Renal Keypoints Flashcards
1
Q
How does hypertension cause nephropathy?
A
Hyperfiltration causes slow deterioration of nephron functioning.
2
Q
A pt involved in a MVA is brought to the ED with an abdominal wound with acute blood loss and hypotension. Which of the following mechanisms best describes control of renal blood flow?
A
Sympathetic vasoconstrictor activity increases occurs as a result of hypovolemia and hypotension, overiding renal autoregulation.
3
Q
What is the most prominent electrolyte abnormality that results from a tumor that autonomously secretes vasopression/antidiuretic hormone?
A
Hyponatremia with normal blood volume is common in SIADH as lack of renal water excretion dilutes the ECF sodium.
4
Q
Which kidney-regulating substance increases to compensate for states of hypervolemia and hypertension?
A
B-type natriuretic peptide
5
Q
Which of the renal capillary Starling Forces exhibits the largest change when blood flows from glomerular capillaries to peritubular capillaries and capillary filtration changes to capillary reabsorption?
A
Capillary hydrostatic pressure.
6
Q
What is the outer layer in kidney structure?
A
Cortex
7
Q
What is the inner layer of the kidney structure?
A
MedullaW
8
Q
What does renal pelvis collects?
A
Urine that exits via the ureter
9
Q
What are the two types of nephrons?
A
Cortical Nephrons 90%
Juxtamedullary Nephrons 10%
10
Q
What are parts of the nephron structures?
A
Glomerulus
Proximal tubule
Descending loop of henle
thick ascending limb of loop of henle
Juxtaglomerular apparatus
Distal tubule
Connecting tubule
Collecting duct
11
Q
What is Glomerulus?
A
Filtration
12
Q
What is Proximal tubule?
A
Bulk reabsorption, some secretion
13
Q
What is descending loop of Henle?
A
Water reabsorption
14
Q
What is Thick Ascending limb of loop of Henle?
A
Sodium/potassium/chloride reabsorption
15
Q
What is Juxtaglomerular apparatus?
A
Nephron regulation
16
Q
What is distal tubule?
A
Electrolyte reabsorption
17
Q
What is connecting tubule?
A
Secretion of potassium and acid
18
Q
What is collecting duct?
A
Sodium and water reabsorption
19
Q
Each nephron has its own vascular supply, what does the blood supply consist of?
A
- Afferent arteriole
- Glomerular capillary
- Efferent arteriole
- Peritubular capillary (vasa recta for juxtamedullary nephorns)
- Venule
20
Q
What is the primary role of the kidney?
A
Has several functions contribute to homeostasis but primary role is to maintain fluid and electrolyte balance over a wide range of body states and varying intake of water, electrolytes, and nutrients.
21
Q
How does kidney play in endocrine roles?
A
Production of erythropoietin, which stimulates red blood cell production
- Activation of Vit D
- Production of renin
22
Q
How much water does the body has?
A
50% to 60% depending on sex, age, and body composition, and kidneys regulate the amount of water as well as its composition.
23
Q
What is the functional unit of kidneys?
A
Nephrons and each kidney contains 1 million nephrons.
Considered functional reserve, this is why someone with a healthy kidney function can donate a kidney and still maintain normal kidney function
24
Q
What is a Starling Forces?
A
Forces influencing capillary filtration and reabsorption in tissues and organs other than the kidneys
25
What is a Capillary hydrostatic pressure?
PUSH favors filtration, movement from capillary to tissue, average 27 mm Hg
26
What is Capillary Oncotic pressure?
PULL favors reabsorption, movement from tissue into capillary average 25 mm Hg
27
What is true about tissue hydrostatic and oncotic pressures around capillary?
Pressures are low and stable
28
What is a Net Filtration pressure?
Favors filtration at arteriole end (+12 mm Hg), reabsorption at venule end (-8mm Hg)
29
Capillary filtration continually bathes tissues --- excess is absorbed by lymph vessels. True or False
True
30
What is glomerular capillary hydrostatic pressure?
