BECOM 2 Exam #3 Flashcards
renal blood flow
Renal artery -> segmental arteries -> interlobar arteries -> arcuate arteries -> interlobular arteries (aka cortical radiate arteries) -> afferent arterioles -> glomerulus -> efferent arterioles -> vein
Podocytes and Pedicels
- are cells in the Bowman’s capsule in the kidneys that wrap around capillaries of the glomerulus
- star like projections off of the cell body
Restrict Lamina densa Lamina rarae Fenestraiton Filtration Slits
Lamina densa: Restricts passage of larger proteins (middle)
lamina rarae: restricts passage of organic ions (internal and external)
Fenestration: RBCs and platelets
Filtration slits: small proteins, organic ions
Mesangial cells
- Have contractile properties
- Provide support for capillaries
- Phagocytose mesangial matrix and protein aggregates that adhere to the filter
PCT stain
Darker stain
Slightly larger cells
Occluded lumen
DCT stain
Lighter stain
Smaller cells
Empty lumen
Juxtaglomerular apparatus (JGA)
is a specialized sensory organ that helps to regulate blood flow through the glomerulus
macula densa role
monitor the levels of ions in the lumen of the TAL
Glomerulonephritis
Inflammation within the glomeruli
ureteric bud makes up
ureter
renal pelvis
major/minor calyx
collecting duct
metanerphric mesoderm makes up
Connecting tubule distal convoluted tubule loop of henle proximal convoluted tube renal (Bowman's) capsule renal glomerulus
bladder is made from?
- upper portion of the urogenital sinus
- mesonephric ducts are incorporated into the posterior wall of the bladder to form the trigone of the bladder
Renal agenesis vs Unilateral renal agenesis
- occurs when the ureteric bud fails to develop, thereby eliminating the induction of metanephric vesicles and nephron formation
- can be one kidney (assymptomatic) or both kidneys (still born)
abnormal position (ectopic kidneys)
- Failure of the kidneys to ascend
- Pelvic kidneys are close to each other and usually fuse to form a discoid (“pancake”) kidney
Renal fusion
- occurs when the inferior poles of the kidneys fuse across the midline
- A horseshoe kidney may also cause urinary tract obstruction due to impingement on the ureters:
- May lead to recurrent urinary tract infections
Duplications of the urinary tract
ureteric bud divides abnormally or prematurely
urachal cysts
- Remnants of the epithelial lining of the urachus form: urachal cysts
- Abnormal membranous sacs with fluid or semisolid material
urachal sinus
- the patent inferior end of the urachus may dilate
- The lumen in the superior part of the urachus may also remain patent to form a urachal sinus that opens at the umbilicus
urachal fistula
- Allows urine to escape from its umbilical orifice
- urine can seep from bladder to umbilicus
Exstrophy of the bladder
is a deficiency of the anterior abdominal wall resulting from failure of mesoderm to migrate between the ectoderm and endoderm of the abdominal wall
Epispadias
Urethra opens on dorsum of penis and wide separation of the pubic bones
Supernumerary pelvic kidney
Results from the development of two ureteric buds
Renal clearance equation
(U x V) / P
-MUST BE IN mL and mins
Th1
-intracellular virus and bacteria
-Differentiating cytokine: IL-12
Release:
-INF-y: inc NK cells, inc macrophage phagolysosome, CSR -> IgG, inc INF-1 -> anti-viral state
-IL-2: activate CTLs
Th2
-allegens, parasites (helminth)
-Differentiating cytokine: IL-4
Release
-IL-4: CSR -> IgE
-IL-5: basophil and eosinophil recruitment/degranulation, mast cells
-IL-13: mucous production, anti-inflammation
Th17
-extracellular bacteria and fungi
-Differentiating cytokine: IL-23
Release:
-IL-17: inc neutrophil (via G-CSF, CLXL8, IL-8), inc antimicrobial peptide, release pro-inflammatory cytokines
-IL-22: wound healing
T reg
-absence of infection
-Differentiating cytokine: TFG-B
Release:
-TGF-B: FOXP3 expression in naive CD4+ cells
-IL-10: down regulate effector T cells, out compete CTLs and Th1 for IL-2, express CTLA-4
BTK
required for B cell development. Deficiency causes X-linked agammaglobulinemia (XLA).
