2. Histology of the Kidney and Urinary Tract Flashcards
1
Q
The Kidney • Main function: • Filtration of blood supplied by the renal arteries. • Layers: • \_\_\_\_. • \_\_\_\_. • \_\_\_\_.
A
capsule
cortex
medulla
2
Q
The Uriniferous Tubule: ____ + Collecting Duct
- Functional unit of the kidney: filtration, excretion, reabsorption.
- 1.3 million/kidney.
- Segments:
- Nephron:
- Renal corpuscle:
- ____
- Glomerulus
- Renal tubule:
- ____
- Loop of Henle
- ____
- Collecting tubule/duct:
- ____ segment.
- ____ medullary segment
- ____ medullary segment
• Composed of two parts ○ Nephron ○ Collecting tubule § Derive from diff \_\_\_\_ tissues § Differen,t but complementary functions
A
nephron
capsule of bowman
proximal convoluted tubule
distal convoluted
cortical
outer
inner
embryological
3
Q
Cortical vs. Juxtamedullary Nephrons
• In kidney there are two tpyes of nephrons based on \_\_\_\_ inside the kidney ○ Cortical § Have \_\_\_\_ functional unit of nephron (from renal corpuscle to loop of henle until connects CT) > restricted to the \_\_\_\_ of the organ ○ JM § Part of nephron (glomerulus and P and DCT > located in cortext; but the loop of henle is in the \_\_\_\_) □ No glomeruli in the \_\_\_\_ ® Only \_\_\_\_, and sections of \_\_\_\_
A
location
full
cortex
medulla
medulla
4
Q
The Kidney: Cortex and Medulla
• Cortex:
• Contains ____ and
____.
• Medulla:
• No ____.
• Mostly ____ and
ducts of the ____.
• Distinct morphologies
A
renal corpuscles nephron ducts renal corpuscles collecting tubules nephronq
5
Q
The Renal Corpuscle
- Filtration unit.
- ____
- ____• Made of two substructures
○ Capsule of bowman
§ ____ takes place
○ Glomerulus
• Combine vessels, with the space where the filtrate will be in close apposition to the ____ enviroment (urinary space)
• Each corpuscle is composed of capsule of bowman that surrounds a space, that’ penetrated by ____ that divide into anastomsoing cap’s
○ Within - formation of ultrafiltrate into the urinary space > formation of ____ urine > blood leaves capillaires through the efferent arterioles
• In close proximity > will find parts of ____ itself
A
capsule of bowman glomerulus filtration external arterioles primary nephron
6
Q
The Renal Corpuscle: Capsule of Bowman
- Parietal layer:
- Attached to the surrounding ____.
- ____ epithelium.
- ____ membrane.
- Visceral layer:
- Attached to the ____.
- Podocytes: ____ cells.
- ____ membrane.
- Urinary space (or Bowman’s space):
- Between ____ layers.
- Receives the ____ ultrafiltrate.
- Continuous with the lumen of the ____ at the urinary pole.• Parietal layer
○ Formed by squamous that surround the entire corpuscle
§ Secretes a basal lamina/BM
• Visceral layer
○ More interior layer
○ Formed by podocytes
§ The cell body ALWAYS looks into the ____ bt visceral and parietal layers
□ The urinary space - the space that gets the ultrafiltrate from the capillaries, and then exported through the urinary pole > part of RC that is connected to PCT
○ On the other side: instead of urinary pole > ____ > where the two arterioles enter/exit the RC
A
conn tissue
simple squamous
basement
glomerular capillaries
epithelial
basement
visceral and parietal
plasma
PCT
empty space
vascular pole
7
Q
The Renal Corpuscle: Glomerulus
• Components:
Glomerular capillaries:
____ endothelium (____ epithelium with ____ basal lamina).
____ basal lamina: endothelial cells + ____ (in the visceral layer of the capsule).
• Mesangium:
• Mesangial ____.
