Renal Flashcards
what other complex control systems does the kidneys have?
endocrine
neural
local control
what else does the kidney control?
electrolyte balance*
blood pressure*
acid base balance*
blood volume
what are the renal functions?
Regulate Blood Volume/Pressure
Regulate Electrolyte Composition of Blood
Eliminate Metabolic Wastes
Eliminate Drugs and Toxins - renal and liver
Produce Hormones – Renin & Erythropoietin
how much cardiac output goes to the kidneys?
22%
what are the two small arteriolar system?
Afferent Arteriole (Glomerulus Capillary System)
Efferent Arteriole (Peritubular Capillary System and Vasa Recta)
whats the difference between afferent and efferent arteriolar systems?
high pressure - slighting bigger - afferent
low pressure - efferent
What is they kidney surrounded by?
Renal fibrous capsule
what is some physical differences btwn proximal and distal convoluted tubule cells?
proximal have microvilli and more mitochondria
what is the structural difference btwn distal convoluted tubules and collecting ducts?
collecting ducts have less mitochondria
what cell of the kidney detects the pressure in the JG apparatus?
macula densa cells stimulating releases paracrines
How does the kidney local autoregulation?
macula densa - one way the body can sense a control
how does hydrostatic pressure in the glomerulus create a filtrate?
net outflow is greater so that it flows across
What essentially is the kidney a combination of?
Filtration and collection systems
What are the 3 steps of urine creation?
Filtration -> Reabsorption -> Secretion
How many renal artery does each kidney have?
1
How many segmental arteries does each kidney have?
5
Name the arteries that supply the kidney?
Lobar arteries Interlobar arteries Arcuate arteries Afferent arterioles Efferent arterioles
What’s the outermost structure of the kidney called?
cortex
What’s the inner region of the kidney called?
medulla
What does a nephron consist of? (6)
Glomerulus Bowman’s Capsule Proximal Tubule Loop of Henle: Descending/Ascending Limbs Distal Tubule Collecting Duct
What completely surrounds the glomerulus?
Bowman’s capsule
What does the inner layer of bowman’s capsule contain?
It contains octopus like cells - Podocytes
What do podocytes form?
Podocytes form a porous membrane around the glomerulus
List and explain the nephron functions
<b>Glomerular filtration</b> (occurs glomerular capillaries through glomerular capsule)
<b>Tubular resorption</b> (renal tubule lumen through peritubular capillaries)
<b>Tubular secretion</b> (peritubular capillaries to renal tubule lumen)
What gets filtered out during glomerular filtration?
All the small molecules
what would create the filtrate during glomerular filtration?
Hydrostatic Pressure
What does filtration of protein usually indicate?
Renal disease
What are the foot processes of the podocytes called and what do they make up?
They are called pedicels and they make up filtration slits.
What does the glomerular filtration rate equal?
It equals the amount of filtrate formed by both kidneys each minute
What is a normal GFR?
125 ml/minute or 180 liters every 24 hours in healthy adult
What is an important marker in monitoring renal disease?
GFR
what do the kidneys regulate?
Fluid balance
Electrolyte balance
Acid/base balance
Blood pressure is normally cause by central hypertension (unknown). What could be another secondary cause to hypertension?
renal artery stenosis
what is the vasa recta?
(peritubular capillaries) tiny blood vessels that travel alongside nephrons allowing reabsorption and secretion between blood and the inner lumen of the nephron
where does the vasa recta start and end?
