male reproductive system Flashcards
what is the inguinal region?
- The groin; junction between anterior abdominal wall and thigh
- Inguinal canal 2.5-4cm long originates from deep to abdominal wall
- Passes infero-medially towards genitalia
- Natural weak point in abdominal wall; inguinal hernia
what is the inguinal canal formed between?
- Anterior: external oblique muscle/fascia
- Posterior: internal oblique muscle/fascia
- Superior: transversus abdominus muscle
- Inferior: inguinal ligament
what does the inguinal canal contain?
- Spermatic cord structures (male) / round ligament and genital nerve
(female)
- Inguinal nerve
what is the deep ring and superficial ring regarding the inguinal canal?
deep ring:
- midway between ASIS and symphysis pubis, lateral to inferior epigastric vessels
- beginning of tubular evagination (‘pouch’) of abdominal wall transversalis fascia covering internal canal structures (internal spermatic fascia)
superficial ring:
- distal end, superficial to pubic tubercle
- Triangular opening through external oblique muscle
- Tubular evagination of external oblique fascia (external spermatic fascia)
what is an inguinal hernia and what are the 2 classifications?
- Protrusion of sac of peritoneum into the inguinal canal
- May contain omental fat or potentially bowel loops
classifications:
-Indirect
-Direct
indirect inguinal hernia
- through the deep inguinal ring (lateral to inferior epigastric
vessels)
- More common (especially in men)
- Result of processus vaginalis remaining open (congenital)
Direct inguinal hernia
- Through weakness of posterior inguinal wall
- Medial to inferior epigastric vessels
- More common in older men; acquired due to weakness
Complications include bowel obstruction and potential strangulation and necrosis.
what are the functions of the male reproductive system? what organs are involved?
- Production, maturation, and storage of sperm
- Delivery of sperm into the female reproductive system
- Excretion of urine
organs-
gonads (testes), ducts, accessory sex glands, penis.
what are the functions of the organs of the male reproductive system
- Gonads - Testes: produce sperm and testosterone
- Ducts: transport, store, and mature sperm
- Accessory sex glands: secrete liquid portion of semen
- Supporting structures -Penis: passage for excretion of urine and ejaculation of sperm
what are the main structures of the male reproductive system?
- scrotum
- testes
- ducts:
-ductus deferens, ejaculatory ducts, urethra
- accessory sex glands:
-Seminal vesicles, prostate gland, bulnourethral glands - penis
what is the scrotum and what describe its features externally and internally
- Pouch / sack supporting testes- (literally means bag)
Externally:
- Loose skin, superficial fascia and smooth muscle separate by median ridge - raphe
- Attached to root of penis
Internally:
- Septum divides into two sacs with a testis
- Fascia/dartos muscle
what are the testes?
- Paired oval glands
- Covered by white fibrous capsule that extends inwards to create internal compartments – 200-300 lobules
- Each lobule contains 1-3 coiled seminiferous tubules
- Seminiferous tubules -lined with spermatogenic cells
what is the role of the testes?
- Against the basement membrane of the tubules are spermatogonia
- Towards the lumen are layers of cells in advancing maturity, once mature they are released into the lumen
- Between the sperm cells are sustentacular cells (Sertoli)
- protect and nourish spermatogenic cells, phagocytize degenerative cells, secret fluid and release the hormone inhibin
- Between the tubules are interstitial cells (Leydig) – secrete testosterone.
what are the ducts of the male reproductive system?
- eminiferous tubules
- Epididymis
- Ductus (vas) Deferens
- Ejaculatory ducts
- Urethra
what are the ducts of the testes
- Continual release of sperm into the lumen of seminiferous tubules, and fluid secreted by the sustentacular cells propels them along the ducts
- Travel through convoluted seminiferous tubules to straight tubules distally and into a network of ducts called the rete testis
- Move then through efferent ducts into epididymis
what is the epididymis?
