Lesson 21 Basic Organs and Structures in the Abdominal and Pelvic Cavity, the Kidneys

What diagnostic technique is used? What is the organ?

Ultrasound and Kidney

When estimating the size of the kidneys in dogs or cats on radiograph, what lumbar vertebrae is used as the reference?

L2

In dogs, which kidney is ventral to the last thoracic and first two/three lumbar vertebrae?

Right kidney

In dogs, which kidney is below the first/second to fourth lumbar vertebrae?

Left Kidney

Which kidney is more restricted by being deeply recessed within the caudate lobe of the liver?

Right

Is the right kidney more cranial or caudal to the left kidney?

Cranial

Why is it difficult to visualize the right kidney for imaging as well as to access for surgery?

Due to it being hidden in the recess of the liver and being more cranial, under the ribcage.

The cranial end of the right kidney is within the ribcage usually bisected by which rib?

T13

The right kidney is closely related to which gland?

right adrenal gland

The right kidney is medially close to which major blood vessel?

Caudal vena cava

The right kidney is ventrally in contact with what organs

right lobe of the pancreas

Descending duodenum

Ascending colon

The cranial end of the left kidney is in contact with which organs?

Spleen

Greater curvature of the stomach

Pancreas

Left adrenal gland

The left kidney is caudally in contact with which part of the colon?

Descending colon

The left kidney is medially related to which parts of the GI?

Descending colon

Ascending duodenum

Describe the location of the kidneys against the dorsal abdominal wall on either side of the vertebral column.

retoperitoneally

What does it mean to be retroperitoneally?

They sit behind the lining of the abdominal cavity

What is the shape of the kidneys in a dog and cat?

Bean shaped

How can you differentiate kidneys of a dog and cat?

Cats have more prominent Capsular veins in the surface of the kidneys

What is the lining of the kidneys called?

Renal capsule

The lateral border of the kidney is what shape?

Convexed

What is the shape of the medial border of the kidneys?

Concaved and indented at the hilus

Where does renal artery and vein, ureter enter the kidney?

The hilus

What are the two regions of the internal structure of the kidney?

Cortex

Medulla

What does the appearance of the renal cortex?

Granular

What is the appearance of the renal medulla?

Striated

In cows, the cortex remains unfused to form lobes while the medulla is undused and form medullary projections, what are these projections called?

Renal pyramids

What region of the kidney contains renal corpuscles and convoluted parts of the tubules?

Cortex

What region of the kidney contains the collecting ducts?

Medulla

What is the inner margin of the medulla where the ducts empty into the renal pelvis?

Renal crest

What is a false pyramids, and which species have this?

Pyramids will be seen in the paramedian sagittal section only but there are no true renal/medullary papillae present. This is seen in dogs and cats

What part of the kidney is a wide, funnel-shaped structure that collects the urine. It is the terminal dilated part of the ureter within the kidney.

Renal Pelvis

What part of the kidney is a depression caused by extension of the renal pelvis into the medulla on both sides of the crest?

Renal/pelvic recesses

What part of the kidney is a fat-filled space surrounding the renal vessels and the ureter?

Renal sinus

The kidneys are clearly seen in what percentage of the plain studies of the abdomen of the dog?

50%

What type of radiography is used for more detailed studies of the kidneys?

Contrast radiography

What type of views are usually performed to visulize the kidneys?

Lateral and VD

Which lateral is used more often to visualize the kidneys?

Right lateral

How sound the kidneys look on a radiograph of a cat/dog?

Bean shaped

Smooth

Homogenous

Stoft tissue opacity

The kidneys are often superimposed on one another, which kidney is more more cranial?

The right kidney

What is the normal canine kidney size?

2.5-3.5x of L2

What is the normal kidney size of a feline?

2.4-3x L2

In VD, the canines right kidney should lie in the area of which vertebrae?

T13-L2

In VD, the canines left kidney should lies in the area of which vertebrae?

L1-L3

In VD, the feline right kidney should lie in the area of which vertebrae?