CD21
bind to C3b opsonized antigen during cross linking
NKCC channel
- TAL symport Na+, K+ (or NH4+), Cl-, Cl-
- needs ROMK to work
- main transport of Na+ at TAL
ROMK channel
- TAL K+ secretion
- allows NKCC to work
- responsible for reabsorption of Mg+ because causes filtrate to become positive pushing Mg+ to blood via paracellular transport
Loop diuretics
inhibit NKCC
- Na+, K+, and Cl- loss
- can result in hypokalemia and hypocalcemia because no longer a positive gradient pushing positive ions via paracellular diffusion
NCC channel
- DCT1 Na+ and Cl- symport
- main Na+ transport in DCT1
- Thiazide diuretic-sensitive channel
BK channel
upregulated in the DCT2 and principal cell (CD) as a result of shear stress from increase flow rate
aldosterone effect at DCT
increases activity of ROMK, BK, NCC, ENaC, Na+-K+-ATPase (↑Na+ absorption, ↑K+ secretion)
upregulated ENac in collecting duct principal cells
Insulin ADH/AVP Catecholamines ↑Tubular fluid flow Renal AngII Aldosterone
upregulates ROMK in collecting duct principal cells
Aldosterone
↑dietary K+
Tubuloglomerular Feedback
- changes in systemic BP doesn’t have a huge impact because of Tubuloglomerular Feedback and Myogenic autoregulation
1. high Na+ concentrations in DCT (means high GFR)
2. activation of macula densa cells that release ATP/ADP and activate extraglomerular mesangial cells via paracrine signaling
3. extraglomerular mesangial cells constrict the afferent capillary reducing GFR
Myogenic autoregulation
- changes in systemic BP doesn’t have a huge impact because of Tubuloglomerular Feedback and Myogenic autoregulation
- Myogenic autoregulation: an increase of pressure on the renal capillaries causes smooth muscles to contract via membrane depolarization opens voltage-dependent Ca2+ channels
Congenital nephrotic syndrome cause of edema
Leakage of excessive protein into the GF. This results in a decrease of oncotic pressure in the systemic capillaries because of hypoproteinmia. H2O will leave the capillary to the interstitial fluid causing edema
-nephrin problem (holds pedicles together)
Net filtration pressure
glomerular capillary blood pressure – (plasma-colloid osmotic pressure + Bowman’s capsule hydrostatic pressure
Prostaglandin
- released when NaCl is low in DCT due to low Na+
- AA: dilated
- EA: dilated
- increases renal blood flow but no effect on GFR
- NSAIDs inhibit prostaglandin release
Atrial Neuritic Peptide
- released from heart when it has been stretched too far
- AA: dilate
- EA: constrict
- Inc GFR
Sympathetic stimulation
- AA: constrict
- EA: normal
- decrease GFR and renal blood flow but increase in Na+/H2O reabsorption
Angiotensin High and Low Levels
LOW -AA: normal -EA: constrict -Inc GFR HIGH -AA: constrict -EA: constrict -Dec GFR
Filtration fraction and equation
Amount of plasma that gets filtered = 20% (normal)
FF = GFR / renal plasma flow
Filtration load and equation
The amount of substance that is filtered per time unit
Filtration load = GFR x Plasma conc
increases renin
- reduced AA BP
- Dec NaCl in DCTn (means hyponatremia (low Na+) inc renin -> inc Na+ reabsorption
- inc sympathetic stimulation (via b1-adrenergic receptors)
Effects of Angiotensin II
- Constricts arteriolar smooth muscle, causing mean arterial pressure to rise
- Stimulates the reabsorption of Na+ via aldosterone
- Release ADH from hypothalamus and activates the thirst center
- Constricts efferent arterioles (DECREASES PERITUBULAR CAPILLARY HYDROSTATIC PRESSURE WHICH INCREASE FLUID REABSORPTION)
- Causes glomerular mesangial cells to contract (dec surface area for filtration
ACEinh/ARB + diuretic + NSAID
- diuretic decreases BP
- normally anigiotensin will be released to keep GFR normal even with hypotension by constricting EA
- NSAIDs block prostaglandin and so no dilation of AA
NCB1
HCO3- and Na+ out of cell to blood
OAT1
alpha KG in exchange for PAH-
MRP
multidrug-related protein/ pump
-PAH- to lumen with ATP
Removal of cations and anions (acidic and basic)
cation (+) removal: acidic (H+)
anion (-) removal: basic (HCO3-)
Threshold concentration
plasma conc. At which a solute (e.g. glucose) will begin to appear in urine
transport maximum (Tm)
refers to the maximum amount of a given solute that can be transported per minute at the renal tubules
Calculation of Tm for solute reabsorption (Tr) (in mg/min) equation
(GFR or Cinu x Py) – (Uy x V)
RPF
UPAH x V ÷ (arterialPAH –venousPAH)
Cpah or ERPF / .9
-ERPF = CPAH
parathyroid hormone controls
Na+/phosphate uptake is under the control of PTH at the PCT (reduces the Tm for phosphate ions)
-Ca2+ reabsorption (vitamin D3)
Osmotic diuretics
- mannitol (I.V.) and glycerol (oral)
- increase the osmolarity of the filtrate keeping water in the filtrate and not allowing for a lot of reabsorption
- Useful in acute conditions such as cerebral edema and to reduce I.O. pressure in glaucoma
Thick ascending limb vs thin
The thin segment is permeable to water only, the thick is primarily permeable to salts
Tm secretion equation
(Uy x V) - (GFR or Cinu x Py)
loop diuretics (lasix)
- inhibit NKCC resulting in K+ and Na+ loss
- Thiazides downregulate TRPM6 causing hypomagnesemia
- Side effects: hypokalemia, hypocalcemia, hypomagnesia, increase urine bc increase filtrate solute
NKCC expression and phosphorylation is increased by
ADH
Change of osmolality along the nephron
PCT: isosmotic
Descending tubule: hyper osmotic (H20 reabsorbed)
TAL: hypotonic (Na+, Mg+, Ca2+ reabsorbed)
DCT: hyposmotic
loop diuretics causing hypertrophy
- loop diuretic inhibit Na+ reabsorption in the TAL
- this causes high levels of Na+ at the DCT1 which causes hypertrophy of the cells there and increase in NCC concluding in resistance to loop diuretics (thiazide)
ENaC filtration
-Influx of Na+ causes luminal fluid NEGATIVE -> increased paracellular absorption of Cl-
Aldosterone increases
- ENaCs (Na+ absorption) and ROMK (K+ secretion) trafficking and expression.