- Comma-shaped organ on posterior border ofeach testis
- Efferent ducts join epididymis superiorly at head
- Continue as tightly coiled ductus epididymis to form main body
- Smaller distal tail continues as ductus (vas)deferens
what is the ductus epididymis
- 6m long if laid out (<4cm in length when coiled), 1mm diameter
- Site of sperm storage and maturation (up to a month)
- Helps propel the sperm during arousal by peristaltic contraction of the smooth muscle into the ductus (vas) deferens
ductus deferens
- Distal to tail of epididymis on inferior aspect of testis
- Larger diameter, straighter
what is the long course of ductus defers
- Superiorly along posterior aspect of epididymis and penetrates the inguinal canal
- Supero-medially along inguinal canal (part of spermatic cord)
- Through deep inguinal ring and into pelvic cavity,
- Over ureter, and inferiorly along posterior aspect of bladder
- Dilated most distally at ampulla where joins ejaculatory ducts
what are the ejaculatory ducts
- Formed at junction between ampulla of vas deferens and duct from seminal vesicles
- Short - Approximately 2cm long
- Pass from superior to prostate, inferiorly and anteriorly through prostate
- Terminate into prostatic portion of urethra
- Release sperm and secretions from seminal vesicles into the urethra prior to ejaculation
what is the urethra
- The terminal duct
- Conveys both sperm and urine
Passes through:
- inferior portion of the prostate,
- deep muscles of the perineum
-opening is called the external urethral orifice.
what is spermatogenesis
Sperm production – involves Mitosis and Meiosis
mitosis of spermatogonium- somatic cell division
- Stem cell (46 pairs of chromosomes) – divides into two daughter cells (23 pairs of chromosomes)
- Diploid cells – one stays a stem cell, one enters meiosis called primary spermatocyte
meiosis- two cycles of division
- At then end of Meiosis I cells now 2 secondary spermatocytes (23 chromosomes and a pair of
duplicate chromatids) - Meiosis II produces 4 haploid spematids – each have 23
individual chromosomes (one from each pair)
what is the last step of spermatogenesis
v- Last step of Spermatogenesis – each spermatid matures into a spermatozoon (sperm) with a flagellum (tail)
- Takes about 5 weeks to complete
what is the role of semen in regulating the male reproductive systems
- mixture of sperm and semen
-typical ejaculation 2-5ml containing between 50-150 million sperm per ml
-acidic prostate secretion and alkaline overall pH 7.2 - 7.7; helps neutralise acid in urethra and vagina.
-provides medium to transport and give nutrients to sperm
-contains antibacterial agent to kill bacteria
-Coagulates initially but then re-liquifies due to enzymes from prostate to allow movement of sperm.
what are the accessory sex glands
- seminal vesicles
- prostate
- bulbourethral glands
what are the seminal vessels, and what do they secrete?
- Paired pouch-like structures, convoluted
- 5cm long
- Posterior/base of urinary bladder, anterior to the rectum
- Secrete viscous/sticky fluid 60% semen volume
- Alkaline – neutralise acids harmful to
sperm - Rich in fructose - ATP production by
sperm - Prostaglandins - sperm viability/motility
- Fluid passed into ejaculatory duct
some features of the prostate
- Doughnut shaped – size of a golf ball
- Lies inferior to bladder, surrounds prostatic urethra
- Grows slowly until puberty, then rapidly until around 30
- Typically grows again from age of 45
- Produces milky slightly acidic fluid (around 25% semen volume) which aids sperm motility and viability
- Citric acid; ATP production
- Acid phosphatase
- Proteolytic enzymes (regulated by testosterone):
-Prostate-specific antigen (PSA); liquefies semen dissolves
cervical mucous - Pepsinogen, amylase, lysozyme, hyaluronidase
- Enters urethra through numerous prostatic ducts
what is the bulbourethral glands?
- Also known as Cowper’s glands
- Paired pea-sized organs
- Inferior to prostate, within urogenital diaphragm either side of the urethra
- Ducts open onto spongy urethra in root of
penis
what fluid does the bulb-urethral gland produce and why?
Produces fluids during arousal to protect
sperm:
* alkaline substance to neutralise acids in urethra and vagina
* mucous to lubricate tip of penis an urethra
what is the penis and its main components
- Contains urethra as passageway for urine and semen
- Method to deliver semen
- Consists of:
- Body
- Root
- Glans
- Supported by two ligaments continuous with fascia of penis:
- Fundiform ligament; inferior part of linea alba
- Suspensory ligament of penis; from pubic
what is the structure and the body of the penis
- Three cylindrical masses, each surrounded by fibrous tunica albuginea
- Consists of tissue permeated with sinuses for blood
- Paired corpus cavernosum (hollow body) on dorsal surface
- Penetrated by deep arteries of penis
- Smaller corpus spongiosum on ventral and midline surface
- Contains spongy urethra, keeps patent during ejaculation
