Comparative Anatomy of Urogenital System

Segments of urinary system

Kidneys > Ureters > Urinary bladder > Urethra

Segments of female mammalian reproductive tract

Ovary > Oviduct (uterine/fallopian tube) > Uterus > Vagina > Vulva

Segments of male mammalian reproductive tract

Testes > Epididymis > Ductus deferens > Accessory sex glands > Pelvic and penile urethra > Scrotum > Inguinal canal > Penis > Prepuce

Accessory sex glands

• Ampullae

• Vesicular gland (Seminal vesicle)

• Prostate gland

• Bulbo-urethral (Cowper’s gland)

Dilated portion of the ductus deferens at the region of the urinary bladder; well developed in stallion, bull, and ram; but absent in boar

Ampullae

Pear-shaped in stallion; lobated in bull, ram, and boar

Vesicular gland (Seminal vesicle)

Only accessory gland present in dogs

Prostate gland

Segments of avian reproductive tract responsible for egg production

• Ovary = produces/stores immature ova

• Infundibulum = site of fertilization

• Magnum = adds albumen

• Isthmus = adds shell membranes

• Uterus = eggshell formation

Regions of the kidneys

Renal cortex, Renal medulla, Renal pelvis

Fibroconnective tissue covering of the kidneys

Renal capsule

Indented portion of the kidneys

Renal hilus

Structures that enter the renal pelvis

Renal artery, Renal vein, Ureter

Internal (gross) structures of the kidneys

Renal capsule > Renal hilus > Renal pelvis > Collecting tubules > Renal lobes > Renal pyramid > Renal papilla > Major and minor calyx

Parts of nephron and functions of each segment

• Renal corpuscles

  • Glomerulus

  • Bowman’s capsule

• Renal tubules

  • Proximal convoluted tubule

  • Proximal straight tubule

  • Loop of Henle

  • Distal straight tubule

  • Distal convoluted tubule

  • Collecting tubule

Renal corpuscles functions

Filtration of blood

Proximal convoluted and straight tubule function

Site for glucose and amino acid reabsorption

Loop of Henle function

Water reabsorption

Distal straight and convoluted tubule function

Target site for antidiuretic hormone and diuretic agents

Collecting tubule function

Concentration of urine

Flow of blood thru the kidneys

Aorta > renal artery > segmental artery > interlobar artery > arcuate artery > cortical radiate artery > afferent arteriole > glomerulus (capillaries) > efferent arteriole > peritubular capillaries (vasa recta) > cortical radiate vein > arcuate vein > interlobar vein > renal vein > inferior vena cava

Renal blood vessels

• Renal artery and vein

• Interlobar arteries and veins

• Interlobular arteries and veins

• Arcuate arteries and veins

Parts responsible for sperm formation

Seminiferous tubules

Parts responsible for sperm maturation

Epididymis

Muscular tube that undergoes contraction during ejaculation

Ductus deferens

Secrete semen/seminal fluid

Accessory sex cells (seminal vesicle, Cowper’s gland, prostate gland, ampullae)

Common passageway for urine and seminal fluid

Male urethra

Male organ of copulation

Penis

Invaginated fold of skin that surrounds and protects the free extremity of penis

Prepuce

Surrounds and suspends the testicles

Cremaster muscle

Progesterone and estrogen secreting structures

Ovary

Extruded from the graafian follicle to the exterior of the ovary during ovulation

Ovum

Finger-like projections at the free extremity of the infundibulum which helps catch the ova

Fimbriae

Funnel-shaped portion of the uterine tube

Infundibulum

Site of fertilization in mammalian reproductive tract

Magnum

Type of uterus in single and multiple bearing animals

• Single bearing = Bipartite

• Multiple bearing = Bicornuate

Type of uterus with shorter horns but longer body

Bipartite

Type of uterus with longer horns but shorter body

Bicornuate

Uterine neck

Cervix

Birth canal for delivery of fetus

Vagina

External female genitalia

Vulva

Shape of uterus in horse

• Bipartite (Short horn, long body)

• Cornua slightly curved, or nearly straight; both dorsal and ventral fornices present in vagina

Shape of uterus in ox

• Bipartite (Short horn, long body)

