Urinary system

Question 1

What is the position of kidneys in relation to quadratus lumborum muscle and vertebral column?

Answer 1

• Anterior to quadratus lumborum muscle

- Bilateral to vertebral column.

Question 2

Why is the right kidney lower than the left kidney?

Answer 2

This happens due to presence of right lobe of liver on upper right quadrant of abdominal cavity.

Question 3

What are the functions of kidneys?

Answer 3

• Regulation of blood volume and pressure. This happens via filtration of intestinal fluid and blood under direction of certain hormones.
  
  • Regulation of erythrocyte and production via erythropoietin. Kidneys can measure oxygen levels in blood. If oxygen level low -> cells in kidney can secrete hormone called erythropoietic, which increases production of erythrocytes. More erythrocytes -> more oxygen.
  • Regulation of the blood’s inorganic ion balance –sodium, potassium and phosphate ions.
  • Acid-base balance through changes in the rates of hydrogen ion and ammonium secretion.

Question 4

What are the superior parts, medial parts and inferior pole of left kidney associated with?

Answer 4

Superior part of kidneys, covered by suprarenal glands.
Left upper part of left kidney is associated with spleen and stomach.

Upper part of right kidney lies against liver.

Medially, descending part of duodenum (which is retroperitoneal) is in contact with right kidney and left kidney is in contact with pancreas, more inferiorly with left colic flexure and descending colon of large intestine.

Inferior pole of left kidney is associated with jejunum and inferior pole of right kidney is associated with right colic flexure of large intestine and other aspects of small intestine.

Question 5

What are the relations of posterior surface of kidneys?

Answer 5

Posteriorly, both kidneys are associated with the diaphragm,

Medially with psoas major muscles and intermediately with quadratus lumborum

Laterally with transversus abdominis.

Question 6

What keeps the kidneys immobile and in place?

Answer 6

Kidneys are retroperitoneal organs.

They’re immobile and kept in place via a lot of fat, but also fascia around them.

Question 7

What does the renal fascia surround?

Answer 7

Renal fascia (gerota’s fascia) = fascia that surrounds kidney laterally and anterior-posteriorly, but not medially.

Question 8

What does the renal fascia associate with laterally and posteriorly?

Answer 8

Laterally, renal fascia becomes continuous with transversalis fascia.

Posteriorly, renal fascia associates with fascia of psoas major but also, quadratus lumborum muscle.

Question 9

What is the pathways of filtered blood in kidneys?

Answer 9

Once filtration of blood takes place within the glomerulus:

Filtrate or urine funnels down through the medulla-> into tip of medulla -> into renal papilla -> into minor calices -> into major calices -> down into renal pelvis, urine exits kidney -> enters ureter.

Question 10

What is the hilum of kidney and sinus of hilum?

Answer 10

Hilum of kidney = renal pelvis and some blood vessels exit the kidney.

Sinus of hilum = area that has minor and major calices, and blood vessels is this fat over here and renal pelvis.

Question 11

What are the contents of renal hilum and renal sinus?

Answer 11

In hilum, there is blood vessels, renal artery, renal vein, segmental arteries, segmental vein and ureter.

In sinus, there is blood vessels, calyces, renal fat and renal pelvis.

Question 12

Pathway of blood in kidney via renal arteries.

Answer 12

Renal artery projects towards behind inferior vena cava. Blood gets into kidneys via segmental arteries -> flows into interlobar arteries -> projects and surrounds medulla of kidneys -> interlobar arteries branch into arcuate arteries (this surrounds base of pyramid) -> arcuate arteries will branch into interlobular arteries (this is at cortex of kidneys).

Blood gets into interlobular arteries -> branched into afferent arteriole -> afferent arteriole will take this rich in oxygen blood into glomerulus for filtration -> rich in oxygen filtrated blood will leave glomerulus via efferent arteriole -> urine, so toxins and waste, they will leave glomerulus via tubular part -> and get into nephron (first in proximal convoluted tubular, then loop of henle and then into distal convoluted tubular -> filtration of this filtrate will get into peritubular capillaries -> then vasa recta -> blood will be poor in oxygen -> blood will get into interlobular vein -> then arcuate vein -> interlobar vein -> segmental vein -> renal vein -> before it gets into right atrium of heart.

Question 13

Where does oxygenation, the gas exchange take place?

Answer 13

Peritubular capillaries.

Question 14

Pathway of Urine:

Answer 14

From proximal convoluted tubule, filtrate is called tubular fluid -> gets down into loop of henle -> distal convoluted tubular -> urine will go to tip of pyramid of medulla of kidney via collecting duct -> then into minor calyces, major calyces, renal pelvis -> it gets into ureter -> leaves kidney, so that urine moves down into urinary bladder for storage.

Question 15

What is the function of proximal convoluted tubule, distal convoluted tubule, collecting duct and loop of henle.

Answer 15

Proximal convoluted tubule:
• Reabsorbs ions, nutrients, plasma proteins, vitamins and water
• Filtrate is now called tubular fluid

Distal convoluted tubule:
- Secrets ions into the tubular fluid and reabsorbs water

Loop of Henle:
Reabsorption of ions and water.