It average 55 mm Hg, strongly favoring filtration.
31
What happens to capillary oncotic pressure during glomerular capillary hydrostatic pressure filtration?
Increases due to high rate of filtration concentrating plasma proteins average 30 mm Hg
32
What happen to Bowman's capsule hydrostatic pressure during glomerular capillary hydrostatic filtration?
pressure of 15 mm Hg opposes filtration but provides pressure to move filtrate down the narrow tubules of the nephron
33
What happen to the net filtration pressure during glomerular capillary filtration?
Pressure of 10 mm Hg favors filtration along the length of the glomerular capillary
33
What is true about peritubular capillaries in starling forces in renal capillaries?
Located after efferent arteriole, the additional resistance causes a large pressure drop such as peritubular capillary hydrostatic pressure is below that in systemic capillaries, favoring reabsorption along the length
33
What is true about glomerular capillaries if starling forces in renal capillaries?
Glomerular capillaries are located between afferent and efferent arterioles, thus they maintain much higher hydrostatic pressure than other systemic capillaries, strongly favoring filtration
34
What is peritubular capillary oncotic pressure?
Higher than that in systemic capillaries due to extensive filtration at the glomerulus that concentrate plasma protein. Contributes to high rate of reabsorption
35
What are the fates of solutes arriving in the glomerular capillary?
1. some are filtered and enter the tubule
2. Of those filtered, many are reabsorbed by tubular mechanisms
3. some are secreted by tubular mechanisms
4. Filtered solutes that are not reabsorbed are excreted in urine, along with solutes that are secreted
36
What is fact about high renal blood flow and glomerular filtration?
Kidney receives greater blood flow 20% C/O than its size and et 0.5% of body wt would dictate.
- High renal blood flow (RBF) enables a high rate of glomerular filtration (GFR).
37
What are the two principals that a high rate of glomerular filtration is enabled?
- Net filtration pressure in glomerular capillaries is much higher than in other capillary beds, primarily due to a high glomerular capillary hydrostatic pressure
- Glomerular capillary permeability is much higher than in other capillary beds ,with a three-layer structure that promotes high rate of fluid movement while restricting filtration of proteins
38
What is the process of filtered fluid?
Water and small molecules and electrolytes of the plasma, generally w/o plasma proteins enter nephron, processed by the cells of nephron tubules, where than 99% of the filtrates is reabsorbed and volume is reduced to less than 1% of original filtered, which is excreted as urine.
39
What is the reabsorption of most filtered substances?
Carrier-mediated process of movement from lumen of tubule to interstitial space.
Abundant transporters, ion channels, and water channels in apical and basolateral membranes of tubule cells conduct this movement across tubular membrane. From interstitial space, the reabsorbed substances then move passively into the peritubular capillaries
40
A pt with PUD is prescribed a medication that inhibits histamine receptors on parietal cells. Which of the following effects is expected?
Decreased HCL secretion
41
A adolescent presents with symptoms of liver disease and is diagnose d with nonalcoholic fatty disease (NAFLD). What is a likely contributing factor?
Obesity
42
How does metabolic waste products, toxins, neurotransmitters, hormones, and drugs enriched in the urine?
Metabolic waste products, toxins, neurotransmitters, hormones, and drugs are enriched in the urine by the process of tubular secretion.
43
How does the process of tubular secretion works?
Transporters carry the wastes substances from the interstitial space around the peritubular capillaries into the lumen to clear them from the blood by urinary excretion.
43
What is proximal tubule?
Major site of secretion of wastes, drugs, and drug metabolites
43
How much does the proximal tubule reabsorbs?
The bulk of renal processing in the proximal tubule reabsorbs about 70% of filtered water, sodium, and chloride, 100% glucose and amino acids, and 85% of bicarbonate.
43
What is the major site of secretion of wastes, drugs, and drug metabolites?
