Lecture 8 - Urinary System Flashcards
from which embryological germ layer is the urinary system derived
mesoderm, intermediate mesoderm
the intermediate mesoderm swells to form
urogenital ridge
urogenital ridge comes from intermediate mesoderm and differentiates into
genital ridge and nephrogenic cord
we get our urinary system from
nephrogenic cord/ridge
what embryological phenomenon would contribute to accessory renal arteries or extra
problems with ascent of kidneys
as they kidney’s ascend, the kidneys pass through an arterial fork formed by the __ arteries
umbilical arteries
in horseshoe kidney’s what do they get snag on while ascending
IMA
the definitive kidney arises from the
metanephros
the most cranial part of the kidney and first to form
pronephros
Appears at beginning of: 4th week; degenerated by end of 4th week Functional? Rudimentary; not functional in humans Found within cervical region:
pronephros
2nd part of the kidney appears in the 4th week and is functional until the 10th week
functional or nah
mesonephros
yes functional
mesonephros : from intermediate mesoderm of upper __ to upper__ segments
thoracic to upper lumbar segments
the definitive (permanent) kidney - appears in 5th week
metanephros
what are the two components of the metanephros and their derivatives
ureteric bud - from mesonephric duct gives rise to collecting ducts
and metanephric blastema - gives rise to excretory portion (nephrons)
gives rise to collecting ducts in kidney (collecting tubules, major and minor calyces, renal pelvis, ureter)
ureteric bud -
gives rise to excretory portion (nephrons) of metanephros (bowman’s capsule, proximal convoluted tubule, loop of henle, distal convoluted tubule)
metanephric blastema
during weeks 4-7, ___ divides cloaca into urogenital sinus and anal canal
urorectal septum
which germ layer does the urorectal septum arise from
mesoderm
the bladder arises from which part of the urogenital sinus?
vesical part
trigone of bladder, a triangular area of the incorporated __ on posterior bladder wall
mesonephric duct
caudal ends of mesonephric ducts and attached ureteric buds become incorporated into
posterior wall of bladder
which portions of the urogenittal sinus contribute to the formation of the urethra in the female
pelvic part
which portion of the urogenital sinus gives rise to the vestibule of vagina
phallic part
which portions of the urogenittal sinus contribute to the formation of the urethra in the male
pelvic and phallic part
in the male the pelvic part and the phallic part of the urogenital sinus give rise to what
pelvic part - prostatic and membranous uretha
phallic part - penile (spongy) uretha
produces urine, pull out the ultra filtrate from the blood
kidneys
transports urine toward the urinary bladder
ureter
temporarily stores urine prior to elimination
urinary bladder
conducts urine to exterior, in males transports semen as well
uretha
1) Regulation of Blood Ionic Composition
2) Regulation of Blood Volume and Blood Pressure
3) Regulation of Blood pH
4) Conservation of Valuable Nutrients
5) Production and Secretion of Hormones (Endocrine Function)
6) Assisting the Liver in Detoxification of Poisons
7) Elimination of Organic Waste Products and Foreign Substances – the kidneys help to excrete wastes; these wastes include the wastes produced in metabolic reactions such as ammonia* (deamination of amino acids), urea* (deamination of amino acids), bilirubin* (breakdown of hemoglobin), creatine* (breakdown of creatine phosphate in muscle fibers), and uric acid* (breakdown of nucleic acids). Other wastes excreted in urine include foreign substances from diet such as drugs and environmental toxins
functions of the urinary system
the deep vertical fissure along the medial concave border of the kidney, is where renal vessels, nerves, and renal pelvis pass into/out of the kidney.
hilum
Just past the hilum of the kidney is an internal space called the ____, which is filled with loose connective tissue and adipose tissue, along with part of the renal pelvis, the calyces, and branches of the blood vessels and nerves.
renal sinus
In a cut kidney, the ____(i.e., functional part of the organ) can be divided into two distinct regions:
____superficial outer area
and the __ deeper inner area
parenchyma
Renal Cortex – superficial (outer) area.
