Male Reproductive Anatomy Flashcards
The manufacturing and assembly plant that must be air conditioned
testes
What is the manufacturing complex?
the process of producing fertile sperm and transporting it outside of the male reproductive tract
What are the five stages of the manufacturing complex?
sperm is produced in the testis, fluid is absorbed and the spermatazoa undergo changes that will allow them to become fertile in the head and body of the epididymis, spermatozoa is stored in the tail of the epididymis, spermatozoa travel to the accessory sex glands fluids in the seminal plasmsa, and then are emitted through ejaculation from an erection in the penis
What are the male gonads referred to as?
testes
What do the testes produce?
male gametes (spermatozoa) and hormones (testosterone, others), fluids
What are the different layers of the scrotum? Hint: There are 3 before you reach the testis.
skin, stratum subdarticum, tunica dartos muscle
How is the scrotum thermoregulated?
It has thinner skin (leading to low insulation and is outside the body), has sweat glands, and has thermosensitive nerves (sweat glands, respiratory rate)
Which component regulates the temperature of the testes?
tunica dartos
How does the tunica dartos regulate the testes?
smooth muscle contractions (varying with scrotal temperature) and sustained contractions (close to body, away from body, increases surface area)
What controls the contractions used to regulate the teste temperature in the tunica dartos?
Androgens
What are the four different parts of the testes?
testicular capsule, parenchyma, mediastinum, rete tubules
What are the two parts of the testicular capsule?
tunica vaginalis (parietal, visceral) and tunica albuginea
What is the function of the Leydig cells?
to produce testosterone
What are the two compartments of the testicular parenchyma?
tubular and interstitial
What are the two functions of the epididymis?
environment for maturation of sperm (motility and fertility) and stores sperm
What is the fertility and motility of sperm in the body of the epididymis?
some motility and some fertility (can bind to the ova)
What is the fertility and motility of sperm in the head of the epididymis?
not motile, not fertile
What is the motility and fertility of sperm in the tail of the epididymis?
motile, fertile, can bind to ova
What are the two functions of the spermatic cord?
suspends/supports testis and is a pathway for lymphatics, nerves, and vasculature to/from testis, houses ductus vas deferens, testis temperature control (pampiniform plexus and cremaster muscle)
What are the 4 functions of the cremaster muscle?
supports and aids in temperature control, continuous with abdominal oblique, contracts/relaxes, non-sustainable contractions
What are the 3 structures of the spermatic cord?
cremaster muscle, pampiniform plexus, vas deferens
The testes must be how many degrees Celcius cooler than body temperature?
4-6
What complications does the disruption of cooling mechanisms cause in the testis?
severely compromises spermatogenesis
__ extends from the inguinal ring to its attachment on the dorsal pole of the testis.
spermatic cord
What anatomical structure suspends the testis in the scrotum?
spermatic cord
What is the function of the spermatic cord?
provides pathway to/from body for testicular vasculature, lymphatics, and nerves
What 3 anatomical parts does the spermatic cord house?
ductus deferens (vas deferens), cremaster muscle, pampiniform plexus
The majority of the spermatic cord consists of what 2 things?
testicular artery and testicular veins
___ serves as a pulse pressure eliminator (pulse pressure is decreased going from inguinal ring into testis).
testicular artery
___ surround the testicular artery, forming the pampiniform plexus.
testicular veins
What are the three functions of the pampiniform plexus?
1) important for temperature control of the testis 2) complex network of spermatic artery and veins forms a countercurrent heat exchanger 3) this network of veins eventually forms a single vein which runs into caudal vena cava
What are the two functions of the cremaster muscle?
primary support for testes, control of testicular temperature by a contracting and relaxing pampiniform plexus to facilitate blood flow
T/F The cremaster muscle is not capable of sustained contractions.
True
Scrotum?
two lobed sac that protects and supports testes, necessary for proper temperature regulation, composed of four layers
What are the four layers of the scrotum?
skin, tunica dartos, scrotal fascia, parietal vaginal tunic
What 3 components of the skin of the scrotum assist with temperature control?
sweat glands - temp control through evaporative heat transfer; thermosensitive nerves - govern degree of scrotal sweating and respiratory rate of animal (high temp = high respiratory rate); contains little fat - if too much fat then could interfere with cooling mechanism of scrotum and pampiniform plexus
Tunica Dartos?
mesh-like smooth muscle layer, lies beneath scrotal skin
T/F The tunica dartos cannot maintain sustained contractions.
