L26 Anatomy of the Renal Tract

Question 1

Where do the Kidneys lie?

Answer 1

The kidneys are either side of the midline at either side of the IVC and aorta. They lie from T12-L3. The left lying slightly higher at T11, and the right lying at T12 due to the presence of the liver.

Question 2

What are the muscles of the posterior abdominal wall?

Answer 2

Muscles:
- Psoas major and psoas minor sat on top of it
- Iliacus muscle - the psoas muscle and ilacus muscle are considered together as they attach to the femur together at the lesser trochanter. Since they have the same attachment point, they have the same action and so can be called the iliopsoas. It is known as the iliacus as it resides in the iliac fossa.
- Laterally from the psoas major is the Quadratus lumborum. It acts as an antagonist for the rectus abdominus. It antagonises flexion of the trunk - and allows extension of the trunk.
There is also the transversus abdominis - the most inter muscular layer of the lateral abdominal wall

Question 3

From anterior to posterior, give the structures that enter the hilum of the kidney.

Answer 3

From anterior to posterior: the vein, the artery and the ureter, enter and leave the kidney. This helps to orientate between a left and right kidney.

Question 4

Describe the collecting system of the kidney.

Answer 4

• Towards the tip of the renal pyramid is collecting ducts containing urine meeting together known as renal papilla, this is the tip of the renal pyramids. The renal papilla opens out into a minor calyces. This is where we have the pure collecting system of the kidney.
  
  • The minor calyces all join together to form a major calyces (2 or 3 join together).
  • The major calyces join together to make the renal pelvis.
    From the renal pelvis, it narrows to form the ureter.

Question 5

Where are the 3 constrictions of the ureter?

Answer 5

• At the renal pelvis
  
  • As it passes over the iliac vessels - as it passes over the pelvic brim
  • The ureters become encompassed within the wall of the bladder as they grow. The angle of the ureters as the enter the bladder, is slightly transverse. This is another constriction and so prevents backflow.

Question 6

What is the clinical significance of the constrictions of the ureter?

Answer 6

These constrictions means that kidney stones can get stuck - occur when solutes in the urine crystallises.

Question 7

What elements of the reproductive system cross the ureter in the pelvis?

Answer 7

In the male: The vas deferens - The prostate gland in the male sits just underneath the bladder - the urethra has to pass through the prostate gland. This is where sperm is deposited in the urethra.

Female - The uterine artery

Question 8

What is a staghorn stone?

Answer 8

Staghorn calculi refer to branched stones that fill all or part of the renal pelvis and branch into several or all of the calyces.

Question 9

Give the peritoneal pouches of the pelvis.

Answer 9

In the male:
Vesicorectal pouch - The peritoneum passes over the rectum and the bladder. As it passes over it forms patches as it delves between them. In the male there is a vesicoureteral pouch - between the rectum and the bladder.

In the female:
Vesicouterine pouch and a vesicouterine pouch - Between the bladder and the rectum is the uterus.

Question 10

What is the trigone of the bladder? What is its purpose?

Answer 10

There is a smooth triangular region called the Trigone of the bladder. The lateral edges of the trigone is where the ureter empties in. The rest of the bladder had rugae (folds). The trigone does not contract. When we want to urinate, it does not contract to prevent the bladder contracting and bursting. We funnel urine to the trigone as the bladder contracts, to the internal urethral office so urine can empty through the urethra.

Question 11

What type of muscle is the bladder made from?

Answer 11

Detrusor muscle

Question 12

What are the parts of the male urethra?

Answer 12

The bladder just behind the pubic symphysis.

1. The first part of the urethra known as the pre-prostatic urethra - Just before it gets to the prostate glad 
2. Prostate part of the urethra 
3. Intermediate 
4. Spongy/penile urethra

Question 13

What is the significance of the shorter urethra in women?

Answer 13

In the female, the urethra is only 4-5cm. This increases the chance of infection as bacteria does not need to travel far before she gets a UTI.

Question 14

What is benign hyperplasia of the prostate?

Answer 14

Just underneath the neck of the bladder is where the prostate sits and the urethra passes through it. As the make gets older, the prostate enlarges (occurs in the majority of men). This is known as benign hyperplasia of the prostate. If the prostate becomes enlarged, it starts to squeeze on the wall of the urethra. This can lead to urinary problems, impeding urination. This can lead to increased urination of night (nocturia), dysuria and urgency. Can also lead to problems with the flow of urine, urine can also be trapped in the urine and so the make feels they need to go to the toilet.

Question 15

What is the micturition reflex?

Answer 15

Bladder filling is due to sympathetic control. When it is filling, we need to contract the external urethral sphincter, and the internal urethral sphincter and relax the muscular bag. This is all sympathetic control. Emptying, is under parasympathetic control. Parasympathetic control contract the detrusor muscle and relax the internal urethral sphincter.

The external urethral sphincter is under somatic control. We can then contract the sphincter to “hold it.”

Question 16

What are the nerves of the posterior abdominal wall?

Answer 16

• Lumbar plexus gives rise to the subcostal nerve (just underneath the 12th rib); also a common stalk that splits into the iliohypogastric and ilioinguinal nerve (can arise as two separate stalks). These three nerves transverse around to the anterior aspect.
  
  • As the nerves go round, they supply the muscles. The ilioinguinal nerve supplies some of the skin as it goes around, the quadratum lumborum and some of the iliacus muscle. They also supply the parietal peritoneum as they transverse around.
  • The ilioinguinal nerve as it transverse around, it goes between the transversus abdominis and the internal oblique and passes within the inguinal canal. It does not go through the deep ring. It then goes down to the genital region to supply some of the skin.
  • On top of the psoas major muscle is the genitofemoral nerve. There is a genital part (goes through the inguinal canal) and a femoral part (supplies skin around the femur).
  • The spermatic cord goes through the inguinal canal to leave the abdominal wall. The ilioinguinal never and GF nerve, which is within the fascial layers, they take a layer of fascia with it. The Ilioinguinal nerve does not go through the deep ring and so does not have fascial layers around it and so is not encompassed within the spermatic cord.
    Sacral plexus