The Urinary System

Question 1

What are the functions of the urinary system?

Answer 1

• stabilisation of blood pH
• regulates fluid balance
• regulates electrolyte balance
• blood pressure control
• metabolism of toxic waste products and drugs
• stimulates RBC production
• required for absorption of calcium

Question 2

Describe the epithelium of the urinary system

Answer 2

• ureter and upper urethra: uroepithelium capable of stretching
• distal urethra: protective stratified squamous epithelium

Question 3

Describe the locations of the kidneys

Answer 3

• retroperitoneal
• left kidney: left hyochondrium, epigastric, left lumbar and umbilical
• right kidney: right hypochrondrium, epigastric, right lumbar and umbilical

Question 4

Describe the layers that surround the kidneys from deep to superficial

Answer 4

• renal capsule
• perinephric fat
• renal fascia
• paranephric fat
• parietal peritoneum
• anterolateral abdominal wall muscles

Question 5

Describe the structure of the kidneys

Answer 5

• outer cortex and inner medulla
• renal pyramids and renal columns
• renal columns: extensions of cortex around pyramids
• apex of pyramids converge on minor calyces that go to major calyces into the renal pelvis which continues as ureter

Question 6

Describe the structure of the nephron

Answer 6

• renal corpuscle (cortex)
• proximal convoluted tubule (cortex)
• loop of Henle (medulla)
• distal convoluted tubule (cortex)
• collecting duct (medulla)

Question 7

Describe Nutcracker Syndrome

Answer 7

• compression of left renal vein by SMA

- in males results in varicocele in left spermatic cord

Question 8

What are the branches of the renal artery?

Answer 8

• segmental artery
• interlobar artery
• arcuate artery (anastomosis between interlobar arteries)
• interlobar artery
• afferent arterioles to glomerulus

Question 9

Describe the abdominal path of the ureter

Answer 9

• passes anterior to psoas major and branches of lumbar plexus
• closely related to gonadal vessels and crosses common iliac artery at its bifurcation

Question 10

Describe the pelvic path of the ureter

Answer 10

Females:

• crosses umbilical artery and obturator neurovascular vessels
• forms posterior border of ovarian fossa crossed superiorly by uterine artery near cervix

Males:

• crosses umbilical artery and obturator neurovascular vessels
• crosses the ductus deferens

Question 11

Describe the anatomy of the intramural ureter

Answer 11

• passes into bladder obliquely creating valve flap
• pressure of urine in full bladder forces valve closed
• prevents ureteric reflux

Question 12

What are the 3 ureteric constrictions?

Answer 12

1. pelvi-ureteric junction
2. ureter crossing iliac vessels at pelvic inlet
3. uretic orifice as it passes through bladder wall

Question 13

What innervates the ureter and where does referred pain go?

Answer 13

• renal, abdominal aortic and superior hypogastric plexuses
• visceral afferent fibres to T11-L2
• pain referred to loin, groin, scrotum/labia
• vagus can cause nausea/vomiting

Question 14

What arteries supply the ureter?

Answer 14

Branches from:

• renal arteries
• gonadal arteries
• aorta
• common iliac arteries

Question 15

Describe the lymphatic drainage of kidneys and ureter

Answer 15

• kidneys: lateral aortic lymph nodes

- ureter: lateral aortic, common and internal iliac lymph nodes

Question 16

What will you find between the bladder and rectum in males?

Answer 16

• seminal vesicles

- retrovesical septum

Question 17

Describe the clinical correlations of catheters and child birth, and the bladder

Answer 17

• catheters can be placed urethrally or suprapubically

- repeated childbirth can weaken pelvic floor allowing bladder drop which can affect urinary continence

Question 18

Describe the anatomy of the detrusor muscle

Answer 18

• 3 layers of smooth muscle
• internally lined with mucosa
• involuntary muscle (PSNS)

Question 19

Describe the internal features of the bladder

Answer 19

• trigone: area between ureteric orifices and urethral orifice
• urothelium: urine proof and allows distension
• internal urethral sphincter (male): involuntary and contracts to prevent passage of semen into bladder

Question 20

What are the supportive structures of the bladder?

Answer 20

• fascial condensations (eg. puboprostatic/pubovesical ligaments)

Question 21

What are the different parts of the male urethra?

Answer 21

• pre-prostatic urethra
• prostatic urethra
• membranous urethra
• spongy (penile) urethra

Question 22

Describe the neurovascular and lymph drainage of the bladder and urethra

Answer 22

• arterial: branches of internal iliac and internal pudendal
• venous: vesical (and prostatic) plexuses converging on internal ilaic veins
• lymph: internal and external iliac nodes

Question 23

Describe the innervation of the bladder and urethra

Answer 23

• inferior hypogastric plexus
• parasympathetics from S2-4 by pelvic splanchnic nerves:
• contracts detrusor muscle and relaxes internal urethral sphincter in males
• sympathetics from T11-L2:
• contract internal urethral sphincter in males)
• somatic motor from pudendal nerve (controls external urethral sphincter)

Question 24

Describe the first stage of micturition

Answer 24

• storage phase
• PSNS supply to detrusor muscle switched off so bladder can relax and fill
• when volume reaches 500ml it activates stretch receptors (and pain in abdomen and perineum)
• afferents sent to S2-4
• inhibition lifted
• PSNS fibres synapse in walls of bladder
• contract detrusor muscle

Question 25

Describe the second stage of micturition

Answer 25

• voiding
• contraction of detrusor muscle by PSNS
• relaxation of external urethral sphincter by pudendal nerve
• contraction of abdo wall
• sensation of urine in urethra maintains reflex