False
The development and maintenance of the tunica dartos are under __ control.
androgen
What is the function of the testes?
to produce male gametes, hormones, proteins, fluids
What hormones do the testes produce?
testosterone, inhibin, estrogens, and others
What proteins do the testes produce?
proteins for spermatozoa function
What fluids do the testes produce?
rete fluid which serves as a vehicle for suspension and removal of spermatozoa
What are the four parts of the testes?
testicular capsule, parenchyma, mediastinum, rete tubules
What are the two functions of the testicular capsule?
covering of the testis, capable of undergoing changes in response to hormones and neurotransmitters
What are the two layers of the testicular capsule?
vesceral vaginal tunic, tunica albuginea
Functions of the tunica albuginea?
sends many finger-like projections into the parenchyma of the testicle that join with the mediastinum; contains smooth muscle which controls rhythmic contractions that provide a pumping action to movement of spermatozoa into rete tubules and efferent ducts
Parenchyma?
specific cellular mass of a gland or organ supported by a connective tissue network
What do the two comparments of the parenchyma consist of?
tubular and interstitial compartments
What are the four tubular compartments of the parenchyma?
seminiferous tubules, sertoli cells, tight junctions, blood testis barrier
Where does spermatogenesis take place in the seminiferous tubules?
tubulus contortus (convoluted portion)
What 3 components comprise the seminiferous tubule?
contractile peritubular cells, basement membrane, seminiferous epithelium (germinal epithelium)
What are the two major regions of the seminiferous epithelium?
basal compartment, adluminal compartment
What is the purpose of the basal component of the seminiferous epithelium?
houses spermatogonia and early primary spermatocytes
What is the function of the adluminal compartment of the seminiferous epithelium?
houses primary and secondary spermatocytes and spermatids
What are the only somatic cells in seminiferous epithelium?
sertoli cells
Where are the sertoli cells located?
they are anchored to the basement membrane in seminiferous epithelium and surround the developing germ cell
___ are the cellular governors of spermatogenesis.
sertoli cells
Each sertoli cell holds multiple ___ cells.
germ
What does a high number of sertoli cells indicate?
a high number of spermatozoa
Sertoli cells are analogus to __ cells of ovarian follicles.
granulosa
The sertoli cells contains receptors for what 2 hormones?
FSH and testosterone
What four substances do the sertoli cells produce?
androgen binding protein, sulfated glycoproteins 1 & 2, transferrin, inhibin
What are the 2 functions of tight junctions of the tubular compartments of the parenchyma?
1) Separate germinal epithelium into basal compartment and adluminal compartment 2) Prevent large molecular weight materials and immune cells from getting into adluminal compartment
What is the blood testis barrier?
formed from the peritubular cells surrounding seminiferous tubule and the sertoli cell junctional complexes
What is the function of the blood testis barrier?
prevents autoimmune destruction of developing germ cells
What does the interstitial of the parenchyma compose of?
blood vessels, connective tissue, lymphatics, nerves, interstitial cells of Leydig
What is the function of the interstitial cells of Leydig?
produce testosterone
What is the function of the mediastinum?
central connective tissue core of the testis that houses ducts called rete tubules and prevents their collapse so sperm can move freely out of testis
What are rete tubules? Function?
tiny channels that transport sperm out of testis
What is the function of the excurrent duct system?
allows for final maturation, storage, and delivery of spermatozoa to pelvic urethra
What are the three parts of the excurrent duct system?
efferent ducts, convey newly formed spermatozoa and rete fluid into epididymal duct, epididymal duct
What is the epididymal duct?
single, highly convoluted duct, surrounded by smooth muscle
What are the 2 functions of the epididymal duct?
