Module 5 Urinary, DM nephropathy Flashcards Preview

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Flashcards in Module 5 Urinary, DM nephropathy Deck (168)
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Development of Urinary System

- Develop at 3rd-4th week embryonic life
- Germ layer of origin intermediate mesoderm


Kidneys arise from two sources:

1. Ureteric bud - ureter pelvis calyces and collecting duct

2. Renal blastema - nephron except collecting duct


Development of renal anlage

Develop along cranio-caudal gradient
Three stages
1. Pronephros - forekidney transitory structure
- develop during 4th wk and atrophies 5th wk
2. Mesonephros - functional for awhile
3. Metanephros - definite kidney



Upper urinary system
- collecting duct, calices, renal pelvis and ureter
- arise from ureter anlage

Lower urinary system
- bladder and urethra
- formed from the endoderm of the posterior intestine


The intermediate mesoderm forms a longitudinal elevation along the dorsal body wall called the __

urogenital ridge


A portion of the urogenital ridge forms the __, which gives rise to the urinary system.

nephrogenic cord


The nephrogenic cord develops into three sets of nephric structures:

1. pronephros
2. mesonephros
3. metanephros.


- develops by the differentiation of mesoderm within the nephrogenic cord to form pronephric tubules and the pronephric duct
- is the cranial-most nephric structure and is a transitory structure that regresses completely by week 5
- is not functional in humans.



- develops by the differentiation of mesoderm within the nephrogenic cord to form mesonephric tubules and the mesonephric duct (Wolffian duct)
- is the middle nephric structure and is a partially transitory structure.
- Most of the tubules regress, but the mesonephric duct persists and opens into the urogenital sinus.
- is functional for a short period.



- develops from an outgrowth of the mesonephric duct (called the ureteric bud) and from a condensation of mesoderm within the nephrogenic cord called the
metanephric mesoderm.
- is the caudal-most nephric structure
- begins to form at week 5 and is functional in the fetus at about week 10.
- develops into the definitive adult kidney



Development of the collecting system

The ureteric bud is an outgrowth of the mesonephric
duct. This outgrowth is regulated by WT-1 (an
anti-oncogene), GDNF (glial cell line–derived
neurotrophic factor), and c-Ret (a tyrosine kinase receptor).

The ureteric bud initially penetrates the metanephric mesoderm and then undergoes repeated branching to form the URETERS, RENAL PELVIS, MAJOR CALYCES, MINOR CALYCES, AND COLLECTING DUCTS.


Development of the nephron

The inductive influence of the collecting ducts causes the
metanephric mesoderm to differentiate into metanephric vesicles, which later give rise to primitive S-shaped renal tubules, which are critical to nephron formation.

The S-shaped renal tubules differentiate into the connecting tubule, distal convoluted tubule, loop of Henle, proximal convoluted tubule, and Bowman’s capsule. Tufts of capillaries called glomeruli protrude into Bowman’s capsule. Nephron formation is complete at birth, but functional maturation of nephrons continues throughout infancy.


The transitional epithelium lining the ureter, pelvis, major calyx, and minor calyx and the simple cuboidal epithelium lining the collecting tubules are derived from __ of the ureteric bud.



The simple cuboidal epithelium lining the connecting tubule and distal convoluted tubule, the simple squamous epithelium lining the loop of Henle, the simple columnar
epithelium lining the proximal convoluted tubule, and the podocytes and simple squamous epithelium lining Bowman’s capsule are derived from __.

metanephric mesoderm


Development of Urinary Bladder

A. The urinary bladder is formed from the upper portion of the urogenital sinus, which is continuous with the allantois.
B. The allantois becomes a fibrous cord called the urachus (or median umbilical ligament in the adult).
C. The lower ends of the mesonephric ducts become incorporated into the posterior wall of the bladder to form the trigone of the bladder.


Development of Urinary Bladder 2

D. The mesonephric ducts eventually open into the urogenital sinus below the bladder.
E. The transitional epithelium lining the urinary bladder is derived from endoderm because of its etiology from the urogenital sinus and gut tube.


The female urethra is formed from the __ of the urogenital sinus.

lower portion


The female urethra develops __ outgrowths into the surrounding mesoderm to form the urethral glands and paraurethral glands of Skene (which are homologous to the
prostate gland in the male).



The transitional epithelium and stratified squamous epithelium lining the female urethra are derived from __.



- These parts of the urethra are formed from the lower portion of the urogenital sinus. The transitional epithelium and stratified columnar epithelium lining these parts of the urethra are derived from endoderm.

Prostatic urethra, membranous urethra, bulbous urethra, and proximal part of penile urethra


__ is formed from an ingrowth of surface ectoderm called the glandular plate. Ectodermal septa appear lateral to the navicular fossa and become canalized to form the foreskin. The stratified squamous epithelium lining of the distal penile urethra is derived from ectoderm.

Distal part of the penile urethra


The __ joins the proximal penile urethra and becomes canalized to form the navicular fossa.

glandular plate


__ occurs when the ureteric bud fails to develop, thereby eliminating the induction of metanephric vesicles and nephron formation.

Renal agenesis


__ occurs when there is a congenitally small kidney with no pathological evidence
of dysplasia.

Renal hypoplasia


__ occurs when there is a disorganization of renal parenchyma with abnormally developed and immature nephrons

Renal dysplasia


__ occurs when one or both kidneys fail to ascend and therefore remain in the pelvis or lower lumbar area (i.e., pelvic kidney). In some cases, two pelvic kidneys fuse to
form a solid mass, commonly called a pancake kidney.

Renal ectopia


The most common type of __ is the horseshoe kidney. A horseshoe kidney occurs when the inferior poles of the
kidneys fuse across the midline. Normal ascent of the kidneys is arrested because the fused portion gets trapped behind the inferior mesenteric artery. Kidney rotation is also arrested, so that the hilum faces ventrally.

Renal fusion


The __ consists of the paired kidneys and ureters, the bladder, and the urethra. This system’s primary role is to ensure optimal properties of the blood, which the kidneys continuously monitor.

urinary system


This general role of the kidneys involves a complex combination of renal functions:

■ Regulation of the balance between water and electrolytes (inorganic ions) and the acid-base balance
■ Excretion of metabolic wastes along with excess water
and electrolytes in urine
■ Excretion of many bioactive substances, including many
■ Regulation of arterial blood pressure by secretion of


__ is a protease secreted into the blood that helps regulate blood pressure by cleaving circulating angiotensinogen to angiotensin I.