Renal Physiology Flashcards
1
Q
The functional units of the urinary system.
A
Nephrons
2
Q
The smallest units that are capable of performing the processes involved in urine formation
A
Nephrons
3
Q
They number from 1 - 1.5 million per kidney (total of 2 – 3 million)
A
Nephron
4
Q
Types of nephron according to location:
A
Cortical and Juxtamedullary Nephrons
5
Q
This is the outer layer wherein Cortical nephrons are located
A
Cortex – outer layer
6
Q
This is the inner layer wherein Juxtamedullary nephrons are located
A
Medulla – inner layer
7
Q
What nephron is being described?
- Nephrons that are localized in the renal cortex.
- Constitute the majority of nephrons (85%).
A
Cortical Nephron
8
Q
These are the Main functions/Primary roles of what nephron?
o Immediate reabsorption of essential
substances;
▪ Supposed to bring back everything
the body needs to circulation.
o Immediate removal of wastes
A
Cortical Nephrons
9
Q
These are the Main functions/Primary roles of what nephron?
- The other 15%.
- “Have long Henle’s loops that extends deep in the
medullary region.”
A
JUXTAMEDULLARY NEPHRONS
10
Q
a structure that extends well below the medullary region.
A
Loop of Henle
11
Q
Parts of a Nephron:
A
RENAL CORPUSCLE
RENAL TUBULE
VASCULAR COMPONENTS
JUXTAGLOMERULAR APPARATUS
12
Q
Has two components – the glomerulus and the
Bowman’s capsule.
A
RENAL CORPUSCLE
13
Q
The glomerulus is enclosed by what structure?
A
Bowman’s Capsule
14
Q
consists of a specialized tuft of capillaries that is enclosed by the Bowman’s capsule, which forms the beginning of the renal tubule
A
GLOMERULUS
15
Q
The product of filtration in the glomerulus is
first conveyed where?
A
Bowman’s Capsule
16
Q
The fluid that is conveyed into the
Bowman’s capsule flows along what segments?
A
Segments of the renal tubule
17
Q
This RENAL TUBULE functions by immediately reabsorbing
essential substances
A
Proximal Convoluted Tubule (PCT)
18
Q
The thick and thin ASCENDING loop of Henle do NOT have major differences in function.
TRUE OR FALSE
A
FALSE
It is the DESCENDING loop of Henle that do not have major differences in function between its thick and thin loops
19
Q
These are the two classifications of the Ascending Loop of Henle
A
Thick and Thin Ascending Loop of Henle.
20
Q
Responsible for the final adjustments (along with the collecting duct) in sodium (DCT) and water level (collecting duct) via the reabsorption process.
A
Distal Convoluted Tubule (DCT)
21
Q
Responsible for the final adjustments in sodium via the reabsorption process
A
Distal Convoluted Tubule (DCT)
22
Q
Responsible for the final adjustments in water level via the reabsorption process
A
Collecting Duct
23
Q
What part of the nephron is being described?
- Blood vessels associated with the nephron.
- Nephrons will not be able to carry out their reabsorptive
and secretory functions without blood vessels.
A
VASCULAR COMPONENTS
24
Q
Supplies oxygenated blood from a branch of the renal artery to the glomerulus or glomerular capillaries
A
Afferent arteriole
25
The largest blood vessel that supplies the kidney
Renal Artery
26
The left and right renal artery gets
blood from?
Aorta
27
Each nephron is supplied by this structure in a ratio of 1:1
Afferent Arteriole
Each nephron is associated with 1 Afferent Arteriole, if there are 1.5 million nephrons then there are also 1.5 million Afferent Arterioles
28
The blood that circulates in these loops of capillaries will be filtered and will eventually exit through the?
Efferent Arteriole
29
Carries blood from the glomerulus to the renal
tubules or renal tubular area
Efferent arteriole
30
Surround the renal tubules, primarily the PCT
and DCT.
Peritubular capillaries
31
A network of blood vessels that are adjacent to the loop of Henle. They make the reabsorptive and secretory processes taking place in the nephrons possible
Vasa recta
32
A structure that is composed of two types of cells:
o (1) Juxtaglomerular cells;
o (2) Macula densa cells.
JUXTAGLOMERULAR APPARATUS
33
Secretes RENIN when there are changes in plasma volume, blood pressure, and plasma sodium content.
JUXTAGLOMERULAR APPARATUS
34
represents the entirety of the functions of the kidneys of the urinary system.
Urine Formation
35
While urine is being formed, there is
reclamation of essential substances and
secretion of waste products, which is equally
important in the maintenance of?
Homeostasis
36
The three major processes involved in urine formation:
glomerular filtration
tubular reabsorption,
tubular secretion.
