Urinary System Flashcards
The urinary system is responsible for _________.
Excretion of metabolic products
Parts of urinary system
- Kidneys
- Ureters
- Urinary bladder
- Urethra
Function of kidney: ______ blood concentrations of ions, wastes, nutrients, etc.
Regulate
Function of kidney: _____ the blood from wastes.
Clear
Function of kidney: ______ pH, body temperature, blood volume.
Regulate
Kidney’s endocrine functions includes production and release of _______ for erythropoiesis and ______ for regulation of blood pressure.
- Erythropoietin
- Renin
In males, the urethra also has a ______ function.
Reproductive
The kidneys are paired, _______, and enclosed in a _____ made of dense CT.
- Retroperioneal
- Capsule
The kidneys consist of:
- Cortex
- Medulla
- Renal sinuses
- Pelvis and columns
- Major and minor calyces
The medulla of the kidney has 6-10 ______ with bases toward cortex and apex (papillae) in medulla.
Renal pyramids
Tip of papilla is called ______ with about 25 pores.
Area cribrosa
What composes a renal lobule?
One pyramid + surrounding tissue
Medulla of the kidney is differentiated into _______ each with a portion of _______.
- Inner and outer medulla
- Uriniferous tubules
Medulla of the kidney also has medullary rays which are continuation of bundles of straight tubules from ________.
Renal pyramids
Two functional portions of the uriniferous tubule
- Nephron (collects and filters blood and forms urine)
- Collecting tubules (absorb and concentrate the filtrate)
There are about _____ nephrons per kidney.
1.5 million
The nephron contains _____ morphologically distinct segments at different levels in the cortex and the medulla.
Six
The nephron contains _____ major subdivisions which are further subdivided - a terminology developed by the _________.
- Four
- International Union of Physiological Sciences
Four Subdivisions of the Nephron
- Proximal Tubule
- Intermediate Tubule (Loop of Henle)
- Distal Tubule
- Collecting System
The Proximal Tubule consists of:
- Pars convoluta (PCT)
- Pars recta (PST)
The Intermediate Tubule (Loop of Henle) consists of:
- Descending thin limb (DTL) or pars descendens
- Ascending thin limb (ATL) or pars ascendens
The Distal Tubule consists of:
- Distal straight tubule (DST)
- Distal convoluted tubule (DCT)
Bowman’s capsule and glomerulus together are called ______.
Renal corpuscle
The Bowman’s capsule is a double walled cup of squamous epithelium enclosing a urinary or ________.
Bowman’s space
Bowman’s capsule also has a ______ where PCT originates and a _______ which houses (entry and exit of) afferent and efferent arterioles.
- Urinary pole
- Vascular pole
During embryogenesis the glomerulus is pushed into a blind end of uriniferous tubule forming _______ and ________.
- A layer of visceral or glomerular epithelium
- A layer of parietal or capsular epithelium
________ of Bowman’s capsule become cuboidal at the urinary pole and continue to form ________ of the PCT.
- Squamous cells
- Cuboidal epithelium
During development the parietal epithelium remains ________ but the ________ is extremely modified.
- Polygonal squamous
- Visceral epithelium
The cells of the visceral epithelium become _______ which are stellate cells with primary and secondary foot processes or pedicels. Interdigitating processes of podocytes form an elaborate system of intercellular clefts called ________, so the only barrier then is the basal lamina
- Podocytes
- Filtration slits
Electron microscopy of the basal lamina of the Renal Corpuscle shows:
- _________ toward epithelium of capsule
- _________ toward glomerular endothelium
- __________ – the central zone
- Lamina rara externa
- Lamina rara interna
- Lamina densa
Glomerular epithelium of the Renal Corpuscle is ________.
Fenestrated
Intercapillary spaces of the Renal Corpuscle are occupied by ______ which consists of phagocytic mesangial cells that maintain basal lamina.
Mesangium
The _______ of the Renal Corpuscle consists of fenestrated endothelium, basal lamina and filtration slits between foot processes
Filtration barrier
The Proximal Tubule begins from urinary pole and has two parts:
- Pars convoluta (PCT)
- Pars recta (PST)
The Proximal Tubule forms ______ of the renal cortex.
Bulk
Epithelium _________ or microvilli
- Tips of brush border with _______
- Nuclei ______
- Brush border has _________
- 3D structure shows ridges that continue underneath base of neighboring cells
- Simple cuboidal with brush border
- Glycocalyx
- Spherical
- Apical canaliculi
_____ absorbs nearly all of glucose and amino acids and nearly 70% of water and Na+.
Proximal Tubule
The principal pump of the Proximal Tubule is ________ in the _________.
