TPR 13 - Reproductive System

Question 1

Role of testes.

Answer 1

The testes have two roles: 1) synthesis of sperm (spermatogenesis), and 2) secretion of male sex hormones.

Question 2

The site of spermatogenesis.

Answer 2

The seminiferous tubules located in the testes.

Question 3

Sertoli cells. Also called sustentacular cells.

Answer 3

Sertoli cells protect and nurture the developing sperm.

Question 4

Function of leydig/interstitial cells of the testes.

Answer 4

The tissue b/t seminigerous tubules is made of interstitial cells. They are responsible for androgen (testosterone) synthesis.

Question 5

The path of sperm.

Answer 5

Semiferous tubules > epididymis (long coiled tube back of testicle) > ductus deferens > ejaculatory duct + duct of seminal vesicle > urethra.

Question 6

Fucntion of seminal vesicles.

Answer 6

They secrete 60% of the total volume of the semen into the ejaculatory duct.

Question 7

Semen is a nourishing fluid for sperm and is produced by three glands:

Answer 7

Seminal vesicles, prostate gland, and bulbourethral glands. Collectively referred to as the accessory glands.

Question 8

Corpus cavernosum versus corpus spongiosum.

Answer 8

Erectile tissue. There are two corpus cavernosa and one corpus spongiosum.

Question 9

Three stages of male sexual act.

Answer 9

Arousal, orgasm, resolution.

Question 10

Arousal is dependent on the (parasympathetic/sympathetic NS) and can be subdivided into two stages:

Answer 10

Arousal is dependent on parasympathetic NS and can be subdivided into erection and lubrication.

Question 11

Erection.

Answer 11

The dilation of arteries supplying erectile tissue, causing swelling and obstructing venous flow.

Question 12

Lubrication.

Answer 12

A function of the parasympathetic system. The bulbourethral glands secrete a viscous mucus which serves as a lubricant.

Question 13

Stimulation by the (parasympathetic/sympathetic NS) is REQUIRED for an orgasm, which can be decided into two stages:

Answer 13

Stimulation by the sympathetic NS is REQUIRED for an orgasm, which can be decided into two stages: emisison and ejaculation.

Question 14

Emission versus ejaculation.

Answer 14

Emission is the movement of sperm and semen compoenents into the urethra; ejaculation is the movement of semen from the urethra out of the body.

Question 15

The gametes produced by the male are known as __ and females, ___.

Answer 15

The gametes produced by the male are known as spermatozoa and females, ova.

Question 16

The germ cells.

Answer 16

a cell containing half the number of chromosomes of a somatic cell and able to unite with one from the opposite sex to form a new individual; a gamete.

Question 17

The precursor to all sperm.

Answer 17

Spermatagonium. The spermataGOnium is GONNA becone a sperm. These mitotically reproduce prior to meiosis. They replicate DNA in the S phase of meiosis.

Question 18

When is primary spermatocyte produced? Secondary?

Answer 18

Primary spermatocyte is produced from a spermatagonium. Its role is to undergo meiosis 1. Secondary spermatocyte is produced after meiosis 1; it’s role is to undergo the SECOND meiotic division, turning into a spermatid.

Question 19

Spermatid versus spermatozoan.

Answer 19

The spermatid is a haploid cell produced after meiosis 2. This matures into a spermatozoan. Unlike spermatocytes, both have tails, although the tail on the spermatid is premature.

Question 20

Where do spermatozoan finish maturing?

Answer 20

They first mature in the seminiferous tubules ( the site of spermatogenesis) and then finally the epididymous.

Question 21

Mature sperm cell.

Answer 21

Spermatozoan.

Question 22

True or false. Recombination b/t sister chromatids during gametogenesis increases the genetic diversity of offspring.

Answer 22

FALSE. Sister chromatids don’t recombine, HOMOLOGOUS chomosomes do. Sister chromatids are identical and made during DNA replication. Homologous chromosomes consist of a maternal and paternal chromosome.

Question 23

Function of acrosome.

Answer 23

The acrosome is a compartment on the head of the sperm that contains hydrolytic enzymes required for penetration of the ovum’s protective layers.

Question 24

The name of the protein on the sperm’s surface that attaches to the receptors on the zone pullucide surrounding the ovum.

Answer 24

Bindin.

Question 25

The function of the luteinizing hormone in men.

Answer 25

LH stimulats the interstitial cells to secrete testosterone, which is important for spermatogenesis. GnRH reaches its target tissues via the portal system. GnRH stimulates the anterior pituitary to release LH.

Question 26

Which two hormones do the posterior pituitary secrete?

Answer 26

Oxytocin and vasopressin. POV

Question 27

The function of follicle stimulating hormone in men.

Answer 27

FSH stimulates the sertoli (sustenacular cells), which are cells that protect and nurture developing sperm, physically and chemically. In addition to LH, this is another gonadotropin secreted by the anterior pituitary.

Question 28

The two gonadotropins released by the anterior pituitary.

Answer 28

LH and FSH.

Question 29

During the early weeks of embryo development, males and females are indistinguishable, as they have undifferentiated gonads and possess both ___ and ___.

Answer 29

Wolffian ducts and Mullerian ducts.

Question 30

What do Wolffian and Mullerian ducts develop into?

Answer 30

Wolffian - male INTERNAL genitalia (epididymis, seminal vesicles, and ductus deferens) Mullerian - female INTERNAL genitalia (uterine tubes, uterus, vagina)

Question 31

Which gonadal duct develops by default?

Answer 31

Mullerian ducts develop by default, and the female internal genitalia results. If the embryo is XY, the presence of Y leads to the development of testes, which causes male internal and external genitalia to develop by producing testosterone and Mullerian inhibiting factor (MIF)

Question 32

If an XY genotype embryo fails to secrete testoterone, will it have testes or ovaries?

Answer 32

The very presence of the Y chromosome leads to the development of testes. These embryonic testes, if functional, produce testoterone which can lead to wolffian duct development and external male genatalia.

Question 33

Which external genitalia is default.

Answer 33

Like internal genitalia, external genitalia defaults to female. So, the labias and clitoris.

Question 34

Mullerian inhibiting factor is produced by the ___, and causes ___.

Answer 34

Mullerian inhibiting factor is produced by the testes and causes regression of the Mullerian ducts, preventing the development of female internal genitalia.

Question 35

Testosterone secretion by cells which will later give rise to the testes begins around week ___ of gestation. By week 9, the testes are formed and their interstitial cells supply ___.

Answer 35

Testosterone secretion by cells which will later give rise to the testes begins around week 7 of gestation. By week 9, the testes are formed and their interstitial cells supply testosterone.

Question 36

The testosterone that is responsible for the development of male external genitalia enters the systemic circulation and must be converted to ____ in target tissues in order to exert its effects.

Answer 36

Dihydroxytestoerone.