lecture 35 - male reproductive system 2

Question 1

What is the purpose of having the testes in the scrotum on the outside of the abdomen?

Answer 1

Maintains a lower temperature than the body - 34 degrees celsius - which is optimum for spermatozoa development

Question 2

What is the optimum temperature for spermatozoa development?

Answer 2

~34 degrees celsius

Question 3

What is the name of the muscle that lines the scrotum?

Answer 3

Dartos muscle

Question 4

How does the dartos muscle minimise heat loss from the scrotum?

Answer 4

Wrinkles the skin of the scrotum to reduce surface area for heat loss

Question 5

Where is the cremaster muscle located?

Answer 5

Covers the testes and spermatic cords of the scrotum.

Question 6

What is the function of the cremaster muscle?

Answer 6

Contracts to draw the testes up towards the body to conserve heat in the testes

Question 7

Where do the spermatic cords run between?

Answer 7

The abdomen and testes

Question 8

What do the spermatic cords contain?

Answer 8

Ductus deferens, blood vessels (testicular arteries and veins), nerves, lymphatics

Question 9

What is the function of the venous/pampiniform plexus of the spermatic cords?

Answer 9

Forms a network around the arteries supplying the testes and allows the transfer of heat from the arteries to the cooler retuning blood to cool it to testicular temperature, and to warm the returning blood

Question 10

What are the 2 functions of the penis?

Answer 10

Urination, copulation

Question 11

What is the shape of the penis?

Answer 11

‘Cylindrical’

Question 12

What is the name for the base of the penis that adheres it to the body wall?

Answer 12

The root/bulb

Question 13

What is the name for the main length of the penis?

Answer 13

The body

Question 14

What is the name for the head of the penis?

Answer 14

The glans penis

Question 15

What is the glans penis covered by?

Answer 15

Prepuce/foreskin

Question 16

What are the 3 cylindrical erectile tissues of the penis?

Answer 16

2 corpora cavernosa, 1 corpus spongiosum.

Question 17

What is the main erectile tissue of the penis?

Answer 17

The 2 corpora cavernosa

Question 18

Where are the corpora cavernosa located?

Answer 18

On the dorsal aspect of the penis (when erect)

Question 19

Where is the corpus spongiosum located?

Answer 19

On the ventral aspect of the penis (when erect)

Question 20

What do the corpora cavernosa branch into?

Answer 20

They run adjacent until forking out in the crura (singular crus) or roots of the penis

Question 21

What penis erectile tissue is the urethra contained within?

Answer 21

The corpus spongiosum

Question 22

What are the bulb and glans of the penis formed from?

Answer 22

The corpus spongiosum erectile tissue

Question 23

What is the key reason that the corpus spongiosum does not become as erect as the corpus cavernosum?

Answer 23

Corpus spongiosum contains that urethra, so excess erection would flatten the urethra inhibiting the passage of sperm

Question 24

In what medium are spermatozoa carried to the female reproductive tract in?

Answer 24

In seminal fluid

Question 25

What is the name for the combination of spermatozoa and seminal fluid?

Answer 25

Semen

Question 26

What are the purposes of seminal fluid?

Answer 26

Provides fluid medium for efficient transport of spermatozoa, activates spermatozoa propulsion abilities and provides nutrients and energy, protects against an acidic environment in penis and particularly in the female vagina.

Question 27

What protects spermatozoa from the acidic environment of the female vagina during intercourse?

Answer 27

Seminal fluid

Question 28

Where is seminal fluid produced?

Answer 28

In 3 accessory glands - seminal vesicles, prostate gland, bulbourethral glands

Question 29

What are the seminal vesicles?

Answer 29

Glands in males that secrete alkaline seminal fluid

Question 30

How many seminal vesicles do males have?

Answer 30

2

Question 31

Where are the seminal glands located?

Answer 31

posterior to the bladder, lateral to the ampulla

Question 32

What is the physical nature of the secretion from the seminal vesicles?

Answer 32

Viscous

Question 33

What proportion of semen is secreted by the seminal vesicles?

Answer 33

60%

Question 34

What is the relative pH of seminal vesicles secretions, and why?

Answer 34

Alkaline - too protect spermatozoa from acidic environment in urethra and vagina

Question 35

Where is the prostate gland located?

Answer 35

Inferior to the bladder and wrapped around the prostatic urethra

Question 36

What proportion of semen is secreted by the prostate gland?

Answer 36

30%

Question 37

What is the relative pH of secretions from the prostate?

Answer 37

slightly acidic

Question 38

What is a distinctive component of seminal fluid from the prostate?

Answer 38

PSA - prostate-specific antigen

Question 39

What is the function of PSA rich secretions from the prostate?

Answer 39

Contributes to sperm activation, viability and motility

Question 40

How many bulbourethral glands do males have?