L2-L4

In VD, the feline left kidney should lie in the area of which vertebrae?

L3-L5

While viewing an ultrasound of the kidneys how does the echotexture compare to the spleen?

Fine

Granular

Markedly hypoechoic much like the spleen

What is the echotexture of the renal cortex?

Hypoechoic or isoechoic ( much like liver)

hat is the echotexture of the renal medulla?

Hypoechoic or anechoic

What is it called when there is a presence of bright hyperechoic specks that represent the arcuate vessels?

Corticomedullary junction

What divides the renal medulla into segments on an ultrasound?

Diverticula and the vessels

Why is the renal pelvis hyperechoic?

The presence of fat and fibrous tissue

What makes the bovine kidney more primitive than a dog or cat?

The kidney is lobated (18-20 lobes), no renal crest or renal pelvis

What is the shape of the bovines right kidney?

Flattened

Oval

Which kidney’s cranial pole embeds in the liver?

Right Kidney

What is the shape of the bovines left kidney?

Slightly twisted, pointed cranially.

Which bovine kidney is displaced to the right by the rumen?

Left kidney

The lobes of the bovine kidney form pyramids that have what distinct structure?

Renal papillae

Where do the renal papillae drain into?

Minor renal calices

Where do the minor renal calices drain into?

Cranial/Caudal collecting ducts (Major Calyces)

The cranial and caudal calyces join to form what?

ureter

How is the small ruminant kidney similar to the canine?

Fusion of the cortex and medullary region

Bean shaped with renal hilus

medullary region fuses to form a single renal pyramid/renal crest

How is the porcine kidney different than any other species kidney?

No external lobation because the cortex is fused and smooth but has internal evidence of lobation.

What species is the only domesticated mammal whose kidneys are at the same level, meaning there is no contact between right kidney and liver?

Porcine

What are the internal features of the porcine kidney?

10 Medullary pyramids →10 minor calyces → two major calyces → renal pelvis → ureter

Where is the right equine kidney located in relation to what vertebrae?

T16-L1

The cranial pole of the equine right kidney makes what on the caudate process of the liver?

renal impression

What is the shape of the equine right kidney?

heart-shaped

flattened

small

transverse diameter = longitudinal diameter

Which organ is cranial to the horses right kidney?

The liver

Which organs are ventral to the horses right kidney?

Descending duodenum

Pancreas/base of cecum

Small colon/intestine

Which gland/blood vessels are medial to the horses right kidney?

Right adrenal gland and aorta

Where is the left equine kidney located in relation to what vertebrae?

T17-L2

What is the shape of the horses left kidney?

Flattened

bean-shaped or 6 shaped

What organs are cranial to the horses left kidney?

Spleen

Stomach

What organs/blood vessels are medial to the horses left kidney?

Aorta

Small colon

Small intestine

What makes the equine kidney more phylogenetically advanced than the bovine kidney?

It is a modified Unipyramidal type with a renal crest → renal pelvis → ureter

What structure of the equine kidney is unique to the equine species?

The terminal recess

What is the terminal recess?

Two polar recesses extend from the poles of the kidneys connecting the papillary ducts to the renal pelvis

Describe the vasculature of the kidney and its nephron going from the aorta to the kidney.

Aorta → Renal artery → Interlobar → Arcuate → Interlobular → cortex → Afferent arterioles→ renal corpuscles which will divide to form the capillary loop of the glomerulus

Describe the efferent vasculature of the kidney and its nephron from the glomerular to the tubules.

Glomerular capillaries→ Efferent arterioles (second capillary system) → peritubular capillaries that surround the tubules.

What is the renal pelvis?

The dilated terminal part of the ureter within the kidney

What blood vessel directly branches the afferent arterioles?

Interlobular artery

What is the renal sinus?

The region/space filled with fat that accommodates the ureter, renal artery, and vein

What is the renal papillary?

The terminal part of the renal pyramid within the kidney

What is the papillary junction?

The junction between the cortex and the medulla

What is the minor calices?

The parts that fuse to form the major calices