These vessels branch off the efferent arterioles of juxtamedullary nephrons (those nephrons closest to the medulla), enter the medulla, and surround the loop of Henle.
what test is a good estimate of the GFR?
creatinine
what would affect creatinine level in the blood?
ingesting meat
renal failure
muscle problem
what does Rhabdomyolysis lead to and why?
acute tubular necrosis from increased protein in the blood damaging the tubular structure
what is the juxtoglomerular apparatus responsible for?
controls blood flow
filtration
renin secretion
what are the 3 main components of juxtoglomerular apparatus?
mucula desa
smooth muscle cells of afferent arterioles
JG Apparatus cells
what part of the nephron descends into the medulla?
loop of henle
What part of the nephron has proliferations in it resulting in leaky membrane? What is it called?
the visceral layer of the capsule has fenestrations called fenestrated endothelium of the glomerulus
whats the ascending limb of the Loop of Henle responsible for?
it’s only permeable to salt and ions but not permeable to water
what type of solution would you consider the medulla (surrounding the loop of henle) to be?
hypertonic because all the ions are being released into the medulla
what is the descending limb of the loop of Henle responsible for?
reabsorption of water
What makes up the renal corpuscle?
glomerular capillaries
glomerular capsule
What is paracrine? what does it effect?
localized hormones
effects afferent arteriole diameter
what type pressure is found in the glomerual?
hydrostatic pressure
what type of pressure is found in the capsule?
capsular hydrostatic pressure
what pull pressure is associated with albumin in regards to filtration pressure?
blood colloid osmotic pressure
how do you determine net outward pressure?
glomerular hydrostatic pressure - (capsular hydrostatic pressure + blood colloid osmotic pressure)
what is anasarca?
full body edema
what does altered glomerual permeability and loss of negative charge cause? (list steps)
increased filtrates of plasma proteins ->
Proteinuria ->
Hypoalbuminemia –>
edema and liver issue with hepatic synthesis of proteins ->
hypolipoproteinemia ->
lipiduria
what is GFR?
amount of filtrate formed by both kidneys each minute
what systems/mechanisms are affected in response to low BP in the renal blood vessels?
Myogenic Autoregulation
Tuboglomerular Mechanism
Renin-Angiotensin System (mechanism)
extrinsic Neural Controls
how does Myogenic Autoregulation increase GFR?
affects renal smooth muscle
vasodialation of afferent arterioles
how does Tuboglomerular mechanism of autoregulation increase GFR?
reduced flow and osmolarity in distal tubules
- > macula densa cells sense changes in distal tubules
- > stimulates vasodialation of afferent arterioles and renin angiotensin mechanism
how does Renin-Angiotensin System (mechanism) increase GFR?
JG cells of juxtaglomerual apparatus of kidney
releases renin
which converts angiotensin to angiotensin 2
stimulates adrenal cortex and systemic arterioles
adrenal cortex > releases aldosterone > kidney tubules increase Na+ and water follows > increase blood volume
systemic arterioles > vasoconstrict > increases peripheral resistance > increases systemic BP
how does extrinsic neural controls increase GFR?
baroreceptors in blood vessels of systemic circulation
sympathetic NS
stimulates systemic arterioles > vasoconstrict > increases peripheral resistance > increases systemic BP and renin angiotensin mechanism
what does the body do if you have too much GFR?
flow through tubules increase >
flow past macula densa increases >
macula densa dumps paracrine to afferent arterioles > afferent arterioles constrict >
resistant in afferent arterioles increase > hydrostatic pressure decreases >
decreases GFR
what is completely reabsorbed by the tubular?
glucose
how much of all filtrate formed is reabsorbed into the blood?
99%
what % is excreted to the urine?
1%
which ions are reabsorbed? (6)
Phosphorus (HPO42- ) Potassium (K+) Calcium (Ca2+) Chloride (Cl-) Bicarbonate (HCO3-) Sodium (Na+)
where else are ions excreted?
vomiting
diarrhea
sweat
what is not actively reabsorbed? (5)
UREA Nitrogenous Waste Products Uric Acid Creatinine Certain Drugs
What plays an important role in acid-base balance?
secretion
what are actively secreted back into tubules?
Ammonium ions, Urea and H+ (amount that was passively reabsorbed)
through active secretion what is almost entirely secreted from the body?
Urea and creatinine
what is the counter current exchange system?
