The Urinary System

By Laura Hunter (laura.hunter@glasgow.ac.uk)

The Urinary System

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Intended Learning Outcomes

FP1058: Describe the structure, function and topography of the kidney and how the kidney contributes to the maintenance of homeostasis. FP1059: Describe the structure, function and topography of the lower urinary tract including the physiology of micturition Content ILOs 1) Recognise the kidneys from a range of species. 2)Interpret normal diagnostic images relating to the urinary system. 3) Demonstrate the relative positions and topographical relationships of the kidneys, ureters and bladder in the male and female.

Before you start

Online practicals are a complement to on campus practicals and do not replace the in person experience - these are meant to help you prepare for the lab practicals and are a good resource for revision. Make sure you have your notes and lectures slides on hand to consult while you complete the session. Questions are for self-testing purposes only and will not be individually scored. These will be a summary table at the end on the internal & external appearances of the kidneys in different species. You may wish to take notes as you move through the practical to fill in the table at the end. Some images will have icons which you can hover over to get the correct answer.

Station 8 - Radiography & Ultrasonography

Station 7 - Lower Urinary Tract

Index

Station 1 - Canine Kidney

Station 6 - Porcine Kidneys

Station 5 - Equine Kidneys

Station 4 - Bovine Kidneys

Station 3 - Small Ruminant Kidneys (Sheep & Goat)

Station 2 - Feline Kidney

Activity: Watch this video which demonstrates the features of a unilobar kidney.

Kidney Features Video

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Station 1: Canine Kidneys (Image 1)

This is the kidney of a dog. Activity: 1) Identify A & B in this image. 2) What type of tissue does B consist of? 3) What type of kidney is this?

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Canine Kidneys: Image 2

These are embalmed canine kidneys. The right kidney has somewhat swollen during the embalming process such that the parenchyma has become tightly compressed against the kidney capsule which does not extend. In life swelling of the kidney parenchyma could lead to necrosis. Activity: 1) What structures enter and leave the kidney at the hilus? 2) Urine moves passively through the ureters to the bladder- true or false? 3) The renal arteries arise directly from the abdominal aorta- true or false? 4) The renal veins drain directly into the caudal vena cava- true or false?

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Canine Kidneys: Image 3

This is a freshly sectioned kidney. Note the change in coloration as we move from the cortex into the medulla at the corticomedullary junction. The renal recesses of the renal pelvis are also partially exposed in this specimen. Activity: 1) Identify the labelled features in this sectioned canine kidney.

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Canine Kidneys: Image 4

This is a resin cast showing the complex nature of the renal pelvis associated with the canine kidney (yellow). The interlobar arteries arising from the renal artery follow the path of the recesses in the renal pelvis towards the corticomedullary junction. Activity: 1) Identify the labelled features in this resin cast. 2) Which arteries do the interlobar arteries lead into?

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Canine Kidneys: Image 5

Contrast medium has been injected into the ureter in these radiographs to reveal the complex nature of the renal pelvis. Activity: 1) Identify the labelled structures in this image.

Station 2: Feline Kidneys (Image 1)

The kidney of the feline is quite distinctive because the sub-capsular veins (arrowed) which run towards the hilus. The size of the kidney can be estimated by palpation or via imaging. On a ventrodorsal radiograph, normal kidney size is usually between two to three times the length of second lumbar vertebra (3 - 4.5 centimetres).

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Feline Kidneys: Image 2

Internally the feline kidney conforms to the unilobar form. The arcuate blood vessels (circled) at the corticomedullary junction are indicated in this specimen. The real crest (A), renal pelvis (B) and renal sinus (C) have also been labelled in this specimen. Activity: 1) From which branches of the renal artery do these vessels arise? 2) The renal crest is where the urine drips from the papillary ducts to enter the renal pelvis. Do all species have a renal crest? 3) What kind of epithelium lines the renal pelvis? Do all species have a renal pelvis? 4) Once the urine enters the renal pelvis and exits the kidneys it will remain unchanged until it is voided- true or false? 5) What type of tissue fills the renal sinus?

Station 3: Small Ruminants (Image 1)

These are fresh sheep kidneys. The kidney of small ruminants resembles that of the canine in shape and external appearance but is larger in comparison. They are bean-shaped and smooth, without any lobulation and elliptical in form. Positional information: The right kidney is slightly more cranial than the left. The left kidney tends to be more pendulous, and the forestomach may push the left kidney to the right as far as the median plane or beyond, particularly when the rumen is full.