• Cornua have slightly spiral twist; dorsal fornix only

Shape of uterus in ewe

• Bipartite (Short horn, long body)

• Cotyledons are umbilicate

Shape of uterus in sow

• Bicornuate (Long horn, short body)

• Cornua very long; no fornices

Shape of uterus in bitch

• Bicornuate (Long horn, short body)

• Cornua are straight and shaped like a Y; cervical canal is at an angle

Blood vessels beside right and left kidneys

Aorta (left) and vena cava (right)

Kidneys located ventral to these vertebrae

First few lumbar vertebrae (1st, 2nd, 3rd, 4th)

Renal corpuscles components

Glomerulus and Bowman’s capsule

Renal blood vessels segments

• Renal artery and vein

• Interlobar artery and vein

• Interlobular artery and vein

• Arcuate artery and vein

Connects renal pelvis of the kidneys to the urinary bladder

Ureter

Muscle in the ureters responsible for peristaltic waves

Smooth muscles

Hollow pyriform muscular sac at the floor of pelvic cavity that serves as temporary storage site for urine

Urinary badder

Main part of urinary bladder

Body

Constricted portion of the urinary bladder that is continuous posteriorly with the urethra

Neck

Blunt, flask-shaped anterior extremity of the urinary bladder

Fundus

Scar on the fundus which indicates the fetal attachments of urachus

Centrum

Triangular area in the vicinity of the neck, formed by modified mucous membrane that is especially sensitive to pressure

Trigone

Peritoneal folds that kept the bladder in position

• Middle umbilical fold

• Two lateral umbilical fold

Part of male urethra from bladder to ischial arch

Pelvic urethra

Part of male urethra from ischial arch to glans penis

Extra-pelvic (penile) urethra

Lining epithelium of urinary tract from renal pelvis to urethra

Transitional epithelium

Lining epithelium near urethral orifice

Stratified squamous epithelium

Comparative description of kidneys per animal

• Horse = right is heart-shaped; left is bean-shaped; renal papillae fused to form renal crest

• Ox = lobulated; no renal pelvis; minor calyces embrace the renal papillae, lead into major calyces and into ureter

• Sheep = bean-shaped; renal papillae fused to form renal crest; renal crest has two projections (dorsal and ventral buttresses)

• Pig = bean-shaped; renal pyramids are fused but their papillae are separate; minor calyces embrace papillae, lead into major calyces and hence into ureters

• Dog = bean-shaped; renal pyramids fused into renal crest; renal crest projects into distinct renal pelvis

• Cat = Stellate veins are subcapsular renal vessels found in the kidneys of Felidae

Rght is heart-shaped; left is bean-shaped; renal papillae fused to form renal crest

Horse kidney

Lobulated; no renal pelvis; minor calyces embrace the renal papillae, lead into major calyces and into ureter

Ox kidney

Bean-shaped; renal papillae fused to form renal crest; renal crest has two projections (dorsal and ventral buttresses)

Sheep kidney

Bean-shaped; renal pyramids are fused but their papillae are separate; minor calyces embrace papillae, lead into major calyces and hence into ureters

Pig kidney

Bean-shaped; renal pyramids fused into renal crest; renal crest projects into distinct renal pelvis

Dog kidney

Subcapsular renal vessels found in the kidneys of Felidae

Stellate veins

Parts of epididymis

Caput (head), Corpus (body), Cauda (tail)

Ampullae is well-developed in these animals

Stallion, bull, ram

Ampullae is absent in this animal

Boar

Seminal vesicle is pear-shaped in this animal

Stallion

Seminal vesicle is lobated in this animal

Bull, ram, boar

Other term for bulbo-urethral gland

Cowper’s gland

Accessory sex gland in especially large in boar

Bulbo-urethral gland

Smooth muscle in scrotum that contracts in cold conditions

Tunica dartos

Structures that passes thru inguinal canal in male

• Spermatic cord

• Tunica vaginalis

• External cremaster muscle

• External pudendal artery

• Inguinal lymph vessels and nerves

Structures that passes thru inguinal canal in female

External pudendal vessels and nerves

Anterior boundary of internal ingunial ring 

Internal oblique muscle

Posterior boundary of internal inguinal ring

Inguinal ligament