• Mesangial ____.
• Capillaries ○ Fenestrated endothelium § In combo with podocytes in visceral layer > deposit dual BL > establish the filtration barrier bt capillaries and urinary space • Mesangium
A
fenestrated discontinuous continuous dual podocytes cells matrix
8
Q
The Renal Corpuscle
• Parietal layer ○ \_\_\_\_ epi, that separates the RC from the rest of the kidney (containing CT, ducts, tubules) • Visceral layer ○ Formed by \_\_\_\_ - more difficult to follow • Between two layers - \_\_\_\_ ○ Cannot see the urinary pole here ○ But can see the vascular pole • Glomerular capillaries can be seen because full of \_\_\_\_
A
simple squamous
podocytes
urinary space
RBC
9
Q
The Renal Corpuscle
• Visceral layer of RC • The cells seen are all podocytes ○ The body of the cells protude into the \_\_\_\_, and cover the glomeurlus ○ The capillaries are inside ○ They extend the \_\_\_\_ that branch again until they form pedicels
A
urinary space
cytoplasmic bodies
10
Q
The Renal Corpuscle: Podocytes
• Pedicels ○ Formation of filtration barrier takes place • Section of capillary inside glomerulus ○ Epi: \_\_\_\_ epithelium § In tissues with excahgne of substances • The podocyte wraps around the capillary, and extends cytoplasmic processes (primary) that split into secondary/tertiary processes > at the end > \_\_\_\_ (not pedicles!) • Cell body of podocytes - contains \_\_\_\_ and most of \_\_\_\_ ○ Extends cytoplasmic processes (primary, then secondary, and then \_\_\_\_ > filtration slits) • Middle panel: ○ One side have the podocyte extending the pedicels ○ Other side have the endothelial cells
A
fenestrated pedicels nucleus organelles tertiary
11
Q
The Renal Corpuscle: The Filtration Barrier
- Fenestrated endothelium of glomerular capillaries:
• Permeable to ____, small molecules.
• Low permeability of large ____. - Basal laminae:
• ____ basal lamina produced by endothelial cells and podocytes.
• ECM (e.g. ____) and adhesive (e.g. ____) proteins.
• ____ down filtration of anionic proteins. - Podocytes*:
• Interdigitating processes (pedicels) attach to the ____.
• Filtration slit: ____ between pedicels.
• Diaphragm: formed by the protein ____ joining the pedicels.• Contact bt podocytes and capillaries
• At capillary level
○ Fenestrated epi that allows filtration of water easily, but because of the elctrical cahrge of PM of endothelial > prevents the exit/filatration of large molecules that are charged negatively > prevent leaking through barrier
• Then a dual BL
○ Complex BL produced by products secreted/assembled by podocytes, and endothelial cells on the other
○ BL is a specialized type of ECM that is rich in laminin and fibronectin (adhesive protein)
• Podocyte side
○ Ultimate cyto processes: pedicels > interdigitating
§ Attached BL through ____ receptor in the podocyte binding to BL components (laminin)
○ Between two pedicels > empty space/slit > filtration takes place here
§ Nephrin - high MW protine that binds to pedicels
□ This configurarion of pedicel and barrier protein > makes this epithelium ofrmed by the podocytes as a ____ epithelium with diaphragm
□ ____ - select what goes through capillary into urinary sapce; preventig uncontroleld leak of substances into the bloodstream
A
water anionic proteins dual laminin fibronectin slows
basal lamina
space
nephrin
integrin
fenestrated
biological sieve
12
Q
The Renal Corpuscle: The Filtration Barrier
• Below we have a capillary, lined by fenestrated endothelium ○ \_\_\_\_ goes form BS into the urinary space • Up top - podocyte • In between - the pedicels that form the filtration slits ○ In the arrow - can see the diaphragn formed by \_\_\_\_ binding to two different pedicels
A
ultrafiltrate
nephrin
13
Q
The Renal Corpuscle: The Mesangium
• Made of mesangial cells that secrete/assemble an ECM that maintains the \_\_\_\_ of the glomerular capillaries ○ The ECM prevents \_\_\_\_ of capillary network § At this level they're very \_\_\_\_ § In addition to binding dual BL, have to be reinfocrced by these \_\_\_\_ cells
A
physical structure
collapse
fragile
mesangial
14
Q
The Renal Corpuscle: The Mesangium
• ____ structure between the glomerular capillaries.
