Male Reproductive Flashcards
gametes
for males, are sperm
for females, are oocytes
gonads
produce gametes and sex hormones
- males have testes, females have ovaries
- testes produce hormones for building muscles, and sperm growth and development
- ovaries produce hormones that regulate the reproductive system
components of a reproductive system
gonads, ducts, glands and supporting structures (aid in storage of before things leave the body)
- glands produce fluids and hormones, ducts carry things places
functions of the male reproductive system
- testes produce sperm and male sex hormones (testosterone)
- ducts transport, store and assist in maturation of sperm
- glands secrete liquid portion of semen
- penis contains urethra which is the passageway for urine and semen
scrotum
sac of loose skin, fascia and smooth muscle divided into 2 pouches by scrotal septum and contains the testes
raphe
ridge where septum attaches to scrotum
temperature regulation of the testes
- sperm survival requires 2-3 degrees below core body temp
- cremaster muscle and dartos muscle help bring testes closer to the body so when it’s cold
- when it’s super hot out, these muscles relax
cremaster muscle
a part of the spermatic chord
- skeletal muscle that runs from pelvic area into scrotum to pull testes closer to the body for warmth
dartos muscle
makes scrotum smaller to make surface area less, allowing less heat to leave the testes, makes skin wrinkly
testes
- paired oval glands (5cm x 2.5cm)
endocrine function: release testosterone into blood supply
exocrine function: produce sperm and a bit of fluid to carry sperm
tunica albuginea
a CT layer that compartmentalizes the testes
- separates them into 200-300 compartments called lobules
seminiferous tubules
each testis is filled with 1-3 seminiferous tubules where sperm is formed
tunica vaginalis
- more superficial than tunica albuginea
- gonads of testes form in abdominal cavity during embryological dev’t, and were above peritoneal serous membrane which now becomes the tunica vaginalis
cells of sperm formation
found inside seminiferous tubules
sertoli (sustentacular) cells
interstitial (Leydig) cells
sertoli cells
aka sustentacular cells
- large cells that have a protective role for gametes, span the lumen and wrap around developing gamete cells to create the blood-testis barrier (the stem cells need protection from the immune system)
- produce fluid and control release of sperm into lumen
- can digest some extra materials and debris produced during meiosis
- secrete inhibin which slows sperm production by indirectly decreasing testosterone
interstitial cells
aka Leydig cells
- located b/w adjacent seminiferous tubules
- secrete testosterone
spermatogenesis
spermatogonia to mature sperm
- spermatogenic cells are stem cells
spermatogonia
diploid stem cells that differentiate into diploid primary spermatocytes
- meiosis occurs and forms haploid spermatids
spermatids
haploid
don’t have final sperm structures yet (flagellum, acrosome)
spermiogenesis
maturation of spermatids into sperm cells (final step of spermatogenesis)
spermiation
release of a sperm cell from a sertoli cell
- fluid produced in sertoli cells pushes sperm into seminiferous tubules and hydrostatic pressure moves them onwards through ducts
inhibin
controls production of sperm
- when sperm production IS sufficient, sertoli cells release inhibin and indirectly decrease testosterone levels, decreasing sperm production
- when sperm production is proceeding too slowly, less inhibin is released from sertoli cells, indirectly increasing testosterone levels, increasing sperm production
sperm facts
- 300 million produced/day
- adapted for reaching and penetrating a secondary oocyte
- middle piece contains mitochondria to produce ATP and provide energy for sperm to swim
- tail is flagellum used for locomotion which is active and present after 2 weeks
acrosome
tip on the head of the sperm that contain enzymes that break down the zona pellucida during the acrosomal reaction
pathway of sperm flow in the testes
seminiferous tubules (in each lobule) straight tubules rete testis efferent ducts ductus epididymis (ductus) vas deferens which exits scrotum and goes up into pelvic cavity
epididymis
coma shaped organ, 4cm long along posterior border of each testis
- has head, body and tail regions
- multiple efferent ducts become a single ductus epididymis in the head region (tube is 6 metres long if uncoiled to provide lots of area to store sperm)
- tail region continues as ductus deferens
ductus epididymis
lined w pseudostratified columnar epithelium
- layers of smooth muscle outside epithelial layer (not super highly arranged, some circular and some longitudinal)
- stereocilia: microvilli for reabsorption of degenerated sperm: if they aren’t being used, and sit for a couple of months, sperm get broken down and reabsorbed
functions of epididymis
- site of sperm maturation (motility increases after 2 weeks)
- storage for 1-2 months (upwards of 3 months in some)
