Renal Flashcards
What are the three functions of the Renal System?
- Cleans the Blood2. Regulates many ECF Components3. Endocrine Tissue
How Does the kidney Clean the Blood?
It removes waste products through filtering and then reabsorbs what it wants. Undesirable components are expelled through the urine.
How does the renal system regulate ECF?
It receives 25% of cardiac output so it can regulate the levels of blood components especially ions (Na+, K+, and Ca2+) and acid base balance
How is the kidney an endocrine tissue?
It releases hormones important for regulating BP (renin) and rBC production (EPO and Erythropoietin)
How much cardiac out put does the kidney receive?
25%
where are the kidneys located?
Side of spinal column in the dorsal body cavity
In humans which kidney is more anterior?
Left Kidney/more cranial
What color and texture are the kidneys?
Red, Brown and smooth
How big are the kidneys in humans?
10-12 cm long
What supplies the kidney with blood?
Each kidney has a renal artery
What drains the kidney?
Each kidney has a renal vein
What does the ureter do?
Moves urine from each kidney by a peristalsic motion and gravity to bladder
Describe the bladder
Thin stretchy bag of muscle that stores urine
What does the urethra do?
Expels urine out of the body from the bladder.
What would we see in a sagittal section of the kidney?
Cortex(Dark), Medulla and Renal Pelvis(Pale)
Why is the cortex of the kidney darker?
More vasculature, different cell types
What explains the coloration difference between the cortex and medulla?
Different cells, more vasculature in the cortex
What color is the renal pelvis?
pale, creamy yellow
What is the renal pelvis?
An extension of the ureter that expands to fill out the hollow cavity of the kidney
What does the renal pelvis do?
collect urine that is formed and emerges from the innermost medulla
In what direction does the kidney work?
from the outside in
Where does blood enter the kidney?
blood enters cortex of the kidney from the renal artery
What happens to the blood in the cortex in general terms?
It gets filtered
What fluid emerges from the medulla?
Urine
What is the boundary called between the cortex and medulla?
Cortico-medullary boundary
What is the kidney composed of?
Hundreds of epithelial lined tube structures called nephrons
What is the functional unit of the kidney?
The nephron
Is there connective tissue in the kidney?
no
Where is the Macula Densa?
Cortex
What part of the kidney are distal tubules found?
Cortex
What part of the kidney do you find loop of Henle?
Medulla
Where do you find proximal tubule in the kidney?
Cortex
Where do you find collecting duct of the kidney?
Medulla and cortex
Where do you find bowmens capsule?
Cortex
Where do you find a connecting tubule?
Cortex
Where is the renal corpusle?
Cortex
What does the renal corpusule do?
filters the blood and generates filterate
What does the proximal tubule do?
Selective reabsorbtion
What does the proximal tubule reabsorb?
Na, K, glucose, amino acids , bicarbonate
Where does the epithelial type change?
at the loop of henle
What does the loop of henle do?
Reabsorb water and Sodium Chloride
What is another name for the thick ascending limb?
distal straight tubule
Where does the distal tubule run?
From the outer medulla to the cortex
What does the distal tubule do?
Selective reabsorption but not as powerful as the proximal tubule
What does the collecting duct do?
Fine tuning (secretion and reabsorption)
Which molecule reabsorbs Na+ at the luminal membrane of the early proximal tubule?
Na-glucose symporter
How is Na+ reabsorbed at the basolateral membrane of the early proximal tubule?
Via Active Transport
What molecule reabsorbs Na+ at the luminal membrane of the early proximal tubule?
the Na-Glucose symporter
Where does the Na-Glucose symporter reabsorb Na+ in the early proximal tubule?
At the luminal membrane
What is the number one job of the kidney?
To clean the blood
What is the second most important function of the kidney?
regulate many components of the extracellular fluid
What are the two parts of the renal corpusle?
- A bundle of capillaries (glomerulus)2. Bowmans Capsule (surrounds glomerulus)
Where does the glomerulus receive blood from?
An Afferant Arteriole
Where does blood leave the glomerulus?
An Efferent Arteriole (E for Exit)
Where does the blood get filtered?
in the glomeruli
As the blood flows through the capillaries of the glomerulus is it under high or low pressure?
High because part of the fluid portion of the blood is squeezed through capillaries into bowmans capsule
How much of the fluid portion of the blood is squeezed into bowmens capsule during filtration?
20-25%
Where does the filterate go from bowmans capsule?
To the proximal tubule where selective reabsorbtion occurs
If a sodium ion wants to enter bowmans capsule from the glomerulus what does it have to do?