- Na+ / K+ ATPase
- Basolateral membrane
The three segments in the Proximal Tubule:
- S1 (cells tall cuboidal in proximal PT with highest Na+ absorption)
- S2 (cells medium cuboidal - distal PT)
- S3 (cells cuboidal with tallest mv)
The Distal Tubule is shorter and somewhat thinner than the Proximal with two parts:
- Medullary thick ascending limb (MTAL)
- Cortical thick ascending limb (CTAL)
CTAL of the Distal Tubule has plaques of cells called ______.
Macula densa
Distal to macula densa, the DT is called distal convoluted tubule (DCT) or ________.
Pars convoluta
The Epithelium of the Distal Tubule is _________.
- Round or ovoid nucleus displaced toward lumen
- Basal infoldings have very high ________.
- Lumen is wider that that of PT
- No _______ (some cells with short microvilli) or ________
- Simple cuboidal
- ATPase activity
- Brush border or apical canaliculi
The thick ascending limb of the Distal Tubule is nearly __________.
Impermeable to water
Principal function of thick ascending limb of Distal Tubule is the ________ from the filtrate.
Absorption of Na+ and Cl-
The ATPase activity of the _______ of the Distal Tubule is the greatest.
Thick ascending limb
The cells of the Distal Convoluted Tubule are __________ and have a role in ________.
- Cuboidal, thinner, lack microvilli
- Secreting solutes
When the descending Pars Recta suddenly narrows from 60 to 15 micrometers, this segment is then called _________.
Descending thin limb
The epithelium of the Intermediate tubules or Thin segments is _______ and ________ terminates.
- Cuboidal to squamous
- Brush border
Short Looped Nephrons predominantly have _______ which are polygonal with no interdigitations.
Type I cells
Long Looped Nephrons have 3 squamous cell types identified:
- Type II (cells with radiating processes and interdigitations)
- Type III (cells with decreased radiating processes and no interdigitations)
- Type IV (cells where both radiating processes and interdigitations resume)
Zonation of collecting tubules following distal tubule
- Short connecting tubule
- Collecting duct with 3 successive segments (cortical collecting duct, outer medullary collecting duct, inner medullary collecting duct)
About seven conversion of several inner medullary collecting ducts in the medulla form a papillary duct or _______.
Duct of Bellini
Papillary duct open into ________ of renal pelvis through area cribrosa of each renal papilla.
Minor calyx
Epithelium of the collecting tubule is ______.
Simple cuboidal
Four cell types of the collecting tubules
- DCT cells (similar to DT cells)
- Connecting tubule cells (similar to DT cells, smooth apical surface, less lateral interdigitations)
- Intercalated (I) cells (with many vesicles in cytoplasm)
- Principal (P) cells (short mv, central flagellum, central ovoid nucleus)
The _______ are large ducts resulting from fusion of collecting ducts.
Papillary Ducts
The papillary ducts are composed of _____ cells with no _______.
- Cuboidal
- Brush border
The function of the papillary ducts is:
To collect urine from many nephrons
The ______ occupies space external to renal tubules basal lamina.
Renal Intersititum
The volume of the Renal Intersititum in the _____ is relatively small, but increases in ______.
- Cortex
- Medulla
The Renal Interstitium contains:
- Fibroblast like cells
- Mononuclear cells
- Small bundles of collagen fibers in hydrated proteoglycan matrix
In the Renal Cortex of the Renal Interstitium there are two types of cells identified:
- Fibroblasts (with long tapering processes, abundant actin filaments and lipid droplets)
- Mononuclear cells (with spherical large nuclei, thin rim of cytoplasm, closely associated with fibroblasts and free ribosomes)
In the Renal Medulla of the Renal Interstitium there are two types of cells identified:
- Slender pleomorphic fibroblast like cells (with long processes and multiple lipid droplets)
- Mononuclear cells (similar to cortical mononuclear cells)
Slender pleomorphic fibroblast like cells are believed to synthesize ________ which is later activated to _______, a ________ and an _______ substance.
- Medullipin-I
- Medullipin-II
- Vasodilator
- Antihypertensive
The Juxtaglomerular Complex contributes to the kidney’s role in regulation of blood pressure by release of _____.