Answer 40

2

Question 41

Where are the bulbourethral glands located?

Answer 41

In the urogenital diaphragm

Question 42

Where do the bulbourethral glands open into?

Answer 42

The spongy/penile urethra

Question 43

What proportion of semen is made by the bulbourethral glands?

Answer 43

5%

Question 44

What is the function of bulbourethral glands secretions?

Answer 44

Lubrication and neutralise acidity in urethra prior to ejaculation

Question 45

What proportion of semen is mace up of spermatozoa?

Answer 45

5%

Question 46

What is a vasectomy?

Answer 46

Surgical method of male sterilisation where the ductus deferens are cut and then tied or cauterised.

Question 47

What affect does a vasectomy have on the volume of semen?

Answer 47

No decrease in seminal fluid volume because glands unaffected. However, with no spermatozoa in semen, there is a 5% decrease in semen volume.

Question 48

What is gametogenesis?

Answer 48

The formation of gametes/sex cells

Question 49

What is the name for the process of gametogenesis in males?

Answer 49

Spermatogenesis

Question 50

What is the name for the process of gametogenesis in females?

Answer 50

oogenesis

Question 51

Are gametes diploid or haploid?

Answer 51

Haploid

Question 52

What are the products of meiosis 1?

Answer 52

2 haploid cells are produced from 1 original diploid cell

Question 53

What are the products of meiosis 2?

Answer 53

Each haploid cell produced from meiosis 1 divides to product 2 haploid cells with 23 chromosome.

Question 54

What transformation occurs in spermatogenesis?

Answer 54

Spermatogonia are transformed to mature spermatozoa

Question 55

What are the 2 types of spermatogonia after mitosis?

Answer 55

Type A and Type B

Question 56

Where are spermatogonia/stem cells located before/during the first division?

Answer 56

The basement membrane of the seminiferous tubules

Question 57

Where does the type A spermatogonium sit during spermatogenesis?

Answer 57

Stays at the basement membrane of the seminiferous tubule

Question 58

Which spermatogonia (type A or B) will differentiate into a primary spermatocyte which will undergo meiosis 1?

Answer 58

Type B

Question 59

What happens to primary spermatocytes in spermatogenesis?

Answer 59

They undergo meiosis 1 to form 2 secondary haploid spermatocytes

Question 60

What happens to the 2 secondary spermatocytes formed from each cell in spermatogenesis?

Answer 60

Undergo meiosis 2 to form 4 total haploid round spermatic spermatids.

Question 61

What is the shape of spermatids?

Answer 61

Round

Question 62

What is the name of the process in which spermatids differentiate into spermatozoa?

Answer 62

Spermiogenesis

Question 63

What is spermiogenesis?

Answer 63

The process of different ion of a round spermatid into spermatozoa with head, body and tail

Question 64

Where are spermatozoa released after differentiation from spermatids?

Answer 64

The lumen of seminiferous tubules

Question 65

What organelle is abundant in developing spermatozoa, and why?

Answer 65

Mitochondria - vital for motility

Question 66

What is the general name for a hormone that acts on the gonads?

Answer 66

Gonadotropin

Question 67

What does GnRH stand for?

Answer 67

Gonadotropin releasing hormone

Question 68

Where is GnRH (gonadotropin releasing hormone) produced?

Answer 68

The hypothalamus

Question 69

What hormones does GnRH stimulate the release of?

Answer 69

LH (luteinising hormone) and FSH (follicle stimulating hormone) from the anterior pituitary

Question 70

What gonadotropins are released by the anterior pituitary?

Answer 70

LH (luteinising hormone) and FSH (follicle stimulating hormone)

Question 71

Where is LH (luteinising hormone) produced?

Answer 71

The anterior pituitary gland

Question 72

Where is FSH (follicle stimulating hormone) produced?

Answer 72

The anterior pituitary

Question 73

What hormone is released from nurses/sertoli cells?

Answer 73

Inhibin

Question 74

Where is inhibin produced in males?

Answer 74

Nurse cells in the testes

Question 75

Where is testosterone produced?

Answer 75

Interstitial endocrine cells in the testes

Question 76

What type of hormone is testosterone?

Answer 76

An androgen - type of steroid hormone

Question 77

What is the function of androgens?

Answer 77

Responsible for male characteristics: maturation of sex organs, spermatogenesis, secondary sex characteristics, libido

Question 78

What is the process of the negative feedback loop involved in male gonadotropin regulation?

Answer 78

GnRH released by hypothalamus, stimulates FSH (stimulates inhibin production) and LH (which stimulates testosterone production in testes), FSH and testosterone control spermatogenesis. Inhibin suppresses FSH production and testosterone suppresses LH and GnRH production, creating a negative feedback loop