Exam 1 lecture 3 Flashcards
Name 6 physiological functions of kidney
Endocrine function
control of solutes and fluids
BP control
Acid/base balance
Drug metabolism and excretion
Metabolic waste excretion
What are the two big components of nephrons
Tubules
blood vessels
What is the relationship between tubules and blood vessels in kidney
There is reabsorption and excretion between tubules and blood vessels
What happens in glomerulus
Filtration (100% filtrate produced)
What structure is present after filtration in glomerulus
PCT
What happens in PCT
Major reabsorption site (both active and passive).
Glucose and aa reabsorbed.
Lots of blood vessels present for reabsorption
What structure is present after PCT
loop of henle
What are the two parts of loop of henle and what are their functions
descending (thin) limb- primary site for H2O absorption
Ascending (thick) limb- permeable to ions (salts reabsorption)
What is after loop of henle
DIstal tubule
Percent of filtrate reabsorbed at distal tubule
9%
What structure comes after distal tubule
collecting duct
Percent of filtrate reabsorbed at collecting tubule
4%
percent of filtrate reabsorbed from loop of henle
6%
Percent of filtrate reabsorbed from proximal tubule
80%
average kidney has how many nephrons
1 million
afferent vs efferent arteriole
afferent- brings blood to glomerulus
efferent- carries blood away from glomerulus
difference between PCT and proximal tubule
proximal tubule- secretions and reabsorption of organic acids and bases, uric acid and most diuretics
PCT- reabsorption of 65% of ions, 100 % of aa and glucose
function of thick ascending loop
active reabsorption of 15-25% of filtered NA/K/Cl.
secondary reabsorption of Ca and Mg
function of distal convoluted tubule
PTH control
Function of medullary collecting duct
Water reabsorption under vasopressin control
Water permeability of
Proximal tubule
Thick ascending loop
DCT
proximal- very high
thick ascending loop- very low
DCT- very low
What are some different ways of measuring kidney function
serum creatinine
blood urea nitrogen (BUN)
creatinine clearence
Glomerular filtration rate (GFR)
What does serum creatinine measure? How would an increase or decrease affect our body?
measures how well kidneys filter waste from blood.
Increase in this is bad
What does Blood urea nitrogen measure (BUN), how would change affect it?
Measures waste from liver breakdown of AA
increase is bad
What does creatinine clearence measure
Useful for predicting secretion and drug clearence
What are some markers for damage for kidney
Urinary abnormalities- protein, RBC in urine suggest membrane malfunction
Imaging abnormalities (MRI/CTI scans)
Kidney functions decline with age due to
Decline in kidney mass (nephrons)
How does renal injury lead to decrease in number of nephrons
Decrease in number of nephrons lead to compensatory rise in size and function of remaining nephrons
Increase in size and function of nephrons lead to glomerular and tubular lesions
lesions lead to loss of nephrons, leading to decline in GFR
decrease in GFR leads to azotemia and uremic syndrome (death)
Criteria to determine acute kidney failure (AKF)
1.Increase in Scr of 0.3 or more
- Increase in Scr by 50% (1.5x) baseline, which is known to have occured within the prior 7 days
- A reduction in urine output of less than 0.5 ml/kh/h for 6 H
How is normal GFR maintained under decreased perfusion pressure and reduction of GFR by drugs
The kidney has an internal mechanism for autoregulation.
how does the kidneys internal autoregulation of perfusion pressure work
Normal GFR is maintained by afferent vasodilation and efferent vasoconstriction
How is afferent vasodilation maintained
Increased vasodilatory prostaglandins- dilation
how is efferent vasoconstriction maintained
Increased angiotensin II
How would taking NSADIs affect autoregulation of kidney
NSAIDs affect prostaglandin. This will affet vasodilation of efferent arterioles leading to low GFR
We can use NSAIDs with renal injury t/f
False
What drugs could affect angiotensin II levels
ACE inhibitors
Major causes of intrinsic acute kidney injury
sepsis, ischemia, nephrotoxicity
What are some causes of obstruction leading to post renal AKI (acute kidney injury)
Kidney- kidney stones, blood clots, tumor
Bladder- Prostate enlargement, blood clots, cancer
Urethra- obstructed foley catheter
What are some common key elements of progressive nephropathies?
Increased glomerular capillary pressure
Proteinuria
Glomerulosclerosis
2 main abnormalities that give rise to CKD-MBD (chronic kidney disease- mineral bone disease)
- impaired phsophate excretion
- decreased production of 1,25 dihydroxy vitamin D3
why cant patients with CKD produce active vit-D3
Vitamin D3 becomes active invivo. goes through liver and then kidney to become activated. CKD patients can not undergo kidney portion.
That is why CKD patients require Ca homeostasis checks
What is uremia
Uremic illness due to buildup of organic waste products
signs and symptoms of uremia
Endocrine and metabolic
neural and muscular
nephropathy meaning
Damage or disease of kidney
Name 5 nephropathies
Nephritic syndromes
nephrotic syndromes
Cystic disease of kidney
nephrolithiasis
contrast induced nephropathy
differentiate nephritic and nephrotic syndromes
Nephritic- INFLAMMATION distrupting glomerular basement membrane (hematuria, cola colored urine)
Nephrotic- pOdocyte damage leading to glomerular charge barrier disruption (massive proteinuria)
Which has more proteinuria nephritic or nephrotic
Nephrotic
How does proteinuria affect serum albumin?
lowers serum albumin
How does low albumin affect the body?
Edema
proteinuria–>low albumin–>edema
What is generally observed with nephritic syndrome
Hematuria
What is glomerulonephritis? two forms?
inflammation of glomerulus. Can have chronic or acute. Presents with both proteinuria and hematouria
cause of glomerulonephritis
Primary- genetics
secondary- infection, drugs etc
pathogenesis of glomerular disease
antibody associated immune rxn
cell mediated immune rxn
what is pyelonephritis
Inflammation of kidney caused by bacteria from blood or UTI
clinical presentation of pyelonephritis?
Painful urination, white cells in urine
What is the major cause of pyelonephritis
Bacteria from UTI go against the floe of urine using flagella and go into the kidney.
What is interstitial nephritis? what is AIN (acute interstitial nephritis caused by?)
Interstitial nephritis is the primary injury to renal tubules and interstitium. It has several different causes.
70-75% Drugs- penicillin and diuretics
4-10% Infections
10-20% autoimmune infections
What is the most common form of cystic renal disease
cystic disease of kidney
2 forms of cystic disease
APKD- autosomal dominant polycystic kidney disease (adult)
autosomal recessive polycystic kidney disease (childhood)
What is the difference between autosomal dominant polycystic kidney disease and autosomal recessive polycystic kidney disease
autosomal dominant affects adults
autosomal recessive affects children
autosomal dominant is characterized by multiple expanding cysts of both kidneys that ultimately destroy the parenchyma.
autosomal recessive is ultimately fatal, those who survive will have liver disease
what is nephrothiasis
Kidney stones
what percent of men and women are affected by nephrothiasis
10% of men, 5% of women
how does nephrothiasis occur?
supersaturation of calcium (kidney stones are predominantly calcium phosphate)