Proximal Tubule
44
What are the remainder of the nephron; loop of henle, distal tubule, and collecting duct primarily focuses on?
Retention of sodium, chloride, and water; fine-tuning of potassium, acid, calcium, and phosphate levels by reabsorption or secretion; and final processing to produce a concentrated urine, excreting wastes without excessive loss of water.
45
What is the kidney responsible for?
Responsible for whole body fluid and electrolyte balance and are the targets of hormones and factors that regulate the levels of retention and excretion of water, sodium, potassium, calcium, and phosphate.
46
What moderate the processes of the remainder of the nephron; loop of henle, distal tubule, and collecting duct?
Moderated by hormones to maintain systemic fluid and electrolyte homeostasis.
47
What is the renin-angiotensin-aldosterone system (RAAS)?
Activated when blood volume drops and when BP drops. Purpose is to increase blood volume and BP.
48
What are the reasons for renin(enzyme) to be release?
Drop in BP in Afferent arteriole
Drop in sodium concentration in Distal convoluted tubule
Increased Sympathetic system innovation
49
What does angiotensin 1 does?
Vasoconstriction ( combined of renin and angiotensionoge)
50
What does angiotensin II does? (meet w/ ACE in lung)
Generalized vasoconstriction (increased BP)
Constrict Afferent arteriole (increase GFR and sodium in distal convoluted tubule)
Stimulate the release of aldosterone in adrenal gland (aldosterone travel to distal convoluted tubule to throw sodium out to body to increase volume)
Stimulate release of ADH from post pituitary (increase H2O reabsorbs)
51
What are sensors for hypotension and hypovolemia?
Arterial and venous baroreceptors and volume receptors, intrarenal baroreceptors
52
What are the effector systems for hypotension and hypovolemia?
Sympathetic nervous system
RAAS
AVP
53
What does sympathetic nervous system do for hypotension hypovolemia?
Vasoconstriction of renal arterioles, stimulation of renin secretion
54
What does RAAS do for hypotension and hypovolemia?
Angiotensin promotes thirst and drinking, as well as vasoconstriction
Aldosterone secretion promotes late distal tubule sodium transport, restoring total body sodium
55
What does AVP do for hypotension and hypovolemia?
Released from posterior pituitary, increases collecting duct water permeability to restore blood volume
56
What is the renal compensation for hypertension and hypervolemia?
Inhibition of systems responding to hypotension (sympathetic nervous system, RAAS, and AVP).
- Stimulation of natriuretic hormones from heart promoting vasodilation and reducing sodium reabsorption
57
What are the facts about hyponatremia?
Na+ add tonicity to the ECF H20 so maintenance of both osmotic strength and circulating blood volume depend of total body sodium
Hyponatremia is often secondary to changes in water intake or secretionW
58
What are the clinical findings for hyponatremia?
Neurological alterations ) confusion, nausea, HA, vomiting)
Increased intracranial pressure are caused by movement of hypotonic fluid into brain's interstitial spaces, swelling the tissue within rigid skull
59
What is the most common mechanism of hyponatremia?
Dilutional where excess sodium is excreted, while H20 is retained.
When H20 is too high for kidneys to excrete, or when renal water excretion is below normal, existing solutes are diluted in excess H20 resulting in hypotonicity.
60
What is a hypotonic hyponatremia?
Very common imbalance. Can be euvolemic and caused by use of diuretics with or without overhydration indicated by low urine osmolality.
61
What can indicate syndrome of inappropriate ADH (SIADH)?
Hyponatremia with normal to high urine osmolality
62
What is isotonic hyponatremia?
Hyponatremia with normal tonicity. Caused by an excess of non-Na+ containing fluids
63
What is pseudohyponatremia?
Isotonic hyponatremia with occurs when volume of solid particles in plasma increases as in conditions such as hypertriglyceridemia or hyperproteinemia.