- aldosterone increases activity of ROMK, BK, NCC, ENaC, Na+-K+-ATPase (↑Na+ absorption, ↑K+ secretion)
- H+ ATPase and AE1
NCC is increased by
aldosterone, angiotensin II, insulin and ADH
PTH and vitamin D3 upregulate
TRPV5
TRPM6 stimulation
-STIMULATED BY EGF
up regulate ENaC
Insulin ADH Catecholamines Tubular fluid flow Renal AngII
Diabetes insipidus
is caused by the failure of the posterior pituitary gland to release vasopressin (ADH)
Gestational: placental vasopressinase break down mother’s vasopressin
Central: lack of ADH or hypothalamic osmoreceptors
Nephrogenic: lack of functioning ADH receptors or AQP2
Amyloid degeneration, polycystic kidney
Syndrome of inappropriate ADH secretion (SIADH)
-continued secretion or action of ADH
-normal levels of Na+ but significant retention of H2O
Hyponatremia
Concentrated urine
Elevated urinary Na
-Individual that has hyponatremia give Na+ will drag H2O out of the neurons causing demyelination destroying the brain
AE1
-CD type A intercalated cell exchange HCO3- (in to blood) for Cl- (out of blood)
NDCBE and Pendrin
NDCBE: CD type 2 intercalated cell exchange Cl- (into lumen) for HCO3- and Na+
Pendrin: CD type 2 intercalated cell exchange HCO3- (into lumen) for Cl-
SN1 transporter
allows glutamine to enter cell from interstitial fluid during gluconeogensis
- at PCT
- increase during acidosis
Effect of acidosis on gluconeogenesis
↑ renal gluconeogenesis
↓ hepatic gluconeogenesis
↑ Glutamine basolateral transporters (SN1)
-uptake glutamine from blood into cell
In diabetic ketoacidosis ↑↑ renal gluconeogenesis
HPO4-2 Pka
- 8
- H2PO4- in acidic environments
- HPO42- in basic environments
NH4+ Pka
9
NHE3
- exchanges Na+ (in) for H+ or NH3+ (out)
- main Na+ reabsorbed at PCT
Rhcg/Rhbg
secrete NH3
Isosmotic dehydration
-Caused by hemorrhage, exudation of plasma from burned skin, GI fluid loss (vomiting, diarrhea)
Hyperosmotic dehydration
-Cases: Decreased intake, increased urinary loss (diabetes mellitus, diabetes insipidus, alcoholism, fever, excessive evaporation from skin .. Etc)
Isosmotic overhydration
-Caused by administration of large volume of isotonic NaCl and edema
Hyperosmotic overhydration
Cases: Oral or parentral intake of large amounts of hypertonic fluid
Hyposmotic overhydration
Excessive ingestion of water and inappropriate ADH secretion
The hypothalamic thirst center osmoreceptors are stimulated by and release
- ↑ Plasma osmolality of 2–3%
- Angiotensin II or baroreceptor input
- Dry mouth
- Substantial decrease in blood volume or pressure
-Release AVP (ADH)
Congestive heart failure and AVP production
During CHF the heart cannot pump blood effectively so the kidneys sees this as decrease blood volume. As a result there is an increase in AVP (ADH) production. This causes water retention and HYPONATREMIA -> edema
AVP signaling
- AVP binds to V2 receptor on CD epithelial cell
- activate G protein AC to make cAMP
- cAMP -> inc PKA increase aquaporins in collecting duct