Definition of glomerular capillary blood pressure
the fluid pressure exerted by the blood within the glomerular capillaries
Glomerular capillary blood pressure average
55 mmHg
Glomerular capillary blood pressure:
favours filtration
Plasma colloid osmotic pressure
caused by the unequal distribution of plasma proteins across the glomerular membrane. Opposes filtration.
Plasma colloid osmotic pressure average
30 mmHg
Bowman’s capsule hydrostatic pressure
the pressure exerted by the fluid in the initial part of the tubule
Bowman’s capsule hydrostatic pressure average
15 mmHg
Glomerular filtration rate
the actual rate of filtration. Depends on the net filtration pressure as well surface area and permeability.
GFR average
125 mL/min
As glomerular capillary blood pressure goes up…
the net filtration pressure increases and the GFR increases correspondingly
If afferent arteriolar resistance is reduced…
more blood flows into the glomerulus and the GFR increases
In total, how much Na is reabsorbed?
99.5%
How much sodium is reabsorbed in the proximal tubule?
67%
What role does Na reabsorption in the proximal tubule play?
Plays role in reabsorbing glucose, amino acids, water, chloride and urea.
What percentage of sodium is reabsorbed in the ascending loop of henle?
25%
what role does sodium reabsorption in the ascending loop of henle play?
plays a role in the kidneys ability to produce urine of varying concentration and volume.
what percentage of sodium is reabsorbed in the distal and collecting tubules?
8%
what role does sodium reaborption in the distal and collecting tubules play?
plays a role in regulating ECF volume. Is variable and subject to hormonal control.
where is K almost completely reabsorbed?
in the proximal tublue
what percentage of urea is reabsorbed?
50%
In total, how much water is reabsorbed?
99%
What percentage of water is passively reabsorbed by the end of the proximal tubule?
65%
what percentage of water is obligatory reabsorbed from the loop of henle?
15%
where is the remaining 20% of water reabsorbed?
in the distal and collecting tubules. this is subject to hormonal control depending on bodies state of dehydration
Filtered load of glucose:
125 mg/min
Filtered load
the quantity of any substance filtered per minute
Tubular maximum
reached when all carriers for a specific substance are full
Tubular maximum for glucose
373 mg/min
Plasma clearance
the volume of plasma completely cleared of that substance by the kidneys
plasma clearance of glucose:
zero
Secretion
the transfer of substances from the peritubular capillaries to the tubular lumen
H secretion
Important in maintaining acid-base balance
can be secreted in the proximal, distal and collecting tubules
K secretion
keeps plasma concentration at appropriate level to maintain normal membrane excitability. Secreted only in the distal and collecting tubules and is under the control of aldosterone.
Organic ion secretion
accomplishes more efficient elimination of foreign organic compounds from the body. Secreted only in proximal tubule.
Macula densa cells
part of autoregulation and the tubuloglomerular feedback. They detect changes in the salt level of the fluid flowing past them.
which nephron structure is important in producing urine of varying concentration?
loop of henle
Blood flowing through the kidneys is _____ % of cardiac output
20-25%
What occurs after stimulation of the macula densa cells?
vasoconstriction of the afferent arteriole
Sodium uses ___% of the total energy required by kidney
80%
Inulin
is completely filtered and not reabsorbed or secreted