Week 3 Lesson 21 Basic Organs and Structures in the Abdominal and Pelvic Cavity, The Kidneys
Page 1: Title
Systems 2: Water Balance and Eliminating Basic Organs and Structures in the Abdominal and Pelvic Cavity, The KidneysDr. Narindra Roopnarine
Page 2: Learning Outcomes
By the end of this session, students will be able to:
Identify the topographic location and medical imaging features of the kidneys in cats and dogs.
Describe the external and internal structure of the kidneys.
Describe variations in the structure of kidneys across various species: feline, porcine, bovine, equine, and ovine/caprine.
Page 3: Activity - Prework Bridge
Word Cloud Activity
Questions:
What is the diagnostic method/technique?
What is the organ?
Page 4: Kidney Size Estimation
When estimating kidney size in dogs or cats on radiographs, the lumbar vertebrae used as a reference is specified (MCQ).
Page 5: Hotspot Activity
Identify the right side of the animal by tapping on the image.
Page 6: Location of the Kidneys
Topographic Location and Imaging:
In dogs:
Right kidney is ventral to the first three lumbar vertebrae.
Left kidney is ventral to the second to fourth lumbar vertebrae.
Right kidney is more cranial and deeply recessed within the caudate lobe of the liver; related medially to the right adrenal gland and caudal vena cava.
Visualizing the right kidney for imaging and surgical access is more challenging due to its location.
Page 7: Relation of the Kidneys to Other Organs
Topographic Location and Imaging:
Right kidney:
Cranial end is within the rib cage, typically bisected by the 13th rib.
It is closely related to the right adrenal gland, ventrally in contact with the right limb of the pancreas and ascending colon.
Left kidney:
Cranial end contacts the spleen, greater curvature of the stomach, and left adrenal gland.
Caudally, it is in touch with the descending colon.
Page 8: Summary of Organ Relations
Topographic Location:
Canine organs around the kidneys include the adrenal gland, caudal vena cava, abdominal aorta, descending duodenum, and colon.
Page 9: Kidney Location Context
Paired kidneys lie retroperitoneally, pressed against the dorsal abdominal wall
Typically ventral to the lumbar vertebrae and extending cranially under the last ribs.
Variability exists depending on the species (e.g., in ruminants, the left kidney is displaced by the rumen).
Page 10: External Features of the Kidney
Shape and Structure:
Bean-shaped in dogs and cats.
Cat kidneys present capsular veins on the surface.
Surrounded by a well-developed renal capsule.
Retroperitoneal position with convex lateral border and concave medial border (indented at hilus).
Renal artery and vein, and ureter enter at the hilus.
Page 11: Internal Structure of the Kidney
Two main regions:
Outer Cortex:
Granular appearance, primitive in bovine species.
Inner Medulla:
Striated appearance.
Page 12: Evolution of the Kidney
In bovines, the cortex doesn't fuse, forming lobes, while the medulla remains unfused, creating renal pyramids.
Kidney evolution involves fusion of cortex and/or medulla in various species.
Page 13: Internal Kidney Features
Medulla contains collecting ducts
Renal crest: Inner margin of the medulla where ducts empty into the renal pelvis
Cortex contains renal corpuscles and convoluted tubule segments.
Page 14: Medullary Structures
Medullary pyramids/papillae present in pigs and cows, divided by inter-lobar vessels.
Dogs and cats show only false pyramids, visible in paramedian sagittal sections.
Page 15: Renal Pelvis and Surroundings
Renal Pelvis:
Wide, funnel-shaped structure collecting urine; terminal end of the ureter inside the kidney.
Renal/Pelvic Recesses: Extensions of the renal pelvis into the medulla.
Renal Sinus: Fat-filled space surrounding renal vessels and ureter.
Page 16: Summary of Renal Anatomy
Features associated with the renal pelvis and pelvic recesses.
Page 17: Radiology of the Kidneys
Kidney Visibility:
In dogs, seen in 50% of plain abdominal studies; better delineated in cats.
Contrast radiography often necessary for detailed studies via intravascular perfusion.
Views include lateral and ventral, with right lateral views preferred.
Page 18: Radiology Overview
Reiterates imaging techniques for assessment of kidney location and structure.
Page 19: Normal Radiologic Appearance
Both kidneys appear bean-shaped with smooth, homogenous opacity.
Depending on positioning, the cranial pole of the left kidney may overlap the right.
Dimensions: Canine kidney = 2.5-3.5 times length of L2; Feline = 2.4-3 times L2.
Page 20: Kidney Position on Radiographs
Right kidney positioned from 13th thoracic to 3rd lumbar vertebra; may be obscured by liver unless adequate penetration occurs.
Left kidney positioned from 2nd to 4th/5th lumbar vertebra with more variable positioning in cats compared to dogs.
Page 21: Contrast Studies Insights
Both kidneys should be well-visualized; renal cortices should appear diffusely opaque with smooth outlines.
Collecting channels and renal pelvis should also be visible during contrast studies.
Page 22: Break Time
10 minutes
Page 23: Ultrasonography of the Kidneys
Echotexture: Fine, granular, markedly hypoechoic compared to spleen.
Renal cortex: Hypoechoic or isoechoic compared to liver.
Renal medulla: Hypoechoic or anechoic relative to renal cortex.
Page 24: Ultrasonography Features
Corticomedullary junction defined by bright hyperechoic vessels, and the renal medulla is anechoic, divided by diverticula and vessels.
Renal pelvis appears hyperechoic due to fat and fibrous tissue presence.
