Canine Urogenital System - Dr. Reddish

The pelvis has two components:

1.) two hip bones

2.) sacrum

hip bones are aka...

os coxa

each hip bone consists of three fused bones:

1.) ilium

2.) ischium

3.) pubis

The ventral attachment of the left and right hip bones is...

the pelvis symphysis (midline)

The dorsal attachment of the left and right hip bones is...

with the sacrum

Sacrum

fusion of the bodies and processes of the three sacral vertebrae

The sacrum has three structures:

1.) wing

2.) promontory

3.) median crest

wing of sacrum

the flat projections on the cranial aspect lateral to the promontory

promontory of sacrum

ridge projecting along cranial edge of S1

median crest of sacrum

The midline ridge on the sacrum

Pelvic canal/cavity

passage from the pelvic inlet to the pelvic outlet

The pelvic canal is long ________ and short ________

dorsally

ventrally

lateral boundary of the pelvic canal

each hip bone/os caxa

dorsal boundary of the pelvic canal

sacrum and the first caudal vertebra

The cranial aperature of the pelvic canal is called the...

pelvic inlet

Three boundaries of the pelvic inlet:

1.) dorsally

2.) ventrally

3.) bilaterally

dorsal boundary of the pelvic inlet:

promontory of the sacrum

ventral boundary of the pelvic inlet:

cranial border of the pubis

bilateral boundary of the pelvic inlet:

arcuate line of the ilium

The caudal aperture of the pelvic canal is called the...

pelvic outlet

Three boundaries of the pelvic outlet:

1.) dorsally

2.) ventrally

3.) bilaterally

dorsal boundary of the pelvic outlet:

first caudal vertebra

ventral boundary of the pelvic outlet:

ischiatic arch

bilateral boundary of the pelvic outlet:

sacrotuberous ligament

Perineum

wall and associated structures closing the pelvic outlet

The perineum surrounds two canals:

1.) anal canal

2.) urogenital canal

perineal region

projection of the perineum upon the skin

Dorsal boundary of the perineum

base of the tail

Lateral boundary of the perineum

skin on the sides that cover the paired superficial gluteal and internal obturator muscles, and ischial tuberosity

Ventral boundary of the perineum

base of the scrotum or beginning of vulva

Pelvic diaphragm

vertical closure of the pelvic cavity through which the rectum and urogenital tract passes

The pelvic diaphragm is the main _______ component of the perineum

muscular

Two muscular components of the pelvic diaphragm:

1.) levator ani muscle

2.) coccygeus muscle

The levator ani muscle is located on the ________ aspect of the pelvic diaphragm

The coccygeus muscle is located on the ________ aspect of the pelvic diaphragm

medial

lateral

levator ani muscle

broad and thin muscle that lies medial to the coccygeus muscle

Innervation of levator ani muscle

S3 and C1 spinal nerves

Functions of levator ani muscle (2):

1.) presses tail against the anus and urogenital tract

2.) initiates defecation

What nerve passes through the levator ani muscle?

obturator nerve (but does not innervate!)

Coccygeus muscle

shorter and thicker muscle that lies lateral to the levator ani muscle

Innervation of coccygeus muscle

S3 spinal nerve

Functions of coccygeus muscle (2):

1.) presses tail against anus and urogenital tract

2.) moves tail between rear legs

Two muscle control passage through the anal canal:

1.) external anal sphincter

2.) internal anal sphincter

external anal sphincter

striated muscle; voluntary control and encircles the anal sacs

internal anal sphincter

smooth muscle; involuntary control and thickened portion of circular coat of anal canal

What lies between the internal and external anal sphincter?

anal sacs

Ischiorectal fossa

the space on either side of the anus between the pelvic diaphragm and the sacrotuberous ligament; usually filled with fat

sacrotuberous ligament

connects sacrum to ischial tuberosity

The urinary system has four components:

1.) kidneys

2.) ureters

3.) urinary bladder

4.) urethra

The kidneys are located in what region?

sublumbar region (against the sublumbar muscles)

