosterone on spermatogenesis are mediated directly or indirectly

Answer 8

LH-> Leydig cells -> testosterone -> spermatogenesis FSH-> Sertoli cells (direct) -> promote spermatogenesis Androgens (testosterone) acts INDIRECTLY on spermatogenesis because germ cells do not have androgen receptors

Question 9

List the major clinically important male reproductive diseases/problems

Answer 9

Cryptorchidism Infertility Benign prostatic hyperplasia Testicular tumors

Question 10

Wolffian duct

Answer 10

develops in males, forms the epididymus, vas deferens, seminal vesicles and ejaculatory ducts

Question 11

urogenital sinus

Answer 11

Males: becomes the prostate Females: becomes the caudal part of the vagina

Question 12

Mullerian duct

Answer 12

Developed in females, becomes ovaries, uterine horns, vagina (cranial 1/3), uterus, oviducts

Question 13

Mullerian inhibiting substance (MIS)

Answer 13

important in degeneration of the Mullerian ducts during fetal development in males, secreted by Sertoli cells

Question 14

testes

Answer 14

produces sperm and secretes hormones

Question 15

epididymis

Answer 15

major function is maturation of sperm; also involved in storage and transport

Question 16

seminal vesicles

Answer 16

provide about 60% of semen volume, secrete alkaline, viscous fluid containing fructose, prostaglandins, and clotting proteins (different from blood)

Question 17

prostate

Answer 17

present in all species, provides about 25% of semen volume, secretes milky, slightly acidic fluid containing citric acid, several proteolytic enzymes, acid phosphatase

Question 18

bulbourethral glands

Answer 18

BUGs; secrete alkaline fluid that protects passing sperm by neutralizing acids from urine in urethra, mucus lubricates end of penis and lining of urethra (not present in all species)

Question 19

penis

Answer 19

organ used in urination and copulation

Question 20

spermatogenesis

Answer 20

Drives it: Leydig cells and the androgens they produce Dependent on androgens (act indirectly) Takes a variable period of time, cells go through meiosis

Question 21

benign prostatic hyperplasia

Answer 21

seen in dogs and humans; benign hyperplasia, enlargement of the prostate gland clinical symptom (dogs)- incontinence treatment- castration

Question 22

cryptorchidism

Answer 22

bilateral or unilateral undescended testicle; can be at any point along the descent tract; testicle continues to produce testosterone and makes animal more prone to testicular cancer if untreated; 0.8-15% in dogs; can be medically or surgically treated

Question 23

infertility

Answer 23

sterile; sperm are not viable and cannot produce viable offspring; frequently idiopathic

Question 24

testicular tumors

Answer 24

types: Sertoli cell tumors, Seminomas, Interstitial cell tumors; all can be malignant; have seen increased incidence of testicular tumors in veterinary medicine

Question 25

What is testicular feminization?

Answer 25

Androgen insensitivity syndrome; XY, no development of secondary sex characteristics but MIS still secreted which leads to degeneration of Mullerian ducts