Kidney size varies significantly in dogs due to body size; less variability in cats.
Page 25: Imaging of Kidneys in Dorsal and Sagittal Planes
Visual representations of normal dog and cat kidneys in various imaging planes.
Page 26: Kidney Structures Across Species
Description of kidneys in different mammals:
Rat/Rabbit: Simple, no lobation; single renal papilla.
Dog/Sheep: Lobes visible internally.
Pig: Lobes not visible externally; true renal pyramids present.
Horse: Presents lobation by blood vessels, with clear renal crest.
Page 27: Bovine Kidney Characteristics
Bovine kidneys are lobated (18-20 lobes); lack renal crest or pelvis.
Right kidney: Flattened, oval, related ventrally to colon and descending duodenum, with cranial pole embedded in liver.
Left kidney: Twisted, cranially pointed, displaced by rumen.
Page 28: Bovine Kidney Overview
Reiteration of characteristics; considered a primitive type within domestic mammals.
Page 29: Internal Features of Bovine Kidney
Lobes form pyramids with distinct renal papillae, drained by minor renal calices, leading to major calyces and ureter.
Page 30: Porcine Kidney Attributes
No external lobation; smooth cortex with internal lobation evidence.
Dorsoventrally flattened and smooth, kidneys are at the same level (last rib to L4) without contact to the liver.
Page 31: Internal Features of Porcine Kidney
Up to 10 minor calices draining separate renal pyramids; two major calyces drain into the renal pelvis.
Page 32: Porcine Kidney Detailed Structure
Differences from canine kidneys, highlighting true renal pyramids in pigs.
Page 33: Small Ruminant Kidney Features
Similar to canine kidneys, with cortex and medullary fusion resulting in a single renal pyramid/renal crest.
Page 34: Equine Kidney Positioning
Right Kidney: Located ventral to last 2-3 ribs (T16 – L1), cranial pole makes an impression on the liver.
Left Kidney: More caudal, ventral to T17 – L2, flattened and retain a unique morphology compared to right kidney.
Page 35: Equine Kidney Characteristics
More advanced structure, showing modified Unipyramidal type features with a common renal crest and unique papillary ducts.
Page 36: Summary of Renal Dimensions
Overview of kidney structure across different species and relation to anatomical landmarks.
Page 37: Kidney Anatomy Overview
Renal cortex and medulla relationship, renal pelvis, and representation across different domestic mammals.
Page 38: Blood Supply of the Kidney
Main blood supply from renal artery branching into interlobar arteries which further divides into arcuate arteries and interlobular arteries.
Page 39: Kidney Nephron Vasculature
Efferent arterioles recombine to form peritubular capillaries, feeding into the nephron structures.
Page 40: Knowledge Check on Renal Pelvis
Multiple-choice question regarding the definition and anatomy of the renal pelvis.
Page 41: Knowledge Check on Blood Supply
Multiple-choice question regarding the blood vessel supplying the renal glomerulus.
Page 42: Next Steps & Questions
Complete pre-work for lesson 22 at the lab.
Contact Email: nroopna1@sgu.edu.
Humor: "ARE YOU KIDNEY-ING ME?"
Systems 2: Water Balance and Eliminating Basic Organs and Structures in the Abdominal and Pelvic Cavity, The Kidneys
Dr. Narindra Roopnarine
Learning Outcomes
By the end of this session, students will be equipped with the knowledge and skills to:
Identify Topographic Location: Accurately locate the kidneys in both cats and dogs, using imaging techniques to differentiate between them. Students will learn about the anatomical landmarks in relation to the lumbar vertebrae, as kidney positioning can vary significantly due to age, breed, and size of the animal.
Describe External and Internal Structures: Provide a comprehensive description of the kidney's morphology, including the external renal capsule, internal medullary and cortical layers, and the specific adaptations seen in different species. In-depth discussions on the differences between species such as felines, porcine, bovine, equine, and ovine/caprine will highlight evolutionary adaptations and functional implications.
Analyze Clinical Significance: Evaluate the relevance of kidney anatomy in clinical practice and diagnostic imaging. Understanding normal variations in kidney structures will aid in the recognition of pathological conditions during diagnostics and treatment.
Activity - Prework Bridge
Word Cloud Activity
Diagnostic Techniques: Students will participate in a discussion on diagnostic methods utilized for kidney evaluation, including ultrasound, X-ray, and CT scans, discussing the benefits and limitations of each method in a veterinary context.
Organ Involvement: Focus on the urinary system's single most critical organ, the kidney, and its relation to other organs such as the bladder and ureters, emphasizing how kidney health impacts overall bodily functions.
Kidney Size Estimation
When estimating kidney size in canine or feline radiographs, the chosen lumbar vertebrae serve as a reference point, necessitating a thorough understanding of anatomical landmarks for precise measurement. Moreover, students will engage with case studies illustrating how variations in kidney size can mislead diagnoses if not correctly interpreted. Factors such as sex, breed, age, and body condition score can impact the size and shape of kidneys.
Hotspot Activity
An interactive task where students will be required to identify the right side of the anatomical model by tapping on designated areas of the image. This exercise reinforces the foundational concept of anatomical orientation and lateralization in clinical diagnostics, facilitating critical thinking about organ placement in relation to the anatomical planes of the body.
Additional Considerations
As veterinary students, understanding renal anatomy through varying perspectives is crucial for effective communication in a clinical setting. This detailed exploration of the kidneys will provide students with the foundational knowledge necessary to continue advancing in renal physiology and pathology eventually leading to better patient care in veterinary medicine.