Urinary System 1 - The kidney and urinary tract

Question 1

What are the contents of the urinary tract?

Answer 1

• Kidneys
• Ureters
• Urinary bladder
• Urethra

Question 2

Describe the position of the kidneys

Answer 2

• Retroperitoneal in the upper abdomen
• Covered with a dense fibrous capsule and fascial pouch containing peri-renal adipose tissue
• Overlapped posterosuperiorly by the diaphragm and pleural cavity
• Right kidney is lower than the left

Question 3

Describe the spinal level of the kidney

Answer 3

• Superior pole of the right kidney is at the level of the 11th intercostal space
• Left kidney superior pole is at the 11th rib
• Hilum is at the level of L1

Question 4

List the layers around the kidney

Answer 4

• Perinephric fat
• Renal fascia
• Paranephric fat
• Transversalis fascia

Question 5

List the posterior relations of the kidney

Answer 5

• Transversus abdominis muscle (lateral under rib 12)
• Quadratus lumborum muscle (between transversus and psoas major muscles)
• Psoas major muscle (under rib 12, medially)
• Diaphragm covers the kidneys down to rib 12

Question 6

List the anterior relations of the kidney

Answer 6

• Right - liver, hepatic flexure (hilus behind 2nd part of duodenum)
• Left - stomach, pancreas, spleen and splenic flexure

Question 7

What is the hepatic flexure?

Answer 7

The sharp bend between the ascending colon and the transverse colon

Question 8

Describe the blood supply of the kidney

Answer 8

• Rich supply via renal arteries
• Short direct branches from the abdominal aorta
• Blood pressure drives ultrafiltation
• Renal veins drain into the IVC

Question 9

What is attached to the superior pole of the kidney?

Answer 9

Adrenal/supradrenal glands

Question 10

Describe the structure of the kidney

Answer 10

• Cortex is granular-looking due to random organisation
• Medulla striated because of radial arrangement of tubules and micro-vessels
• Human kidney is multilobar – like a lot of simple kidneys stuck together
• Each lobe drains through its own papilla and calyx via the renal medulla

Question 11

Describe the position of the ureters

Answer 11

• Run vertically down the posterior abdominal wall in the vertical plane of the tips of the transverse process of the lumbar vertebrae
• Cross the pelvic brim anterior to the sacro-iliac joint & bifurcation of the common iliac arteries
• Descend anteromedially to enter bladder at the level of the ischial spine

Question 12

How do the ureters transport urine?

Answer 12

By peristalsis of the smooth muscle walls

Question 13

List the sites of ureteric constriction

Answer 13

• Pelviureteric junction
• Where the ureter crosses the pelvic brim
• Where the ureter transverses bladder wall

Question 14

Describe the shape of the bladder

Answer 14

Triangular pyramid with apex pointing anteriorly and base posteriorly

Question 15

Describe the anatomy of the bladder and its location

Answer 15

• Pelvic organ
• Lined with urothelium
• 3-layered epithelium with slow cell turn over
• Large luminal cells have highly specialised low-permiability luminal membrane
• Prevents dissipation of urine-plasma gradients

Question 16

Where is the pubovesical ligament?

Answer 16

Attaches the neck of the bladder to the inferior aspect of the pubis bones

Question 17

Where is the puboprostatic ligament?

Answer 17

Extends laterally from the prostate to the tendinous arch of the pelvic fascia and continues forward and medially from the tendinous arch to the pubis.

Question 18

What are the two urinary sphincters?

Answer 18

• Sphincter vesicae (internal sphincter - smooth muscle)

- Sphincter urethrae (external sphincter - striated muscle)

Question 19

Describe the control of the sphincter vesicae

Answer 19

• Smooth muscle, internal
• At the neck of the bladder
• Reflex opening in response to bladder wall tension
• Relaxed by PNS, contracts by SNS

Question 20

Describe control of the sphincter urethrae

Answer 20

• In the perineum (external)
• Tone maintained by somatic nerves in pudenal nerve (S2, 3, 4)
• Opened by voluntary inhibition of nerves

Question 21

Summarise the nervous control of the bladder

Answer 21

• Bladder fills stimulating stretch receptors
• This stimulates parasympathetic nerves to make the bladder contracts, opening the internal urethral sphincter
• Stretch receptors inhibit motor neurons, which opens the external urethral sphincter. Cerebral cortex stimulation causes the sphincter to become closed

Question 22

How is the urethra different in males and females?

Answer 22

• Shorter in females, 2 inches compared to 8 inches in males

- In males there are multiple parts of the urethra

Question 23

List the parts of the urethra in males

Answer 23

• Preprostatic part of urethra
• Prostatic part
• Membranous part
• Spongy part

Question 24

Describe lymphatic drainage of the urinary system

Answer 24

• Vessels from the superiolateral region drain into external iliac lymph nodes
• Vessels from the neck and fundus draining into the internal iliac lymph nodes and some into the sacral or common iliac lymph nodes.