Male Reproductive Gross Anatomy

Question 1

list the layers you will cut through or expose between the skin and the vaginal cavity to reach the visceral layer of the vaginal tunic of the testis (7)

Answer 1

1. skin of scrotum
2. dartos muscle (cutaneous, smooth muscle)
3. spermatic fascia
4. cremaster muscle (skeletal, last branch from internal abdominal oblique)
5. parietal layer of vaginal tunic (thick, leathery white membrane)
6. vaginal cavity (space between tunic layers)
7. visceral layer of vaginal tunic (adherent to surface of testes)

Question 2

describe the scrotum (3)

Answer 2

1. a cutaneous pouch: lightly haired and pigmented in the dog and densely covered n hair in the cat
2. divided into 2 cavities by a scrotal septum, demarcated by the median groove and raphe scrotum
3. houses one testis in each cavity

Question 3

describe the vaginal tunic (5)

Answer 3

1. evaginated peritoneal pouch
2. passes through the vaginal ring, deep inguinal ring, inguinal canal, and superficial inguinal ring
3. attached to scrotum via spermatic fascia
4. cremaster muscle runs alongside the surface of the vaginal tunic and attaches to it but is anatomically separate
5. two layers:
   a. parietal vaginal tunic: attached to inner surface of scrotum via spermatic fascia; incised during open castrations, NOT closed castrations
   b. visceral vaginal tunic: inseperably attached to tunica albuginea of testis, epididymis, ductus deferens, and testicular vasculature

Question 4

which layer of the vaginal tunic is incised in an open castration that is not incised during a closed castration?

Answer 4

parietal vaginal tunic

Question 5

describe the inguinal canal (3)

Answer 5

1. short, flattened, oblique intermuscular space
2. a potential space; is only a canal if something is residing there or passing through, otherwise is flattened and empty
3. connects two orifices: deep inguinal ring (triangular) and superficial inguinal ring (an oval slit)

Question 6

define cryptorchidism

Answer 6

when one or both testes fail to completely descend from the abdomen into the scrotum; may either stop at the inguinal canal or simply remain in the abdominal cavity

Question 7

define the boundaries of the deep inguinal ring (3)

Answer 7

more like a muscular triangle with 3 boundaries:
1. cranial boundary: caudal edge of the internal abdominal oblique muscle
2. medial: lateral border of rectus abdominis muscle
3. caudolateral: inguinal ligament (rounded edge of the aponeurosis of the external abdominal oblique muscle)

Question 8

describe the superficial inguinal ring

Answer 8

a slit like opening in the aponeurosis of the external abdominal oblique muscle that is normally sealed off with connective tissue

Question 9

what structure pulls the testis from its developmental position in the abdomen down into the scrotum? list the two ligaments that are remnants of this structure

Answer 9

the gubernaculum:
1. proper ligament of the testis
2. ligament of the tail of the epididymis

Question 10

differentiate between the superficial inguinal ring, the vaginal ring, the deep inguinal ring, and the inguinal canal

Answer 10

deep inguinal ring: muscular borders, inner triangle exit from abdominal cavity

superficial inguinal canal: actual hole punched through aponeurosis of external obdominal oblique to exit peritoneal cavity and allow spermatic cord to enter testes

inguinal canal: connects deep and superficial inguinal rings

vaginal ring: inside peritoneal cavity, inside deep inguinal ring

Question 11

list the contents of the inguinal canal in the male; differentiate between the contents of the neurovascular bundle (3) that passes through the canal and describe the purpose of these structures (4)

Answer 11

1. connective tisse
2. spermatic cord
3. cremaster muscle
4. neurovascular bundle:
   4a. external pudendal artery and vein (artery terminates in a preputial and scrotal branch)
   4b. genitofemoral nerve (motor to cremaster muscle)
   4c. lymphatics from superficial inguinal lymph node

Question 12

describe the boundaries of the structure referred to by clinicians as the spermatic cord (5)

Answer 12

definition: the parietal vaginal tunic and its contents that extend between the superficial inguinal ring and the testes

1. parietal vaginal tunic
2. visceral vaginal tunic
3. testicular veins: form pampiniform plexus
4. ductus deferens
5. supporting mesentery:
   5a. mesoductus deferens: connects to ductus deferens
   5b. mesorchium: connects to testicular vasculature
   5c. mesofuniculus: connects to parietal vaginal tunic

Question 13

list the structures passing through the vaginal ring and include whether they are entering or exiting the peritoneal cavity (2)

Answer 13

1. testicular artery, vein, nerve: EXITing the peritoneal cavity
2. ductus deferens: ENTERing the peritoneal cavity (leaving the testis, coming back into abdominal cavity)

Question 14

differentiate between the mesoductus deferens (and the ductus deferens), and the mesorchium (and the testicular vasculature) both within the peritoneal cavity (adjacent to the vaginal ring) and within the spermatic cord

Answer 14

just gonna have to look at pics for this one

Question 15

what is a pampiniform plexus? what is its function?

