Exam 4: Renal & Endocrine Flashcards
What do the kidneys do to blood?
Filters it
What is the primary nitrogenous waste?
Urea
Where does the N in urea come from?
The breakdown of proteins (Amino acids, DNA, RNA)
What is the term used for the measure of nitrogenous waste in blood?
Blood Urine Nitrogen (BUN)
What is a normal BUN?
7-18 md/dL
What does BUN help measure? (What organ’s functioning does it test?)
Kidney function
Where does creatinine come from?
The breakdown of creatine phosphate
What is creatine phosphate used for?
Transferring a phosphate to ADP to make ATP
What is a normal creatinine level in humans?
0.7-1.2 mg/dL
What enzyme carries out the reaction where creatine phosphate + ADP –> creatinine + ATP?
Creatine kinase
What % of blood is protein?
7%
What % of urine is protein?
0.03%
Should there be a lot or a little protein in urine?
There should be VERY LITTLE protein in urine
How many liters of fluid do the kidneys filter daily?
180L
What % of fluid that the kidneys filter gets reabsorbed?
99.3%
What hormone does the kidneys produce that regulates the production of blood cells?
Erythropoietin
What hormone does the kidneys produce that increases intestinal absorption of Ca++ and PO4-3?
Vitamin D3
What does the body do with the increased Ca++ and PO4-3 absorption brought by vitamin D3?
Build bones
What hormone is produced in the juxtaglomerular apparatus?
Renin
Renin is produced when BP and sodium levels are high or low?
Low
Renin is produced when potassium levels are high or low?
High
What does renin split? What does it turn into?
Renin splits angiotensinogen into angiotensin 1
What splits angiotensin 1 into angiotensin 2?
Angiotensin-converting enzyme (ACE)
What does angiotensin 2 do to blood vessels?
Vasoconstricts, thus raising BP
What hormones does angiotensin 2 trigger the release of?
Aldosterone and vasopressin/antidiuretic hormone (ADH)
What do aldosterone and vasopressin/ADH do? (Retention or release)
Causes the kidneys to retain sodium and water
Does the retention of sodium and water raise or lower BP and blood volume?
Increases blood volume and blood pressure
What is the process of eliminating nitrogenous wastes?
Excretion
What do the kidneys do to the pH of blood?
Buffers the blood (maintains a stable level)
What do the kidneys do for blood volume and fluid osmolarity?
Balance fluid levels and electrolytes
What are the kidneys involved in detoxifying?
Reactive Oxygen Species (ROS) and free radicals
Where are the bladder and kidneys located anatomically?
Retroperitoneal (outside/below the peritoneum)
What are the basic filtering units of the kidneys?
Nephron
How many nephrons per kidney?
1 million
What level of nephron filtration is like “windows” or “holes” in the glomerular capillaries?
Fenestrae
What level of filtration in the nephron repels proteins that are smaller than the opening of fenestrae and podocytes?
Basement membrane
What type of charge does the basement membrane in nephrons have?
Negative charge
What level of filtration in the nephron are cells with filtration slits that cover the glomerular capillaries?
Podocytes
What are the two types of nephrons?
Cortical
Juxtamedullary
Where are cortical nephrons?
Superficial in the cortex
Where are juxtamedullary nephrons?
Deep in the cortex
Which nephron’s loop of Henle goes deeper into the medulla?
Juxtamedullary goes deep into the medulla
Cortical does NOT
Which arteriole brings unfiltered (dirty) blood to the corpuscle?
Afferent arteriole
Which arteriole brings filtered (clean) blood back to the circulatory system?
Efferent arteriole
What is the outer shell of the renal corpuscle?
Bowman’s capsule
What tissue is the Bowman’s capsule made of?
Simple squamous epi
Where is filtrate collected in the renal corpuscle?
Bowman’s space
What fills capillaries in the renal corpuscle with fenestrae?
Glomerular capillaries (glomerulus)
What are the cells with filtration slits in the renal corpuscle that cover glomerular capillaries?
Podocytes
What in the nephron takes filtrate from the corpuscle to the loop of Henle?
Proximal convoluted tubule
Which limb of the loop of Henle is where WATER leaves?
Thick descending limb
What is the concentrating limb in the loop of Henle? Why?
The thick descending limb, as water is leaving
Which limb of the loop of Henle is where SALT leaves?
Thick ascending limb
What is the diluting limb in the loop of Henle? Why?
