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
What is the function of the Juxtaglomerular (JG) apparatus?
Fxn = regulates blood flow + filtrate production
What are the components of the JG apparatus? Include location and function.
JG Cells
- Location: in afferent arterioles (as modified SMCs)
- Function: secrete renin -> regulates blood pressure
Macula Densa
- Location: Distal convoluted tubules
Mesangial Cells
- Location: Glomerulus
- Stimulated by angiotensin 2
Explain the RAAS system
- JG cells secrete Renin = converts angiotensinogen → angiotensin 1
- In the lungs, angiotensin 1→ angiotensin 2
- Angiotensin 2 stimulates the 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. Function
- 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. Function
- Epithelium: simple squamous
- Fxn: reabsorption of Na+ & H2O from the filtrate
Loop of Henle – Thick Ascending Limb
1. Epithelium
2. Function
- Epithelium:= simple cuboidal w/ few microvilli
- Fxn: reabsorption of Na+ from the filtrate
Collecting Duct (CD)
1. Epithelium
2. Function
- Epithelium: simple cuboidal w/ few microvilli + basal striations
- Fxn:conc. or dilute the urine as needed via ADH before it exits the kidney
Distal Convoluted Tubule (DCT)
1. Epithelium
2. Function
- Epithelium: simple cuboidal w/ few microvilli
- Fxn:reabsorption of Na+ & H20 from the filtrate
Where do we see transitional epithelium?
Urinary system
Urinary system
- Location
- Function
- Location: :major/minor calyx (inside kidney) + ureters + bladder
- Fxn: plasma membrane protects structures from damage d/t contact with urine
What are transitional epithelial cells?
- Stratified epithelium w/ 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 (the inner and outer longitudinal and middle circular)
Ureters
- Epithelium?
- Location?
- Function?
- Epithelium: = transitional
- Location: travel from kidneys-> bladder
- Fxn: transport urine
Identify the structure(s) in the image
HIGH yield
- Glomerulus
- Proximal convulated tubule
- Distal convulated tubule
Identify the structure(s) in the image
- Kidney
- Vein
- Artery
- Adipose
- Capsule
- Cortex
- Glomeruli
Identify the structure(s) in the image
Identify the structure(s) in the image
- Distal convulated tubule
- Glomerulus
- Proximal convulated tubule
Identify the structure(s) in the image
- Straight Tubules
- Collecting duct
Identify the structure(s) in the image
- Collecting duct
- Straight tubule
Identify the structure(s) in the image
Identify the structure(s) in the image
Ureter
Identify the epithelium in the image
Transitional epithelium
- Identify the epithelium:
a. Stratified squamous
b. Stratified columnar
c. Transitional
d. Pseudostratified columnar
c. Transitional
- Identify the indicated structure:
a. Distal convoluted tubule
b. Descending straight tubule
c. Proximal convoluted tubule
d. Collecting duct
d. Collecting duct
- Identify the structure:
a. Straight tubule
b. Collecting duct
c. Macula densa
d. Juxtaglomerular cells
c. Macula densa
- Which of the following is (are) involved in blood filtration at the glomerulus?
a. Endothelial cells and podocytes
b. Podocytes and lamina rara externa
c. Pedicles and parietal layer of bowman’s capsule
d. Endothelial cells only
a. Endothelial cells and podocytes
- In what part of the kidney can the loop of Henle be found?
a. Renal corpuscle
b. Renal medulla
c. Glomerulus
d. Renal cortex
b. Renal medulla
- The visceral layer of bowman’s capsule is made up of:
a. Juxtaglomerular cells
b. Simple squamous epithelial cells
c. Mesangial cells
d. Podocytes
d. Podocytes
- Pedicles associate with the filtration slit membrane in the production of filtrate in the kidney. Which of the following structures contain the pedicles?
a. Parietal layer of bowman’s capsule
b. Visceral layer of bowman’s capsule
c. Lamina densa
d. Afferent arterioles
b. Visceral layer of bowman’s capsule
- What type of epithelium lines the distal convoluted tubules?
a. Non-keratinized simple squamous
b. Ciliated simple columnar
c. Simple cuboidal with microvilli
d. Transitional with umbrella cells
c. Simple cuboidal with microvilli
- Blood travels to the glomerulus through the afferent arterioles for filtration. The filtrate then occupies the urinary space in bowman’s capsule and drains into which structure?
a. Distal convoluted tubule
b. Proximal convoluted tubule
c. Parietal layer of bowman’s capsule
d. Proximal straight tubule
b. Proximal convoluted tubule
Which of the following are considered modified smooth muscle cells in afferent arterioles?
a. Juxtaglomerular cells
b. Mesangial cells
c. Podocytes
d. Endothelial cells
a. Juxtaglomerular cells
- The proximal convoluted tubule is responsible for 70-80% of reabsorption from the filtrate. Which epithelial structure allows for this reabsorption?
a. Microvilli
b. Basal striations
c. Mitochondria
d. Cilia
a. Microvilli