Cross the wall of the capillary and then the wall of bowmans capsule
What makes up the filteration barrier in the renal corpuscle?
Wall of the capillary in the glomerulus and the lining of bowmans capsule.
What can cross the filteration barrier of the renal corpuscle?
Anything super small : Ions (Na,K, Mg)Anything with a neutral charge or no net charge Example: glucose, Water, very small proteins
What cannot cross the filteration barrier of the renal corpuscle?
Cells (RBCs and WBCs)antibodies (large blood borne molecules)Most Protein
T/F The blood has lots of protein
TRUE
Describe the path of the proximal Tubule in the kidney.
- Begins in the cortex and winds around
- Dives into the medulla and turns into the loop of henle
- goes down the descending limb
- makes a hairpin loop in the deep medulla
- Comes back out in the ascending limb
- Turns into the distal straight tubule
- distal straight tubule goes back to glomerulus where it touches it at the vascular pole
Where is the vascular pole located in the renal corpuscle?
Where the afferent and efferent enter and exits
What is the distal tubule associated with?
The renal corpuscle
What are the specialized cells are the interface of the distal tubule and glomerulus called?
The macula densa
What are the cells of the macula densa important for?
regulation of control of filtration but not filtration itself
Why compels something to move out of the bloodstream to cross the glomerulus into bowmans capsule and then into the proximal tubule?
Starlings forces combined (net filtration pressure)
Are starlings forces unique to the glomerulus?
no, they function at any capillary bed
Define Hydrostatic Pressure
the pressure exerted by the fluid on the container that contains it. Fluid pushing out against cup
What are the two categories of starlings forces?
Hydrostatic and Oncotic Pressure
Define Oncotic Pressure
Osmosis generated by proteins in the blood
If there was a container with two fluids (one of water and one with sodium chloride) and a semipermeable membrane what way would the water move?
Toward the sodium chloride due to osmosis. (Sodium Chloride generates an osmotic pressure by pulling water across the membrane)
What can generate osmotic pressure?
Na+, Cl-, glucose, colloids, proteins
What is a colloid?
High molecular weight particle in the ECFUsually proteins
What are the two hydrostatic pressure?
Glomerular hydrostatic pressure and Bowmans space pressure
What is Glomelular (Capillary) Hydrostatic Pressure? (Pc)
As blood runs through the glomerulus it is under pressure and it exerts a pressure pushing out
What is bowmans hydrostatic pressure?
The pressure of the filterate in bowmans capsule pushing out. Opposes the glomerular hydrostatic pressure
What are the two oncotic pressures?
Glomerular colloid oncotic pressure
Bowmans space oncotic pressure (should be very small)
In the renal corpuscle, where is the protein that exerts oncotic pressure?
It should be in the blood and not in bowmans space
What is capillary oncotic pressure? (symbol pi subscript c)
It is the pressure generated by protein in the blood pushing inward in the glomerulus
Why is the oncotic pressure small in bowmans space?
There is only a small amount of protein generating that pressure
What way does the oncotic pressure in bowmans space pull?
Out
What way does the hydrostatic pressure in bowmans space pull?
in
How do we calculate the net filteration pressure in the glomerulus?
Glomerular Hydrostatic Pressure - Bowmans capsule pressure (Hydrostatic) - Glomerular oncotic pressure
Given the following Starlings forces, what is the net pressure at the glomerulus? Bowmans space hydrostatic pressure = 24 mmHgCapillary Oncotic Pressure = 26 mmHgBowmans space oncotic pressure = 0 mmHgCapillary Hydrostatic pressure = 58 mmHg
58 mmHg - 24 mmHg - 26mmHg = 8mmHg
How does the kidney regulate the rate at which filtrate is generated? (Glomerular filtration rate)
The capillary hydrostatic pressure determines the glomerular filtration rate. If it increases so does the filtration rate.
How does the kidney increase or decrease the capillary hydrostatic pressure to change the glomerular filtration rate?
Constricting or dilating the arterioles controls how much blood can flow in and out of the glomerulus and then change the capillary hydrostatic pressure. (
Are arterioles a good conduit of blood alone?
No, they are small
What do the arterioles at the vascular pole of the renal corpuscle have that aid in changing the filtration rate?
Smooth muscle in their walls:If the smooth muscle tightens the arteriole constricts and less blood flows through (Pc decreases and filtration rate decreases)If the smooth muscle relaxes, the arteriole expands and more blood can go through.
What happens when the afferent arteriole constricts?
Pc decreases and GFR decreases
What are extra renal triggers?
They tell the kidney to adjust (constrict or dilate the afferent or efferent arterioles)
What is autoregulation?