Thick ascending limb, as salt is leaving
What in the nephron sends the message to the juxtaglomerular apparatus to release renin?
Macula densa
Where is the macula densa located?
Distal convoluted tubule
What % of water reabsorption is in the proximal convoluted tubules?
65%
What % of water reabsorption is in the loop of Henle?
15%
What % of water reabsorption is in the distal convoluted tubules?
10%
What % of water reabsorption is in the collecting duct?
9.3%
What % of water is left to eliminate after the rest is reabsorbed?
0.7%
Where does water go from the collecting duct?
Papilla
Where does water go from the papilla?
Minor calyx
Where does water go from the minor calyx?
Major calyx
Where does water go from the major calyx?
Renal pelvis
Where does water go from the renal pelvis?
Ureter
Where does water go from the ureter?
Urinary bladder
Where does water go from the urinary bladder?
Urethra
What mOSM is isotonic in the cortex?
~300 mOsm (280-296 mOsm)
Where is the water reabsorbed so that it can find its way back to the blood?
Peritubular capillaries
What do Na+ and urea make the deep medulla compared to the cortex? (Hypo, hyper, isotonic)
Hypertonic
What is the medulla concentrated to in mOsm?
1200-1500 mOsm
What hormone makes the Na-K pump:
3 Na+ H2O goes back to blood
2 K+ excreted in urine
Aldosterone
Is this water retention or loss?
3 Na+ H2O goes back to blood
2 K+ excreted in urine
Water retention
What hormone makes the Na-K pump:
3 Na+ H2O excreted in urine
2 K+ back to blood
Atrial natriuretic peptide (ANP)
Is this water retention or loss?
3 Na+ H2O excreted in urine
2 K+ back to blood
Water loss
What hormone turns on genes that produce more water channel proteins?
Antidiuretic hormone (ADH)
What does producing more water channel proteins do? (Make you pee more or less?)
Make you pee LESS (ANTI-diuretic)
Does water passively or actively exit the urine to be returned to blood when more water channels are opened [thanks to ADH]? Why?
PASSIVE, because the medulla is so hypertonic
What does ADH do to urea?
Causes its reabsorption
Where do aldosterone, ANP, and ADH have their effects take place?
At the distal convoluted tubules and their collecting ducts
What is the last 0.7% of water that is filtered out regulated by?
Hormones
What hormone is associated with water retention?
Aldosterone
What hormone is associated with water loss?
Atrial natriuretic hormone (ANP)
What elemental levels can abnormal levels of aldosterone or ANP have clinical effects on?
K levels
What is an example effect from abnormal K levels caused by abnormal aldosterone/ANP?
Cardiac arrhythmias
Does ADH cause vasoconstriction or vasodilation?
Vasoconstriction
Where is ADH produced?
Hypothalamus
Where is ADH stored and released from?
Posterior pituitary gland (Neurohypophysis)
What is the primary hormone responsible for tonicity homeostasis and BP control?
ADH/vasopressin
What is the mOsm for hyperosmolarity?
> 280-296 mOsm
What states trigger ADH release to initiate water retention for dilution of conditions/bring it back to isotonicity?
Hyperosmolar states
What sort of diets/conditions would result in increased ADH secretion?
High salt diets and hypertension (high BP)
What does ADH do for arterial blood volume and pressure?
Increase effective arterial blood volume and increase blood pressure to maintain tissue perfusion
When BP drops or blood becomes hypertonic (hyperosmotic), what turns on protein synthesis to increase the # of water channels in the renal tubules to allow more water retention?
ADH
What hormone causes an increase in ADH release during times of a woman’s cycle? (This can be to the point of edema and BP rise)
Estrogen
What inhibits ADH when you drink?
Ethanol
What inhibits ADH in the sympathetic NS?
Epinephrine and norepinephrine
What kind of drug are epi and norepi?
Alpha-adrenergic agonists
What hormone released from the heart inhibits ADH?
Atrial natriuretic peptide (ANP)
What does GFR stand for?
Glomerular filtration rate
What does GFR measure?
Quantity of filtrate that passes through the glomerulus per unit time
What is a normal GFR? (in ml/min)
125 ml/min
What is a normal GFR? (in L/hour)
7.5 L/hour
What is a normal GFR? (in L/day)
180 L/day
What % of water is reabsorbed from the filtrate?
99.3%
What must the GFR be maintained at REGARDLESS of changes in overall BP?
