Male reproductive system

Question 1

what bones make up pelvis

Answer 1

sacrum + ilium + ischium + pubis + coccyx

Question 2

joints of pelvis

Answer 2

acetabulum (hip bone + femur), sacroiliac (sacrum + ilium) and pubic symphysis (pelvis + femur)

Question 3

pelvic inlet

Answer 3

top of pelvic bone - open, always larger than outlet

Question 4

pelvic outlet

Answer 4

bottom of pelvic bone, closed by muscles

Question 5

subdivisions of pelvis

Answer 5

false/greater and true/lesser

Question 6

features of false/greater pelvis

Answer 6

Superior region, Above pelvic inlet, Contains GI tract

Question 7

features of true/lesser pelvis

Answer 7

Inferior region, Between inlet and outlet, Contains internal reproductive organs

Question 8

female pelvis

Answer 8

Broader subpubic angle, Oval inlet, Straighter coccyx - facilitate childbirth

Question 9

male pelvis

Answer 9

Narrower subpubic angle, Heart shaped inlet, Curved coccyx

Question 10

pelvic floor muscles + openings

Answer 10

Two muscles: levator ani (ant.) and coccygeus (post.). Openings are urethra, anal canal and vagina (in females)

Question 11

perineum

Answer 11

Region inferior to the pelvic floor and between upper region of the thighs. Contains external genitalia and anus

Question 12

urogenital triangle

Answer 12

anterior, urethral/vaginal opening and external genitalia

Question 13

anal triangle

Answer 13

posterior, anal canal and fat

Question 14

male reproductive tract

Answer 14

Testes –> Epididymis –> Ductus (vas) deferens –> Ejaculatory duct –> Urethra

Question 15

what does scrotum contain

Answer 15

2 testes; 2 spermatic cords; arteries and veins

Question 16

function of testes

Answer 16

produce sperm, testosterone and inhibin

Question 17

what surrounds testes

Answer 17

dense fibrous capsule called tunica albuginea which invaginates into testes to form seminiferous tubules in which sperm is produced

Question 18

structure of seminiferous tubules

Answer 18

Testes have lobules containing seminiferous tubules. Tubules join to form rete testis. Join to form ductules leading to epididymis

Question 19

cells in seminiferous tubules and what they produce

Answer 19

Leydig cells produce testosterone. Sertoli cells produce inhibin. Spermatogenic cells produce spermatozoa

Question 20

blood-testis barrier

Answer 20

sertoli cells joined by tight junctions to form a lining around inside of seminiferous tubules

Question 21

features of epididymis

Answer 21

Sperm enter from seminiferous tubules and exit via ductus deferens.

Site of sperm maturation. By the time sperm exits, sperm is fully capable of swimming and fertilising

Very long when unravelled (60m)

Question 22

features of ductus deferens

Answer 22

In spermatic cord

Covered by smooth muscle - for ejaculation

Runs behind urinary bladder

Dilates to form ampulla

Storage site for sperm

Question 23

structure of spermatic cord

Answer 23

One on each side

Runs between abdomen and testes

Contains:

• ductus deferens
• blood vessels - testicular arteries and veins
• nerves
• lymphatics

Question 24

ejaculatory duct

Answer 24

Formed by the union of the duct from the seminal vesicle and the ampulla

Opens in the prostatic urethra

Question 25

structure of male urethra

Answer 25

Epithelium changes: transitional, columnar, stratified squamous 3 sections: prostatic, membranous, penile/spongy urethra 2 sphincters: * External: skeletal muscle, voluntary control of urination * Internal: detrusor muscle

Question 26

function of internal sphincter

Answer 26

Closes bladder thus ensures sperm ejaculated through the urethra Retrograde ejaculation: sphincter doesn’t close, therefore sperm ends up in bladder

Question 27

2 functions of penis

Answer 27

urination and copulation

Question 28

two types of erectile tissue in penis

Answer 28

1. 2 corpora cavernosa - main erectile tissue, dorsally located 2. 1 corpus spongiosum - contains urethra, forms bulb and glans, ventrally located when erect

Question 29

muscles in scrotum

Answer 29

Dartos lines scrotum and cremaster holds testes

Question 30

function of dartos muscle

Answer 30

smooth muscle that contracts to wrinkle skin to make scrotum smaller so less SA for heat exchange, when its cold

Question 31

function of cremaster muscle

Answer 31

come from inside and contract to draw testes up into body for heat conservation

Question 32

structure of seminal vesicle

Answer 32

2 of them Location = Posterior to bladder and lateral to ampulla or ductus deferens Merges with ampulla to form ejac duct

Question 33

function of seminal vesicle

Answer 33

Produce viscous secretion - 60% of semen, fructose to nourish sperm, alkaline pH to protect against acidic vagina

Question 34

function of prostate gland

Answer 34

Produces secretion - 30% of semen; slightly acidic, milky fluid containing enzymes (PSA - prostate specific antigen); contains citrate to nourish sperm; contributes to sperm activation, viability and motility

Question 35

location of bulbourethral glands

Answer 35

2 glands located in the urogenital diaphragm - part of pelvic floor Ducts open into spongy/penile urethra

Question 36

function of bulbourethral glands

Answer 36

Contribute 5% of semen volume Secretions lubricate and wash out urinary acids in urethra prior to ejaculation

Question 37

process of spermatogenesis

Answer 37

1. During development, spermatogonia migrate from yolk sac to testes and remain dormant until puberty 2. At puberty, spermatogonia divide by mitosis into type A and type B spermatogonia 3. Type B spermatogonia differentiates into primary sex cell (primary spermatocyte - diploid), which undergoes meiosis I 4. Forms secondary spermatocytes (haploid n) 5. These undergo meiosis II to form spermatids (haploid) 6. Spermatids differentiate into spermatozoa with a head, body and tail via spermiogenesis 7. Spermatozoa released into lumen 8. 1 type B spermatogonium forms 4 spermatozoa

Question 38

spermiogenesis

Answer 38

maturation of Spermatid to spermatozoa Develop tail Nucleus condenses Mitochondria contained in midpiece Shed any unnecessary cytoplasm

Question 39

Luteinising hormone

Answer 39

gonadotropin from ant. pit, stimulates Leydig cells to secrete testosterone. Testosterone gives negative feedback to ant. pit

Question 40

follicle stimulating hormone

Answer 40

gonadotropin from ant. pit, controls spermatogenesis. Inhibited by inhibin

Question 41

testosterone

Answer 41

from Leydig cells, it is an androgen - hormone which develops male characteristics (gonads into testes; spermatogenesis; aggression & libido)

Question 42

GnRH

Answer 42

gonadotropin releasing hormone released from hypothalamus