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Small Ruminants: Image 2

These are whole and sectioned sheep kidneys. The extent of fused medulla from the corticomedullary junction to the renal crest is indicated in the sectioned kidney in this image. Activity: 1) Why do you think the medulla is paler than the cortex in the fresh specimen?

Station 4: Bovine Kidneys (Image 1)

These are fresh bovine kidneys. The kidneys of the bovine do not lose their foetal lobulation and are an example of a multilobar kidney. There are typically about 18-20 renal lobes giving the kidney a fissured appearance. The hilus is located on the medial surface. The bovine kidney has no renal pelvis but rather the ureters enter the kidney and divide into a cranial and caudal branch. These branches then subdivide and the papilla at the apex of the pyramids open and drain into calices. Due to the rumen taking up most of the left side of the abdomen it is normal in the bovine to find the more pendulous left kidney positioned caudoventral to the right one usually in the region between the 2nd and 4th lumbar vertebrae. The right ureter passes along the roof of the abdomen to the pelvis in a standard pattern. The left ureter however moves across the dorsal surface of its kidney to return to the midline and follow a course as if the kidney was located on the left.

Bovine Kidneys: Image 2

These are embalmed bovine kidneys which have been injected with latex. The main structures entering and leaving the hilus of the bovine kidney are illustrated in this image. A) Renal artery B) Renal vein C) Ureter

Bovine Kidneys: Image 3

The natural colour has been lost from this embalmed specimen. The cortex (red line) and medullary pyramid of one renal lobe are indicated (blue line). Instead of a renal pelvis the ureter (C) forms branches which terminate in 18-20 cup like extensions – calices. The calices (B) in this specimen are grey in colour and are surrounded by deposits of fat (A). The unfused medullary pyramids each empty into a calyx.

Bovine Kidneys: Image 4

This is a resin cast of the bovine kidney. The distribution of blood vessels (red) and the presence of renal calices (yellow) arising from the ureter. The large red vessel (A) represents the renal artery entering what would have been the renal hilus. The medullary pyramid of each renal lobe drains directly into one of the cuplike calices that have been exposed in this specimen. There is no ’common’ renal pelvis or renal crest in the multilobar kidney.

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Bovine Kidneys: Image 5

Contrast medium has been injected into the ureter of these bovine kidneys to reveal the presence of renal calices. Note: You can clearly see the ureter subdividing into the two branches as it travels into the kidney.

Station 5: Equine Kidneys (Image 1)

The equine kidneys not only have very different shapes compared to the rest of the domestic species, but also each kidney is a different shape. A - The left is described as being pyramidal or almost bean shaped. B - The right kidney is described as being heart shaped.

Equine Kidneys: Image 2

These are embalmed equine kidneys. The attachments of the renal arteries to the abdominal aorta have been preserved in this specimen. In this image we are looking at the ventral side of each kidney - branches of the renal artery run in grooves before entering the kidney parenchyma on this surface.

Equine Kidneys: Image 3

Each kidney weighs approximately 700g and both are dorsoventrally flattened. The kidneys are basically unilobar and the only demarcation between what were the multiple pyramids of the foetus are the interlobar arteries.

Equine Kidneys: Image 4

The renal pelvis of the equine kidney is large and irregular with 2 recesses (finger like processes)- only one of which is visible in this sectioned kidney. Note: The cells of the renal pelvis in the equine secrete mucin giving the urine a cloudy stringy appearance. Activity: See how many of the labelled features you can identify on this specimen.

Equine Veterinary Journal, Volume: 45, Issue: S45, Pages: 31-38, First published: 05 December 2013, DOI: (10.1111/evj.12167)

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Equine Kidneys: Image 5

This image shows a 3D reconstruction of the left equine kidney and details the complex nature of the renal pelvis in this species. The cranial and caudal terminal recesses of the renal pelvis arise from the renal pelvis. The renal crest is also indicated 1) Cranial terminal recess 2) Caudal terminal recess 3) Renal crest 4) Renal pelvis

Station 6: Porcine Kidneys (Image 1)

These are fresh porcine kidneys with the fibrous capsule removed. The kidneys are dorsoventrally flattened. The renal pelvis opens into quite a large space of two major calyces from which bud about 10 minor calyces. These attach to one renal papilla each. The kidneys have a smooth cortical surface.

