Session 1 ILOs - Introduction and Anatomy of the Renal and Urinary System

Question 1

State the anatomical position of the kidneys

Answer 1

• The kidneys are retroperitoneal organs
• Located between the T12 (upper pole) and L3 vertebrae (lower pole)
• Partially protected by the 10-12th ribs
• Hilum at L1
• Right kidney is slightly lower because it’s pushed down by the liver

Question 2

Describe the normal size of each kidney

Answer 2

Usually:

• 11cm long
• 6cm wide
• Weighs approximately 140g each (0.14kg)

Question 3

Describes the entry point of the renal artery and how it splits

Answer 3

• Renal artery enters kidneys at the hilar region

- Usually divides to form an anterior and a posterior branch

Question 4

State some ulterior arteries that the kidneys are sometimes supplied by

Answer 4

• Superior mesenteric artery
• Suprarenal artery
• Testicular artery
• Ovarian artery

Question 5

Describe the course of the ureters and the relationships in the pelvis to the iliac vessels and uterine vessels, ovary/vas and the urethra in both males and females

Answer 5

• The ureters arise from the renal pelvis and are part of the retroperitoneal area
• At the area of the sacroiliac joints, the ureters cross the pelvic brim, thus entering the pelvic cavity (this is where they are most vulnerable to injury)
• They also cross the bifurcation of the common iliac arteries at the pelvic brim
• Within the pelvic cavity, the ureters travel down the lateral pelvic walls and then anteromedially, moving towards the bladder

Female:

• When ureters cross the pelvic brim, they are in close proximity to the ovaries
• Ureters also run underneath the uterine artery = ‘water under the bridge’.

Male:
- Instead of the uterine arteries, the ureters run underneath the vas deferens

Question 6

Describe how the ureter enters posterolateral surface of bladder and runs obliquely through the bladder wall

Answer 6

• The ureter pierces its lateral aspect of the bladder in an oblique manner
• This creates a one way valve
• High bladder pressure collapses the ureters, preventing the backflow of urine)
• Name: vesicoureteral junction

Question 7

State the anatomical position of the bladder

Answer 7

• The bladder is situated posterior to the pubic symphysis
• When empty, the bladder rests on the pubic symphysis
• In females: the vagina is posterior
• In males: the rectum is posterior
• Inferiorly, the muscles of the pelvic diaphragm support the bladder

Question 8

Describe the bladder wall composition

Answer 8

• The detrusor muscle is the primary muscle that makes up the bladder wall, which is smooth muscle composed of transitional epithelium
• The cells change shape depending on the volume of urine in the bladder
• There are rugae within the mucosa, which further allows bladder to expand

Question 9

Describe the three openings of the trigone and how the walls differ compared the the rest of the bladder wall

Answer 9

• 2 ureters and the entry to the urethra

- The wall of the trigone is smooth, whereas the rest of the bladder wall is rough/rugae

Question 10

Describe the neck of the bladder with the internal urethral sphincters (differing in males and females)

Answer 10

Females:

• Internal urethral sphincter thought to be a functional sphincter (i.e. no sphincteric muscle present)
• It is formed by the anatomy of the bladder neck and proximal urethra

Male:

• Internal urethral sphincter consists of circular smooth fibres, which are under autonomic control
• It is thought to prevent seminal regurgitation during ejaculation

Question 11

Identify the anatomical position of the prostate

Answer 11

In males, the prostate gland lies inferior to the neck of the bladder

• The urethra runs through the prostate gland (prostatic urethra), along with the convergence of the seminal vesicles to form the ejaculatory duct
• Inferior to the internal urethral sphincter and superior to the external urethral sphincter
• The prostate gland is also located in front of the rectum and can be felt on a digital rectal examination

Question 12

Describe its muscle layers in the urethra the ultra-structure of the urethra in males

Answer 12

Urethra is coated in transitional epithelium (urothelium) which allows for the stretching of the lining once filled

Urethra divisions (male):

• Pre-prostatic urethra
• Prostatic urethra
• Membranous urethra
• Bulbous urethra
• Spongy/penile urethra