53. Embryology - Development of the Kidney, Bladder, & Suprarenal Gland

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Questions and Answers

What type of cells give rise to the definitive cortex of the adrenal gland?

Neural crest cells

Mesenchymal stem cells

Axillary mesothelial cells (correct)

Immature chromaffin cells

What is the primary fate of the fetal cortex after birth?

It degenerates while retaining important outer layers. (correct)

It remains unchanged throughout life.

It completely transforms into the zona reticularis.

It increases in size to enhance adrenal function.

Which cells originate the chromaffin cells within the adrenal medulla?

Neural crest cells (correct)

Mesenchymal cells

Epithelial cells

Mesothelial cells

What is the structure called that forms the initial layer of the adrenal gland before differentiation into definitive zones?

Primitive adrenal cortex Signup and view all the answers

Where do the neural crest cells that contribute to the adrenal medulla migrate from?

The sympathetic chain ganglion Signup and view all the answers

What does the proximal portion of the allantois give rise to?

Urinary bladder Signup and view all the answers

Which part of the urogenital sinus gives rise to the prostatic and membranous urethra in males?

Pelvic portion Signup and view all the answers

What additional structure is formed from the proliferation of urethral epithelium in males?

Prostate gland Signup and view all the answers

At what developmental week do the suprarenal glands begin to form?

6th week Signup and view all the answers

From how many germ-layer sources are the suprarenal glands derived?

Two Signup and view all the answers

Where does the ligament connecting the urinary bladder extend to?

Umbilicus Signup and view all the answers

In females, which part of the urogenital sinus does the narrowed portion give rise to?

Membranous urethra Signup and view all the answers

What is the correct order of development of the urinary bladder from the allantois?

Proximal allantois → Urogenital sinus → Urinary bladder Signup and view all the answers

What role do the two germ layers play in the formation of the prostate gland?

They allow for outgrowths into mesenchyme Signup and view all the answers

What structures arise from the ureteric bud?

Ureter, renal pelvis, major and minor calyces Signup and view all the answers

From where does the excretory system of the metanephric kidney derive?

Metanephric mesoderm Signup and view all the answers

What structure does the renal vesicle develop into during nephron formation?

S-shaped tubule Signup and view all the answers

What are the components of a complete nephron?

Proximal convoluted tubule, Henle's loop, and Bowman’s capsule Signup and view all the answers

What initiates urine production during kidney development?

Connection of the distal convoluted tubule to the collecting tubule Signup and view all the answers

How many nephrons are estimated to develop per kidney by birth?

1 million Signup and view all the answers

Which structure forms the filtration unit in the nephron?

Glomerulus Signup and view all the answers

What initiates the development of renal vesicles?

Condensation of metanephric mesoderm influenced by tubule cells Signup and view all the answers

What is the primary role of the metanephric tissue cap?

To cover the distal end of collecting tubules Signup and view all the answers

Which structure does not directly arise from the renal vesicle?

Ureter Signup and view all the answers

What structure forms when a glomerulus is surrounded by a Bowman’s capsule?

Renal corpuscle Signup and view all the answers

What initiates the formation of segmented excretory tubules in the thoracic and upper lumbar region?

Somite segmentation Signup and view all the answers

During which week does the mesonephric kidney function begin to degenerate?

Week 5 Signup and view all the answers

What is the shape of the excretory tubules as they elongate?

S-shaped loop Signup and view all the answers

Which structure remains after the transient function of the mesonephric kidney?

Distal portion of the mesonephric duct Signup and view all the answers

What does the tuft of capillaries at the terminal end of the excretory tubule develop into?

Glomerulus Signup and view all the answers

How does the terminal end of the excretory tubule acquire a tuft of capillaries?

Via a reciprocal signaling mechanism Signup and view all the answers

In males, what does the distal portion of the mesonephric duct contribute to?

Development of the genital ducts Signup and view all the answers

What is the role of WT1 in kidney development?

It induces the mesenchyme to respond to ureteric bud signaling. Signup and view all the answers

Which growth factor is released by the mesenchyme in response to WT1?

Hepatocyte growth factor (HGF) Signup and view all the answers

How does FGF2 contribute to kidney development?

It blocks apoptosis and stimulates cell proliferation. Signup and view all the answers

What triggers the upregulation of PAX2 and WNT4 in mesenchyme during kidney development?