125 ml/min
What would happen without the autoregulation mechanisms within the kidneys if there was a slight increase in renal BP?
A drastic increase in filtration
What would happen without the autoregulation mechanisms within the kidneys if there was a slight decrease in renal blood pressure (15%)?
Filtration would stop entirely
What is the glomerular (blood) hydrostatic pressure in mm Hg?
55 mmHg
What is the blood colloid osmotic pressure in mm Hg?
30 mmHg
What is the capsular hydrostatic pressure in mm Hg?
15 mmHg
What is the net filtration pressure in mm Hg?
10 mmHg
How do you calculate the net filtration pressure? (What values do you use)
Blood HP - (Blood CP + Bowman’s capsule HP)
55 - (30+15) = 10
Is hydrostatic pressure (HP) a pushing or pulling force?
Pushing
Is colloid pressure (CP) a pushing or pulling force?
Pulling
How much pressure pushes out the arteriole?
55 mmHg
How much pressure is pulled in the arteriole? (Total. Includes HP + CP)
45 mmHg
What goes with the 10mmHg pushing force out of the blood?
Urea, Na+, water
What forces increase GFR?
Plasma HP
Bowman capsule CP
What forces decrease GFR?
Plasma CP
Bowman capsule HP
What is another way of saying plasma/glomerular hydrostatic pressure?
BP in capillaries
What pressure is pushing out of blood?
Plasma/glomerular HP
What pressure is pulling back in the blood?
Plasma CP
What pressure is pushing back in towards the blood?
Bowman’s capsule HP
What pressure is pulling out of blood?
Bowman’s capsule CP
What is Bowman’s capsule CP in mmHg?
Near 0 mmHg
What is the filtering pressure of the kidneys? (in mmHg)
10 mmHg
Would this increase or decrease GFR?
Increase glomerular/plasma HP (AKA BP)
Increase
Would this increase or decrease GFR?
Decrease Bowman’s capsule HP
Increase
Would this increase or decrease GFR?
Increase plasma CP
Decrease
Would this increase or decrease GFR?
Decrease Bowman’s capsule CP
Decrease
How would liver failure affect GFR?
Decrease GFR
What mechanism within the loop of Henle creates a hypertonic medulla?
Counter current multiplier
What mechanism within the vasa recta helps maintain the hypertonic medulla?
Counter current exchanger
Does water go towards the hypertonic or hypotonic according to the rules of osmosis?
Water goes to the hypertonic (where there is more solute and less water)
What does the body change in order to maintain a steady filtration rate/GFR?
BP
What intrinsic controls (autoregulation) are used to regulate GFR?
Myogenic mechanism
Tubuloglomerular feedback mechanism
What does the myogenic mechanism do in response to an increase in BP?
An increase in BP stretches/dilates the afferent arteriole, so the muscles vasoconstrict to reduce filtration back to normal
What does the tubuloglomerular feedback mechanism do in response to an increase in BP?
The macula densa causes vasoconstriction of the afferent arteriole to reduce filtration
What does the tubuloglomerular feedback mechanism do in response to a decrease in BP?
The macula densa causes vasodilation of the afferent arteriole to increase filtration
How does the body use neural control to regulate GFR?
When your body has a fight or flight response, BP increases
What hormone/NT causes vasoconstriction of the afferent arteriole to regulate filtration?
Epinephrine
What system in the kidneys helps regulate the GFR if blood pressure drops?
Renin-angiotensin system
Where in the kidneys/what structure is where the renin-angiotensin system works?
Juxtaglomerular apparatus, specifically, the macula densa
What are the tubules in the kidney that monitors blood pressure through urine flow?
Macula densa
Does the macula densa monitor blood pressure directly or indirectly?
Indirectly, as it bases blood pressure off of the urine output
In what two situations might the macula densa activate means to control BP?
Increased flow or increased urine concentration signals the macula densa to get to work and do the opposite (decrease flow and decrease concentration)
What does the juxtaglomerular apparatus signal the release of?
Renin
Where is renin released from?
Granular cells in the afferent arteriole
Where does renin turn angiotensinogen into angiotensin 1?
The liver
What type of substance is renin?
An enzyme
Where does ACE turn angiotensin 1 into angiotensin 2?
The lungs
Does angiotensin 2 cause vasoconstriction or vasodilation? How does this affect BP?
Vasoconstriction, increases BP
What hormone is released by angiotensin 2?
Aldosterone
Where is aldosterone released from?