Fluid flows in opposite directions in parallel tubes
Concentration Gradient causes fluid exchange
Gradient increases from cortex to tip of medulla
describe dilute urine
Filtrate is hypo-osmotic, no ADH
describe concentrated urine
Need ADH to make concentration higher
Water reabsorbed
Can become highly concentrated (1400 mOsm)
what are primary regulators of acid-base?
Renal
Pulmonary
which one is fast but limited?
pulmonary
how does the body regulate acid and base? (with what?)
Body will adjust Carbon Dioxide and Bicarbonate to achieve normal range
alkalemia
pH above 7.45
acidemia
pH below 7.35
what is a state of of excess HCO3-?
alkalosis
what is a state of state of excess H+?
acidosis
how does acid- base regulation response to increase CO2?
CO2 converts to carbonic acid (H2CO3) on its way to becoming Bicarb
CO2+ H2O → H2CO3→ H++HCO3−
what are other buffers that regualte ph?
Phosphate, Blood (Hemoglobin) and Protein Buffers
what Acids Produced as By-products of
Metabolism
Phosphoric acid
Lactic acid
Fatty acids
what is Renal Acid-Base Regulation?
Proximal Tubule Resorbs Bicarbonate
Ammonium Synthesis Produces Bicarbonate
Distal Nephron Excretes H+ to Produce New Bicarbonate
Bicarbonate System formula:
CO2+ H2O H2CO3 H++HCO3−
what is the Goal ratio of renal acid base?
maintain the ratio of Bicarbonate to Carbonic Acid at 20:1, even if absolute numbers are abnormal
what is normal PaCO2 in ABG?
35-45 mm Hg
what is noraml Bicarbonate in ABG?
22-26 mEq/L
give pH PaCO2 and HCO3- in metabolic acidosis
low ph, normal PaCO2, low bicarb
give pH PaCO2 and HCO3- in metabolic alkalosis
high, normal, HCO3- high
give pH PaCO2 and HCO3- in respiratory acidosis
low, high, normal
give pH PaCO2 and HCO3- in respiratory alkalosis
high, low, normal
what determines the blood pH?
Balance between H+ ions and HCO3- ions d
When blood too acidic (pH too low) what happens?
More H+ will be secreted into filtrate (lost) AND
More HCO3- ions will be reabsorbed (added)
When blood is too alkaline (pH too high) what happens?
More H+ ions will be reabsorbed (added) AND
More HCO3- will be excreted by kidney (lost)
whats Urine pH?
4.5 -8.0
what happen for your blood to become alkaline?
blew off CO2 - hyperventilation
what happened for your blood to become acidic?
didnt blow off CO2 - hypoventilation
what part of the nephron is responsible for the main activity is reabsorption of solutes and nutrients?
Proximal Tubules
what is the Descending Limb responsible for?
Freely permeable to water, not to NaCl
how is water reabsorbed in the loop of Henle?
the ascending limb is permeable to NA+ CL- making the medulla a hypertonic enviroment. This then drives water in the descending limb to follow salt into the medulla
what is the ascending Limb permeable to?
NA+ and CL-
what is the Distal Tubule responsible for?
Selective secretion/reabsorption
where does urine concentrate in the presence of ADH?
collecting duct
what is the Collecting Duct responsible for?
Selective secretion/reabsorption
Permeable to water if ADH present, concentrates urine
what is the tonicity within each of these ducts?
proximal tubule
loop of henle
distal tubule
proximal tubule - isotonic
loop of henle - isotonic, hypertonic, hypotonic
distal tubule -isotonic, hypotonic
6 test for renal fuction?
BUN – Blood Urea Nitrogen Creatinine BUN/Creatinine Ratio 24 Hour Urine Creatinine Clearance U/A – Urinalysis
What is azotemia?
Azotemia: elevation of blood urea nitrogen and creatinine levels
what is azotemia largely related to?
decreased GFR
What are the two types?
Prerenal Azotemia
Postrenal Azotemia
What is prerenal azotemia?
hypoperfusion of kidneys
What is postrenal azotemia?
urine flow obstructed below kidney
what does BUN reflect?