37
carries oxygenated blood from a
branch of the renal artery to the glomerulus or
glomerular capillaries.
Afferent Arteriole
38
The structure that first receives the filtrate coming out of the efferent arterioles
Bowman's capsule
39
fluid that flows along the renal tubules from the Bowman’s capsule
Glomerular Filtrate
40
Fluid upon exiting the collecting ducts
Urine
41
glomerular filtrate and urine are the same
TRUE OR FALSE
FALSE
Glomerular Filtrate will first undergo compositional changes or modifications as substances are reabsorbed and secreted. It is only called URINE upon exiting the collecting duct
42
The glomerular filtrate will flow along the PROXIMAL
convoluted tubule (PCT), which is immediately
attached or continuous to the Bowman’s capsule
TRUE OR FALSE
TRUE
43
A process that returns filtered essential substances to
the blood
TUBULAR REABSORPTION
44
From the PCT down to the descending limb of the Loop
of Henle, SODIUM will be reabsorbed
TRUE OR FALSE
FALSE
IT IS WATER THAT IS REABSORBED
45
A significant amount of water is reabsorbed
from what loop of henle?
Descending Loop of Henle
46
The walls of the thin ascending Loop of Henle
are made up of what type of epithelium?
single layer of squamous epithelial cells
47
Epithelium of Thick walls of the loop of henle
Cuboidal renal tubular epithelial cells.
48
The thickness and thinness of the walls are determined by the type of cells in the epithelium
TRUE OR FALSE
TRUE
49
this is the primary function of the juxtamedullary nephrons; removal of water from the filtrate.
Renal Concentration
50
If water is removed from the filtrate, it will become DILUTED
TRUE OR FALSE
FALSE
IT WILL BECOME CONCENTRATED
51
When the fluid ascends through the thin and thick ascending limbs of the Loop of Henle what kind of reabsorption takes place?
solute reabsorption (primarily urea) takes place
52
It is a waste product of metabolism and 50% of it is filtered and brought back to circulation
UREA
53
In the thick ascending Loop of Henle, more WATER are reabsorbed (primarily salts).
TRUE OR FALSE
FALSE
more SOLUTES are absorbed
54
Selective Reabsorption of the Descending Loop
only water is reabsorbed.
55
Selective Reabsorption of the Ascending Loop
only solutes are reabsorbed
56
More sodium and bicarbonate are reabsorbed here
Thick ascending limb → DCT
57
Sodium reabsorption in the PCT, TAL, and DCT is under the influence of?
Aldosterone
58
not all substances which the body has to get rid of are actually filtered. The body gets rid of these substances through what back-up mechanism?
TUBULAR SECRETION
59
Takes place in the DCT; there are also significant secretory processes taking place in the proximal convoluted tubule (PCT), which is the major site for the removal of toxic substances and waste products
TUBULAR SECRETION
60
Secreted substances in Tubular Secretion
Drugs (parent drugs or metabolites, hydrogen and potassium ions).
61
For many drugs and their metabolites, they circulate bound to what proteins?
Plasma proteins
62
Spared from glomerular filtration; the complex is too large to pass through the glomerular filtration barrier
drugs and their metabolites
63
Plasma is still concentrated; plasma osmolality is still high in what structure?
Collecting duct
64
Water reabsorption in the collecting duct is also hormone-controlled; also under the influence of what hormone?
ADH (anti-diuretic hormone).
65
Pathway of Urine Flow:
Major and minor calyces → renal pelvis → ureter → bladder → urethra.
66
What is being described?
* Filtration is dictated upon by the amount of blood
supplied.
* Blood supplied to the kidneys or to the nephrons.
RENAL BLOOD FLOW
67
THE RENAL BLOOD FLOW RATE
Approx. 1,200 mL/min/1.73 m2 (body surface area).
▪ Greater body surface area = >1,200 mL/min.
▪ Smaller body surface area = <1,200 mL/min.
68
THE RENAL PLASMA FLOW RATE
Approx. 600 – 700 mL/min
69
Afferent arteriole gets blood from a branch of the renal artery → glomerulus → efferent arteriole → peritubular capillaries → Aorta
TRUE OR FALSE
FALSE
THE CORRECT ORDER IS: Renal Artery → Afferent Arteriole → glomerulus → efferent arteriole → peritubular capillaries → vasa recta
Blood from the vasa recta will then be returned to the renal vein.
70
The path of Blood Flow starts with oxygenated blood and ends with deoxygenated blood.
TRUE OR FALSE
TRUE
71
The kidneys filter how many Liters of blood every single minute?
1.2 L
72
is filtered by the glomeruli, which
would only amount to 600 – 700 mL/min.