The kidneys have a __________ position in the abdominal cavity

retroperitoneal

The kidneys are only covered by peritoneum on their ________ surface

sublumbar

The right kidney is located opposite ___-___ vertebrae

L1-L3

The left kidney is located opposite ___-___ vertebrae

L2-L4

Poles of the kidneys

cranial & caudal ends of the kidney

Which kidney is always palpable? Which one will only be able to be palpated in thin animals?

always palpable: left kidney

only palpable in thin animals: right kidney

In the female dog, the caudal poles of both kidneys are related to...

the fat-filled mesovarium and ovaries

How are the cat kidneys different than the dog?

they are relatively large, more mobile, and both are readily palpable

Distinctive appearance of cat kidneys

covered by capsular veins converging over the surface toward the hilus

Eight structures of the kidney:

1.) renal hilus

2.) renal sinus

3.) renal pelvis

4.) renal cortex

5.) renal medulla

6.) renal pyramid

7.) renal crest

8.) pelvic recesses

renal hilus

indentation on the medial border of the kidney

The renal hilus is an entry/exit point for three things:

1.) renal vessels

2.) ureter

3.) nerves

renal sinus

the fat filled space surrounding the renal pelvis containing renal vessels and ureters

renal pelvis

funnel shaped structure that collects urine within the kidney

The renal pelvis will narrow into the...

ureter

renal cortex

outer layer of renal parenchyma; granular appearance and contains primarily the renal corpuscles and convoluted portions of the tubules

renal medulla

inner layer of renal parenchyma; striated appearance due to

numerous collecting ducts

the renal medulla is organized into...

renal pyramids

renal pyramid

part of renal medulla, fuses at the center to form renal crest

renal crest

a longitudinal ridge projecting into the renal pelvis, through which collecting tubules of the kidney excrete urine into the renal pelvis

pelvic recesses

parts of renal pelvis that project outward between the renal pyramids

Order of blood supply to the kidney

aorta --> renal artery --> interlobar arteries --> arcuate arteries --> interlobular arteries

Order of venous return from the kidney

stellate veins --> interlobular veins --> arcuate veins --> interlobar veins --> renal veins --> caudal vena cava

Ureters

connect the kidneys with the urinary bladder

The _______ portion of the ureter will form the renal _________

proximal; pelvis

Ureters enter at the neck of the urinary bladder _________

dorsally

In the male, where is the ureter located?

dorsal to the ductus deferens

*ureter can be torn during castration!

In the female, where is the ureter located?

enters the bladder in the lateral ligament of the uterus nearby the cervix

*during ovariohysterectomy, care must be taken to not cut ureters!

Urinary bladder

highly distensible hollow organ; reservoir for urine from the kidney

The urinary bladder has three parts:

1.) neck

2.) body

3.) apex

neck of the urinary bladder

narrow caudal portion attached to the urethra

body of the urinary bladder

main central portion

apex of the urinary bladder

blind cranial border

Three ligaments of the bladder:

1.) median ligament

2.) lateral ligaments

3.) round ligaments

median ligament of the bladder

Connects the ventral surface of the bladder to the pelvic symphysis

The median ligament of the bladder extends _______ toward the ________

cranially; umbilicus

In the fetus, the median ligament contains the...

urachus

urachus

stalk of the embryonic allantois; normally disappears after birth

patent urachus

occurs when the urachus fails to close in newborn animals; urine may drip from the umbilicus

Lateral ligaments of the bladder

right and left ligaments that connect the lateral surface of the bladder to the lateral pelvic walls

In the fetus, the lateral ligaments of the bladder contain...

the umbilical arteries

After birth, the umbilical arteries regress and form the...

round ligaments of the bladder

Round ligaments of the bladder

remnants of the fetal umbilical arteries found within the lateral ligaments of the bladder

Trigone of the bladder

dorsal triangular region of the bladder

The trigone of the bladder is formed by two things:

1.) two ureter openings

2.) opening of the urethra

Urethra

membranous canal that carries urine from the bladder to the exterior of the body

Urethral muscle

striated muscle associated with the urethra that contributes to voluntary control of urination

Adrenal gland location

near the cranial pole of the kidney

Two arteries that pass around the adrenal glands:

1.) cranial abdominal artery

2.) caudal phrenic artery

Inguinal canal

a connective tissue-filled fissure (potential space)

The inguinal canal is located between...

the external and internal abdominal oblique muscles and their aponeuroses