1) where sperm mature and acquire motility and potential fertility 2) storage reservoir for sperm
What are the three parts of the epididymal duct?
head, body, tail
Epididymal transit time?
time required to go from head to tail
Extragonadal reserves (EGR)?
total spermatozoal content of the epididymal duct, the ductus deferens and the ampulla
What are the accessory sex glands dependent on?
testosterone for full development and maintenance of their structure and function
Where are most of the secretions of the accessory glands found?
in the blood
What is a unique secretion of the accessory sex glands?
fructose, which is an energy source for sperm
The seminal plasma includes secretions from what two anatomical parts?
epididymis and accessory sex glands
Seminal plasma?
the liquid, noncellular portion of semen
__ is the vehicle for spermatozoa.
seminal plasma
The seminal plasma is produced by what four anatomical parts?
ampulla, vesicular glands, prostate glands, bulbourethral glands (Cowper’s glands)
Where does the ampulla open?
directly into the pelvic urethra
Which species does not have a noticeable ampulla?
boar
What does the ampulla increase?
mucosa
Ampulla?
enlargements of ductus (vas) deferens
Vesicular glands?
paired glands that are dorsocranial to pelvic urethra
Where do the secretions of the vesicular glands empty?
directly into the pelvic urethra
What are the vesicular glands also known as?
seminal vesicles
The ___ is known as the lobulated gland.
vesicular gland
The __ consists of the large amount of ejaculate volume.
vesicular glands
Where is the prostate gland located?
near bladder and pelvic urethra
What are the 2 structural forms of the prostate gland?
corpus prostate, disseminate prostate
Corpus prostate?
prostate is outside the urethralis muscle
Disseminate prostate?
distributed along the dorsal and lateral walls of the pelvic urethra; sometimes referred to as the urethral gland
What is the corpus prostate of a boar shaped like?
heart-shaped
What is the corpus prostate of a stallion shaped like?
H-shaped
Bulbourethral glands (Cowper’s glands)?
paired glands located on either side of the pelvic urethra near ischial arch
The Cowper’s glands are typically small and avoid and dense but in the which species are they very large?
boar
The ___ gland is made up of high fibrous connective tissue.
Cowper’s (Bulbourethral)
In the ram, bull, and stallion the bulbourethral glands are small and buried under the ___ muscle.
bulbospongiosus
The bulbourethral gland produces what?
viscerous secretions
Viscerous secretions?
gel fraction of ejaculate
What do the viscerous secretions cause?
seminal plasma to coagulate after ejaculation
What is the function of the penis?
the copulatory organ
What are the 3 parts of the penis?
base, shaft, glans penis
Function of the base of the penis?
root of the penis; attached to ischial arch
Function of the shaft of the penis?
main portion; made up of corpus cavernosum
Corpus cavernosum?
spongy erectile tissue
Glans penis?
highly specialized distal end, heavily populated with sensory nerves
__ is the homologue of the female clitoris.
glans penis
What is the primary factor for initiating mechanisms of ejaculation?
stimulation by the glans penis
In which species is the glans penis covered with spines?
tom
In which species is the glans penis a stiff, spiny appendage (cartilagenous process)?
alpaca
In which species is the glans penis a corkscrew shape?
boar
Which three species have a fibroelastic penis?
boar, bull, ram
Species with a __ penis have limited erectile tissue encased in a non-expandable, dense connective tissue.
fibroelastic
Species with a fibroelastic penis have what three parts?
sigmoid flexure, corpus cavernosum, corpus spongiosum
Sigmoid flexure?
S-shaped configuration of the penis
Function of the sigmoid flexure?
allows the penis to be retracted inside the body
How is the sigmoid flexure maintained?
by the retractor penis muscle
Function of the retractor penis muscle?
when contracted, it holds penis inside; when relaxed, penis extends/protrudes
Corpus cavernosum?
makes up majority of penile interior; area of spongy erectile tissue
Corpus spongiosum?
area surrounding penile urethra, erectile tissue
How does an erection occur?
when the retractor penis muscle relaxes blood rushes into the corpus cavernosum and corpus spongiosum
The penis is controlled by what 3 muscles?
ischiocavernosus muscles urethralis, bulbospongiosus muscle
Ischiocavernosus muscles?
muscles associated with pelvic urethra and penis; short paired muscles in area of root of penis
___ are strong muscles enclosing the crura that insert broadly on the lateral surface of the penis above the sigmoid flexure.
ischiocavernosus muscles
Function of the ischiocavernosus muscles?
connect the penis to the ischial arch
Urethralis?
striated muscle that surrounds pelvic urethra
Function of the urethralis?
responsible for moving spermatozoa and seminal plasma into penile urethra
Bulbospongiosus muscle?
overlaps root of penis; extends down caudal and ventral surfaces; covers bulbourethral glands
Function of bulbospongiosus muscle?
to empty extrapelvic part of urethra