Artifactual finding rather than a pathophysiological state
64
What is hypernatremia?
Hypertonicity where Na+ ions is high compared to H20.
- Cellular dehydration
- exacerbated and sustained when thirst and access to water are lacking in elder, babies, and those with inability to access own H20
65
What are the clinical findings of hypernatremia?
CNS dysfunction (muscle weakness, insomnia, restlessness, lethargy, coma).
66
What is hypokalemia?
Metabolic alkalosis
- Aldosterone promotes Na retention and potassium excretion; hyperaldosteronism is associated w/ hypokalemia
67
What are the clinical findings for hypokalemia?
GI symptoms ( constipation, ileus)
Neuromuscular (extreme weakness, muscle cramps)
Cardio ( V-tach, V-fib, cardiac arrest, heart blocks)
68
What is hyperkalemia?
Acute shift of K+ ions out of cells (rhabdomyolysis)
- Impair kidney ability to excrete K+ ( AKI or CKD is common cause )
- SE drug ( inhibitors of RAAS AND beta-blockers)
69
What are clinical findings for hyperkalemia?
ECG changes, cardiac arrhythmias and cardiac arrest, and muscle weakness leading to paralysis
70
What is the body primary source of acid (H)?
Carbon dioxide (CO2)
71
Body primary source of base?
Bicarbonate ion HCO3
72
What are the sensors for acid-base balance?
chemoreceptors (aortic and carotid bodies regulating resp rate and depth)
renal cells regulating HCO3 absorption or H+ secretions
73
What is main function of 3 buffer systems in acid-base balance?
Minimize pH changes due to rapid changes of acid or base status due to ability to readily absorb or release H+
- Bicarbonate/carbonic acid
- Phosphate
- Proteins (hgb)
74
What is respiratory acidosis?
Most often seen in acute or chronic respiratory disorders that disrupt CO2 elimination
- Upregulation of renal H+ excretion and HCO2 production and retention
75
What is metabolic acidosis?
Excess H+ production or HCO3 loss
- Resp compensation is rapid, increase rate and depth that blow off CO2, raising pH
76
What are common causes of metabolic acidosis?
Lactic acidosis, DKA, salicylate overdose, kidney failure, chronic diarrhea
77
What help to assist with metabolic acidosis differential dx?
Anion gap calculation
78
What is resp alkalosis?
hyperventilation lower PCO2. generally transient
79
What is metabolic alkalosis?
Due to excess H+ loss of HCO2 retention
- Vomiting loss of gastric acid
- excess consumption of antacids
- other metabolic imbalances
80
What is the the mechanism of homeostatic adjustments to hypovolemia and hypotension, hypervolemia and hypertension, hyponatremia and hypernatremia, and hypokalemia and hyperkalemia?
Renal compensation
81
What does kidney secrete that remove source of acid?
Hydrogen ion
82
What is the major acid-base buffer?
Kidney synthesize and retain bicarbonate ion in plasma
83
What is CKD a common consequences of?
Diabetes mellitus (50% of all CKD cases)
Hypertension (25% of CKD)
or BOTH
84
What is AKI a common consequences of?
Common in critical care settings
- Consequences of hypovolemia and hypotension from causes such as sepsis, trauma, and acute heart failure.
85
What are the additional sources of AKI?
Nephrotoxicity from medications, hemolysis, rhabdomyolysis
86
What is the third source of AKI?
Urine blockage from kidney stones or neoplasms
87
Is AKI treatable?
AKI resolve with treatment but risk factor for later CKD development
88
The glomerular is a primary site of injury for which pt population?
Pt with diabetes and hypertension although disease progression later extends to tubular dysfunction
89
Why is the glomerular more vulnerable to immune-mediated injury?
Due to ability of antibodies and antigen, antibody complexes to pass through the highly permeable glomerular capillary walls to be deposited in Bowman's space.
90
What is the cons about immune activation in the glomerular?
