Male Reproductive System Flashcards
-no seasonal period of increased or decreased sexual activity.
-Rather, they can be stimulated at any time by nearby females that are in season (heat).
Male Reproductive System
*Canine Lower Urinary Tract
which expels urine, is the smooth muscle coat of the bladder apex and body;
detrusor muscle
*Canine Lower Urinary Tract
is the muscle coat of the bladder neck & cranial urethra;
smooth muscle sphincter (internal urethral sphincter)
*Canine Lower Urinary Tract
is the urethralis muscle which encircles the caudal urethra.
striated urethral sphincter (external urethral sphincter)
- In males it contributes to erection, the contractions of orgasm and ejaculation. In females it contributes to clitoral erection and the contractions of orgasm, and closes the vagina.
- This muscle serves to empty the canal of the urethra, after the bladder has expelled its contents; during the greater part of the act of micturition its fibers are relaxed, and it only comes into action at the end of the process.
bulbospongiosus muscle (bulbocavernosus in older texts)
- It helps flex the anus, and (in males) stabilize the erect penis or (in females) tense the vagina during orgasm.
- This muscle compresses the crus penis, and retards the return of the blood through the veins, and thus serves to maintain the organ erect.
Ischiocavernosus muscle
Traced from behind forward, each crus begins by a blunt- pointed process in front of the tuberosity of the ischium, along the perineal surface of the conjoined (ischiopubic) ramus.
Crura (crus of penis)
- Membranous pouch divided by a median septum into 2 cavities
- Located approximately two-thirds of the distance from the opening of the prepuce to the anus
- Lies on the back portion of the abdomen between the hind legs
Scrotum
Sperm need temperatures between 2-10 degrees Centigrade _____ than the body temperature to develop.
lower
The ____ of the scrotum is covered with fine hairs.
skin
The ______ of the scrotum is a layer of tissue that lies just under the skin and is made up of muscle and other tissue.
dartos
Under the dartos is ________ ______ and a shiny tissue that lines the scrotum.
connective tissue
Blood supply of the scrotum (3)
external pudendal artery
cremasteric artery
scrotal arteries
Nerve supply of the scrotum
genital ramus (branch of the genitofemoral nerve and perineal nerve)
*Clinical Considerations
Scrotal and inguinal hernias
– Scrotal hernia is more common in ____
dogs
*Clinical Considerations
Wounds and injuries to scrotum
– Local treatment; ?
if testes are exposed, castration is done to relieve pressure irritation
*Clinical Considerations
Tumors of the scrotum are also treated by
__________
castration
*Clinical Considerations
Malformed, underdeveloped scrotum is the result of _____________ ______
undescended testes
- Fresh organ weighs 7.8 to 8.2 gm.
*Epididymis is adherent to the dorsolateral surface of the organ with its tail located at the caudal extremity of the testis, and its head at the cranial end.
- Produces SPERMATOZOA and
TESTOSTERONE
Testes
- Left testicle usually lies slightly ______ the right.
- Each testicle is ____ in shape and thicker in the middle than from side to side
behind
oval
*Envelopes of the testis
– Continuation of the parietal peritoneum of the abdominal cavity
Visceral vaginal tunic
*Envelopes of the testis
– Dense white fibrous capsule connected to the mediastinum testis by septuli testis
Tunica albuginea
*Envelopes of the testis
main lobule that contains the testicular parenchyma and the seminiferous tubules –> rete testis
Lobuli testis
*Envelopes of the testis
cord of connective tissue situated lengthwise through the middle of the testis
mediastinum testis
- contain seminiferous tubules that manufacture sperm.
Testes
*Testes
- Special cells near the seminiferous tubules, called _______ _____, support and supply nutrition to the sperm cells.
Sertoli cells
Blood supply of Testes & Epididymis (2)
testicular artery
the artery of ductus deferens
Nerve supply of Testes
testicular nerve
*Anomaly of the testes
_____________ is the MOST important
congenital anomaly of the testis
– 1 or both testes are retained either in the
abdominal cavity or between the external
inguinal ring and the scrotum
– Of economic importance in horses and swine
Cryptorchidism
*Anomaly of the testes
bilateral absence of the testes
Anorchidism
*Anomaly of the testes
presence of only one testis
Monorchidism
- Most heat sensitive region of the male reproductive tract
- Site of maturation & storage organ for spermatozoa before ejaculation; has circular smooth muscles that aid in the transport of sperm to ductus deferens
Epididymis
*Epididymis
- Divided into: (3)
Head/caput epididymis – largest part
Body/corpus epididymis – runs along the dorsolateral surface of the testis
Tail/cauda epididymis – continued to ductus deferens
- Or deferent duct
- It passes through the prostate and empties into the urethra.
Vas deferens
*Vas deferens
Begins at the tail of the epididymis and runs along the border of the testicle, entering into the abdominal cavity through an area called the _________ _____
inguinal canal
*Vas deferens
has several layers: (3)
the tunica adventitia
muscularis
mucosa
Blood supply of the vas deferens
urogenital artery
Spermatic cord consist of (5)
a. ductus deferens
b. testicular artery, vein and nerve
c. artery and vein of the deferent duct
d. mesoductus deferens
e. mesorchium
*Spermatic cord
structure that attaches the vas deferens to the mesorchium
mesoductus deferens
*Spermatic cord
fold of peritoneum or a part of the visceral vaginal tunic that covers that vessels and nerve
mesorchium
- migration of the testis from the abdominal cavity into the scrotal sac
Descent of the Testis
*Descent of the Testis
- expansion of the ______or ___________ part of the gubernaculums beyond the external inguinal opening toward the scrotal sac
- _______ on the proximal or intra abdominal part of the gubernaculums pulling it distally into the inguinal canal
- expansion of the proximal part of the gubernaculums thus _______ the testis toward the internal inguinal ring
- rapid descent of the testis through the ________ ______ due to sudden increase in intra-abdominal pressure
- ___________ of the core of the gubernaculums resulting to formation of the proper ligament of the testis and the ligament of the tail of the epididymis
caudal or extra-abdominal
traction
pulling
inguinal canal
regression
- The only accessory gland in dog
- Encloses the neck of the bladder; prosthetic urethra and the vas deferens
- Lies in the abdominal cavity until the animal is 2 months after which it is confined in the pelvic cavity
Prostate Gland
*Functions of Prostate Gland
essential in providing an optimum environment for sperm ________ and ________
survival and motility.
