Lecture 5 - Kidney and urogenital development

Question 1

Allantois

Answer 1

Goes from cloaca to connecting stalk. Eventually it will meet up with the vitaline duct and make up the umbilical cord.

Question 2

How does the cloaca get divided?

Answer 2

There is a urogenital septum that goes straight through the cloaca. Once this happens, the cloaca has two parts, the urogenital sinus and the anorectal canal.

Question 3

What happens to the allantois?

What happens if what is supposed to happen doesn’t happen?

Answer 3

It fuses and turns fibrous and into what is called the median umbilical ligament. If it doesnt fuse properly then you can get an urachal cyst, urachal sinus, or urachal fistula. Can detect this if you see urine coming out of the umbilical cord.

Question 4

What is the deal with urination and what are two conditions in which it is not working properly?

Answer 4

So generally the fetus just pees out of the mesonephric duct, through the urogenital sinus into the amniotic cavity and then he swallows the urine. It is a dynamic equilibrium.
Oligohydromnios - There is not enough amniotic fluid because of an issue in urinary tract.Can result in potter sequence.
Polyhydromnios - abnormally increased amount of amniotic fluid. Caused by interference with swallowing caused by disruption in GI tract or trouble with swallowing reflexes

Question 5

Potter sequence

Answer 5

abnormalities in lung development, limb development, and facial development. Also has a flattened appearance. Results from oligohydromnios.

Question 6

Horseshoe kidney

Answer 6

When the inferior mesenteric artery halts the “ascent” of the kidney. Makes it look like a horseshoe

Question 7

What goes into the hilum or the kidney?

Answer 7

renal artery, renal vein, renal pelvis

Question 8

Order of kidney starting from renal pelvis

Answer 8

renal pelvis –> major calyx –> minor calyx –> renal pappila, renal pyramid
Also a renal column in bettween each pyramid

Question 9

Order of renal arteries

Answer 9

renal artery –> segmental arteries –> interlobar arteries–> arcuate arteries –> interlobular arteries

Question 10

Differences between branches of the IVC in left and right side

Answer 10

Gonadal vein goes straight into IVC on right. On left, it goes into renal vein which then goes into IVC.
Right renal vein is very short, left renal vein is much longer because it has to pass the aorta directly under the superior mesenteric artery.

Question 11

Constrictions

Answer 11

Areas in which the ureter gets smaller. It most happens right outside of the hilum, as it’s passing over the biforcation at the aorta, and right by the bladder. That makes these the most likeely places for stones.
- to break up the stones they use what is called extracorporeal shock wave lithotripsy.

Question 12

areas of the male bladder

Answer 12

detrusor muscle - parasympathetically innervated
bladder trigone - incorporates mesonephric ducts
internal sphincter - sympathetically innervated
external sphincter - somatically innervated

Question 13

why are the bladder and ureter diagnoally connected?

Answer 13

To prevent backward flow from the bldder to the kidney. Vesicouretal reflux.

Question 14

autonomic in kidney and upper ureter inervation

Answer 14

• The sympathetics will be T10-L1, so they will incorporate the lesser splanchnics, least splanchnics, and lumbar splanchnics
• The parasympathetics will be T10-L1 and will incorporate vagus nerve and pelvic splanchnic nerves

Question 15

autonomic in urinary bladder and lower ureter

Answer 15

• The sympathetics will incorporate L1 and L2 so it will be lumbar splanchnics and sacral splanchnics
• The parasympathetics will only be pelvic splanchnic nerves

Question 16

Intermediate mesoderm breakdown

Answer 16

Part of mesoderm.
There are three layers, lateral plate, intermediate mesoderm, and paraxial mesoderm.
Intermediate mesoderm is broken down into the urogenital sinus and the anorectal canal.
Urogenital ridge is broken down into a nephrogenic ridge and a gonadal ridge.
The urogenital ridge is broken down into pronephros, mesonephros, and mesonephric duct.
COming from the mesonephric duct is the ureteric bud, which gives off the ureters, major and minor calyces, collecting tubules, and renal pelvis. The ureteric bud and metanephrogenic blastema induce each other to form their respective things. Ureteric bud does conduction. The mesonephric blastema does filtration. Mesonephric blastema makes nephrons and the cortex of the kidney

Question 17

sensory innervation

Answer 17

in kidney and upper ureter is vagal trunks (T10-L2). in bladder and lower ureter it is pelvic splanchnic S2-S4

Question 18

WHat are is the source of primordial germ cells?

Answer 18

yolk sac

Question 19

TDF

MIF

Answer 19

TDF = testis determining factor. Causes the gonad to become the testis. In the absence, it will become the ovary. Once you have a testis, you will see littig cells, which create testosterone. In the presence of testrosterone and dihidrotestrosterone you will see development of the rest of the male sexual system.

Not only that, but you need to stop the development of all female characteristics (default is to become a female unless you have a Y chromosome). MIF (mularian inhibiting factor) is responsile for inhibiting the growth of the female stuff. MIF is made by the sertoli cells that are made by the testis.

Question 20

WHat will dissapear in males vs. females?

Answer 20

paramesonephric duct will disappear in males and mesonephric duct will disappear in females.

Question 21

what does paramesophric duct become?

Answer 21

There is two of them and they fuse to become the uterus.

Question 22

In the male which patts are from the urogenittal sinus and which parts are from the mospnephric duct?

Answer 22

urrogenital sinus - bladder, urethra, prostate

mesonephric duct - seminal vesicle, vas defrens, ejaculatory duct

Question 23

In female what comes from the paramesonephric duct and what comes from the urogenital sinus?

Answer 23

PD - uterine tubes, uterus, upper part of vagina

urogenital sinus - lower vagina, vestibule, urethra, bladder

Question 24

Homologues of the external genitalia

Answer 24

Genital tubercle - M: head of penis F: clitoris
Urethral folds - M: ventral penis F: labia minora
labioscrotal folds - M: scrotum F: labia majora

Question 25

hypospadia

Answer 25

failure of fusion at midline of ventral penis.

Question 26

muscles in the bladder - what are they and what are their innervations?

Answer 26

detrusor muscle - parasympathetics
internal sphincter - sympathetic
external sphincter - somatic (pudendal)
- also knows as the sphincter urethrae