The kidney and urinary tract

Question 1

What does the urinary tract consist of

Answer 1

Kidneys
Ureters
Urinary bladder
Urethra

Question 2

Where does the kidney lie

Answer 2

Retroperitoneal in upper abdomen

They lie on the posterior abdominal wall

Question 3

What surrounds the kidney

Answer 3

Surrounded by dense fibrous capsule
Outside the capsule is a fascial pouch (renal fascia) containing the peri-renal adipose tissue
Paranephric fat may be found outside the renal fascia
the fat allows the kidneys to move

Question 4

Describe the differences between the right and left kidney

Answer 4

Right kidney is usually slightly lower than the left
Superior pole of the R kidney lies at the level of the 11th intercostal space and that of the L at the 11th rib
Hilum lies at about the level of L1 (R & L)

L1 is a large vertebrae- this is why they have their hilum at the same vertebral level

Question 5

What are the kidneys overlapped by postero-superiorly

Answer 5

Overlapped postero-superiorly by the diaphragm and pleural cavity
The diaphragm intervenes between the kidneys and ribs

Question 6

Describe the renal fascia

Answer 6

At the lateral margins of each kidney, the anterior and posterior layers of the renal fascia may fuse and connect with the transversalis fascia
Medially, and anteriorly, the fascia continues over the vessels in the hilum and fuses with the connective tissue associated with the abdominal aorta and IVC, in some cases it may continue to the other side and fuse with its companion layer
Posteriorly and medially, passes through the fascia surrounding the quadratus lumborum, and fuses with the fascia containing the psoas major
Inferiorly, both the anterior and posterior fascia fuse to enclose the ureters.

Question 7

Where does the paranephric fat accumulate

Answer 7

Posteriorly and postero-laterally

Question 8

Describe the posterior relations of the kidneys

Answer 8

The superior part of each kidney is related to the diaphragm which intervenes between ribs 11 and 12.
Laterally, the kidney is related to the transversus abdominis muscle
more medially, the quadratus lumborum muscle
more medially, the psoas major muscle
Also posteriorly related to the subcostal nerves (and some intercostals), iliohypogastric and ilio-inguinal nerves

Question 9

Which nerves supply the kidney

Answer 9

The nerves (posterior) that supply the kidneys include: Relate to below.
o 11th intercostal and sub-costal nerves.
o Iliohypogastric nerve.
o Ilioinguinal nerve.

From renal, aortic, superior hypogastric, and inferior hypogastric plexuses

Question 10

Describe the anterior relations of the right kidney

Answer 10

Liver (huge part of upper surface of kidney- separated from liver by a layer of peritoneum)
Medially- the desencing part of the duodenum ( region 2) is retro-peritoneal and contacts the kidney (hilus behind the duodenum)
Hepatic flexure

Question 11

Describe the anterior relations of the left kidney

Answer 11

Superior pole- covered by intraperitoneal stomach and spleen
Moving inferiorly, the retroperitoneal part of the pancreas covers the middle part of the kidney
Also related to splenic flexure

Question 12

What is meant by the flexures

Answer 12

Hepatic- ascending becomes transverse

Splenic- transverse to descending

Question 13

Why do the flexures exist

Answer 13

Corners of colon attached to the posterior abdominal wall- giving an M- SHAPE of large intestine

Question 14

Summarise the blood supply to the kidney

Answer 14

Abundant blood supply via renal arteries - short direct branches from abdominal aorta
Blood pressure drives ultrafiltration by glomerular capillaries
Renal veins drain into the IVC
renal arteries need to be short to keep the blood at high pressure for ultrafiltration

Question 15

Describe the difference between the right and left renal arteries

Answer 15

The left renal artery usually arises from the abdominal aorta a little higher than the right
Right renal artery is longer ( aorta is to the left of the midline) and passes posteriorly to the IVC

Question 16

Describe the difference between the right and left renal veins

Answer 16

The IVC usually lies to the right of the midline

Left renal vein is longer and passes in front of aorta underneath the superior mesenteric artery

Question 17

Where do the renal arteries arise from

Answer 17

Just inferior to the origin of the superior mesenteric artery

Question 18

What is a consequence of the passage of the left renal vein

Answer 18

Aneurysms ( in SMA or aorta) can occlude flow from the left kidney into the IVC

Question 19

What happens to the renal arteries at the hilum

Answer 19

the renal arteries divide to anterior and posterior branches to supply the parenchyma

