Reproduction 2 Flashcards
Name the 5 main components of the male reproductive system
Scrotum Testes Ducts Accessory Glands Penis
Describe the Scrotum
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
Describe the Testes
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
Name the 2 layers that make up the structure of the testes
Tunica vaginalis
Tuncia albuginea
Describe the tunica vaginalis of the testes
derived from peritoneum, encapsulated tests and is formed during testes descent
Describe the tunica albuginea of the testes
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
Describe what the lobules of the tunica albuginea do
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
Describe Sperm (Spermatogenesis)
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
Hormones secretion has an effect on the following …
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
Name the 3 ducts
Epididymis
Vas deferens
Ejaculatory ducts
Describe the Epididymis
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
Describe the roles of the epididymis
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
Describe the vas deferens
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
Describe the roles of the vas deferens
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
Describe the ejaculatory ducts
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
Describe the Seminal Vesicles - Accessory Glands
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
Describe the alkaline nature of the fluid and what roles fibrinogen and testosterone play
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
Describe the Prostate - Accessory Glands
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
Describe the tubuloalveloar glands of the prostate
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
Describe the Bulbourethral Glands - Accessory Glands
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
Describe the Urethra
extends from neck of bladder to end of penis, approx 15-20cm long, divided into 3 sections
Name the 3 sections of the urethra
Prostatic Urethra
Membranous Urethra
Penile Urethra
Describe the Prostatic urethra
passes through prostate, approx 2-3cm long, prostatic duct opens here, ejaculatory ducts also opens into prostatic urethra at a point called prostatic utricle
Describe the Membranous urethra
middle section, from apex of prostate to bulb of penis, approx 1cm long, surrounded by urethral sphincter
Describe the Penile urethra
approx 10-15cm long
Describe the Penis
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
Name the smaller mass within the penis
the smaller mass containing the urethra is called the corpus spongiosum - distal part is slightly bulging forming the glans penis
Describe the Prepuce and External urethral meatus of the penis
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
