Male reproductive system (1)

Question 1

What makes up the reproductive organs? (4)

Answer 1

• Primary sex organs – the testis
• Ducts – epididymis, sperm duct (vas deferens) and urethra • Accessory glands – e.g. prostate gland
• External genitalia – the penis

Question 2

What is the scrotum?

Answer 2

The scrotum contains the testis.

Question 3

What is the function of the scrotum?[2]

Answer 3

1. The scrotum acts as a temperature regulator, keeping the testis 2 to 3°C lower than body temperature. The lower temperature is necessary for the formation of fertile sperm. In cold conditions testis are pulled closer to the abdomen for warmth. In warm weather the testis are suspended well away from the body. In this way the developing sperm are always kept at a constant temperature.
2. The scrotum houses and protects the testis.

Question 4

What are the testis?

Answer 4

The testis, two oval structures, are suspended outside the body in the scrotum.

Question 5

In the _____ stage the testis are in the abdominal cavity just below the kidneys. Before birth they descend into the scrotum

Answer 5

embryonic

Question 6

What is the structure of the testis? (3)

Answer 6

• The testis consist of many compartments or lobules, which contain highly convoluted tubules, the seminiferous tubules. These total about 250 metres in each testis.
• Germinal epithelium lines the tubules.
• Between the tubules are groups of endocrine cells, the interstitial cells, or cells of Leydig.

Question 7

What are the functions of the testis?

Answer 7

The testis produce:

1. sperm (male gametes), by the germinal layer
2. testosterone (a male hormone), by the interstitial cells

Question 8

What is the vas deferens?

Answer 8

The muscular sperm ductis a continuation of the epididymis. It leaves the scrotum, passes through the prostate gland and then enters the urethra.

Question 9

What is the function of the sperm duct?

Answer 9

The sperm duct pushes mature sperm forward by strong peristaltic waves, from the epididymis into the urethra. This is known as ejaculation

Question 10

What is a peristaltic wave?

Answer 10

peristaltic wave = strong contraction of smooth muscle in the walls of ducts

Question 11

What is the urethra?

Answer 11

The urethra is the duct at the end of the uro-genital system leading to the exterior.

Question 12

What is the function of the urethra?

Answer 12

The urethra forms a common duct for thetransportation of semen and urine, although these two processes never occur together.

Question 13

What is a prostate gland?

Answer 13

The prostate gland, a plum-sized gland, surrounds the urethra at the base of the bladder.

(With increasing age this gland may enlarge and exert pressure on the urethra, which slows down the emptying of the bladder. The prostate gland can be removed surgically. )

Question 14

What is the function of the prostate gland?

Answer 14

The prostate gland secretes a fluid that aids the transport of the spermand contains enzymes that make sperm more active. This fluid makes up about 1/3 of the seminal fluid (semen).

Question 15

Where are the Cowper’s glands found?

Answer 15

The two Cowper’s glands are found at the base of the penis

Question 16

What is the function of the Cowper’s gland?

Answer 16

Cowper’s glands produce an alkaline mucous-like fluid when sexually aroused. This fluid: 1.neutralizes acidic urine that may still be present in the urethra. 2.lubricates the urethra and external urethral opening to protect sperm from mechanical damage during ejaculation.

Question 17

The urethra passes down the male external organ, the ____.

Answer 17

penis

Question 18

What tissue does the penis consist of?

Answer 18

The penis consists of special spongy tissue (erectile tissue).

Question 19

What are the three sections of erectile tissue in the penis?

Answer 19

Running the length of the penis there are three sections of erectile tissue. Two are situated on the dorsal side, the corpus cavernosa, and one on the ventral side, the corpus spongiosum.

Question 20

How does an erection come about?

Answer 20

The primary mechanism that brings about an erection is the dilation of dorsal and central arteries supplying blood to the penis. This allows more blood to fill the three spongy erectile tissue chambers, causing the penis to lengthen and stiffen. This is called an erection. Without an erection sperm cannot be transferred to the female’s vagina during sexual intercourse.

Question 21

What is the function of the penis?

Answer 21

The penis deposits semen with sperm into the female’s vagina during copulation. In this way sperm are brought closer to the egg for fertilisation, which increases the chance of fertilisation.

Question 22

What is distinctive about the human penis? (2)

Answer 22

• The human male is the only mammal that has no erectile bone (baculum) in the penis; it relies entirely on engorgement (filling up) with blood to reach its erect state.
• The human penis is not attached to the abdominal wall but hangs free. This is in contrast to most other mammals where the penis is stored internally until erect.

Question 23

What does semen consist of? (2)

Answer 23

Semen consists of:

• sperm from the testis • seminal fluid from the sperm duct and accessory glands, e.g. prostate.

Question 24

What is the difference between an erection and ejaculation?

Answer 24

An erection is the stiffening of the penis. Ejaculation is the expulsion of semen.