Reproduction 2

Question 1

Name the 5 main components of the male reproductive system

Answer 1

Scrotum
Testes
Ducts 
Accessory Glands
Penis

Question 2

Describe the Scrotum

Answer 2

external supporting structure for testes connected at root of penis, consists of loose skin and a subcutaneous layer, divided into 2 compartments - each containing one testicle, location of scrotum and associated muscle contractions regulate temp within tests for optimum sperm production

Question 3

Describe the Testes

Answer 3

paired oval glands, approx 5cm long x 2.5cm diameter, approx 10 - 15g, develop just below kidneys and descend before birth into scrotal sac, left testicle = usually 1cm lower than right due to a longer spermatic cord

Question 4

Name the 2 layers that make up the structure of the testes

Answer 4

Tunica vaginalis

Tuncia albuginea

Question 5

Describe the tunica vaginalis of the testes

Answer 5

derived from peritoneum, encapsulated tests and is formed during testes descent

Question 6

Describe the tunica albuginea of the testes

Answer 6

white, fibrous capsule surrounding each testicle, projects into the testicular parenchyma to form septa (partitions) which divide the testis into approx 200 or more cone shaped lobules

Question 7

Describe what the lobules of the tunica albuginea do

Answer 7

contain 1-3 coiled seminiferous tubules which produce sperm and Leydig cells which secrete testosterone - masculinising hormone
the tubules eventually unite to form the rete testis which drain into the epididymis where the sperm is stored

Question 8

Describe Sperm (Spermatogenesis)

Answer 8

mature sperm have a head, body and tail
head is nucleus and filled with DNA - also contains enzymes to penetrate ovum
body contains mitochondria to fuel tail
tail propels sperm along female reproductive tract

Question 9

Hormones secretion has an effect on the following …

Answer 9

Spermatogenesis
Dev. of 2ndry sex characteristics
Dev. of accessory organs (prostate and seminal vesicles)
Influences on adult male sexual behaviour
Male distribution of fat, muscle & hair
Narrow pelvis & wide shoulders
Skin thickening
Larynx enlargement - deepening voice
Promotes closing of epiphyses
Electrolyte metabolism
Libido
Dev. of the male foetus

Question 10

Name the 3 ducts

Answer 10

Epididymis
Vas deferens
Ejaculatory ducts

Question 11

Describe the Epididymis

Answer 11

lies posteriorly to each testicle, approx. 4cm, consist of tightly coiled ductus epididymis - approx. 6cm long, has a head, body & tail
head = larger, superior portion, joins efferent duct from testes
body = narrow, mid portion
tail = smaller, inferior portion, continues as vas deferens

Question 12

Describe the roles of the epididymis

Answer 12

stores sperm and moves them on by peristalsis, provides a pathway from the testis to the exterior, is involved in sperm maturation and increasing sperm motility, secretion of some seminal fluid

Question 13

Describe the vas deferens

Answer 13

known as seminal ducts, ascends the posterior border of the epididymis, consists of 3 muscular layers = outer & inner are longitudinal muscle fibres, middle layer of circular muscle

Question 14

Describe the roles of the vas deferens

Answer 14

conveys sperm from epididymis toward urethra by peristalsis during sexual arousal, surrounded by testicular artery, autonomic veins, the cremaster muscle and lymphatics - all enclosed in fibrous connective covering, all ascend from testes and pass through the inguinal canal as the spermatic cord

Question 15

Describe the ejaculatory ducts

Answer 15

2 ducts, formed at the union of the vas deferens and the ducts of the seminal vesicles, enter the upper, posterior aspect of the prostate, approx 2cm long, directly connected to urethra at the prostatic utricle

Question 16

Describe the Seminal Vesicles - Accessory Glands

Answer 16

pouch-like structures, 5cm, secrete an alkaline, viscous fluid through seminal vesicle ducts, forms 60% of semen volume, contains fructose used by sperm for energy to maintain motility after ejaculation

Question 17

Describe the alkaline nature of the fluid and what roles fibrinogen and testosterone play

Answer 17

The alkaline nature helps neutralise the acidity of the vagina - also contains prostaglandins and fibrinogen
Fibrinogen assists in the coagulation of the semen after ejaculation
Testosterone influences the volume of seminal vesicle secretions

Question 18

Describe the Prostate - Accessory Glands

Answer 18

4cm x 3cm x 2cm, size increases slowly until puberty, then rapidly expands until age 30, further enlargement may occur after age 45, inferior to baller, surrounds prostatic urethra

Question 19

Describe the tubuloalveloar glands of the prostate

Answer 19

approx 30 small tubuloalveolar glands, some of which open into the urethra, the prostate secrets a thin alkaline substance which constitutes about 25% of seminal fluid, this protects sperm from the acid environment within the vagina, contributes to sperm motility as they prefer alkaline environment

Question 20

Describe the Bulbourethral Glands - Accessory Glands

Answer 20

Inferior to the prostate, size of a pea, ducts open in to spongy urethra, during sexual arousal - secrete an alkaline fluid into urethra that protects passing sperm from acidity in urine, secrete mucus that lubricates end of penis and lining of urethra - reaching number of damaged sperm

Question 21

Describe the Urethra

Answer 21

extends from neck of bladder to end of penis, approx 15-20cm long, divided into 3 sections

Question 22

Name the 3 sections of the urethra

Answer 22

Prostatic Urethra
Membranous Urethra
Penile Urethra

Question 23

Describe the Prostatic urethra

Answer 23

passes through prostate, approx 2-3cm long, prostatic duct opens here, ejaculatory ducts also opens into prostatic urethra at a point called prostatic utricle

Question 24

Describe the Membranous urethra

Answer 24

middle section, from apex of prostate to bulb of penis, approx 1cm long, surrounded by urethral sphincter

Question 25

Describe the Penile urethra

Answer 25

approx 10-15cm long

Question 26

Describe the Penis

Answer 26

formed 3 cylindrical masses of erectile tissue enclose in individual fibrous coverings called tunica albuginea, the 2 larger masses of erectile tissue are the corpora cavernosa

Question 27

Name the smaller mass within the penis

Answer 27

the smaller mass containing the urethra is called the corpus spongiosum - distal part is slightly bulging forming the glans penis

Question 28

Describe the Prepuce and External urethral meatus of the penis

Answer 28

Prepuce/Foreskin = loose covering of skin that covers the gland, folds in on itself and is retractable
External urethral meatus = opening of the urethra at tips of glans