Question 20

Describe the gonadal arteries

Answer 20

Arise at the same place in both sexes
Arise below the renal arteries
As gonads develop in the abdominal cavity- they descend (further in males)- dragging their blood supply with them

Question 21

What does the celiac trunk supply

Answer 21

the foregut

Question 22

Describe the differences in the drainages of the gonadal veins

Answer 22

right- drains into IVC

left- drains into renal vein which then drains into IVC

Question 23

Where does blood from the gut drain into

Answer 23

The portal vein- goes to liver first

Question 24

Describe the hilus

Answer 24

Anteriorly veins
Arteries
ureter

Question 25

Describe the development of the kidneys

Answer 25

Develop as functionally distinct lobes- which coalesce into one structure each pyramid is therefore a developmental lobule of the kidney Sometimes- the pyramids fail to coalesce- and so it is quite common to see distinct arteries and veins

Question 26

Summarise the structure of the kidney

Answer 26

Cortex granular-looking because of random organisation (glomerulus) Medulla striated because of radial arrangement of tubules (loop of Henlé) and micro-vessels Human kidney is multilobar – like a lot of simple kidneys stuck together Each lobe drains through its own papilla and calyx

Question 27

Describe the renal columns

Answer 27

Each kidney consist of an outer renal cortex and an inner renal medulla Extensions of the renal cortex (renal columns) project into the inner aspect of the kidney, dividing the renal medulla into the renal pyramids.

Question 28

Describe the renal pyramids

Answer 28

The bases of the renal pyramids are directed outwards towards the renal cortex, while the apex projects inwards towards the renal sinus the apical projection is surrounded by a minor calyx

Question 29

Describe the minor calyx

Answer 29

The minor calices receive urine and represent the proximal parts of the tube that will eventually form the ureter. In the renal sinus, several minor calices join to form the major calyx- and 2 or 3 of these unite to form the funnel shaped end of the renal pelvis- which is the funnel-shaped superior end of the ureters.

Question 30

What forms the glomerulus

Answer 30

renal arteries supplying each pyramid curve around the base and become arcuate arteries, where they anastomose with the branch curving around the same pyramid- glomerulus found here.

Question 31

Summarise the ureters

Answer 31

Run vertically down posterior abdominal wall in the vertical plane of the tips of the transverse processes 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 32

Describe the passage of the ureters

Answer 32

Renal pelvis forms ureters at uretero-pelvic junction Ureters descend retroperitoneally on the medial aspect of the psoas major muscle At the pelvic brim the ureters cross either cross the end of the common iliac artery of the beginning of the external iliac artery, enter the pelvic cavity and continue their journey into the bladder (move anteriorly and medially in bladder)

Question 33

Describe the blood supply of the ureters

Answer 33

Takes blood supply from every major blood vessel that it passes o A renal arterial branch. o A testicular or ovarian arterial branch. o Small direct braches of the aorta itself. o External and internal iliac arterial branches

Question 34

Where are the sits of constrictions of the ureters

Answer 34

3 sites of ureteric constriction: 1. pelviureteric junction 2. where ureter crosses pelvic brim 3. where ureter traverses bladder wall Constrictions are sites of renal colic caused by kidney stones attempting to pass Kidney stones lodge in these constrictions- as the upper muscle contracts- makes the pain worse

Question 35

How is urine transported by the ureter and how does the ureter enter the bladder

Answer 35

Urine transported by peristalsis of their smooth muscle walls Open obliquely through bladder wall

