Urinary System

Question 1

Functions

Answer 1

1. Filter blood/create urine
2. Store urine until micturition
3. Control blood pressure
4. Control blood pH

Question 2

Kidney Locations

Answer 2

• retroperitoneal (behind peritoneum)
• right kidney is lower than left
• between T12-L3 vertebrae

Question 3

Protection for kidney

Answer 3

1. renal fascia

2. perinephric fat (perirenal fat capsule)

Question 4

Kidney structure and features

Answer 4

• fibrous capsule (prevent spread of infection to kidney)
• margins (lateral and medial)
• poles (superior and inferior)
• hilum (entry to renal pelvis: renal artery/vein and ureter)

Question 5

Internal kidney structures

Answer 5

1. Renal cortex
2. Renal medulla
3. Renal lobes
4. Calices
5. Renal pelvis

Question 6

Renal medulla

Answer 6

• renal pyramids and renal papilla

- renal columns separate pyramids (same as renal cortex histologically)

Question 7

Renal lobes

Answer 7

-renal pyramid and cortical tissue external to it

Question 8

Calices

Answer 8

1. minor calyx: collects urine from renal papilla

2. major calyx: collects urine from multiple minor calices and empty into the renal pelvis

Question 9

Renal pelvis

Answer 9

• funnel-shaped expansion of ureter

- collects urine

Question 10

Ureters

Answer 10

• muscular tube
• transitional epithelium
• from renal pelvis to inferoposterior region of bladder
• cross over the common iliac arteries
• empty into ureteric orifaces of urinary bladder

Question 11

3 constrictions of the ureter

Answer 11

1. ureter/renal pelvis junction
2. crossing into pelvis
3. passage into urinary bladder

Question 12

Urinary bladder

Answer 12

• muscular sac for temporary storage of urine
• collapses when empty; rugae appear
• transitional epithelium
• Trigone
• 3 layers of the bladder

Question 13

Trigone of urinary bladder

Answer 13

• smooth triangular area outlined by the openings for the ureters and the urethra
• infections tend to persist in this region

Question 14

3 layers of the bladder wall

Answer 14

1. transitional epithelial mucosa
2. thick detrusor muscle (3 layers of smooth muscle)
3. fibrous adventitia (peritoneum on superior surface only)

Question 15

Female urethra

Answer 15

• 3-4 cm long
• tightly bound to the anterior vaginal wall
• external urethral orifice is anterior to the vaginal opening, posterior to the clitoris

Question 16

Male urethra

Answer 16

• carries semen and urine
• Four named regions:
  1. preprostatic urethra (1cm): between bladder and prostate
  2. prostatic urethra (2.5cm): within prostate gland
  3. membranous urethra (2cm): passes through the urogenital diaphragm
  4. spongy urethra (15cm): passes through the penis and opens via the external urethral orifice

Question 17

Urinary system development

Answer 17

-urinary and genital systems have common beginnings: urogenital tract

Question 18

Tissue origins of urinary system

Answer 18

1. Intermediate mesoderm (most): CT, blood vessels, smooth muscle, epithelium (most of it)
2. Endoderm: epithelium (terminal portions), cloaca (common space that divides to form both the urogenital sinus and the hindgut)
3. splanchnic lateral plate mesoderm: surrounds endoderm portion of urogenital system, CT

Question 19

Kidney development

Answer 19

• kidney origins entirely from intermediate mesoderm
• develop in three steps each more caudal than the prior
• intermediate mesoderm proliferates in week 4 to form the urogenital ridge
• pronephros, mesonephros, and metanephros

Question 20

Pronephros

Answer 20

• formed and degraded in week 4

- forms nephric duct: beginnings of the mesonephric duct

Question 21

Mesonephric duct

Answer 21

• begins formation at the end of week 4
• mesonephric duct: uses nephric duct to begin and proliferates to reach the cloaca, present until end of month 2
• mesonephronic tubules connected to duct: become ducts in testes

Question 22

Metanephros

Answer 22

-develops into the adult kidney
-inductive interaction between ureteric bud and metanephric cap/blastema
-fusion of ureteric and metanephric portions connects the excretory and collecting portions of the kidney
move cranially as mesonephros degenerates and body elongates

Question 23

Ureteric bud

Answer 23

• from end of mesonephric duct: week 5
• induces metanephric cap/blastema to form
• forms collecting portions of kidney: week 5-7 (collecting ducts, calices, renal pelvis, ureters)

Question 24

Metanpehric cap/blastema

Answer 24

• induces ureteric bud to branch

- forms the excretory portions of the kidney: nephrons in week 10

Question 25

Bladder and urethra development

Answer 25

• from hindgut endoderm and splanchnic lateral plate mesoderm
• cloaca is divided into urogenital sinus and hindgut anorectal canal
• urogenital sinus becomes bladder: mesonephric duct connected and moves into bladder to connect ureteric duct; mesonephric duct degenerates in females and becomes epididymis and vas deferens in a male
• opening to exterior becomes urethra

Question 26

Kidney function in embryo

Answer 26

• kidney begins to function in second trimester: completes development after birth
• fetus swallows amniotic fluid–> absorbs it in the GI tract–> returns fluid to blood circulation–> kidney filters blood–> makes more amniotic fluid

Question 27

Exstrophy

Answer 27

• abdominal wall does not seal properly

- urinary bladder is exposed to external environment

Question 28

Allantois

Answer 28

• extension of the urogenital sinus in the yolk stalk
• becomes a ligament–> urachus ligament
• defects: does not seal properly (urachal fistula, sinus, cyst)