Glomerular Filtration and Urine-Concentrating Capacity
what does rising BUN levels indicate?
Decreased Function, Renal Failure, altered protein intake and dehydration
what is normal BUN?
10-20mg/dl
What rises with long-term decline in GFR?
Creatinine (plasma)
what is creatinine? what is it used to monitor?
Product of muscle metabolism
Monitor progress of chronic renal disease
what is normal creatinine?
0.7-1.2 mg/dl
List what a Urinalysis shows
Color, Turbidity, pH, Specific Gravity, Sediment RBC, WBC, Casts, Crystals Glucose = glycosuria if present Ketones = ketonuria if present Bilirubin/Urobilinogen Proteins = proteinuria if present Bacteria, Yeast, Parasites, Sperm Drug Testing
where is urinary cast from?
distal convoluting tubules
what is diabetes insipidus?
LOW SPECIFIC GRAVITY related to hormone
what will Reagent strips (dipsticks) show?
Glucose Bilirubin Urobilinogen Ketones Proteins RBCs, hemoglobin, and myoglobin Leukocyte esterase Nitrates
Name 3 glomerular disorders
Acute Postinfectious Glomerulonephritis
Nephritic Syndromes
Nephrotic Syndrome
which glomerular disorders produce a decrease in glomerular permeability?
Nephritic Syndromes
what Clinical syndrome related to decreased GFR, fluid retention, and nitrogenous waste accumulation?
Nephritic Syndromes
which glomerular disorders produce a increase in glomerular permeability?
Nephrotic Syndrome
what Clinical syndrome related to massive loss of plasma proteins in urine?
Nephrotic Syndrome
what does massive loss of plasma proteins >3.5G/day lead to?
Hypoalbuminemia, also retention of salt/water
Generalized Edema, Pulmonary Edema, Pleural Effusions
= glomerular injury
what is nephrotic syndrome secondary to?
Diabetes
SLE
Drugs, Malignancies
Acute Postinfectious Glomerulonephritis is caused 7-12 days after an infection from what?
Group A Beta-hemolytic streptococcus
what causes kidney damage resulting on Acute Postinfectious Glomerulonephritis?
untreated strep infection causes kidney damage from antibody complexes
Proliferation of endothelial and mesangial cells plus leukocyte infiltration = obliteration of capillary lumen
IgG and complement protein deposition
Sx of glomerulonephritis?
Oliguria/Proteinuria/Hematuria
How does burns or allergic inflammation caused edema?
loss of plasma proteins cause increased tissues oncotic pressure and decreased capillary oncotic pressure.
What causes edema?
Decreased capillary oncotic pressure
Increased tissue oncotic pressure
increased capillary hydrostatic pressure
Lymph instruction
what is an electrolyte?
charged particles that conduct electrical current in aqueous solution
give an example of electrolytes
Sodium, Potassium, Phosphate, Chloride, Calcium, Magnesium, Some Proteins
what is the MOA for dehydration?
excess loss of H2O -> ECF osmotic pressure -> cell uses H2O -> cells shrink
whats the primarily controls fluid balance by it’s influence on excretion?
Antidiuretic Hormone (ADH)
ADH is also known as
Vasopressin
what releases ADH?
Neurohypothesis in the pituitary gland
what is Aldosterone?
Hormone
what does aldosterone do? where is it released?
primarily acts on sodium content of ECF –> water retention primarily follows sodium retention
released adrenal gland
ADH in large amount is __________
a vasoconstrictor (vasopressin)
List the events that would follow when blood volume drops for any reason (hemorrhage or dehydration)
Arterial blood pressure drops ->
Amount of filtrate (GFR) decreases->
Osmoreceptors in hypothalamus pick up signal->
Send message to posterior pituitary ->
Posterior pituitary releases ADH ->
ADH causes renal tubules to ↑ reabsorption of H20 ->
Blood volume/ Blood pressure rises
How is sodium reabsorbed when there is decreased Sodium/increased Potassium
OR Blood volume or pressure drops for any reason?
