Human Reproduction (Male Reproductive System)

Question 1

What species won’t mate during only their fertile periods?

Answer 1

Homo Sapiens

Question 2

What is estrus “heat”?

Answer 2

It’s when females of almost all species except for Homo Sapiens mate during their fertile period. It lasts from a few hours to several weeks. 4-5 days mice. Once a year - wolves.

Question 3

Why did humans mate during their non fertile periods?

Answer 3

The speculation is that it was because of maintaining pair bonds.

Question 4

What are gametes?

Answer 4

Eggs or sperm

Question 5

How are gametes produced?

Answer 5

The process of meiosis in the sex organs or gonads

Question 6

What are the sex organs or gonads?

Answer 6

Ovaries or testes

Question 7

What are the gonads responsible for?

Answer 7

Gametogenesis and the production of sex hormones (estrogen, progesterone, and testosterone)

Question 8

Humans don’t reproduce in what way?

Answer 8

Asexually (cloning)

Question 9

How are the male gametes produced?

Answer 9

By 500 meters of coiled seminiferous tubules within the paired testes.

Question 10

What is Spermatogenesis?

Answer 10

Sperm Production

Question 11

Where does Spermatogenesis occur?

Answer 11

Continuously in the walls of the seminiferous tubules

Question 12

How long does it take for a single spermatozoon to produce?

Answer 12

8-9 weeks

Question 13

How much ejaculation is considered to cause infertility? What is normal?

Answer 13

Less than 100 million sperm per ejaculation. 300-400 is normal.

Question 14

The tubules will have how much spermatozoa in production at any given time?

Answer 14

Couple billion

Question 15

What is the individual spermatozoon highly specialized for?

Answer 15

Delivering its genetic payload

Question 16

What does the spermatozoon consist of?

Answer 16

Nucleus (w/genetic information, flagellum for mobility, a mitochondrion (to supply energy) modified lysosome (acrosome) at its head.

Question 17

What does the acrosome contain?

Answer 17

Powerful hydrolytic enzymes that will enable the sperm to digest its way through cervical mucus and the protective coating around the egg.

Question 18

How long can ejaculated sperm survive? What are the odds?

Answer 18

Up to 5 days. The odds are there won’t be enough survivors to accomplish fertilization after 48 hours.

Question 19

How are immature spermatozoa transported?

Answer 19

From the seminiferous tubules immature spermatozoa are transported to a 7 meter long coiled tube called the epididymis.

Question 20

Where is the epididymis located?

Answer 20

Backpack-like sac on the testis.

Question 21

What does the epididymis store and for how long?

Answer 21

Sperm for up to 3 months.

Question 22

During intercourse how does sperm move?

Answer 22

Sperm moves through the vas deferens which extend up into the body cavity, over the top of the unitary bladder, and backdown to the seminal vesicles just behind the bladder.

Question 23

What do seminal vesicles produce?

Answer 23

A secretion containing fructose which nourishes sperm, and prostaglandins which cause muscular contractions in the uterus and fallopian tubes which may help sperm reach egg.

Question 24

Where does the fructose and prostaglandins enter?

Answer 24

Prostate gland

Question 25

What does the prostate gland contribute?

Answer 25

Milky alkaline fluid that helps to neutralize the acidic female reproductive tract.

Question 26

At the prostate gland, what does the vas deferens join?

Answer 26

The urethra or Cowper's Glands, which runs from the urinary bladder through the prostate, and out through the shaft of the penis.

Question 27

Where is the bulbourethral (or Cowper's) glands located?

Answer 27

On the urethra at the base of the penis

Question 28

What do the Cowper's glands contribute?

Answer 28

A mucoid secretion that may facilitate the movement of seminal fluid through the remainder of the urethra.

Question 29

What makes up the seminal fluid/semen?

Answer 29

Sperm, secretions of seminal vesicles, prostate and Cowper's Glands make up the seminal fluid or semen. 3-6 millimeters per ejaculation.

Question 30

How is an erection accomplished? What mammals don't utilize this method?

Answer 30

Blood flowing into spongy erectile tissues, the twin corpora cavernosa and the single corpus spongiosum. Bats and walruses don't utilize this method, they have a penis bone instead (os penis or baculum)

Question 31

How does the testes descend?

Answer 31

From the body cavity into the scrotum during the ninth month of fetal life. It is essential because human body temperature is too warm for normal spermatogenesis.

Question 32

Who do cremaster muscles do?

Answer 32

In the adult male cremaster muscles raise or lower the testes depending on the environmental temperature.

Question 33

What results in overheated testes and impaired spermatogenesis?

Answer 33

Tight underwear, hot spas, and undescended testes (cyrptochidism) can result in overheated testes and impaired spermatogenesis.

Question 34

What is castration?

Answer 34

Removal of the testes which removes the source of testosterone production and that hormone's effects

Question 35

What is a vasectomy?

Answer 35

Male sterilization operation, vas deferens cut or tied - blocks release of sperm.

Question 36

Where is testosterone produced?

Answer 36

Interstitial cells that are scattered between and outside of the seminiferous tubules

Question 37

Where is testosterone secreted?

Answer 37

Directly into blood capillaries within the testes and carried through veins from the scrotum. The blood flow (testosterone delivery) is not disrupted by cutting off and tying the vas deferens.

Question 38

What are the effects of Testosterone?

Answer 38

Maturation and development of sex organs, body hair, thickening of the skin, hypertrophy - enlargement of larynx (voice box) increasing glandular secretion - including sweat and body odor, hypertrophy of bone and muscle (the tissue-building or anabolic effect) an increase in metabolic rate, and expression of the male pattern baldness gene.