Unit 4ab Flashcards
within the urine what four factors tell us about our health
Colour
Clear/cloudy
Odour
Flavour
What are the 6 keys roles of the kidney
(3R 2E 1I)
Regulating ECF Volume & BP
Regulating plasma osmolaritiy
Regulating plasma pH
Excreting (Removing Waste) waste
Ionic balance
Endocrine functions
What are the ions that a balanced in the kidney
Na, K , CA
What is the 3 function of endocrine within the kidney
Erythropoietin (hormone)- filters blood
Renin (hormone)- regulates Na balance
enzyme production for CA2+ Homeostasis
What is the body mass of the kidney ?
0.5 %
What is the kidneys cardiac output ?
20-25%
What is the cortex
The outer part of the kidney within the capsule
What is the medulla
The inner part of the kidney
What is the cortical nephron
a nephron within the cortex; it filters blood to towards the renal pelvis
What is juxtamedullary nephron ?
Between cortex & medulla more embeneded in medulla ; filters out blood to renal pelvis
What is capsules (biol 240 c:) ?
A tough fibrous layer which surrounds the kidney
what is the renal pelvis
where filtered blood travels to go to the ureter
what is the ureter
where filtered blood exits
what arteriole carries blood out
efferent
what arteriole carries blood in?
afferent
what does the renal corpuscle consist of ?
bowman + glomerulus
what is the glomerulus ?
a vascular capillary bed knot
what is the flow/circulation of the tubular nephron ?
- Bowmans capsules
2.Proximal nephron - Descending Loop of henle
- Ascending loop of henle
- distal nephron
- Collecting duct
what is the 5 step flow/circulation of the vasculature of the nephron and what is the difference between the juxta and cortico nephron
- Afferent Arteriole
2.Glomerular Capillaries - Efferent Arteriole
- Peritubular Capillaries
5.veins
the juxta goes through the vasa recta
what is diabetes mellitus?
a sweet diabetes
what is diabetes insipidus ?
a tasteless diabetes
what parts of the cortical nephron are separated between the medulla and cortex
the bowman capsule, proximal tude and distal tube are in the cortex whilst the loops of henle and collecting ducts are within the medulla
how much plasma does the kidney process a day?
180L/day
what is the urine output and what does this mean
its is 1.5L/ per day, that means 99% of the fluid that passed the kidney is reabsorbed
what is filtration and where does it exactly occur ?
it is the movement of water & solutes form blood into the tubules and it occurs at the renal corpusule
what is reabsorption where does it happen
the movement of water and solutes back into the blood
it occurs in all the tubules e
what is secretion and where does it happen
it is removing molecule from blood into the tubules adding to the filtrate it is more selective than filtration
it happens at the proximal tube and distal nephron
what is the calculation for amount excreted?
(Amount filtered) - (Amount of reabsorbed) + (Amount secreted) = amount excreted
what the starting osmolarity the proximal tube
300 MOSM
what is the percentage filtered in the proximal tube what is it called & the osmolarity
70% is filtered in the proximal tube and there is 300 mOsM and it called iso-osmotic reabsorption
what is the percentage filtered at the end of the loop of henle and the osmolarity
90% is filtered within the loop of henle
and the osmolarity is 100 mOsM and the fluid is hypoosmotic
what is the osmolarity leaving the collecting duct ?
its is between 50-1200 mOsM
what is the percentage of plasma that move out of the capillaries ?
20% plasma moves out
what is the filtration fraction?
the percentage of total plasma volume the filtries into tube
what are the 3 barriers of filtration ?
- glomerular capillary endothelium
- basement membrane
- specialized epithelium around glomerulus
what type of barrier is the endothelium of the glomerular corpuscles and what does/ doesnt allow ?
its is the fenestrated; allow most substance to pass except for protein greater than 50 KDA get filtered in to blood
what type of barrier is the basement membrane and what does/ doesnt pass?
it is a layer of ECM and doesnt allow most proteins (negatively charged) like collegen in, it keeps in in the blood
what type of barrier is the specialized epithelium
it is made up of podocyte foot proccesses that leave a filtration slit
what is nephrin & podocin and where is it expressed
nephrin and podocin both form the filtration slit in podocyte foot processes and they are both expressed in the kidney
what are the 3 starling forces in systematic capillaries
Ph- hydrostatic blood pressure
pi- osmotic pressure due protein in blood
pfluid- fluid pressure (bowmans pressure)
what happens to the systemic capillaries starling forces when blood pressure increases
auto regulating occure and the starling forces shift to balance it
what net force drives glomerular filtration and what is the net filtration rate ?
hydrostatic blood presure as it cancels out the other forces and has a net filtration rate of 10 mm Hg
what are the starling forces number that create the net filtration of 10 mm Hg
Hydrostatic pressure is at 55 mm Hg
Pi is at 30 mm Hg
Pfluid is at 15 mm Hg
why is the filtration pressure lower in the kidney compared to other system
it is due to the gappy fenestrated capillaries with high flow rate
what are the 4 factors the influence GFR?