When an organ detects a change and adjusts to correct it
How does the kidney autoregulate the GFR?
As systemic blood pressure increases more blood flows through the kidney and GFR increases but there is a range where the GFR and blood flowing in will not change even if the mean arteriole pressure increases or decreases
What is mean arterial pressure?
(x axis) systemic blood pressure
What is Renal Blood Flow?
(Y axis) How much blood is flowing through the kidneys
As Mean Arterial pressure increases blood flow ______ and GFR _________
As Mean Arterial pressure increases blood flow increases and GFR increases
As more blood flows into the glomerulus capillary hydrostatic pressure ______ and GFR_______.
increases, increases
What is the goal of renal autoregulation?
To keep blood flow and GFR steady even though systemic BP changes dramatically
Why does the kidney want to autoregulate?
- Prevents mechanical damage to glomeruli caused by spiking BP2. Prevents fluctuations in BP from changing delivery of filtrate to nephron (maintain constant GFR despite changes in BP)
What would happen if the nephron became overwhelmed with the amount of filtrate generated?
It could lose some important components in the urine rather than reabsorbing them
What happens to blood pressure and renal blood flow during anesthesia?
BP fluctuates while renal blood flow stays steady (autoregulation)
What are the two mechanisms that the kidney autoregulates?
Myogenic mechanism
Tubuloglomerular feedback
Describe the Myogenic mechanism
The afferant arteriole can sense if it should constrict or dialate based on if its smooth muscle is streched or relaxed and this adjusts the GFR
What happens when smooth muscle is stretched?
It contracts
T/F when smooth muscle is not stretched it is contracting
False, it is relaxed
If BP is high, the smooth muscle in the afferent arteriole will ________ , intracellular Ca+ will ______, vascular resistance will _________ and the arteriole will ______. Renal Blood flow will _____, _______GFR.
If BP is high, the smooth muscle in the afferent arteriole will stretch, intracellular Ca+ will increase, vascular resistance will increase and the arteriole will constrict. Therefore renal blood flow will decrease, decreasing GFR.
If BP is low, the afferent arteriole will ________ , intracellular Ca+ will ______, vascular resistance will _________ and the arteriole will ______. Renal Blood flow will _____, _______GFR.
If BP is low, the afferent arteriole will relax and dilate, intracellular Ca+ will decrease, vascular resistance will decrease . Renal Blood flow will increase, increasing GFR.
What is the response time of the myogenic mechanism?
1-2 seconds
What is the myogenic response to increased BP?
Afferant arteriole constricts
What is the trigger for Tubuloglomerular Feedback?
changing distal tubule fluid compositon
What is the response time for Tubuloglomerular Feedback to occur?
10-12 seconds (many more steps than the myogenic mechanism)
How does the Tubuloglomerular mechanism work?
The macula densa senses changes in the distal tubule fluid caused by fluctuations in the GFR and responds by changing the resistance of arterioles to correct the GFR by regulate the amount of blood
In the tubuloglomerular feedback mechanism of autoregulation what happens when the BP increases?
Normally a BP increase will increase Pc and GFR would then increase, due to the increase there is more filtrate. The macula densa senses the higher concentration of ions in the distal tubular fluid and transmit a signal to the wall of the afferent arteriole tell the smooth muscle to constrict and thus reduce the GFR
What does it mean when we say the GFR is increased?
More filterate is being dumped into the system.
In the tubuloglomerular feedback mechanism of autoregulation what happens when blood pressure is low?
GFR decreases normally due to lower capillary hydrostatic pressure. In the fluid at the distal tubule thereare less ions and the macula densa senses this. It then needs to increase GFR. The efferant arteriole constricts in the presence of angiotensin II released by renin and the afferent arteriole dilates when prostaglandin is sensed and GFR increases
What is the tubuloglomerular response to lower than expected solute concentration in the distal tubule?
GFR will be increased
What is reabsorption?
The movement of molecules in the tubular fluid accross the epithelial lining of the nephron back into the bloodstream via the peritubular capillary network
After going through the peritubular capillary network in the kidney where does the blood go?
Dumps into the renal vein to exit the kidney
What is the oppostite of reabsoption when talking about the kidney?
Secretion
What is the opposite of reabsoption when talking about the kidney?
Secretion
In the kidney, what is the luminal membrane>
Seperates tubular cell from tubular fluid
In the kidney, what is the basolateral membrane?
The other side of the cell, seperates the cell from the peritubuler interstitium
What is the goal of reabsorption?
To move stuff from the lumen of the tubular cells to the blood
What part of the cell directly interacts with the filterate produced in the kidney?