Question 16

What is the structure of Ureters?

Answer 16

Long fibromuscular tubes.

Question 17

Transport of urine from renal pelvis happen via what type of movement?

Answer 17

Transportation of urine from renal pelvis down into bladder happens via peristaltic action of smooth muscle.

Question 18

Pathway of ureters

Answer 18

Ureters pass into pelvis via pelvic ring -> they pass underneath uterine vessels (in females) or vas deferens or duct deferens (in males).

Question 19

What are three areas of constrictions of ureters?

Answer 19

1) . Uteropelvic junction:
2) . Pelvic inlet: Area of bifurcation of common iliac artery into internal and external iliac arteries.
3) . Entrance to bladder: site where kidney stone lodge and can obstruct urine flow.

U: U
P: Peel
E: eggplants

Question 20

Where are the part of ureters above pelvic ring?

Answer 20

Part of ureters above pelvic rim is within abdomen.

Question 21

What do the ureters enter when they go past bifurcation of common iliac arteries?

Answer 21

Once ureters go past the bifurcation of common iliac artery into external and internal iliac arteries, they enter pelvis via pelvic rim.

Part of ureters below bifurcation and below pelvic rim is part of pelvis.

Question 22

Describe structure of urinary bladder? What is its shape when empty and full?

Answer 22

Urinary bladder is expandable and muscular reservoir for urine. When it is empty, it looks like an upside-down shape, and when it is full it gets a more oval space, and projects towards pelvic rim.

Question 23

Is urinary bladder sub-peritoneal?

Answer 23

Urinary bladder is sub peritoneal.

Question 24

What does the urethra connect to inferiorly?

Answer 24

Inferiorly, urinary bladder connects to perineum via urethra.

Urethra is sexual dimorphic organ and it varies a lot between males and females.

Question 25

Compare urinary bladder in males and females?

Answer 25

In both females and males, urinary bladder has body and apex, and superior surface and inferior lateral surface.

Apex of bladder in males and females projects towards pubic symphysis. It has median umbilical ligament (remnant of embryological urachus that contributes to formation of bladder during embryo development).

Two ureters in males and females enter bladder at upper corners of the base.

In females there a connect via a connective tissue between base of bladder and anterior vaginal wall and most superior aspect of cervix.
There is pubovesical ligaments in females and puboprostatic ligament in males.

Question 26

Where does median umbilical ligament run to?

Answer 26

Median umbilical ligament runs to middle line of abdominal wall in median umbilical fold of peritoneum.

Question 27

What is the superior surface and inferior surface (like what is against) of bladder covered by?

Answer 27

Superior surface of bladder is covered by peritoneum which connects to anterior abdominal wall.

Inferior aspect of bladder are against pelvic diaphragm.

Question 28

What happens at the neck of bladder?

Answer 28

Inferior part of bladder is neck: Area where bladder opens up to urethra on internal urethra orifice via tribune.

Question 29

What happens at the tribune?

Answer 29

Tribune is area that helps funnels urine from ureters at the openings where ureters send urine into bladder and then down to internal urethral orifice and out into urethra.

Question 30

What is a trigone?

Answer 30

Is a posteroinferior triangular area of the urinary bladder wall between the two posterior ureteral openings and the anterior urethral opening.

Question 31

What is a major muscle in walls of bladder?

Answer 31

Detrusor muscle. Contraction of this muscle is important in urination.

Question 32

What is the function of trigone?

Answer 32

It functions as a funnel to direct urine into the urethra as the bladder wall contracts to evacuate the stored urine.

Question 33

Compare size of urethra and starting points of it.

Answer 33

In females urethra is short, and in males it is long.

In both sexes, it proximally starts from the bladder, and extends down to the external urethral orifice.

Question 34

What is prostatic urethra?

Answer 34

When it passes b/w prostatic gland, it’s called prostatic urethra.

Question 35

Where is the erectile tissue of penis located?

Answer 35

Corpus spongiosum

Question 36

What is the prosthetic part of male urethra surrounded by?

Answer 36

Prosthetic glands.

Question 37

What does the membranous part of male urethra contain?

Answer 37

External urethra sphincter.

Question 38

Via what innervation does voluntary control of external urethra happen?

Answer 38

Somatic S2-S4 via pudendal nerve.

Question 39

What are the three part of male urethra? What do they extend to?

Answer 39

• Prostatic urethra: – Extends through prostate gland where multiple small prostatic ducts enter it.
  
  • Membranous urethra : from inferior prostate gland through urogenital diaphragm
    Spongy urethra: Extends to the external urethral orifice

Question 40

Describe the structure and function of internal and external urethral sphincters?

Answer 40

Internal urethral sphincter has smooth muscle and sympathetic innervation, maintains its tone and parasympathetic innervation relaxes it.

External urethral sphincter has skeletal muscle, and is innervated by somatic S2-S4 via pudendal nerve.

Question 41

What are the three parts of External urethral sphincter?

Answer 41

• More inner part, which has circular muscle fibres
  
  • Compressor muscle
  • Urethrovaginal sphincter.