Answer 15

the tendril formed by testicular veins wrapping around the testicular arteries

function is countercurrent heat exchange and countercurrent testosterone reclamation

right vein empties into caudal vena cava
left vein enters into left renal vein

Question 16

describe the testes (3)

Answer 16

1. endocrine organs via interstitial cells that secrete testosterone
2. exocrine organs via spermatozoa production and secretion via ducts
3. blood supply from testicular arteries that arise from the aorta

Question 17

describe the capsule/tunica albuginea of the testes (4)

Answer 17

1. very thick and collagenous
2. fused with visceral vaginal tunic
3. penetrated by branches of testicular artery and vein
4. non-elastic, so orchitis or injury with swelling is extremely painful

Question 18

differentiate between the head, body, and tail of the epididymis and list the structures present within each region

Answer 18

head:
1. most cranial
2. contains efferent ductules
3. beginning of epididymal duct

body:
1. long axis of testes
2. continuation of epididymal duct

tail:
1. most caudal
2. termination of epididymal duct

Question 19

describe the pathway of the ductus deferens between the tail of the epididymis and the prostate gland, including the structures these ducts pass through

Answer 19

function: convey sperm from tail of epididymis to pelvic urethra

blood supply: artery of the ductus deferens

path:
1. enter peritoneal cavity at vaginal ring
2. loop around ventral surface of ureters
3. prior to entering prostate, are connected by a fold of peritoneum known as the genital fold
4. are ducted to the prostatic urethra on either side of the seminal colliculus

Question 20

differentiate between the proper ligament of the testis and the ligament of the tail of the epididymis and list the structures these ligaments contact

Answer 20

proper ligament of testis: connects the testis to the tail of the epididymis

ligament of tail of epididymis: connects tail of epididymis to parietal vaginal tunic

both are remnants of gubernaculum

Question 21

list the 3 means of thermoregulation of the testes

Answer 21

1. tunica dartos/dartos muscle of scrotum: causes scrotum to wrinkle when smooth muscle contracts (cutaneous, in the CT of dermis)
2. cremaster muscle: caudal slip off IAO, contraction draws testicles closer to body wall, innervated by genitofemoral nerve
3. pampiniform plexus: counter-current heat exchange

Question 22

list the 3 divisions of the penis, and include the erectile tissue and skeletal muscle that is present in each division (carnivores, describe the whole penis)

Answer 22

root:
2 crura:
outer muscle: ischiocavernosus muscle
inner erectile tissue: corpus cavernosum; supplied by the deep artery of the penis

1 bulb:
outer muscle: bulbospongiosus muscle
inner erectile tissue: corpus spongiosum; supplied by the artery of the bulb

body: covered by tunica albuginea
contains retractor penis muscle: smooth muscle that returns penis to prepuce
3 erectile bodies, each enclosed within tunica albuginea:
1. corpora cavernosum: 2 erectile bodies dorsally positioned, continuation of erectile bodies of the 2 crura
2. corpus spongiosum: single erectile body ventrally positioned, surrounds urethra, continuation of erectile tissue of bulb

glans: 2 parts, separated by CT
1. pars longa glandis: has its own erectile tissue, supplied by dorsal artery of penis, drains to bulbus glandis
2. bulbus glandis: distal enlarged part of corpus spongiosum, drains to dorsal veins of penis

Question 23

list the 2 parts of the glans penis; the erectile tissue of which of these 2 parts is a continuation of the corpus spongiosum?

Answer 23

1. pars longa glandis: has its own erectile tissue, supplied by dorsal artery of penis, drains to bulbus glandis
2. bulbus glandis: distal enlarged part of corpus spongiosum, drains to dorsal veins of penis

Question 24

what is a baculum? can it be fractured?

Answer 24

penis bone! can be fractured!

has a ventral groove for passage of urethra, this urethral groove is narrow at its base so urinary stones tend to get lodged here

base is attached to tunica albuginea of corpora cavernosa, apex extends in a fibrocartilaginous tip

Question 25

list the 3 terminal branches of the artery of the penis and include which erectile tissue these branches supply

Answer 25

1. dorsal artery of the penis: supplies prepuce and pars longa glandis
2. deep artery of penis: supplies corpus cavernosum
3. artery of the bulb: supplies corpus spongios

Question 26

list the blood supply to the prostate gland and the ductus deferens

Answer 26

prostate: left and right prostatic arteries, which are branches internal pudendal

ductus deferens: artery of the ductus deferens

Question 27

differentiate between the outer and inner laminae of the prepuce, the preputial orifice, and the preputial fornix

Answer 27

the prepuce is a fold of integument

outer haired layer: external lamina
inner layer: mucosa, internal lamina
layers meet at preputial orifice

preputial cavity: between internal lamina and the glans

inner layer reflects onto skin of glans at preputial fornix

Question 28

describe the condition that leads to presence or absence of cornified spines on the glans penis of the male feline

Answer 28

sexually mature intact male glans penis is covered in cornified spines that disappear after castration

Question 29

list the accessory sex glands of the male feline (2)

Answer 29

1. prostate gland
2. bulbourethral glands