The luminal membrane
what are the pathways from the luminal membrane to the blood in kidney reabsorption?
Transcellular route and paracellular route
Describe the transcellular route in reabsorption
Reabsorption through the cytoplasm of tubular cells (Through cells)
Describe the paracellular route of reabsorption in the kidney
Reabsorption between tubular cells across tight junctions (Between Cells)
What pathway is used for the majority of reabsorption in the kidneys?
Transcellular
Define passive transport
NAME?
What are the types of passive transport?
Diffusion and facilitated diffusion
What types of things move using facilitated diffusion?
molecules that don’t easily cross biological membranes (Charge, polar (inbalance of charge) (Na, K, Mg, glucose)
What does facilitated diffusion require?
a transporter
What is a polar molecule?
A molecule with an uneven distribution of charge (Glucose)
What is active transport?
energy is required
What are the types of active transport?
Primary and Secondary
What is all reabsorbtion linked in some way to?
NaK+ ATPase
Where is Na K+ATPase located?
Basolateral membrane
Where is NaK+ATPase not located in the basolateral membrane in the kidney?
Loop of henle
Is there a difference in concentration of molecules that are found in the filterate vs. the molecules in the interstiticial fluid?
No there is no gradient
What makes the nephron tick?
The energy in NaKATPase
How many sodium and potassium molecules does NaK+ATPase move?
3 Na+ ions out and 2 K+ ions in
Does ATPase require energy?
Yes
What is the Na K+ATPase mechanism in the basolateral membrane in the kidney?
To pump 3 Na+ out energy is required because it is moving against its electrochemical gradient
What is the Na K+ATPase mechanism in the basolateral membrane in the kidney?
To pump 3 Na+ out energy is required because it is moving against its electrochemical gradient but since Na is going out an electrochemical gradient is generasted
What is the function of NaKATPase in tubular reabsorption?
Maintains low intracellular Na+ to establish the electrochemical gradient up which all reabsorption depends
Which of the following statements about Na+K+ATPase is correct?AIt transports Na+ and K+ at the luminal membrane of nephron epitheliaBIt moves 3 Na+ into the cells in exchange for 2 K+ out of the cellCNa+ movement is by facilitated diffusionCorrectDIt requires energy in the form of ATPEIt moves K+ paracellularly
D
What does the proximal tubule reabsorb?
67% of filtered water ,Na, and Solutes
99% of filtered glucose and Amino Acids
90% bicarbonate
What reabsorbs most water?
Proximal tubule
What can get secreted from the proximal tubule?
Bases, protons, organic acids
What special features do you find in the cells of the proximal tubule that tell you its function?
Brush Border-microvilli-increases surface area realitive to volume
Mitochondria-generates ATP
What part of the membrane has the brush border in the proximal tubule?
Lumen
What type of transport goes on in the proximal tubule?
Active-Mitochondria indicate that ATP is being made
Where is the Na K ATPase located in the cells at the proximal tubule?
Basolateral membrane
Describe the mechanism of action in the cells of the proximal tubule by where Na is reabsorbed
- NaKATPase pumps 3 Na ions out which creates a concentration gradient at the lumen membrane of the cell. 2. This allows Na to enter the cell via facilitated diffusion at the lumenal membrane3. Sodium goes in and then is pumped out by NaKATPase (reabsorbed)
How does glucose enter the cell in the proximal tubule ?
NAME?
Where do transporters move glucose and amino acids into the cell?
At the basolateral membrane
How to amino acids enter the cell at the proximal tubule?
Secondary active transport
What are Na proton exhangers?
a secondary transporter
How does water enter the cell at the proximal tubule?
It is pulled with sodium by osmosis by NaKATPase
In the first half of the proximal tubule, why does chloride concentration build up?
Water is leaving and chloride is staying in the tubular fluid
What happens to chloride concentration in the second half of the proximal tubule?
Since it built up in the first half, there is now a concentration gradient for chloride and so chloride can move between cells by simple diffusion paracellularly into the blood. This only happens because Water was reabsorbed and water can move because of Na ion reabsorbtion
What happens in the last part of the proximal tubule?
Cl- attracts Na+ paracellularly and more sodium is reabsorbed
What does the loop of henly reabsorb?
25% of filtered NaCl and 15% of filtered water
Where does water reabsorption occur in the loop of henle?
descending limb
In the loop of henly is NaCl reabsorption passive or active?
passive
Where is NacL reabsorped in the loop of henle?
ascending limb
Where does the descending limb of the loop of henle go?
to the medulla
Where does the ascending limb of the loop of henle go?
