renal physio Flashcards
what is the primary goal of the kidney
maintain homeostasis and renal function
- constantly changing and dynamic
what does the kdiney regulate exactly
- water and salt balance (Na, K, Ca); balancing intake and excretion
- remove metabolic waste, drugs, other foreign chemicals
- gluconeogenesis
Production of hormones
what hormones are made by he kidney
Erythropoietin
Renin
1,25-dihydroxyvitamin D
what is the roll of erythropoietin
acts in the bone marrow to stimulate synth of new erythrocytes
what is the roll of renin
Part of renin-angiotensin-aldosterone cascade to regulate blood pressure
what is the roll of 1,25-dihydroxyvitamine D
regulate calcium absorption
does the kidney process and see a lot of the water that the body has
only a small portion/compartment of the total body water
do changes in one compartment in the body change water presence in the other parts of the body
can change other compartments of the body
what is end stage renal disease
a reduced ability to elimiate nitrogenous wastes (urea) and excess nitrogen is converted to ammonium
- extra ammonium has direct effects on health
= alkalized blood
what are the signs and symptoms of End stage renal disease
Ammonia breath
Gingival enlargement
xerostomia
tooth problems (premature loss, narrowing pulp chamberes, necrosis beneath filling/crowns
what are the contraindication for ESRD patients
Nephrotoxic drugs (tetracycline, acyclovir, aspirin, NSAIDS) Increased susceptibility due to descruction of platelets
where is the kidney located
retroperitoneal oran
what is the functional unit of the kidney
Nephron
what part of the nephron does filtration
renal cortex
what part of the kidney does concentration and collection of urine
Renal medulla
how many nephrons are in the kidney
1.2x10^6
what is a nephron made of
renal corpuscle (glomerulus+ capsule) proximal (convoluted) tubule Loop of Henle Distal (Convoluted) Tubule Collecting duct ( shared by multiple nephrons
how thick is the tubulues of the kindey
one cell layer
what are the two types of nephrons based on the location of the renal corpuscle and length of the medullary tubules
Superficial or cortical nephrons
Juxtamedullary nephrons
what is filtration
Solute and water pass from blood into the tubular fluid in the renal capsule (Bowman’s space)
where does filtration occur
Glomerular capillaries
what percent of the plasma is filtered
15-20%
what happens to the blood after it leaves the glomerular capillaries
Flows into peritubular capillaries (vasa recta)
what is secretion
Substances are transported from the blood in the peritubular capillaries into tubular fluid
what is reabsoprtion
substance are transported from the tubular fluid into the blood in the peritubular capillaries
what are the 3 renal processes to regulate blood composition
Filtration
Secretion
Reabsorption
what does the composition of tubular fluid vary with
The location of the tube
what can happen to filtered subsances
secreted and no reasborbed
some secreted and some reasborbed
completed reabsorbed
what is a renal corpuscle made of
glomerulus and renal capsule
where does filtration occur
glomerulus (dense capillary bed)
what is the roll of the renal capsule
Collect the filtrate from the blood entering vai the afferent arterioles
what regulates flood flow throught the glomerulus
Smooth msucel contraction in afferent or efferent arterioles
response of the JUxtaglomerular apparatus
SNS
where is the juxtaglomerular apparatus
intersection of the macula densa and dital tubule with afferent and eferent arterioles
what is the importance of the juxtaglomerular apparatus
secretes renin
what does renin do
regulates systemic blood pressure and glomerular blood flow
what drains the renal capsule
proximal tubule
what does the proximal tubule do
reabsorb 2/3 of filtered salt and water
reabsorbed all filtered flucosa and amino acids
where do diurectics act
some act in the proximal convoluted tubule
very powerful diuretics work in the loop of henle
some in distal convoluted tubule
some in collecting duct
what are the 3 limbs of the loop of henle
Thin descending limb
thin ascending limb
thick ascending limb
where does countercurrent multiplication done
in the loop of henle
what is the importance of the loop of henle
needed to produce concentrated urine but loop itself actually produces dilute filtrate
what drains the loop of henle
distal convoluted tubule
what happens inthe distal convoluted tubules
Contrinued reabsorption of solute
regulate ca
what is the action of the colecting duct
collect fluid from multiple nephrons
where does the colecting duct extend
from cortex through the medulla
what does the collecting duct do
regulates Na, K, and H2O
what is renal clearance
rate of excretion of a solute through the kidney as a unit of time
- the volume of plasma from which all of a particular substance is removed to the urine
what is the imporance of renal clearance
monitor renal function(glomerular filtration rate)
what is glomerular filtration rate
amount of blood filtered by the kidney in unit time
when can Glomerular filtration rate be used
the substance must be free filtered by glomerulus
substance is not sereted
substance is not reabsored
what is Glomerular iltration rate in a normal kidney
125ml/min for females
90-140ml/min in males
what substances are used to meaure renal cleance
Inulin
Creatinine
what is inulin
A small polysaccharide freely filtered and not secreted orabsorbed
what is creatinine
Product of muscle metabolism, freely filtered, not reabsorbed, almost no secretion
what is the normal and unnormal creatinine level
less han 1+- .5mg/dl normal
greater than 10= dialysis
what allows shit to leave th Glomerular capilaries
Fenestration
what is the space between the podocytes of the capillariation
filtration slits
what is not in the filtrate
Acellular
protein free
anything greater than 42 angustrum
what is freely filtered
less than 20 angstrum
glucose
Salts
Amino acids
how does charge affect glomerular filtration
Basal lamina is negative so hard to filter moderately sized, negative solute
what causes filtration
pressure differences between blood in the capillaries and fluid in the capsule (starling forces)
what are the 2 sources of pressure in the filtration
Hydrostatic pressure
Oncotic pressure
what is hydrostatic pressure
pressure due to fluid
what is oncotic pressure
pressure due to solutes(including those not dissolved
is hydrostatic pressure greater in the capilaries or capsule
greater in the capillaries( increases filtration)
is oncotic pressure greater in the capillaries greater or capsule fluid
greater in the capillaries (decreases filtration)
what does net filtration pressure favor
filtration from blood into capule fluid
what changes glomerular filtration rate
Blood flow into and out of glomerulues
Pressure gradient between capillary blood and tubular fluid
does renal blood flow change with systemic blood pressure
No, remains fairly constant
what are the methods of autoregulation of blood through the glomerulus
Myogenic mechanism
Tubuloglomerular feedbackk
what is the myogenic mechanism for autoregulation of the bloodflow through the glomerulus
Vascular smooth muscle contracts when stretched and relaxes when not stretched
- has inverse effects on afferent and efferent arterioles
what is the tubuloglomerular feeback mechanism for autoregulation
feedback from the justaglomarular apparatus adjusts afferent arteriole diameter and Glomerular filtration rate
what is the tubuloglomerular feedback mechanism in response to increase Glomerular filtration rate
- increase in GFR
- increase NaCl in tubular fluid
- increase NaCl at macular densa
- increased resistance in afferent arterioles
- decreased GFR
what are the extrinsic factors that regulate on renal blood flow and glomerular filtration rate
Diet Dehydration Hemorrhage sympathetic nervous system Angiotensin II aldosterone Natriuretic peptide
