Urinary Introduction

Question 1

What is the kidney’s blood flow like in comparison to other organ’s

Answer 1

The kidney receives a comparatively high blood flow per unit mass and percentage of the cardiac outflow compared to other organs such as the heart and liver.

Question 2

Where do the kidneys lie anatomically?

Answer 2

There are two kidneys that sit at the back of the peritoneum (retroperitoneum) at the T11/T12-L2/L3 level, separated from the spine by the psoas muscles. One kidney is slightly lower than the other because of the liver.

Question 3

How is the ureter described?

Answer 3

A smooth muscular tube

Question 4

What surrounds the kidney

Answer 4

The kidney is surrounded by a fibrous capsule

Question 5

What two layers make up the parenchyma of the kidney?

Answer 5

The parenchyma has two important layers the outer cortex and the inner medulla.

Question 6

Describe the macroscopic structure of the inside of a kidney?

Answer 6

In the Medulla sit Renal pyramids that accumulate at a papilla, these papilla feed into minor calyces which themselves feed into a few major calyces. Finally, these major calyces join into the Renal sinus in the middle which feeds into the renal pelvis which itself is continuous with the urethra.

Question 7

What are renal columns?

Answer 7

Where the cortex invaginate between the renal pyramids

Question 8

What is the hilum?

Answer 8

The indent where the vessels and nerves enter

Question 9

Where does the kidney receive it’s blood from?

Answer 9

Blood supply from the renal artery and vein. The artery usually divides into posterior and anterior branch before entering the kidney.

Question 10

What’s special about the left renal vein

Answer 10

The left renal vein is longer as it has to pass the aorta and so takes more drainage and has the Gonadal and adrenal vessels branching off from it (which the right renal vein doesn’t)

Question 11

Where does the ureter cross the pelvic rim?

Answer 11

The ureter crosses the pelvic rim at the level of the sacroiliac joint anterior to the bifurcation of the common iliac artery into the internal and external.

Question 12

Where do the ureters enter the bladder?

Answer 12

They enter the bladder posterolaterally (forming the trigone with the urethra opening).

Question 13

How is anatomy of the ureter different between men and women?

Answer 13

The ureter passes under the ductus deferens superiorly onto the seminal vesicles in men and in woman it descends posteriorly to the ovaries passing under the uterine artery.

Question 14

Where are the 3 most common places for stones to get stuck in the ureter?

Answer 14

There are three change of direction in the ureter where stones are most likely to lodge this is when leaving the Renal pelvis, when joining the bladder and when passing over the iliac vessels.

Question 15

Describe where the bladder lies anatomically?

Answer 15

The bladder lies posterior to the pubic bone and pubic symphysis.

Question 16

How does the position of the bladder vary when fill vs empty

Answer 16

When empty it has a tetrahedron shape and sits completely within the pelvic cavity, when full it has a spherical shape and can reach as far as the umbilicus.

Question 17

What are the main functions of the kidney?

Answer 17

Maintain the internal environment of the body such as pH ion levels and water levels.

Endocrine function such as renin, erythropoietin, prostaglandins.

Metabolism such as active form of Vit D, catabolism of insulin and reaction to the parathyroid – PTH.

Question 18

Describe the distribution of fluid within the body

Answer 18

70kg young male – about 42L of water total body weight about 60% (female 50% as more fat and less bone, infants at about 80%). This fluid is distributed between intracellular fluid (28l) and extracellular fluid (14l), extracellular fluid is itself split into interstitial fluid (11l) and intravascular fluid (3l).

Question 19

Describe the difference between osmole, osmolarity and osmolality.

Answer 19

Osmole – ability to create osmotic pressure
Osmolality – solute per kg of solvent
Osmolarity – number of osmoles of solute per litre

We use osmolality

Question 20

What volumes of blood are filtered a day?

Answer 20

Kidney filters about 180l per day and every litre of your blood is filtered about ten times a day. Almost everything is recovered with only 1.5l of urine being produced a day.

Question 21

What are the main structures in a nephron

Answer 21

Functional unit is a nephron – blood is filtered out at the glomerulus into the bowman’s capsule then pass through the proximal (convoluted) tubule, the intermediate tubule (loop of Henle), the distal tubule and then this is connected to the collecting duct by the connecting tubule.

Question 22

What artery feeds blood into and out of a nephron and what percentage of this blood if filtered?

Answer 22

Afferent arterioles bring blood to the glomerulus (tuft of capillaries) through the vascular pole and leaves from an efferent arteriole. Only about 20% of the blood arriving in the glomerulus is filtered.

Question 23

Where is the main point in the nephron where variable re-absorption can take place for the maintenance of the bodies environment?

Answer 23

Distal convoluted tubule is the main site for variable reabsorption allowing the body to maintain a constant pH and ion balance.

Question 24

What imaging techniques can be used for the Urinary system?

Answer 24

IVU intravenous Urogram – this is a plain X-ray with some contrast put in that passes through the urinary system.

Ultrasound of bladder and kidneys.

MRI and CT scans good for stones

Nuclear medicine

Question 25

Describe the general anatomy of the bladder

Answer 25

The bladder has a ridge between two urethral openings called the interureteric fold. It is a muscular sac with the trigone formed from the opening of the ureters and urethra. Inside it is lines with rugae allowing it to stretch and expand. There are two sphincters - internal and external (internal much more developed in men to prevent retrograde ejaculation). Male prostate lies below surrounding the urethra, seminal vesicles sit just above the prostate.