PLASMA
73
The Normal Glomerular Filtration Rate (GFR):
120mL/min (approx. 10% of the renal blood flow rate).
74
is estimated by using clearance tests.
Glomerular Filtration Rate (GFR):
75
are performed to evaluate the glomerular filtration rate.
Clearance Tests
76
At the level of the Bowman’s capsule, the
filtrate is ISO-OSMOTIC with plasma
TRUE OR FALSE
TRUE
Iso-osmotic meaning osmolarities are almost the same.
77
Glomerular Filtrate has a specific gravity of?
1.010
78
Loss of renal concentrating ability of
the kidneys is consistent with?
glomerular nephritis, renal failure and acute tubular necrosis; which are indications of isosthenuria
79
It is expected that the specific gravity
would DECREASE as a result of the
removal of water
TRUE OR FALSE
FALSE
It should INCREASE upon the removal of water
80
Glomerular FIltrate has no significant number of cells because?
The glomerular filtration barrier does
not allow cells and high molecular
weight substances to pass through.
Water and low molecular
weight substances are the only
ones allowed to
81
Glomerular FIltrate has no significant amount of proteins because?
If the cells and protein found in the
urine are a result of damage in the
glomerular filtration barrier, it is
considered clinically significant
82
This is the pressure in the glomerulus that allows the
filtration of plasma, including water and low molecular
weight substances.
FILTRATION PRESSURE
83
The Net Filtration Pressure is?
10 mmHg.
84
Facilitates or makes the filtration of plasma or
blood possible as it flows along the loops of
glomerular capillaries.
Net Filtration Pressure
85
It is a result of the opposing hydrostatic and
oncotic pressures in the glomerular capillaries
and the fluid in the Bowman’s capsule
Net Filtration Pressure
86
Created by opposing hydrostatic and oncotic pressures
inside and outside the glomerular capillaries and
arterioles.
FILTRATION PRESSURE
87
There is hydrostatic pressure inside the
glomerular capillaries and the afferent
arteriole, amounting to?
+55 mmHg.
88
This is opposed by osmotic/oncotic pressure
in the same blood vessel; contributed to by
proteins.
hydrostatic pressure inside the
glomerular capillaries and the afferent
arteriole
89
They exert this osmotic/oncotic
pressure.
Proteins
90
The fluid inside the Bowman’s capsule also
exerts hydrostatic pressure amounting to?
-15mmHg
91
The osmotic/oncotic pressure exerted by proteins amount to?
-30mmHg
92
are primarily responsible for the large amount of
hydrostatic pressure in the arterioles and glomerular
capillaries.
The varying sizes of the afferent and efferent arterioles
93
There are varying sizes of the afferent and efferent arterioles. Which arteriole is bigger?
Afferent arteriole
94
GLOMERULAR FILTRATION BARRIER
What are its 3 layers?
Fenestrated endothelium (endothelial tissue/cells)
Basement membrane (basal lamina)
Podocyte Layer
95
are large enough to allow the passage of water and low molecular weight substances, but are small enough to restrict the passage of cells and proteins.
Pores
96
these tissues are avascular; nutrients are supplied and waste products are removed via the basement membrane.
Epithelial Tissue
97
Middle layer of the GLOMERULAR FILTRATION BARRIER
Basement membrane (basal lamina)
98
Outermost layer of the GLOMERULAR FILTRATION BARRIER
Podocyte layer
99
Innermost layer of the GLOMERULAR FILTRATION BARRIER
Fenestrated endothelium (endothelial tissue/cells)
100
this perfectly describes the GLOMERULAR FILTRATION BARRIER
molecular sieve
Analogous to 3 layers of filter paper or gauze
101
Size Threshold (limit) of the GLOMERULAR FILTRATION BARRIER
70 kDa, which is the same
as 70,000 Da.
102
Substances with a molecular weight of less than 70
kDa or 70,000 Da will NOT pass through
TRUE OR FALSE
FALSE
They are able to pass through, because they are smaller than the limit
103
What structure is being described?
Negatively-charged substances are naturally repelled
by the negatively-charged basement membrane and
endothelium that make up the glomerular filtration
barrier.
Shield of Negativity
104
Repulsion of negatively charged substances is done by the Shield of Negativity (e.g., proteins); even if they’re small enough to pass through
What protein is the best example of this?
Albumin: Has a molecular weight of less than 70,000 Da, but its a negatively charged protein at physiologic pH. Therefore natural repulsion takes place, because the shield is also negative.
105
is not normally present in
significant amounts in urine.
Albumin
106
If albumin levels increase in the urine, that is indicative of damage to the integrity of the barrier, along with the disruption of the shield of negativity, allowing the
filtration of albumin and all other negatively charged particles.
