Renal Physiology 2 Flashcards
Progression of renal disease results in destruction of
Nephron Destruction and Function
What is Total GFR the sum of?
All filtration by functioning Nephrons so progression of disease would be indicated by reduction in GFR.
What is important plasma or urine
Plasma
What does clearance relate to in measurement of GFR
Volume of plasma cleared
what is the loading IV dose of inulin
polyfructose
Inulin gives how much clearance
100%
Where is inulin freely filtered
at Glomerulus
Why is inulin measurement a measurement of GFR
It is not metabolised by kidney and does not interfere with normal renal function
It is also not reabsorbed or secreted
Substances which are filtered and reabsorbed will have a what clearance compared to inulin
Lower Clearance than Inulin
Substances filtered and secreted will have a what clearance compared to inulin
higher clearance
What is GFR in normal man
125
GFR declines by how much per year after 30
1ml/min/year
What is used in clinical practice instead of inulin
51Cr-EDTA
What is routinely used to estimate GFR
Plasma Creatinine Clearance
Creatine is breakdown produce of what
Creatinine Muscle
Creatine is said to be endogenous or exogenous
endogenous
What factors can affect serum creatinine
Muscle Mass
Diet
Drugs
What is normal GFR
100mls/1.73min
What is glucose’s clearance rate
zero as all glucose reabsorbed
what is urea’s clearance rate
50ml with 50% reabsorbed and 50% excreted
What is used to measure real plasma flow
Organion anion para amino hippuric acid
Para Amino Hippuric Acid is freely filtered where
glomerulus and then remaining in plasma secreted into tubule so 90% of plasma is cleared of PAH content
what is the percentage of clearance of PAH from plasma
90%`
Penicillin clearance
More penicillin excreted than filtered. Clearance rate 150 with 0 reabsorbed
When filtration is greater than excretion this means
Net reabsorption
When excretion is greater than filtration this means
net secretion
when filtration and excretion are the same this means
No net reabsorption or secretion
How does urine flow form kidneys to ureters
via peristaltic contraction of smooth muscle of ureters
what type of muscle is bladder
dertrusor muscle
which muscle is mainly responsible for emptying bladder during micturition
detrusor muscle
The external urethral sphincter is
true sphincter made up of skeletal muscle under voluntary somatic control
the external urethral sphincter is under what control
voluntary somatic
the external urethral sphincter is made up of what type of muscle
skeletal
which urethral sphincter has smooth muscle and acts as a sphincter when smooth muscle relaxes
internal urethral sphincter
what type of epithelium does bladder have
Lined Transitional
Trigone of bladder has how many openings
2 Vesicoureteric
Urethral obstructions go on to be
bilateral renal problems
ureter obstruction goes on to be
unilateral renal problem
when the bladder is at rest what does the external sphincter with skeletal muscle do
stays contracted and internal sphincter is passively contracting
Micturition is controlled by
Parasympathetic Supply
Pressure within the bladder for micturition comes from which nerves
S2-4
Sympathetic supply for micturition is from
Hypogastric Nerves which inhibit contraction and close internal urethral sphincter
Internal Urethral sphincter closure is controlled by which nerves
Sympathetic hypogastric
Main function of hypogastric nerves and sympathetic and L1-3 in micturition
is prevent reflux of semen into bladder during ejaculation
Somatic Motoneurons (Pudental nerves) S2-4 innervate
Sketal Muscle that forms external Urethral sphincter
Sensory innervation of bladder is achieved by
stretch receptor afferents from bladder wall
As bladder fills what happens to discharge in afferent nerves to spinal cord
Increases via interneurons
What happens to parasympathetic in sensory innervation of bladder
Excitation
what happens to sympathetic in sensory innervation of bladder
Inhibition Inc Inhibition of Somatic Motorneurons to ext Sphincter
which neurons stop firing in micturition
motor
which sphincter relaxes in micturition
external sphincter
which type of muscle contracts in migration
smooth
what type of neurons fire in micturition
parasympathetic neurons
Bladder contraction is caused by
stimulation of parasympathetic and relax external sphincter
which neurons need to be inhibited to relax external sphincter
Somatic Motoneurons
Volume of urine in bladder required to initiate spinal reflex is
300-350
Delay in micturition is accomplished by
descending pathways
delay micturition requires
- descending pathway
- inhibit parasympathetic
- stimulate somatic nerves to ext sphincter
voluntary initiation in micturition involves descending pathways which
stimulate parasympathetic
- inhibit somatic motor neurons
What does the male urethra need to expel pee
Contractions of bulbocavernous muscle
Contractions of bulbocavernous muscle cause expelling of pee in which gender
male
One of the most important aspects of the ECF regulated by the kidney is its
volume
Can water freely cross all cell membranes
Yes
What are the major ECF osmoles
Na+ and CI
what are the major ICF osmoles
K+ salts
Regulation of ECF volume =
Regulation of Body Na+
The active transport mechanism that operates on the luminal surface of the thick ascending loop of Henle, involves
K+
Naci
Na+ and K+ 2CI Co Transporter
The active transport mechanism that operates on the luminal surface of the thick ascending loop of Henle, is what type of process
passive process
The active transport mechanism that operates on the luminal surface of the thick ascending loop of Henle, the energy involved comes from
active transport
Where is Na/KATPase found
basolateral membrane
Loop diuretics can cause
K+ Ion Wasting
Any solute which remains in the tubule can cause
Osmotic Diuresis
When a large volume of isotonic urine is excreted what happens to pv
Decreased
Decreased PV will stimulate what
ADH release via baroreceptors
Why does a hypoglycaemic coma happen
Inadequate glucose for the brain available
why does a hyperglycaemic coma happen
inadequate BF to brain
Reabsorption of NaCi to H20 in Renal Tubule. How much is reabsorbed from proximal tubule
65-75%
How much NaCi to H20 is reabsorbed from loop of henle
15-20%
How much NaCi to H20 is reabsorbed from distal tubule to collecting duct
5-20%
What happens in Osmotic Diuresis of Uncontrolled Diabetes
Decreased Proximal Tubule Reabsorption, Loop of Henle Reabsorption, Distal Tubule Reabsorption
In Diabetes Mellitus how much isotonic urine excreted a day
6-8L
What inhibits renin release?
delivery of large volume of NacI to H20 at distal tubule inhibits renin release
what are reabsorbed at distal tubule
NaCi and H20
Fluid delivered to ascending limb is what in concentration
less
The NaCI Pumps in ascending limb are
gradient limited
Regulation of distal tubule Na+ reabsorption is under the control of the adrenal cortical steroid hormone,
aldosterone
Aldosterone secretion controlled by reflexes involving
kidney
Where is renin produced
JG Cells
Renin acts on which large protein a2 globulin fraction of plasma proteins
Angiotensinogen
Angiotensin II stimulates what
Aldosterone
Aldosterone stimulates what in kidney
distal tubular Na+ ion reabsorption
What controls renin release
Increased Renin release when P in afferent arteriole at level of JG Cells Decrease
Increased Sympathetic Nerve Activity via B1 affect
Decreased NaCI Delivery = Increased Renin
What does ADH do to renin
inhibit renin relea
Aldosterone promotes what reabsorption
Na+
ANP Promotes
Na+ excretion
Aldosterone does what two things at distal tubule
increase Na+ reabsroption and K+ secretion