Question 36

Describe the epithelium of the ureter

Answer 36

``` Transitional epithelium Individual cells slide over each other- looks stratified squamous- but when stretch they separate out and become simple squamous Tight junctions- impermeable to urine circular muscle- peristalsis more sparse striated muscle ```

Question 37

Summarise the bladder

Answer 37

Pelvic organ Triangular pyramid with apex pointing anteriorly and base posteriorly Lined by urothelium (transitional epithelium) 3-layered epithelium with very slow cell turnover Large luminal cells have highly specialised low-permeability luminal membrane Prevents dissipation of urine-plasma gradients

Question 38

if you pass a stone without help, where will you experience pain

Answer 38

All 3 sites of constrictions

Question 39

What happens when the bladder is full

Answer 39

Rises into the abdomen As ureter runs obliquely in, as the bladder swells (due to corrugated internal membrane), the ureters are pushed back and function as a self-shutting valve. Ureters enter at supero-posterior angles

Question 40

Describe the structure of the bladder

Answer 40

Apex: directed towards the top of the pubic symphysis and attached to the umbilicus via the medial umbilical ligament Base: inverted triangle and points posteriorly; ureters enter at upper corners, with the urethra draining inferiorly from the lower corner of the base Interior: mucosal lining is smooth and firmly attached to underlying tissue Trigone: smooth area between openings of ureters and urethra Inferolateral surfaces: cradled by pelvic muscles

Question 41

What is special about the trigone

Answer 41

smooth- tightly adherent to the layers below- where bladder cancers are most likely to arise

Question 42

What happens to the superior surface of the bladder when it is full

Answer 42

slightly domed when empty | balloons upwards as the bladder fills and pushes visceral peritoneum backwards- allowing us to insert a catheter

Question 43

What is the role of the pubovesical ligament

Answer 43

Hold the urethra in place in females

Question 44

What is the role of the puboprosatic ligament

Answer 44

Holds the prostate in place (urethra passes through prostate) urethra has to pass through perineal membrane- fixed structure

Question 45

Describe the difference between males and females

Answer 45

Women have 2 holes in the inferior peritoneum (vagina and ureter) while men have 1 (and a prostate).

Question 46

Describe the Sphincter vesicae (internal sphincter – smooth muscle)

Answer 46

``` At neck of bladder Reflex opening In response to bladder wall tension Relaxed by parasympathetic NS Contracts by sympathetic NS ```

Question 47

Describe the Sphincter urethrae (external sphincter – striated muscle)

Answer 47

In perineum Tone maintained by somatic nerves in pudendal nerve (S2, 3, 4) Opened by voluntary inhibition of nerves

Question 48

in terms of the sphincters, what is different between males and females

Answer 48

§ In women, these sphincters are VERY close. | § In men, these sphincters are further apart.

Question 49

Describe voluntary control of the external sphincter

Answer 49

Stretch receptors in bladder wall relay information to the spinal cord- which inhibits the motor neurone to the external sphincter- causing it to relax- babies and people with incontinence However, cerebral cortex can learn to override this inhibition and keep the motor neurone stimulated to keep external sphincter closed

Question 50

Describe reflex control of the internal sphincter

Answer 50

``` Bladder fills stretch receptor activated PSN stimulated Bladder contracts internal sphincter opens ```

Question 51

Describe the urethra

Answer 51

different in each sex, beginning at the base of the bladder and ending with an external opening in the perineum

Question 52

Describe the urethra in women

Answer 52

short urethra, travelling inferiorly through the pelvic floor and deep perineal pouch/membrane to open into the vestibule between the labia minora; small Skene's (mucous) glands associated with lower end

Question 53

Describe the urethra in men

Answer 53

longer urethra, passes inferiorly through the prostate, through the deep perineal pouch and perineal membrane and enter the root of the penis (divided to preprostatic, prostatic, membranous and spongy parts)

Question 54

Why are women more at risk of STIs and bladder infections (cystitis)

Answer 54

urethra is shorter in women | warm, moist environment of vestibule

Question 55

Describe the lymphatics of the urethra

Answer 55

``` Follows the arterial supply Common iliac nodes roots of gonadal artery nodes inferior/superior mesenteric nodes these are called paraaortic nodes ```

Question 56

List the parts of the male urethra

Answer 56

``` Internal urethral orifice Bladder neck, Bladder outlet Prostatic urethra Membranous urethra Bulbar urethra Penile urethra Navicular Fossa External urethral meatus ``` Hard to pass catheter through as two bends 1st bend once it leaves the deep perineal pouch to course anteriorly in the root of the penis when flaccid- the penis makes another bend, this time passing inferiorly when passing from the root to the body of the penis

Question 57

Describe the innervation of the kidney

Answer 57

renal, aortic and sup/inferior hypogastric plexuses all innervate (visceral efferents from both SNS and PSNS sources - visceral afferents return to T11-L2 leading to referred pain at their dermatomes - e.g. Posterolateral abdominal wall pain)

Question 58

Describe the lymphatics of the kidney

Answer 58

lateral aortic (lumbar) nodes at the origins of the renal arteries