Renin
The Juxtaglomerular Complex consists of:
- Macula densa
- Juxtaglomerular cells
- Extraglomerular mesangial cells
Macula densa is composed of ________ with numberous microvilli.
Epithelial cells of DT
Juxtaglomerular cells are modified ________ called myoepithelial cells with granules and sites of _____ formation and release.
- Smooth muscles of afferent arterioles
- Renin
Renal Blood supply
- Renal a.
- Two inter lobar a.
- Several interlobular a.
- Several arcuate a.
- Afferent arterioles
- Efferent arterioles
- Vasa recta (hair pin loop)
- Capillaries
- Arcuate v.
- Interlobular v.
- Interlobar v.
- Renal v.
Renal Lymphatics are found both in ______ and ______ but not in glomeruli and medullary rays.
Capsule and parenchyma
Renal ______ are found but not completely worked out.
Nerves
Two categories of kidney function:
- Excretory – wastes, water etc
- Conservative – water, electrolytes, nutrients etc
Kidney functions involve:
- Filtration
- Passive diffusion
- Active secretion
- Selective reabsorption
Types of pressures that govern kidney functions
- Hydrostatic
- Colloid osmotic
- Capsular
Hydrostatic Pressure
70 mm Hg forces filtrate to Bowman’s capsule
Colloid osmotic pressure
32 mm Hg opposes hydrostatic pressure
Capsular pressure
20 mm Hg opposes hydrostatic pressure
Under the influence of three types of pressure the net filtration pressure is ________.
70 – (32+20) = 18 mm Hg
Net result is filtration of _______ which is called _________. 124 ml of this 125 ml filtrate is reabsorbed and 1 ml is excreted as urine.
- 125 ml fluid / min
- Glomerular filtration rate (GFR)
Kidneys have a ___________ mechanism.
Counter current multiplier
________ forms small amounts of concentrated urine in summer and large volumes of dilute urine in winter.
Counter current multiplier mechanism
In the presence of __________ the CT walls become permeable to water and a concentrated urine is formed.
Vasopressin or antidiuretic hormone (ADH)
In the absence of _____, CT are not permeable to water and dilute urine is produced.
ADH
The medullary interstitium maintains a high concentration of NaCl (range is ________).
300-1,200 mOsmoles
This medullary osmotic gradient is made possible by the following structural features of intermediate tubules (IT):
- Descending IT is impermeable to solutes and freely permeable to water
- Ascending IT is impermeable to water and actively excretes NaCl
- Collecting duct is deep medulla are permeable to urea
- Vasa recta function as counter current exchangers
Kidneys have _____ blood pressure control mechanisms.
Dual
One blood pressure control mechanism is ________ from renal interstitium fibroblast like cells, an _______ substance.
- Medullipin
- Antihypertensive
One blood pressure control mechanism is _______ from renal juxtaglomerular cells, a _______ substance.
- Renin
- Prohypertensive
In the scheme of blood pressure regulation, decreased arterial pressure → plasma globulin ________ from liver is converted into ________ by _____ from kidney.
- Angiotensinogen
- Angiotensin-I
- Renin
In the scheme of blood pressure regulation, a _________ from lungs converts _______ into _______ which is a potent vasoconstrictor. Result is increased arterial pressure.
- Converting enzyme
- Angiotensin – I into angiotensin-II
Calyces → ______ → ureter → ______ → urethra
- Pelvis
- Bladder
Calyces, pelvis, ureter, bladder, and urethra all have similar histological organization with _________.
Transitional epithelium
Calyces, pelvis and ureter all have well developed layers of ________ which are not arranged in circular or longitudinal pattern. Smooth muscles help in _______ in ureter.
- Smooth muscles
- Peristalsis
The urinary bladder has 6-8 layers of ________.
Epithelium is a barrier against osmosis to avoid dilution of urine.
Transitional epithelium
In the urinary bladder, _______ of membrane at luminal surface which gives an ______.
- Stiff plaques
- Angular outline
The urinary bladder has three layers of smooth muscles:
Outer longitudinal, middle circular or spiral and inner longitudinal or oblique
Base of the bladder has an _______ made of smooth muscles. Blood and lymph vessels and nerves are all supplied.
Internal sphincter
The male urethra has three segments distinguishable:
- Prostatic – epithelium transitional to pseudostratified columnar with goblet cells
- Membranous – epithelium stratified columnar
- Penile – epithelium stratified columnar
The female urethra
Epithelium stratified squamous