- peristaltic contraction propel sperm onward, moving sperm and fluid into pelvic cavity and vas deferens
ductus (vas) deferens
45 cm muscular tube along posterior border of epididymis
- passes through spermatic cord and inguinal canal
- reaches posterior surface of urinary bladder and widens at ampulla
- empties into ejaculatory duct at ampulla which leads to prostatic urethra
inguinal canal
a slit in CT in the pelvic floor
- an inguinal hernia is when the pelvic floor muscles push through inguinal canal
histology of vas deferens
- lined w pseudostratified epithelium
- 3 layers of smooth muscle (2 longitudinal with circular in between) responsible for peristaltic contractions which move sperm
ejaculatory ducts
formed by dict of seminal vesicle and ampulla of vas deferens
- eject sperm and seminal vesicle secretions before ejaculation
spermatic cord
- contains all structures passing to and from the testes
- includes cremaster muscle, vas deferens, sympathetic and parasympathetic nerves, blood supply, lymphatic vessels
- runs through inguinal canal opening
accessory sex glands
3 glands that help make seminal fluid
- seminal vesicles
- prostate gland
- bulbourethral (cowper’s) gland
seminal vesicles
- a pair of pouch-like organs found posterior to the base of the bladder
- secretes alkaline, viscous fluid that makes up 60% of semen
properties of fluid from seminal vesicles
- neutralizes acidic male urethra and vagina
- fructose for ATP production
- prostaglandins: stimulate sperm motility and viability
- clotting proteins for coagulation of semen (clump it all together in the body)
prostate gland
- single organ the size of a golf ball found inferior to the bladder and surrounds prostatic urethra
- secretes slightly milky, slightly acidic fluid that makes up 25-30% of semen
- many ducts and opening
properties of fluid from prostate gland
- citric acid for ATP production
- enzymes for seminal liquefication
- seminalplasmin: an antibiotic to destroy bacteria in both male urethra and female reproductive system
- increases sperm motility and viability
bulbourethral (Cowper’s) gland
- paired, peas sized glands within muscles of perineum, lateral to intermediate urethra
- secretes alkaline mucous into spongy urethra (5% if semen)
- fluid preps urethra: neutralizes acid and lubricates urethra just before ejaculation so sperm don’t get damaged
semen
a mixture of sperm and seminal fluid
- glandular secretions and fluid of seminiferous tubules
- slightly alkaline, milky appearance, sticky
- contains nutrients, clotting proteins and antibiotic (seminalplasmin)
typical ejaculate is 2-5 mL
normal sperm count is 50-150 million/mL
coagulation/liquification of sperm
1st coagulates within 5 minutes
2nd reliquifies in 10-20 mins because of enzymes produced by the prostatic glands
- if this doesn’t happen, sperm can’t get away from one another because they’ll be stuck together
penis
a passageway for urine and semen via the urethra has 3 regions: root body glans penis
root of penis
potion nearest the pelvic cavity
- bulb of penis
- crus of penis
bulb of penis
expanded region of corpus spongiosum
- part of root of penis
crus of penis
crura is plural
2 extensions of corpora cavernosa, bilateral
- part of root of penis
body of penis
composed of erectile tissue
includes:
- corpora cavernosa
- corpus spongiosum
erectile tissue
like a sponge, has spaces called sinuses lined with endothelial tissue
- sinuses fill with blood on demand and are surrounded by smooth muscle
corpora cavernosa
paired, dorsolateral
- begins at crura of the penis and attaches to the ischeal and inferior pubic rami
- covered by ischiocavernosus muscle
corpus spongiosum
single, midventral (underside and middle)
- surrounds urethra, helps hold it open and prevents collapsing
- begins as bulb of penis and ends at glans penis
- covered by bulbospongiosus muscle just on spongy urethra end and the other end attaches to the pelvic floor
glans penis
expanded corpus spongiosum includes prepuce (foreskin) and corona
corona
ridge of glans penis
deep artery of penis
brings blood into erectile tissue
ischiocavernosus muscle
pulls penis towards body
- crura of penis or ends of corpora cavernosa are enclosed in this muscle
bulbospongiosus muscle
bulb of penis or base of corpus spongiosus enclosed by this muscle
erection
parasympathetic NS response from sacral region
- sexual stimulation dilates the arteries supplying the penis, relaxation of smooth muscles surrounding sinuses to accommodate more blood as sinuses fill with blood
- blood enters the penis, compressing the veins so that the blood is trapped
- need vasoconstriction of arteries and smooth muscle around sinuses to return to resting state
ejaculation
sympathetic NS response originating from lumbar region of SC
- internal urethral sphincter constricts at base of bladder so things don’t enter the bladder
- peristalsis moves fluids through ductus deferens, seminal vesicles, prostate and ejaculatory ducts into urethra
- ischiocavernosus compresses base of penis (shortens distance) and bulbospongiosus constricts urethra and erects penis