Release of WNT9B and WNT6 from the ureteric bud. Signup and view all the answers

What happens to the appearance of kidneys at birth?

They are lobulated but this appearance disappears with growth. Signup and view all the answers

What is the significance of GDNF in kidney development?

It induces local growth factor release from mesenchyme. Signup and view all the answers

What molecular interactions are critical for nephron differentiation?

Reciprocal interactions between ureteric bud epithelium and metanephric mesoderm. Signup and view all the answers

Which transcription factors are crucial for initiating tubule formation in nephron development?

WNT9B and WNT6 Signup and view all the answers

What occurs when FGF2 is released in the kidney development process?

Stimulates cell proliferation and prevents apoptosis. Signup and view all the answers

What happens to kidney lobulation as development progresses?

It transitions to a smooth structure. Signup and view all the answers

Study Notes

Mesonephric Kidney

The mesonephric kidney forms as excretory tubules from the mesonephric duct
The tubules elongate into a S-shaped loop
A glomerulus forms at the end of the tubule from a tuft of capillaries
The glomerulus is surrounded by a Bowman's capsule which forms from the excretory tubule
The glomerulus and Bowman's capsule form a renal corpuscle
The mesonephric kidney begins to degenerate by week 5, starting at the rostral end and moving caudally
The mesonephric duct remains to be used for development of the metanephric kidney, genital ducts, and urinary bladder structures
The mesonephric kidney has temporary function

Metanephric Kidney

The metanephric kidney forms from an interaction of the collecting ducts and metanephric mesoderm
Metanephric mesoderm condenses around collecting ducts and becomes the metanephric cap
The metanephric cap develops under inductive influences of the collecting tubules
The metanephric cap becomes a renal vesicle (see Figure 5)
Each renal vesicle forms an S-shaped tubule
A glomerulus develops from capillaries at the distal end of the tubule
The proximal end of the tubule connects to the collecting duct
The tubule develops into functional parts of the nephron from proximal to distal: distal convoluted tubule, descending and ascending limbs of Henle's loop, proximal convoluted tubule and ends at Bowman's capsule
The glomerulus plus the rest of the tubule structure makes up the nephron
The distal convoluted tubule connects to the collecting tubule
Urine production begins around week 10 of gestation
Nephrons continue to develop until birth, resulting in over 1 million nephrons per kidney
Newborn kidneys appear lobulated
By the 3rd month, the kidney moves to the pelvis and eventually to the abdomen

Molecular Regulation of Metanephric Kidney Development

Development of the kidneys is regulated by reciprocal signaling between ureteric bud epithelium and the metanephric mesoderm
WT1 is released from the metanephric mesoderm and makes it receptive to signaling by the ureteric bud
WT1 causes the metanephric mesoderm to release GDNF and HGF
GDNF and HGF cause the collecting tubule to release FGF2
FGF2 prevents apoptosis, stimulates cell proliferation of the metanephric mesoderm and stimulates more WT1 release
WNT9B and WNT6 are released from the ureteric bud
The metanephric mesoderm upregulates PAX2 and WNT4 as a result of WNT signaling
The metanephric mesoderm condenses

Urinary Bladder Development

The allantois is a connection between the yolk sac and the developing fetus
The allantois shrinks, forms a ligament and attaches to the apex of the bladder
The proximal portion of the allantois forms the primitive urogenital sinus
The urogenital sinus develops into the urinary bladder
The neck of the bladder forms from the narrowed portion of the urogenital sinus
The neck of the bladder forms the pelvic part of the urogenital sinus
In males, the neck of the bladder develops into the prostatic and membranous urethra
In females, the neck of the bladder only forms the membranous urethra
The penile urethra in males forms from the terminal portion of the urogenital sinus

Suprarenal Gland Development

Development begins in the 6th week
The cortex is derived from mesothelial cells associated with the dorsal mesentery
The adrenal cortex is formed by the proliferation of mesothelial cell
The first cells formed are acidophil cells which form the fetal cortex
The definitive cortex is formed by the second group of proliferating cells
The medulla is derived from neural crest cells
Neural crest cells migrate into the adrenal cortex to form the medulla
The neural crest cells become chromaffin cells in the medulla

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Description

Test your knowledge on the development of the mesonephric and metanephric kidneys. This quiz covers the formation of renal structures, their functions, and the processes involved in their development and degeneration. Perfect for students studying anatomy and physiology.