Renal Medulla – deeper (inner) area;
Renal Medulla – deeper (inner) area; can be divided into:
__6-18 distinct conical or triangular structures; the base faces the cortex; the apex is the renal papilla (which projects into a minor calyx); the tip of the papilla is perforated by papillary ducts
and ___in between pyramids; cortical tissue within medulla.
renal pyramids
renal columns
consists of a renal pyramid, its overlying renal cortex, and one-half of each adjacent renal columns.
renal lobe
which part of the kidney produces the ultrafiltrate
glomerulus
blood flow into kidney
renal artery > segmental a> interlobur a> arcuate a > afferent arterioles> glomerular capillaries > efferent arterioles.
blood flow out of kidney
vasa recta –OR – peritubular cappilaries > interlobular v> arcuate v> interlobar v > renal v.
the fundamental structural and functional unit of the kidney
nephron
each human kidney contains approx. __ nephrons
1 million
a nephron consists of two parts:
__ where glomerular filtration occurs
and ___where tubular reabsorption and tubular secretion occurs
renal corpuscle
renal tubule
for urine to be produced, the nephrons perform 3 processes:
___ – First step; water and most solutes in blood plasma move from the glomerular capillaries into the glomerular (i.e. Bowman’s) capsule.
___– Filtered fluid then moves through the renal tubule; the tubule cells reabsorb ~99% of filtered water and many solutes; these items return to the blood at the peritubular capillaries.
___ – The tubule cells can remove additional substances (ex. wastes, drugs, and excessive ions) from the blood in the peritubular capillaries.
Glomerular Filtration
Tubular Reabsorption
Tubular Secretion
___is the beginning of the nephron and is located in the renal cortex
renal corpuscle
two components of a renal corpuscle
glomerulus and bowmans capsule
is a tuft of capillaries composed of 10 to 20 capillary loops. The glomerular capillaries are supplied by an afferent arteriole and drained by an efferent arteriole.
glomerulus
is a double-walled epithelial cup that surrounds the glomerulus:
Visceral layer – internal layer
Parietal layer – external layer
bowman’s capsule
Blood flowing through the capillary loops undergoes filtration to produce glomerular ultrafiltrate which is collected by Bowman’s capsule – specifically into the urinary or Bowman’s or capsular space located between the two layers. This ultrafiltrate then drains into the ___, the first part of the renal tubule.
proximal convoluted tubule
Bowman’s/Glomerular capsule:
__ layer ;internal layer; consists of modified simple squamous epithelial cells called podocytes; extensions of these cells (pedicels) wrap around the single layer of endothelial cells of the glomerular capillaries; space between two pedicels (~30-40nm) is called a filtration slit and this is where the ultrafiltrate from the blood enters Bowman’s space; semipermeable membrane covering this slit called a slit diaphragm.
___; external layer; simple squamous epithelium.
visceral layer
parietal layer
of the renal corpuscle where the afferent and efferent arterioles enter/exit
vascular pole
of the renal corpuscle where filtrate exits Bowman’s space and enters proximal convulated tube
urinary or tubular pole
the degree of the vascular pole and the urinary pole of the renal corpuscle
180 degrees
consists of a proximal convoluted tubule (PCT), loop of Henle (nephron loop), and distal convoluted tubule (DCT).
renal tubule
where tubular reabsorption and tubular secretion occurs.
renal tubule
parts of the renal tubule:
___attaches to the glomerular capsule; highly coiled tube; lies within the renal cortex.
___extends from the renal cortex into the renal medulla, turns, and returns to cortex.
___last part of the renal tubule; highly coiled tube; lies within the renal cortex; the distal convoluted tubule empties into a collecting duct.
