Pelvic Cavity II

Question 1

Urinary bladder/detrusor muscle

Answer 1

Smooth muscle, arranged in three sheets, squeezes and empties the bladder
Parasympathetic innervation causes contraction of smooth muscle of the bladder and relaxation of the sphincter, resulting in evacuation of bladder
Sensory innervation via pelvic n.

Question 2

Urethralis m.

Answer 2

Skeletal muscle that surrounds the pelvic urethra
Allows for voluntary sphincter
Innervated by pelvic n.

Question 3

Lateral ligaments of bladder

Answer 3

In fetus: each ligament contains a caudal portion of the ureter and a portion of the umbilical a.
In adult: each ligament contains a caudal portion of ureter and the round ligament of the bladder (remnant of umbilical a.)

Question 4

Median ligament of bladder

Answer 4

In fetus: contains portions of umbilical arteries and urachus
In adult: usually does not contain any structures (fetal structures regress)

Question 5

Urethra of female dog

Answer 5

Carries urine from bladder to vestibule

Question 6

Urethra of male dog

Answer 6

Two portions of urethra:
-Pelvic urethra: located within pelvic cavity
-Penile (spongy) urethra: located within the penis

Question 7

Accessory genital glands in male dogs

Answer 7

Prostate and ampullary glands

Decrease in size after castration

Question 8

Accessory genital glands in male cats

Answer 8

Prostate - located more caudally along urethra than in dogs
Bulbourethral gland - located dorsally along ischial arch, just cranial to attachment of penis in ischium
Ampullary glands - not as well developed in cats

Decrease in size after castration

Question 9

Prostate in dogs

Answer 9

Located within the pelvic cavity
Divides pelvic urethra into pre-prostatic, prostatic, and post-prostatic parts
When enlarged, is located in the caudal portion of the abdominal cavity and may impinge on rectum

Question 10

Colliculus seminalis

Answer 10

Located on dorsal surface of prostatic urethra; continuation of urethral crest. Enlarges to prevent urine from entering urethra during copulation

Question 11

Rectum and anus

Answer 11

Rectum: continuation of descending colon within pelvic cavity; suspended by mesorectum
Anal cavity: courses between rectum and anus
Anus: external opening of anal canal

Question 12

Anal sphincters

Answer 12

External anal sphincter
-Striated muscle
-Innervated by caudal rectal nerve
-Located superficial to anal sacs

Internal anal sphincter
-Smooth muscle (expansion of smooth muscle of rectum)
-Located deep to anal sacs

Question 13

Anal sacs

Answer 13

Paired structures located between internal and external anal sphincters
Each sac opens into anal canal by single duct
Forms a pocket into which apocrine and sebaceous glands open
Functions in scent marking

Anal glands are located within wall of anus within the wall of anal sacs

Question 14

Rectococcygeus muscle

Answer 14

Smooth muscle that is continuous with smooth muscle of rectum

Aids in defecation - stabilizes and shortens the rectum; provides for caudal traction during defecation

Question 15

Iliosacral lymphocenter

Answer 15

Medial iliac lnn. - located between deep circumflex iliac and external iliac aa.

Internal iliac or hypogastric lnn. - located between the internal iliac and median sacral aa.