*Functions of Prostate Gland
_________ ______ are added to the sperm to nourish it which aid in its transport from the penis and through the uterus
additional fluids
*Functions of Prostate Gland
It produces an ________ _________ that neutralizes the acidity of the male urethra and female vagina.
alkaline secretion
*Anomaly in the prostate gland
- _________ __________ occurs frequently in old dogs; may be due to hormonal imbalance or dogs that are trained to retain urine for long periods of time
– Surgical intervention
Prostatic hypertrophy
- the male copulatory organ
- located within the prepuce
- When it is not erect it is completely enclosed within the prepuce, which is attached to the lower outside abdominal wall.
Penis
Penis is divided into: (3)
a. root (radix penis)
b. body (corpus penis)
c. distal portion (glans penis)
distal portion (glans penis) – further divided into: (2)
- bulbus glandis
- pars longa glandis
*Penis
the root and body which are continuous are composed of: (2)
corpora cavernosa penis
corpus spongiosum penis
contains enlarged cavernous spaces
corpora cavernosa penis
ventrally located and contains the penile urethra and the proximal end of the penis
corpus spongiosum penis
- the root of the penis is attached to the tuber ischii via its left and right attachments called ____, blending of this forms the body
crura
the corpus spongiosum has a bilobed expansion called the _____ of the _____
bulb of the penis
(or urethral bulb)
*Penis
thickest part and area of greatest potential expansion
bulbus glandis
- also called a “knot” * an erectile tissue structure on the penis of canid mammals.
- responsible for copulatory lock together with the circular muscles of the vagina
- occurs in some pinnipeds, including South American fur seals
Bulbus glandis
Cross section of the root of the penis (7)
A. Crus of the penis
B. Tunica albuginea
C. Ischiocavernosus muscle
D. Urethra
E. Corpus spongiosum
F. Bulbospongiosus muscle
G. Retractor penis muscle
*Extrinsic Muscles of the Penis (paired)
primarily contains smooth muscle fibers
retractor penis muscles
*Extrinsic Muscles of the Penis (paired)
short, broad muscles covering the crura of the penis
ischiocavernous muscles
*Extrinsic Muscles of the Penis (paired)
cover the superficial of the bulb of the penis
bulbospongiosus muscles
*Extrinsic Muscles of the Penis (paired)
originates from the dorsal surface of the ischial tuberosity
ischiourethralis muscles
Blood supply of the penis (2)
internal and external pudendal arteries
External and internal ________ veins collect blood from the penis
pudendal
Nerve supply of the penis (2)
pudendal and pelvic nerves
- the only visceral bone in the dog
- it is long and tapered, the proximal end is broad and is located in the body of the penis caudal to the bulbus glandis
- the distal end of the bone is small and in diameter and is continued by a curved cartilaginous projection
Os penis or Baculum
Os penis or Baculum is divided into: (3)
a. apex
b. body
c. base
*Os penis or Baculum
the tapered end wherein a cartilaginous tip is attached by a fibrous strand
apex
*Os penis or Baculum
elongated part with the urethral groove located along the ventral surface of the base and body
body
*Os penis or Baculum
short portion attached to the outer layer of the cavernous bodies
base
*Mechanism of Penile Erection
filling with blood of cavernous spaces in erectile tissues with stimulation of pelvic nerves resulting to increase blood pressure to penis and inhibition of venous drainage; dilatation of arteries
Erection
*Mechanism of Penile Erection
with contraction of ischiocavernous m., ischiourethralis m., and bulbospongiosus m. and venous occlusion
Intromission
*Mechanism of Penile Erection
____________ then __________of muscles, decrease arterial pressure and venous drainage.
Ejaculation then Relaxation
*Mechanism of Penile Erection
In the dog, delayed erection is due to ____ __________ of the bulbus glandis and the pars longa glandis.
slow engorgement
*Mechanism of Penile Erection
coitus, 2 stages:
- mounted
- lock or tie – longer duration
a hollow tube that carries sperm and urine which extends from the urinary bladder to the very tip of the penis
Urethra
3 Parts of the urethra
- prostatic urethra
- membranous portion of the urethra
- penile urethra
*Part of the Urethra
passed thru the prostate gland
prostatic urethra
*Part of the Urethra
part between the prostate and the bulb of the penis
membranous portion of the urethra
*Part of the Urethra
portion from the bulb to the external opening
penile urethra
- attached to the ventral abdominal wall; its distal open end is free
- contains the preputial muscle which is a part of the cutaneous trunci muscle extending from the area of the xiphoid cartilage to the dorsal wall of the prepuce; they are relaxed during erection
Prepuce
prevents the free end of the prepuce from hanging loosely during non-erection and pulls the prepuce back over the glans penis after erection
Function of the preputial muscle:
plexus of veins drains blood from the
testicles back to the heart.
Pampiniform plexus
*Prepuce
a moist protective covering for the non-erect penis, and is capable of secreting ______, a thick, lubricating liquid
smegma
