Renal Physiology Flashcards
What are the primary roles of the kidney?
- Plasma modification
- Excretion
What are the secondary roles of the kidney?
- Hormone production
- Blood pressure control
What 3 things are modified by the kidney to alter blood plasma?
- Ph
- Electrolytes
- Blood pressure/volume
This substance is a product of nitrogen metabolism (AAs) that is toxic to the body in high concentrations.
Urea
What kidney hormone stimulates red blood cell production?
Erythropoietin
What hormone produced by the kidney is responsible for blood pressure control?
Renin
The nephron begins in what portion of the kidney?
Cortex
Each renal pyramid is associated with what portion of the kidney?
Minor calyx
This kidney tissue consists of a majority of the renal pyramid and is often very highly concentrated.
Medulla
About how many nephrons are in the human body?
~3 million
This functional unit of the kidney is the interface between capillaries and the urine collecting system.
Nephron
What is the pathway of blood flow coupled with a nephron?
Afferent arteriole —> glomerulus —> efferent arteriole —> peritubular capillaries
This vasculature directs blood flow into the glomerulus
Afferent arteriole
This vasculature directs blood flow away from the glomerulus
Efferent arteriole
The renal corpuscle consists of what portions of the kidney?
Glomerulus + glomerular (Bowman’s) capsule
The plasma of the renal corpuscle must pass through what 3 barriers to reach the primary convoluted tubule?
- Capillary fenestrae
- Basement membrane
3 . Visceral layer
The basement membrane of the glomerular corpuscle primarily consists of what?
Collagen
What is the primary layer of the glomerular corpuscle for protein retention?
Visceral layer
In the modification of plasma, the kidney must perform what 3 tasks?
- Filtration
- Reabsorbtion
- Secretion
This renal function occurs in response to changes in blood pressure (increase or decrease) to maintain constancy of flow
Renal Autoregulation
This portion of the juxtaglomerular apparatus releases adenosine in response to increases of water + Na+ in the distal tubule (constricting the arteriole)
Macula densa
What are two types of renal filtration regulation?
- Renal autoregulation
- Sympathetic influences
An anatomical unit of the kidney located at the hilus of the glomerulus; it is believed to be involved in the feedback control of renal blood flow and GFR
Juxtaglomerular apparatus
About how many liters of blood per hour go to the kidneys?
60 liters an hour
About how many liters of blood are processed by the kidneys in 24 hours?
1400 liters
About what percentage of the blood processed by the kidneys enters the renal tubule as filtrate through the glomerular capsule?
13%
How to calculate glomerular filtration rate?
GFR = filtrate volume (mL) / min
About how many liters of urine are produced a day? What percentage of total blood flow to the kidneys is that?
1-2 liters (1%)
What is the obligate urine volume that must be produced by humans to stay alive?
400 mL
Reabsorption of water in the kidneys is predominantly aided by what structure?
Aquaporins
What is reabsorbed from the filtrate?
- Electrolytes
- Glucose
- Amino acids
- Water
what is secreted into the filtrate?
drugs and toxins
what is the mOsm difference from the cortex to the medulla?
900 mOsm
what is the principle role of the proximal tubules?
reabsorption
once in the cell, glucose and AAs diffuse passively to what?
interstitial fluid
a blood glucose level greater than180 results in what condition?
glucosuria
what ion provides the gradient needed to transport glucose/AAs from the filtrate of the proximal tubule into the blood
Na+
this is a portion of the ascending loop of henle that limits passive diffusion of ions from the interstitium into cells
thick wall
these are blood sources that are freely permeable to H20 and NaCl from the filtrate of the Loop of henle
vasa recta (peritubular capillaries)
H2O is lost in moderation in the _______ part of the Henle loop and is regained in the _____ part
descending, ascending
a toxic waste product of protein metabolism that must be removed from the blood
urea
this ion is absorbed via parathyroid hormone-regulated channels AND active pumping
calcium
paratyroid hormone-regulated Ca channels are on what side of the tubule cells?
luminal side
active Ca2+ pumps are found on what side of the tubule cells?
basal
what is the concentration of the urine leaving the distal tubule?
~100 mOsm
this is a hormone secreted by the posterior pituitary in response to an increase in plasma osmolality/dehydration; inserts aquaporins into cell membrane
ADH (anti-diuretic hormone)
this hormone stimulates collecting duct cells to synth luminal Na/K channels and ATPase pumps
aldosterone
this hormone is released in response to decrease Na or increase K; regulates the release of aldosterone
renin
this hormone is released by the atrium in response to an increasing blood volume; decreases Na/K pumps and looses more Na and H2O
ANH (arial-natriuretic hormone)
urine is mostly acidic due to the reabsorption of what?
bicarbonate
Carbonic anhydrase is located where in the nephron?
proximal tubule apical cell membrane
What are 5 renal excretory functions (i.e. what ends up in the urine?)
nitrogenous waste
electrolytes
hormones
toxins
non-normals
this nephron organ actively transports Na+ and water follows it passively
proximal tubule
this nephron organ passively transports water onle
descending loop of Henle
this nephron organ actively transports Na+ and is impermeable to water flow
ascending loop of Henle
