Anatomy of The Urinary System

Question 1

List 4 functions of the kidneys

Answer 1

• Excretion of waste products and drugs
• Regulation of body fluid volume and ions, acid base balance
• Endocrine: makes Renin, EPO and Prostaglandins
• Metabolism: Vit D activated, catabolism of Insulin, PTH and Calcitonin

Question 2

Describe the anatomical location of the kidneys

How much does one weigh?

Answer 2

Retroperitoneum on posterior abdominal wall, either side of vertebral column, between T12 and L3

140g

Question 3

The kidneys are partially protected by which 2 ribs?

At what vertebral level is the Hilum

What percentage of the Cardiac Ouput does the kidney use?

Answer 3

11 and 12

Hilum at L1

20-25%

Question 4

Why is right kidney slightly lower?

Answer 4

Pushed down by liver

Question 5

At what level do the Ureters start moving Medially towards bladder?

Answer 5

At level of Ischial spine

Question 6

What are the layers around the kidney?

From deep to superficial

Answer 6

• Renal Capsule
• Perirenal fat
• Renal/ Garrotter’s fascia
• Pararenal/ Paranephric fat

Question 7

Is the kidney held in place?

What do the surrounding layers do?

Answer 7

No, but the fat layers around it cushion it

Question 8

What do the Renal Vein and Renal Artery drain into/ branch off of?

Answer 8

Vein- IVC

Artery- Abdominal Aorta

Question 9

The kidney is organised into Renal Lobes.

What are the 2 parts of the Renal Lobe?
What do you call the region between the lobes?

Answer 9

(Outer) Cortex and (Inner) Medulla

Renal Column (Help to support everything)

Question 11

The Nephrons start in the Cortex and feed into the Collecting Ducts which travel down and through the Medulla.

Describe how the Collecting ducts feed into the Ureter

Answer 11

Collecting ducts feed into Minor Calyces which feed into Major Calyces.

These feed into Renal Pelvis, where urine accumulates before feeding into Ureter

Question 12

Compare the 2 types of Nephrons

Answer 12

Cortical Nephrons: 85% of nephrons, short Loop of Henle

Juxtamedullary Nephrons: 15%, Longer Loop of Henle, which descends further down (better for concentrating urine)

Question 13

What 2 structures make up a Renal Corpuscle

Answer 13

• Glomerulus

- Bowman’s capsule

Question 14

What cells sit on top of the vessels in the Glomerulus?

What do they do?

Answer 14

Podocytes have foot like projections that wrap around capillaries and creat slits between them

Question 15

Outline the route of fluid from PCT to Minor Calyces

Answer 15

• PCT
• LoH (3 parts)
• DCT
• Collecting Duct
• Minor Calyces

Question 16

What is the Renal Pyramid?

Answer 16

The medullary part of the Renal Lobe

Question 17

What are 3 parts of the Loop of Henle

Answer 17

• Thin descending limb
• Thin ascending limb
• Thick ascending limb

Question 18

The arteries supplying the nephrons all branch off of which artery?

Which arterioles branch off of the same artery?

Answer 18

Arcuate arteries branch off of the Interlobar artery

The Afferent and Efferent Arterioles (To and away from glomerulus) come from the Interlobular Artery

Question 19

Which blood vessels cover and wrap around the Cortical Nephrons?

What do they branch off of?

Answer 19

Peritubular capillaries from Efferent arteriole

Question 20

Juxtamedullary Nephrons have Peritubular capillaries just like the Cortical Nephrons.

What other vessel do they have that the Cortical Nephrons don’t?

Answer 20

The Vesa Recta (An extended Peritubular capillary that covers the longer LoH)

Question 21

Which cells line the DCT as it passes in contact with the Glomerulus?

What do they do?

Answer 21

• Macula Densa, sense how ‘salty’ the fluid is, to determine the appropriate flow of blood
• Constrict Afferent/ Efferent arteriole
• Send signal to Granular/ Juxtaglomerular cells to make Renin

Question 22

The Superior Mesenteric Artery runs over which Renal vessel?

Answer 22

Renal Vein

Question 23

Which renal vessels are longer on 1 side

Answer 23

Right Renal artery> Left Renal artery

Left Renal Vein> Right Renal vein

Question 24

Outline the Arterial branching into the Kidney

Answer 24

Renal artery-> Segmental artery-> Interlobar artery-> Arcuate artery-> Interlobular artery-> Afferent arteriole-> Glomerulus-> Efferent arteriole-» Vasa Recta and Peritubular capillaries

Question 25

Outline the Veinous drainage of the Kidney

Answer 25

Peritubular capillaries and Vasa Recta-> Interlobular Vein-> Arcuate Vein-> Interlobar Vein-> Renal Vein

Question 26

What is the Juxtaglomerular apparatus formed by?

What does it do?

Answer 26

The proximity of the Glomerulus to the Distal Convoluted Tubule

Senses fluid composition and tells kidney to absorb less/ more water

Question 27

State the length and diameter of the Ureters (have smooth muscle fibres)

Where are they in relation to the peritoneum?

Where are they in relation to the Transverse processes of the lumbar vertebrae?

Answer 27

25-30 cm long and 1.5 mm in diameter

Retroperitoneal, lateral to transverse processes of lumbar vertebrae

Question 28

State the 3 segments of the Ureter beyond the Pelviureteric junction, PUJ (where Renal Pelvis becomes Ureter)

Answer 28

• Abdominal
• Pelvic
• Intramural

Question 29

Where is the most common area of Ureteric injury?

Answer 29

Near the pelvic brim

Question 30

Do the ureters enter the badder posteriorly, anteriorly or laterally

Answer 30

Posteriorly?

Question 31

What do we call the junction where ureter enters bladder

Answer 31

Vesico-ureteric junction

Question 32

What 3 structures make up the Trigone of the bladder?

Answer 32

Superiorly: 2 Ureteric openings

Inferiorly: Internal Urethral Meatus (internal urethral sphincter)

Question 33

Describe how urine reflux into ureter is prevented?

Answer 33

A flap that closes when urine pushes against it when entering bladder at oblique angle

Question 34

The bladder is made up of 1 large thick muscle called the Detrusor muscle.

What are the folds of this muscle called? What do they do?

Answer 34

Rugae, contract and expand

Question 35

How much can the bladder hold on average?

When empty, what structure does the bladder rest on?

Where is this structure in Men and Women?

Answer 35

750ml

Rests on Pubic Symphysis; Men- In front of Rectum, Women- In front of Vagina, Uterus, Rectum)

Question 36

What are the bladder, ureters and renal pelvis lined with internally?

Answer 36

Urothelium