Exam3Lec7UrinarySystem Flashcards
What makes up the urinary system? And what are their fxn’s?
- Kidneys -> filtration = removal of fluid + waste from the blood->secreted as urine
- Ureters ->deliver urine from kidney to the bladder
- Urinary Bladder-> storage site for urine
- Urethra ->excretes urine from the bladder
List how the epithelium of the urinary system changes from kidneys to urethra
- Kidneys = changes as urine passes; mostly simple cuboidal w/ microvilli (exception: thin loop of henle = simple squamous)
- Ureters = transitional; stratified epithelium w/ umbrella cells
- Bladder = transitional
- Urethra = (male reproductive)-> prostatic urethra = transitional & penile urethra = columnar
What is the epithelium of the kidneys? What is the exception?
simple cuboidal w/ microvilli
EXCEPTION: thin descending loop of henle = simple squamous
What is the fxn of the kidneys?
filtration of blood -> removal of waste as urine
Ability to reabsorb stuff allows for adjustments to urine as it moves through
What is the organization of the kidney?
- Capsule = dense CT layer: can contain, artery veins and nerves
- Cortex = outer layer
(a)Renal corpuscles=glomerulus + bowman’s capsule
(b) proximal / distal convoluted tubule. - Medulla = inner layer
(a) Straight tubules + loop of Henle + collecting duct
What contains many nephrons in the kindeys?
renal lobules
What is a nephron and the 2 types?
filtration unit = spans across the cortex + medulla
2 types = cortical nephron + juxtamedullary nephron (near medulla)
What is the artery that brings blood to the kidney and its branches?
Renal artery
Arcuate artery (btw cortex+medulla)
Branches: afferent and and efferent arterioles
What is the fxn of the afferent and efferent arterioles that branch of the renal artery?
Afferent arterioles ->supply blood directly to the glomerulus for filtration
Efferent arterioles -> receives filtered blood + leaves the glomerulus
What is the Vasa recta?
network of blood vessels -> provides countercurrent exchange
Surrounds the loop of Henle in the medulla
What is the lxn and fxn of the glomerulus of the kidney?
lxn: in renal corpuscle (in renal cortex)
fxn: site for blood filtration
What are the 4 components of the glomerulus?
- Bowman’s capsule
- Afferent arteriole
- Mesangial cells
- Basement membrane
What is the Bowman’s Capsule of the glomerulis and what is its layers?
BC: outer covering of glomerulus
Parietal layer -> simple squamous epithelial cells
Visceral layer -> podocyte cells
What is the fxn of afferent arterioles in relation to the glomeruls and what does it contain?
fxn:delivers unfiltered blood to glomerulus
Contains JG cells (smooth muscle cells)
What is the fxn of Mesangial cells?
phagocytosis of B.M. + synthesis of GF / IL
support + synthesis of growth factors and interluekins
What is the fxn of the basement membrane of the Glomerulus and list the layers and what they contain
fxn: blocks (-) charge particles + proteins
Outer layer ->Lamina Rara Externa = anions + heparan sulfate
Middle layer->Lamina Densa = type IV (4) collagen
Inner layer ->Lamina Rara Interna = anions + heparan sulfate
Glomerus BM blocks passage of what?
Proteins larger than 70KD and the anions block molecules of smaller size
Slit membrane blocks what?
Fenestrated capillary endothelium blocks passage of what?
bulk diffusion and cellular elements
Filtration apparatus=____ + ____
Filtration apparatus = glomerulus + bowman’s capsule
Glomerulus=____ + ____
Glomerulus = capillaries (endothelial cells) + B.M. (lamina rara externa / interna)
What layer of the Bowman’s capsule is involved in blood filtration?
visceral layer (podocytes w/ their pedicles)
List the steps of how filtration occurs, starting at the glomerulus
- afferent arterioles (contain JG cells) deliver unfiltered blood to the glomerular capillaries
- fluid + waste exit blood as filtrate through gaps b/n endothelial cells of the capillary
- filtrate crosses B.M. of the glomerulus -> filters out (-) particles + proteins (>70kD)
(a) Passes through lamina rara externa 1st ->lamina densa -> lamina rara interna - filtrate passes through membrane of filtration slits b/n the pedicles of podocytes
- filtrate crosses visceral layer of bowman’s capsule->enters bowman’s space
- urine (filtrate) leaves glomerulus -> excreted into the proximal convoluted tubule
What diesease can occur if there is alteration of the Basement membrane of the glomerulus?
Goodpasture’s syndrome & glomerulonephritis
What disease can occur if there are alterations of the pedicles of podocytes in bowman’s capsule
Glomerulosclerosis = fusion of the pedicle foot processes
What is the fxn of the JG apparatus?
Fxn = regulates blood flow + filtrate production
What are the components of the JG apparatus?
JG Cells
Lxn: in afferent arterioles (as modified SMCs)
fxn: secrete renin -> regulates blood pressure
Macula Densa
lxn: distal convoluted tubules
Mesangial Cells
lxn: glomerulus
Stimulated by angiotensin 2
Explain the RAASS system
- JG cells secrete Renin = converts angiotensinogen ->angiotensin 1
- In the lungs, angiotensin 1 -> angiotensin 2
- Angiotensin 2 stimulates adrenal gland to secrete aldosterone
- Aldosterone increases Na+ & H2O reabsorption in the collecting duct
- An increase in blood volume results in increased blood pressure
What are the tubes of the kidney?
- Proximal Convuluted Tubule (PCT)
- Loop of Henle-Thin Descending Limb
- Loop of Henle – Thick Ascending Limb
- Distal Convoluted Tubule (DCT)
- Collecting Duct (CD)
Proximal Convoluted Tubule (PCT)
1. Epithelium
2. Fxn
- Epithelium: = simple cuboidal w/ microvilli
Microvilli -> absorption
Basal striations-> increase SA for more mitochondria - Fxn:reabsorption of 70-80% of filtrate
Na+, sugar, proteins + amino acids leave to re-enter the blood
NOTE: microvilli stain pink -> only see in PCT
Loop of Henle – Thin Descending Limb
1. Epithelium
2. Fxn
- Epithelium: simple squamous
- Fxn: reabsorption of Na+ & H20 from filtrate
Loop of Henle – Thick Ascending Limb
1. Epithelium
2. Fxn
- Epithelium:= simple cuboidal w/ few microvilli
- Fxn: reabsorption of Na+ from filtrate
Collecting Duct (CD)
1. Epithelium
2. Fxn
- Epithelium:simple cuboidal w/ few microvilli + basal striations
- Fxn:conc. or dilute the urine as needed via ADH
Distal Convoluted Tubule (DCT)
1. Epithelium
2. Fxn
- Epithelium:simple cuboidal w/ few microvilli
- Fxn:reabsorption of Na+ & H20 from filtrate
Where do we see transitional epithelium?
Urinary system structures: major/minor calyx(inside kidney) + ureters + bladder
Urinary system w/ transitional epithelium
Lxn?
plasma membrane Fxn?
Lxn:major/minor calyx (inside kidney) + ureters + bladder
Fxn: plasma membrane protects structures from damage d/t contact with urine
What are transitional epithelial cells? Are they permeable to water and ions?
Umbrella cells contain plaques w/ actin -> helps w/ distention
Impermeable to water + ions-> thus, no reabsorption occurs
What are ureters characterized by?
3 layers of muscle
Ureters
Epithelium?
Lxn?
Fxn?
Epithelium: = transitional
Lxn: travel from kidneys-> bladder
Fxn:transport urine