Porcine Kidneys: Image 2

This is a fresh sectioned porcine kidney. Internally the cortex is smooth and confluent, but the medullary pyramids are still evident. Each medullary pyramid is associated with a calyx. Activity: Identify the structures labelled A-E.

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Activity: Compare the external /internal features of the kidneys of the different species provided in this online practical then complete the table using one or more of the terms provided.

Internal appearance:- Multilobed - Unilobar - Intermediate form - Renal pelvis and renal crest - Medullary pyramids - Calices

External appearance:- Smooth outer surface - Fissured outer surface - Kidney bean shaped - Elongated/flattened - R kidney different shape to L kidney - Capsular veins

Summary Table

Activity: Watch this video which demonstrates the urinary system in the male dog. In this video the following structures are shown: 1) Kidneys 2) Lobes of adrenal gland (bisected by phrenicoabdominal blood vessels) 3) Renal vein (thin walled) leading to caudal vena cava. 4) Ureters 5) Bladder 6) Median ligament of bladder 7) Lateral ligament of bladder 8) Ductus deferens 9) Inguinal canal 10) Testicular artery

Male Dog Urinary System Dissection Video

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Station 7: Lower Urinary Tract (Image 1)

The right ureter is shown in this image running towards the neck of the bladder. Activity: 1) List 2 ways in which the ureters structurally adapted to perform their function.

Lower Urinary Tract: Image 2

The medial ligament of the bladder is shown in this image. Activity:

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Lower Urinary Tract: Image 3

The lateral ligaments of the bladder are illustrated in this image. Activity: 1) What important structure(s) are found running in the cranial margin of these ligaments?

Activity: Watch this video demonstrating the key features of the urogenital system in the intact female dog (bitch). In this video the following structures are shown: 1) Kidney 2) Ureter 3) Renal vein 4) Adrenal gland 5) Ovary 6) Uterine horns 7) Body of bladder 8) Lateral ligament of bladder

Intact Bitch Urinary Dissection Video

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Lower Urinary Tract: Image 4

Activity: Identify the labelled structures 1-8 in this image of the specimen shown in the video.

Station 8: Radiography (Image 1)

Contrast medium has been used to outline the kidney, pelvis and parts of the ureters and urethra. The urinary bladder is only partially filled in this lateral view. Activity: Identify the labelled structures A-D.

Radiography (Image 2)

Contrast medium has been used to outline the kidney, pelvis and parts of the ureters and urethra. The urinary bladder is well defined in the D/V view. Activity: Identify the labelled structures A-D.

This series of contrast radiographs shows the bladder at different stages of filling.

Radiography: Image 3

The bladder is full in this radiograph. Activity: Identify the regions of the bladder labelled A - C.

Radiography: Image 4

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An accumulation of deposited salts has been amassed within the bladder in this animal’s body. Activity: Which species and of which sex is this animal?

Radiography: Image 5

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Ultrasound image of the kidney. Activity: 1) Has this image been taken in the long or short axis? 2) Identify X, Y and Z in this image.

Ultrasonography: Image 6

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Ultrasound image of the kidney. Activity: 1) Has this image been taken in the long or short axis? 2) Identify X, Y and Z in this image.

Ultrasonography: Image 7

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Ultrasound image. Activity: 1) Identify the two organs which are imaged and marked (i) and (ii) in this ultrasound image. 2) Was this image taken on the left or right side of the animal? 3) What is the significance of the line x-y represented on this ultrasound image?

Ultrasonography: Image 8

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Feedback

Could you give us some feedback on how you found this online practical please! This helps us to know whether it is worth spending the countless hours creating these practicals for you or if you prefer the Moodle lessons format.

- Transitional epithelium - Smooth muscle enables the flow of urine to be directed towards the bladder

Answer

Summary Table Answers

Answers

1) Interlobar arteries. 2) No. This is a feature of the dog/sheep kidney where the papillary ducts converge. The situation in the horse kidney is complex but suffice to say the term renal crest is described. 3) Transitional epithelium or urothelium. Unilobar kidneys have a renal pelvis, in the pig the renal pelvis equivalent equates to where the calyces collectively fuse to continue as the ureter. 4) True. No further modification of the urine takes place after it leaves the kidney. 5) Fat/ Adipose tissue