• Components:
• ____ cells:
• Specialized ____.
• Characteristics of smooth muscle:
• ____: Regulation of blood flow.
• Synthesis of mesangial ECM: ____ support for the glomerular capillaries.
• Synthesis of active substances: ____ and ____ (regulate local capillary
constriction).
- Characteristics of macrophage:
- ____: Control of turnover of glomerular basal laminae
- Also present outside the glomerulus: ____ mesangial cells (slide 33).• Have a dual phenotype
○ Specialized pericytes
§ (BS III) - cells that associate to capillariesm and have chracteristics of smooth muscle cells - capablae of ____ > the mesangial cells can repsond to stimuli and regualte floow of blood through each ____
§ Being similar to SM cells > synthesize a ECM
□ Mechanical support for capilaries
§ PG/endothelins - ____
□ Act locally inside glomerulus to contract capillaries that regualting bloow flow in and out of RC
○ Phagocytic cell
§ Can behave like a macrophage
§ Renovate the mesangial ECM (can both synthesize, and can remove aging matrix also)
A
intraglomerular mesangial pericytes contractile mechanical prostaglandins endothelins phagocytic extraglomerular contraction glomerulus vasoconstrictors
15
Q
The Renal Corpuscle
• The matrix is highlighted here • Some fo the mesangial cells themselves ○ Can see some nuclei in pkaces ○ Deep pink - ECM produced by \_\_\_\_ cell • Cluster of meangial cells that are outside of glomerulus ○ EG mesangial cells
A
mesangial
16
Q
- Renal tubule:
- ____
- ____
- ____
- Tubule from RC and is formed by PCT, the LH and the DCT all the way to the junction of the CT
- The epithelia are all ____ in each area
A
proximal convulated tubule
loop of henle
distal convoluted tubule
different
17
Q
The Renal Tubule: Proximal Convoluted Tubule (PCT)
- Reabsorption epithelium.
- ____ epithelial cells:
- Apical domain with ____.
- Lateral domain with ____.
- Basal domain with infoldings and ____.
- Apical lysosomes.
- ____-located mitochondria: provide energy for the Na+/K+ ATPase pump (review BS-IV lectures).• Starting at urinary pole - the first segemnt of the RT is the ____ (small diameter, that’s in close prox to the renal corpuscle that is convulated and folded onto itself)
• Reabsorption epithelium
○ The nephron first makes ultrafiltrate (primary urine) - that’s not the urine that reaches the urinary bladder >
• A lot of transport of ions and water in and out of the tubules is going to take place
• This is where the modification of primary urine/ultra filtrate starts taking place
• Thus, this is a reabsorption epithelium
• Lined by cuboidal epithelium
○ Have a brush border - the apical domain forms extensions called microvilli
§ Tissue of cells are involved in absorption
□ Increase ____
§ Require high amounts of energy > cells are rich in mitochondria
□ Located in the basal domain > that attach the cells strongly to the ____
□ In order to trun he Na/K ATPase
§ Rich in lysosomes
□ Contain ____ - used to degrade peptides that get reabsorbed > converted into AA and recycled as part of normal metabolism of the body
A
cuboidal brush border (microvilli) tight junctions interdigitations basally
PCT
SA
BL
hydrolases
18
Q
• Capillaries full of RBC
• PCT
○ Stain ____
○ Tubule has ____ lumen
A
stain
narrow
