Reproductive system: Male reproductive tract

Question 1

What happens if the testes don’t descend?

Answer 1

Males are infertile –> Cryptorchidism

Question 2

Label the diagram

Answer 2

Question 3

Label the diagram

Answer 3

Question 4

What is the movement of sperm from formation to ejaculation?

Answer 4

It is produced in the seminiferous tubules which then coalesces in the rate testis. The sperm then seperate again into the epididymis and then is transported by the vas deferens over the bladder and through the ejactulatory duct and out the penis

Question 5

What does the epididymis do?

Answer 5

It matures sperm, gives it the ability to be motile and fertilise and reabsorbs liquid (therefore concentrates it)

Question 6

How long does it take for sperm to get its motile and fertilising abilities?

Answer 6

10-14 days

Question 7

Where are sperm stored primarily?

Answer 7

Vas deferens

Question 8

What is the average length of the vas deferens? Where does it run from?

Answer 8

45cm

Runs from the epididymis up and around the bladder down to ejaculatory duct

Question 9

What is the purpose of the seminal vesicles?

Answer 9

Secretes a mucoid substance that is alkaline, contains fructose, prostaglandins and clotting proteins

Question 10

What might the function of prostaglandins be?

Answer 10

Induce contractions in the female reproductive tract

Question 11

What are the three components of ejaculatory fluid?

Answer 11

1 - Prostatic fluid

2 - Sperm

3 - Seminal vesicle fluid

Question 12

What is the purpose of the prostate fluid?

Answer 12

It is a secretion that is slightly acidic, contains citrate (for ATP), contains calcium and phosphate and contains Prostate Specific Antigen

Question 13

What is the purpose of the clotting proteins in seminal vesicles?

Answer 13

Holds the seminal fluid in the vagina (like a clot) to prevent it from falling out

Question 14

What is the purpose of Prostate Specific Antigen (PSA)?

Answer 14

Breaks down the co-agulum after a few minutes from the seminal vesicular fluid allowing the sperm to continue moving up to the fallopian tube

Question 15

What is the composition of semen?

Answer 15

Sperm = 10%

Seminal vesicle fluid = 60%

Prostatic fluid = 30%

Question 16

What is the pH of the semen? Explain

Answer 16

7.5, the strong base of the seminal vesicular fluid and the prostatic fluid buffer each other

Question 17

What is Benign Prostatic Hyperplasia (BPH)?

Answer 17

It is excessive growth of the prostate gland

Question 18

What happens as the prostate gland grows?

Answer 18

As the prostate gland grows it is unable to expand outwards because the bladder is hard, this causes inwards growth which results in the prostatic urethra (shared duct into penis for both reproduction and urinal removal) being restricted

Question 19

What is the affect of the prostatic urethra being restricted?

Answer 19

It means that bladder cannot empty completely which causes weakening of the bladder and potential urinary tract infections which could spread to the kidney and cause kidney disease

Question 20

What are some non-invasive methods of treating Benign Prostatic Hyperplasia (BPH)?

Answer 20

Using Selective 5 α - reductase inhibitors finasteride and dutasteride

Question 21

What does the Selective 5 α - reductase do?

Answer 21

It is an enzyme which converts testosterone into its more potent form, dihydrotestosterone

Question 22

What do the Selective 5 α - reductase inhibitors do?

Answer 22

They (i.e. finasteride and dutasteride) inhibit Selective 5 α - reductase so that testosterone is not convert into dihydrotestosterone

Question 23

How does reducing the amount of dihydrotestosterone stop BHP?

Answer 23

BHP is an androgen dependent disease. By removing the more potent androgen, dihydrotestosterone, the prostate growth can be stopped or reversed

Question 24

Prostate cancer is a major disease, who many cancer cases in men are caused by prostate cancer?

Answer 24

29%

Question 25

How is prostate detected?

Answer 25

The amount of PSA produced (Prostate Specific Antigen) increases with prostate cancer and this can be detected

Question 26

What are some of the ways to cure prostate cancer?

Answer 26

Androgen depletion (using Selective 5 α - reductase inhibitors, castration or inhibition or androgen synthesis), block the androgen receptors or perform a prostatectomy (prostate surgery)

Question 27

In New Zealand PSA testing is NOT recommended for men, why is this?

Answer 27

PSA testing has a high number of false positives, the cancer is relatively benign (most people die with, rather than because of it) and to treat it with surgery causes a high rate of complications such as incontinence, erectile disfunction and death

Question 28

What are the main structures of the penis?

Answer 28

Corpora cavernosa, corpus spongiosum and penile urethra

Question 29

What is the function of the Corpora cavernosa?

Answer 29

The main erectile tissue that fills with blood to make the penis stiff

Question 30

What is the function of the corpus spongiosum?

Answer 30

Surrounds the penile urethra and prevent occlusion (closing) during erection

Question 31

What is the function of the penile urethra?

Answer 31

Conduct the semen and urine

Question 32

What causes an erection?

Answer 32

NO (Nitrogen oxide) and Prostaglandin E1 causes the smooth muscle of the corpora cavernosa to relax (vasodilation). This then causes blood to easily get into the corpora cavernosa and also closes the vein that drains it resulting in a large increase in internal pressure creating an erection

Question 33

During an erection, how is the penile urethra kept open?

Answer 33

The spongy urethra also fills with blood creating outwards pressure preventing the corpus cavernosa from completely closing

Question 34

How does viagra create an erection?

Answer 34

Viagra inhibits phosphodiesterase, an enzyme that breaks down GMP (GMP is the 2nd intracellular messenger that reduces Ca2+ inside a cell causing muscle relaxation). By preventing the break down of GMP, there can be more relaxation therefore more blood fills the corpus cavernosum