Renin-Angiotensin mechanism stimulates adrenal cortex->
Release aldosterone-> Sodium reabsorbed-> water follows = Blood pressure rises
whats the most important trigger for aldesterone?
Renin-Angiotensin-Aldosterone Axis
After renin-angiotensin mechanism restores homeostatic plasma levels of Na+ and K+ how does the mechanism know to shut off?
Negative feedback mechanism sends signals to adrenal cortex
What does angiotensin 2 do?
Adrenal aldersterone
Vasoconstriction
H2O reabsorption
what is Juxtaglomerular Apparatus?
specialized cluster of cells near glomerulus
what does the Juxtaglomerular Apparatus do during the Renin-Angiotensin-Aldosterone Axis?
they secretes enzyme Renin -> Angiotensinogen to Angiotensin I ->ACE Released from Lungs->
Angiotensinogen I to II
what are two types of urinating symptoms?
irritative - urgency
obstructive - hesitency, post void dribbling
whats a common type of irritative urination?
dysuria - painful urination, inflammation/infection (urethra women / tip of the penis in men)
what are the 2 structures in the bladder?
detrusor muscle
trigone - micturition reflex
what is the trigone? what does it do?
triangle of smooth muscle - contracts during urination to release urine
what are the sphincters in the urethra?
internal and external
what is the common cause of UTI’s in females?
coliform bacteria (e.coli)
typical length of urethra in male/female is
3-4cm in females
18-20 cm in males
what are two symptoms of obstructive disorder?
Hydroureter
Hydronephrosis
define Hydroureter
distention of the ureter with fluid, due to obstruction.
define Hydronephrosis
the swelling of a kidney due to a back-up of urine
what are 3 obstructive disorders?
Nephrolithiasis
Neurogenic Bladder
Tumors
which obstructive disorder is a condition in which problems with the nervous system affect the bladder and urination?
Neurogenic Bladder
what is a disorder characterized by bladder infection and dysuria on micturition?
cystitis
what is it called when an untreated UTI ascends to the kidneys?
Acute Pyelonephritis
how do you know a pt has polycystic kidney disease (Acute Pyelonephritis)?
Fever, flank pain with UTI, dysuria on urination, tenderness to kidney ascultate and precusion
what is characterized by high serum glucose and protein urea?
diabetic nephropathy
at what level of glucose will it start to spill out into the urine?
180
what happens after high glucose levels upset osmotic balance of blood?
Kidneys overworked trying to remove excess glucose from blood
Urine output too high
what eventually happens from trying to compensate from high glucose levels in the blood?
Filtering surface of glomerular capsule becomes thickened –> Nephrons gradually become damaged –> Filtering ability eventually lost
what is an Infection of kidney parenchyma and renal pelvis ?
Acute Pyelonephritis
what can you get from renal failure?
Uremia = syndrome of renal failure Azotemia = increased serum urea levels
what is it called when your kidney functions:
25% of normal
less than 25%
10% or less of normal
Renal Insufficiency
Renal Failure
ESRD
what are the types of renal failure?
Acute Renal Failure
Chronic Renal Failure
what are the types of acute renal failure?
Prerenal
Intrarenal
Postrenal
a back leak of urine occurs during which type of acute renal failure?
intrarenal
how do you determine what stage renal disease a pt has?
by the GFR
lowest GFR = ESRD
what are the two types of dialysis?
Hemodialysis; Peritoneal
what renal functions change with age?
Decrease in kidney size Decrease in renal blood flow and GFR Number of nephrons decrease due to renal vascular and perfusion changes Glomerular capillaries atrophy Tubular transport response decreases Increased bladder symptoms Urgency, frequency, and nocturia
What flows through fenestration and between the capillary endothelium? Where does it end up?
Plasma
travels through penetration, across basement membrane, in between filtration slit, and filtrate in ____