What complication could this be indicative of?
This results to massive proteinuria, which is consistent to nephrotic syndrome.
107
proteoglycans (in the basement membrane) and sialo
glycoproteins (in the endothelium), are also negatively charged like albumin
TRUE OR FALSE
TRUE
108
is secreted when there are alterations or
abnormalities in plasma sodium content and blood
pressure; both decrease
Renin
109
Combination of changes or stimuli which is sensed by
the juxtaglomerular apparatus
RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM (RAAS)
110
an enzyme that acts on angiotensinogen, a blood-borne substrate (naturally occurring in the blood and is produced by the liver), converting it to angiotensin I (inactive form).
Renin
111
Because angiotensin I is inactive, it has to be
acted on by another enzyme produced by the
lungs, that converts angiotensin I to
angiotensin II (active form).
ACE (angiotensin converting enzyme)
112
is capable of making adjustments in plasma sodium,
blood volume, and blood pressure.
Angiotensin II
113
Mechanisms of Angiotensin II:
To stimulate vasodilation of the afferent arteriole and vasoconstriction of the efferent arteriole;
It stimulates or increases Na+ reabsorption at
the level of the proximal convoluted tubule (PCT).
Stimulates the release or secretion of
aldosterone and in turn, aldosterone increases Na+
reabsorption at the level of the DCT.
Has an effect on ADH secretion, which in turn,
stimulates water reabsorption at the level of the
collecting duct.
114
Both sodium reabsorption in the DCT
(aldosterone) and water reabsorption in
the collecting duct (ADH) are hormone controlled
TRUE OR FALSE
TRUE
115
The collecting duct is NOT naturally permeable
to water.
TRUE OR FALSE
FALSE
The collecting duct is naturally permeable
to water.
116
What is this type of transport?
* Expenditure of energy.
* Takes place at areas or segments of the renal tubule
consisting of renal tubular epithelial cells, which have
multiple mitochondria.
Active Transport
117
These are reabsorbed via active transport by?
Glucose, amino acids, salts.
PROXIMAL CONVOLUTED
TUBULE (PCT)
118
These are reabsorbed via active transport by?
Chloride
THICK ASCENDING LOOP
OF HENLE
119
These are reabsorbed via active transport by?
Sodium
PCT AND DCT
120
point at which tubular reabsorption
stops.
Renal Threshold
121
substances that both have a renal
threshold.
Glucose and sodium
122
Renal Threshold of Glucose
160 – 180 mg/dL.
123
Renal Threshold of Sodium
110 – 130 mmol/L.
124
Type of transport usually in areas with simple squamous epithelial cells
PASSIVE TRANSPORT
125
These are reabsorbed via passive transport by?
Water (under the influence of ADH in the
collecting duct*)
Proximal Convoluted Tubule
Descending Loop of Henle
Collecting Duct
126
These are reabsorbed via passive transport by?
Urea
Proximal Convoluted Tubule
Ascending Loop of Henle
127
These are reabsorbed via passive transport by?
Sodium (aldosterone-controlled).
Ascending Loop of Henle
128
Made possible by selective reabsorption in the Loop of
Henle that serves to maintain the osmotic gradient of
the medulla (primary role of juxtamedullary nephrons).
COUNTERCURRENT MECHANISM
129
What reabsorption is being described?
o At the level of the DLH, only water is
reabsorbed.
o At the level of the ALH, only solutes are
reabsorbed.
Selective Reabsorption
130
IDENTIFY THE LOOP BEING DESCRIBED
Permeable to water
DESCENDING LIMB
131
IDENTIFY THE LOOP BEING DESCRIBED
Impermeable to water
ASCENDING LIMB
132
IDENTIFY THE LOOP BEING DESCRIBED
Impermeable to solutes
DESCENDING LIMB
133
IDENTIFY THE LOOP BEING DESCRIBED
Permeable to solutes
ASCENDING LIMB
134
THE TWO IMPORTANT FUNCTIONS OF TUBULAR SECRETION:
(1) Removal of unfiltered substances
(2) Maintenance of electrolyte and acid-base balance.
135
How is the electrolyte and acid-base balance maintained?
Through the secretion of hydrogen ions which bind to/react with bicarbonate, hydrogen phosphate, and ammonia.
136
Disruption in this function leads to metabolic acidosis and renal tubular acidosis.
Maintenance of electrolyte and acid-base balance.
137
is characterized by low plasma bicarbonate level; both blood and urine are acidic.
Metabolic acidosis
138
results from either failure of hydrogen ion secretion or ammonia production by the RTE (renal tubular epithelial) cells.
Renal Tubular Acidosis
139
Blood is acidic but the urine will be persistently alkaline
Renal Tubular Acidosis