The adrenal cortex
What is the adrenal cortex?
The outer part of the kidney
What type of hormone is aldosterone?
A steroid
Where does aldosterone go after it is released from the adrenal cortex?
Into the kidney
What does aldosterone do in the kidney?
Turns on the Na-K pump
What goes on in the renal Na-K pump? Out/In from where specifically?
3 Na OUT of urine, into blood
2 K INto urine, out of blood
What follows Na to increase BP?
Water
What blocks ACE to lower BP?
ACE inhibitors
What is water loss that you’re generally unaware of?
Insensible water loss
What is water loss you are aware of?
Sensible water loss
Where does insensible water loss happen?
Exhaled from lungs
Perspiration from the skin (NOT sweating from exercise…casual sweat)
Excreted in feces
Where does sensible water loss happen?
Urine
Sweating from exercise
How much urine is excreted daily (in mL)?
1000-1500 mL/day
What is retained thanks to estrogen and what is released? (Think what might cause menstrual-related edema)
NaCl is retained
ADH is released
What drug causes Na resorption/retention resulting in water retention?
Prednisone
What sort of drug is prednisone?
A steroidal anti-inflammatory drug
What is it called when increased BP forces more fluid out of the glomerulus?
Pressure diuresis
What can cause water loss through pressure diuresis?
Hypertension (high BP) with loss of autoregulatory mechanisms
How might tissue damage result in edema?
Tissue damage releases “solute” particles into the interstitium
When solute particles are released into the interstitium due to tissue damage, does the interstitium become hypertonic, hypotonic, or stay isotonic?
It becomes hypertonic due to the increase of solute particles
What mechanism pertaining to the capillaries, along with tissue damage, results in edema?
Increased capillary permeability
As blood approaches the capillary, where does fluid go?
Fluid leaks out into the extracellular matrix (ECF)
As the remaining blood (that didn’t leak out) courses through the capillary, what does it become?
More concentrated, or hypertonic
What happens to fluid that is hypertonic in the capillary as it approaches the venous end?
It pulls fluid in from the ECF
What % of the ECF is drained by lymphatic vessels?
10%
What continuously happens to the interstitium, thanks to fluid being pushed in and out?
It is “washed” by fluid
What happens if the lymphatics are blocked by worms, tumors, etc.?
Massive swelling, such as in elephantiasis
If there is high HP, will fluid be pushed out, pulled in, pushed in, pulled out?
Pushed out
If there is low CP will fluid be pushed out, pulled in, pushed in, pulled out?
Pulled in
If there is low HP, will fluid be pushed out, pulled in, pushed in, pulled out?
Pushed in
If there is high CP, will fluid be pushed out, pulled in, pushed in, pulled out?
Pulled out
What is another name for the extracellular matrix?
Interstitium
What condition can be caused by hypotension due to post-surgical blood loss, sepsis, obstetric complications, burns, ROS?
Renal failure
What pathology is classified as “significant” loss of renal function?
Renal failure
At what mL/day urine output do you have anuria?
< 50 mL/day
What can low glomerular pressure or nephritis, transfusion reactions, and crush injuries cause?
Anuria
What pathology is classified as only 25% normal renal functioning?
Renal insufficiency
What does the GFR drop to in renal insufficiency?
25-30 mL/min
What pathology is when renal function drops to 10% of normal?
End stage renal failure (ESRF)
What causes azotemia?
Abnormal increase in BUN
Abnormal increase in creatinine
What is azotemia with neurological complications called?
Uremia
What is seen in uremia?
Edema, encephalopathy, nausea/vomiting, anorexia, ulcers, CHF
With uremia, what is retained?
Na…So also water!
Increased Na and water seen in uremia results in?
Increased renin, hypertension (fluid overload)
What pathology is where renal failure is so severe that there is glomerular damage, protein loss, edema?
Nephrotic syndrome
How much protein is lost in nephrotic syndrome? In g/day
3.5-10 g/day
Why is edema seen in nephrotic syndrome?
Due to the loss of plasma proteins
How much protein is lost in nephrotic syndrome? In %
Up to 20% loss
What is it called when the skin is pressed and a depression forms for some time after it is no longer depressed?
Pitting edema
Where is pitting edema seen?
Nephrotic syndrome
What system is activated in nephrotic syndrome?
Renin-angiotensin system
What is released in the nephrotic syndrome?
Increased ADH release
What is the urine output in diabetes mellitus?
Up to 12x normal