Accompanied by complement-mediated tissue destruction, further damaging the filtration barrier or completely blocking filtration and acutely or chronically reducing GFR.
91
What is the significant of proteinuria in kidney?
Present in declining kidney function and routinely monitored in pt at risk of kidney disease due to diabetes or hypertension
92
What is a nephrotic syndrome?
Proteinuria is a major manifestation and may present with resulting fluid losses and peripheral edema due to loss of plasma proteins, while aspects of tubular function may be maintained
93
What is Chronic loss of kidney functions is characterized by?
Pt with diabetes and HTN with combination of nephron losses with increased glomerular permeability of remaining nephrons. Manifested by decreased estimated glomerular filtration rate (eGFR) accompanied by proteinuria.
94
What does staging of kidney disease involve?
eGFR values and urine albumin/creatinine ratio
95
How does CKD affects cardio?
CKD at any level increases atherosclerosis and cardo disease
96
What is end-stage renal disease?
Tx w/ dialysis or kidney transplant
- Manifested with consequences of loss of all short or longterm kidney functions
- Increased BUN and Cr
- HTN
- Hyperkalemia, acidosis, anemia (loss or erythropoietin)
- CKD mineral and bone disorder due to loss of Ca and Phosphate homeostasis and metabolic acidosis
97
The kidney is the target for many drugs, some of which may increase kidney vulnerability to damage. True or False.
True
98
What does prematurity and low birth weight associated with?
Reduced nephron numbers at birth and predispose to development of HTN and kidney disease later in life
Nephron development is completed by 36 weeks of gestation
99
What is pediatric urinary disorders include?
Both malformations of urogenital structures and abnormalities of nephron function.
- Minimal change disease often has pediatric onset and results in nephrotic syndrome
100
What is the older adults renal tissue alterations with aging?
Progressive renal tissue alterations including loss of nephrons with glomerulosclerosis
- Progressive reductions in estimated and measured GFR that may not be proportional to histological chart.
101
What is sarcopenia?
Advanced age, Cr production decreases and not certain whether current estimating equations for GFR from serum Cr accurately reflect GFR in older adults
102
What is older adults at a higher risk for?
Due to altered RBF, urine concentrating ability, nephron number, and polypharmacy, older adults at risk for AKI particularly drug-induced kidney injury
103
Can nephron be added more after birth?
No additional nephrons are added after birth. Premature and restriction during gestation can decrease nephron #
104
How much does kidney receive cardiac output?
Highly vascular organs and receive 20% C/O at rest
105
What is function of nephron?
Filter blood, forming glomerular filtrate, and selectively reabsorb needed blood components while enriching urine with wastes and toxins for excretion
106
What does each nephron has?
Two capillary beds
- glomerular capillary
- Peritubular capillary
Work together with tubule system to conduct filtration, then reabsorption
107
What are the two functional components of nephron?
Glomerular; site of high rate of capillary filtration that filtered fluid enters the tubules is made of water, electrolytes, small molecules (glucose, amino acids, Cr, urea, uric acid, hormones, hydrophilic drugs)
- Low oncotic pressure
108
What is the key indicator of kidney function?
Glomerular filtration rate (GFR)
Presence of protein in urine, urinary albumin to creatinine ratio (ACR)
109
What are the glomerular filtration barriers?
Damage by immune mechanisms, infections, and toxic drugs.
110
What does the loop of henle, distal tubule and collecting duct sites collect?
Site of action of many diuretic drugs and hormones that regulate fluid and electrolyte balance
111
What does AKI primarily involve?
Glomerular (Acute glomerulonephritis)
Tubules (Acute tubular necrosis)
- GFR drops and need renal replacement short term
112
What does gradual accumulation of tissue damage due to diabetes or HTN leads to?
Glomerulosclerosis
accumulation of glomerular fibrosis and loss of GFR function
113
What determine the stage of CKD?
Cr
eGFR
Proteinuria