proximal convoluted tubule
loop of henle
distal convoluted tubule
Begins at the urinary pole of Bowman’s capsule
Very coiled
Found in the cortex
Lined with simple cuboidal epithelium
proximal convoluted tubule
In order to tell the difference between the proximal convoluted tubules (PCTs) and distal convoluted tubules (DCTs):
PCTs have a larger outside diameter than DCTs
PCTs cytoplasm is a little more eosinophilic (i.e., stains a little more pinker) due to mitochondria
PCT cells are larger, so find fewer nuclei around the lumen for PCTs, as compared to DCTs
PCTs have a brush border (i.e., long varying lengths of microvilli), while DCTs do not have a brush border (i.e., microvilli of DCTs are fewer and not long)
Luminal edge of PCTs is irregular, fuzzy, narrow, and somewhat star-shaped, unlike the DCTs whose lumen is smoother
Nephron Loop (a.k.a. Loop of Henle) is composed of:
Thick descending limb of the loop of Henle (a.k.a. proximal straight tubule)
– composed of simple cuboidal epithelium
Thin descending limb of the loop of Henle
– composed of simple squamous epithelium
Thin ascending limb of the loop of Henle
– composed of simple squamous epithelium
Thick ascending limb of the loop of Henle (a.k.a. distal straight tubule)
– composed of simple cuboidal epithelium
Very coiled
Found in the cortex
Lined with simple cuboidal epithelium
Smaller cells than found in PCT
Lots of mitochondria here too – therefore eosinophilic cells
Microvilli of distal convoluted tubule are fewer and not long (i.e., no brush border) and, therefore, so lumen of DCT is smoother than PCT
distal convoluted tubule
The final part of the thick ascending limb of the loop of Henle (i.e., distal straight tubule) comes in contact with the afferent arteriole from the same nephron. Cells here in the distal straight tubule are modified to create the ____, a region where the cells are crowded together and become columnar with apical nuclei
macula densa
Alongside the macula densa and the wall of the afferent arteriole are modified smooth muscle cells called
juxtaglomerular cells.
macula cells + juxtaglomercular cells + extraglomerular mesangial cells (aka Lacis cells) =
juxtaglomerular apparatus
the juxtaglomerular apparatas helps regulate __ within the kidneys
blood pressure
Collect” urine from DCT
Merge and become larger as they descend through the cortex and medulla
Simple cuboidal epithelium that transitions to simple columnar epithelium as ducts increase in size
collecting ducts
2 cell populations within collecting ducts: ___Pale staining, along with single primary cilium and relative few short microvilli
Abundance of ADH-regulated water channels
___Denser cytoplasm, along with microvilli
principal cells or cleccting duct cells or light cells
intercalaced cells or dark cells
How do you tell the difference between collecting ducts and PCTs & DCTs?:
Cytoplasm of collecting ducts is relatively clear and cells borders are usually distinct.
within the collecting duct, when cells transition from simple cuboidal epithelium to simple columnar epithelium you are in, toward tip of renal papilla
papillary duct
nephron with its renal corpuscle close to the renal medulla, long loop of henle, important for urine concentration
juxtamedullary nephron
nephron with its renal corpuscle close to renal capsule, shorter loop of henle,
cortical nephron
the middle part of the cortical lobule or renal lobule, consisting of a group of straight tubes connected to the collecting ducts.
medullary rays
Mucosa
Transitional epithelium (a.k.a. urothelium)
Lamina propria
Submucosa
Muscularis Smooth muscle Inner longitudinal layer Outer circular layer Outermost longitudinal layer (distal end of ureter and present in bladder)
Adventitia
urinary system wall
~muscularis layer is mostly first two until you reach the end where its all 3
male uretha:
___; lined by urothelium
__; – lined by stratified columnar epithelium and pseudostratified columnar epithelium
___lined stratified columnar epithelium and pseudostratified columnar epithelium, and then distally by non k stratified squamous epithelium.
prostatic uretha
membranous uretha
spongy uretha
Lined initially by urothelium then by stratified squamous epithelium, with the occasional pseudostratified columnar epithelium.
small only 3-5cm
female uretha
