Lecture 13

Question 1

Exocrine function of reproductive system

Answer 1

Production of gametes and secretions in semen: sperm, seminal vesicle fluid (60%), prostatic fluid (25%), and an alkaline secretion from the Bulbourethral (Cowper’s) glands that neutralizes the acidic male urethra and secretes mucous that lubricates the urethra and glans.

Question 2

Endocrine function of reproductive system

Answer 2

Endocrine secretions are released in the blood and exocrine secretions are released externally. Testosterone secretion is an endocrine function

Question 3

Internal Genitalia

Answer 3

Bulbourethral glands
Ductus deferentes
Epididymides
Prostate
Seminal vesicles
Testes

Question 4

External Genitalia

Answer 4

Penis

Scrotum

Question 5

Male secondary characteristics

Answer 5

Mainly develop during puberty
•Distinguish males from females, and signal sexual maturity
•Pubic and axillary hair are not sexually dimorphic
•Larger skeleton, more skeletal muscle, laryngeal prominence, body hair, facial hair, and deeper voice are
•Important in intersexual selection –mate choice (mainly on the part of females)

Question 6

How is sex determined in development

Answer 6

Y chromosome contains SRYgene (Sex-determining Region of Y)

• Codes for testis-determining factor
• Protein that alters gene expression and causes development of male reproductive structures

Question 7

gonadal ridges

Answer 7

Gonads begin to develop at 6 weeks as gonadal ridges

•Near the primitive kidneys, called mesonephros

Nures cells in testes secrete testosterone which furthers the formation of male reproductive system

•Also, sustentacular cells secrete Müllerian-inhibiting factor, causing degeneration of the paramesonephric ducts

Question 8

Mesonephric Ducts

Answer 8

Develops into male reproductive tract with testosterone

Question 9

Paramesonephric Ducts

Answer 9

Develops into female reproductive tract

Question 10

What chemical do the sustentacular(nurse) cells of the testes secrete early on in the development of a male embryo?

Answer 10

sustentacular cells secrete Müllerian-inhibiting factor, causing degeneration of the paramesonephric ducts

Question 11

Why is testosterone and not estrogen used to determine if an embryo will develop male or female?

Answer 11

Because the levels of estrogen will be very high in the mother during pregnancy and would make all children female.

Question 12

Genital tubercle develops into?

Answer 12

Male: glands and portion of shaft
Female: clitoris

Question 13

Urogenital folds develop into?

Answer 13

Male: Urethra
Female: Labia Minora

Question 14

Labioscrotal folds develop into?

Answer 14

Male: Scrotum
Female: Labia majora

Question 15

Median septum

Answer 15

Separates testes and provides protection against infection or cancer from spreading between your two testes

Question 16

Dartos Muscle

Answer 16

Wall of the scrotum. Helps with thermoregulation to keep testes at a slightly lower than the rest of the body

Question 17

Tunica Vaginalis

Answer 17

Serous membrane that lines the scrotal sac and allows the testes to move around in the scrotum

Question 18

What temperature does sperm production occur at?

Answer 18

35 C

Question 19

Structures that provide thermoregulation of testes?

Answer 19

Ductus deferens - Portion of spermatic cord that helps keep temperature lower than core temp.

Cremaster muscles - derived from interal obliques and travel through spermatic cord. Contract or relax to allow for elevation or lowering of testes

Pampiniform plexus - Counter current heat exchange

Question 20

Exocrine function of testes

Answer 20

produce spermatozoa

Question 21

Endocrine function of testes

Answer 21

produce androgens, male sex hormones

Question 22

Spermatic cords

Answer 22

attached at posterior of testes and pass through inguinal canals. Each contains a ductus (vas) deferens, blood vessels, nerves, and lymphatic vessels

Question 23

What cells in the testes produce testosterone?

Answer 23

Interstitial cells that are located in the areolar connective tissue between the seminiferous tubules produce testosterone

Question 24

What are the functions of the seminiferous tubules?

Answer 24

Location of sperm production

Question 25

List several function of the nurse cells of the seminiferous tubules?

Answer 25

Protect, nourish, and remove wastes from the other epithelial cells

•Secrete androgen-binding protein and inhibin

• Tight junctions between adjacent nurse cells forms blood-testis barrier (BTB)
• Prevents antibody attack due to different chromosome number and antigens
• Limits what chemicals in blood can reach developing sperm

Question 26

Spermatogenesis

Answer 26

Produces four haploid sperm with unique genomes, from a diploid germ cell

Spermatagonium > Primary Spermatocyte > Secondary Spermatocyte > Early Spermatid > Late Spermatid > Spermatozoa

Question 27

Spermiogenesis

Answer 27

Last step of spermatogenesis where spermatids become spermatozoa