- Net fliltration rate
- filtratiion coefficent ( size of gllomeruler and permeabilty
- gas exchange in alveoli
- not big deal but blood presure
why is GFR not really affected by blood pressure
GFR remains constance over a wide range of bp unless it a sharp increase of decrease of BP
what are 3 ways GFR is regulated ?
- Myogenic response
- Tubulo glomerular feedback
3, endocrine & autonomic control
what is the myogenic response for GFR?
when theres an increase in Bp the afferent arteriole vasoconstricts which leads a decrease in BP , GFR and renal blood flow and vasodilation for decrease
what happens when you constrict the efferent arteriole ?
bp & GFR go up but renal blood flow goes down
what is the macula densa and where is it located?
modified tubular epithelium that is between ascending limb and arterioles
what is the 5 step tubulo glomerular feedback pathway that regulates GCF ?
- increase GFR & increased flow rate
- increased flow of Na+
- released paracrine factor from macula densa.
- constriction of afferent arteriole
- decreare BP, ph , GFR
what is the autonomic effect of GFR regulation
a sympathetic vasocontriction of afferent efferent artereioles only at extreme condition etc shap drop in bp
what is the endocrine effects of GFR regulation
hormone angiotensin II that vaso contrincts
does the kidney have parasympathetic or sympathetic or both ?
the kindey only have sympathetic innervation
what control is the distal nephron under?
it under endocrine control
what is the key technique to reabsorption?
creating a gradient via active transportation that pumps out Na+
what are the active transport method moves Na+ out of the proximal tubular into interstial fluid and other involved ?
- ENaC ( Epithelial NA+ Channel) that is expressed on the apical membrane which is on the tubular side & Na+/ K+ ATPase that pumps into the intestial fluid and K+ leaks back in intesital side by leaky channel
- SGLT= which is a Na+ glucose (SECONDARY )transporter on apical (bring both im) & Na+ /K+ Atp pump that bring it into intestial and GLUT facillative diffusion on basal bring glucose in
As Na+ is being pumped out what is also being loss and what is the consequence ?
water and anions follow Na+ out which leaves a concentration of K+ and Ca+ in tubular fluid
how does urea get reabsorbed and how much can be reabsorbed
urea get reabsorbed by moving down it concentration gradient and readily cross the membrane and up to 40% urea can be reabsorbed in prox tube
From the interstial fluid how does the molecule get into the plasma
as the capillaries how low hydrostatic pressure the osmotic pressure is higher and favours reabsorption in the blood
whats is renal handling of small proteins ?
as protein < 50 kda continue into the tubule they still get reabsorbed via microville that convert it into amino acids and it goes to the blood
what is renal threshold ?
it the plasma concentration where saturation occurs at (Tm) transportation maximum
what happens at renal threshold ?
at renal threshold we are excreting glucose which we shouldn’t be doing
what molecules are usually secreted?
organic compounds
what are the 2 secretion organic transporters?
- NaDC - a (SECONDARY) Na+ dicarboxylate co transporter that is on both the apical and basal membranes bring in both Na+ and two carboxyls
- OAT - organic anion transporter are a apical and basal lateral tertiary transport that is driven by dicarboxyls that bring in and out anions
ex endo - salts , nucleotide
exo- penicillin saccharine
what is probenecid ?
is it a drug that competes for an OAT transporters and slow the other cargo to leave out the blood is used as an anti doping (masking agent) , prevents nephrotoxicity and anti biotc agents
what molecule clearance can be used as an indicator of the rate of GFR
- Inulin as it is not reabsorbed or secreted it is all excreted
- creatinine as it it not reabosored only secreted and exctreted
when would glucose be excreted ?
when glucose blood levels are high and not everything is able to be reabsorbed
if a molecule clearance is lower than the GFR what does it mean ?
there is more reabsorption
if a molecule clearance is higher than GFR what does it mean /
there is more secretion
what is the normal GFR. rate ?
100-125ml/min
what is micronutration aka urination and whate are the steps
it is a spinal reflex from the CNS.
1. bladder fills
2. activation of strech receptors
3. afferent info travels
4. parasympathic act on smooth muscle
5. somatic act on motor neurons that goes to the sphincter
