Lecture 7: Urinary System Flashcards
What makes up the urinary system? And what are their functions?
- Kidneys -> filtration = removal of fluid + waste from the blood→secreted as urine
- Ureters ->deliver urine from the 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 the urine passes; mostly simple cuboidal w/ microvilli (exception: the thin loop of Henle = simple squamous)
- Ureters = transitional; stratified epithelium w/ umbrella cells
- Bladder = transitional
- Urethra = discussed in male reproductive (L5)→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 function of the kidneys?
- Filtration of blood -> removal of waste as urine
- The ability to reabsorb stuff allows for adjustments to urine as it moves through
Essential in the maintenance of honeostasis in the body
What is the organization of the kidney?
- Capsule = CT layer
- Cortex = outer layer
(a)Renal corpuscles + proximal/distal convoluted tubule. (b)Corpuscle = glomerulus + bowman’s capsule - 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 kidneys and its branches?
- Renal artery
- Branches: afferent and efferent arterioles
What is the function of the afferent and efferent arterioles that branch of the renal artery?
- Afferent arterioles ->supply blood directly to the glomerulus for filtration
- Efferent arterioles -> receive filtered blood + leave 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 location and function of the glomerulus of the kidney?
- Location: in renal corpuscle (in the renal cortex)
- Function: 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 glomerulus and what are its layers?
- BC: outer covering of glomerulus
- Parietal layer -> simple squamous epithelial cells
- Visceral layer -> podocyte cells
What is the function of afferent arterioles in relation to the glomerulus and what does it contain?
- Fx: delivers unfiltered blood to the glomerulus
- Contains JG cells (smooth muscle cells)
What is the function of Mesangial cells?
phagocytosis of B.M. + synthesis of growth factor (GF)/ Interlukin-1 (IL)
What is the function of the basement membrane of the Glomerulus and list the layers and what they contain?
- Function: 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
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 the membrane of filtration slits b/n the pedicles of podocytes
- Filtrate crosses the visceral layer of the bowman’s capsule->enters the 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