To the cortex
What part of the loop of henle is permeable to water?
Descending Limb
What part of the loop of henle is permeable to sodium and chloride?
Ascending
What type of reabsorption occurs at the loop of henle?
passive
What type of cells line the proximal tubule epithelium?
Low cuboidal
What type if cells line the loop of henle epithelialum?
Simple squamous Epitheilium
Is there mitochondria in the cells of the loop of henle?
not many as no energy is needed
Is Cl- absorbed paracellularly or transcellularly in the proximal tubule?
both-paracellularly at the proximal tubule and transcellularly at the loop of henle
How much water is reabsorbed at the distal tubule and collecting duct?
9-15%
How much NaCl is reabsorbed at the distal tubule and collecting ducts?
7%
What does water permeability depend on at the distal tubule and collecting duct?
ADH must be present
What cell type is found in the distal tubule?
cuboidal
What is the job of the nephron at the distal tubule and collecting duct?
Fine tuning
What is reabsorbed at the distal tubule?
Na, K, Cl, ions
What is secreted at the distal tubule?
protons
In the distal tubule what are features of the cell?
Smaller brush border, some mitochondria
What happens in the early part of the distal tubule (straight tubule)?
There is a very strong lumen postitve potential difference (fluid that runs is positively charged paracellularly) That repels other positively charged ions and they move paracellularly
In the straight distal tubule (early) what is the transcellular method of reabsorbtion at the Lumenal membrane?
NaKATPase moves Na out but there is another molecule called NaKCC2 that can move 1 ion of Na, 1 ions K and 2 ions of chloride into the cell. This is based on the movement of Na.
How is Cl- moved into the cell at the basolateral membrane?
Cl- channels
What happens in the convoluted distal tubule(late)?
NaKATPase works at the basolateral membrane and a sodium chloride symporter works at the luminal membrane moving sodium and chloride in and chloride is then reabsorbed via chloride channels at the basolateral membrane
What transports Na+ at the luminal membrane of the late distal tubule?
Na-Cl symporter
What type of cells are found in the collecting duct in the cortex?
Principal cells and intercalcated cells
What do principal cells absorb?
Na, K+ and some Cl-
What is the function of intercalcted cells found in the collecting duct
Move protons and Bicarbonate (regulate pH)
In the medullarly collecting duct what type of cells are found?
Only principal cells
What do principal cells look like?
Lighter in color cuboidal
Where do you find larger collecting ducts?
In the medulla
What is the major mechanism for reabsorbtion in the collecting duct?
Ions moved basically via channels at the luminal membrane along with NaK ATPase at work in the basolateral membrane
How is tubular reabsorption regulated?
- Glomerulotubular balance
- Starlings forces at the peritubular capillary bed
- Hormones
How does Glomerulotubular balance work?
The more filterate dumped into proximal tubule, the more reabsorbed so as GFR increases, so does reabsorption
How do starlings forces at the peritubular capillary bed regulate reabsoption?
Normally promote reabsorption in the proximal tubule Changes in the capilarry pressure and osmotic capillary pressure will change reabsorbtion
How can hormones regulate reabsorption?
- Increase activity
2. Increase the number of transporter molecules
Define Osmolarity
It is the concentration of osmotically active atoms per L of solvent.
What way does water move in the presence of a high osmolarity substance such as NaCl?
Toward the higher osmolarity substance
In the loop of henle where is it permeable to Na+ and impermeable to water?
ascending limb
In terms of osmolarity, what is the fluid leaving the proximal tubule defined as?
isoosmotic (300 MOsm/kg)
What creates an osmotic gradient in the distal straight tubule?
The active reabsorbtion of Na+. Water follows the Na+ as it is being reabsorbed leaving the descending limb passively (without the use of energy) of the loop of henle
Where does osmolality increase in the loop of henle?
The Medullary interstitium-Na+ leaves the ascending limb contributing to osmolality. It leaves passively
What happens in the hairpin loop in the loop of henle?
Water reabsorption has concentrated Na+ above interstitial concentration so now there is a Na+ gradient
In terms of osmolarity, how do you describe the fluid going into the distal tubules at the end of the loop of henle?
Hypoosmotic
Where are osmoreceptors located?
Hypothalamus
What do osmoreceptors do?
Shrink and swell to detect changes in osmolality
What do baroreceptors do?
Detect changes in plasma volume or pressure
What happens when ADH is low?
A high volume of dilute urine is produced
What happens when ADH is high?
Antidiuresis, where there is a low volume of concentrated urine produced
What preserves medulla hypeosmolarity?
The vasa Recta
What is an effective osmole?
It can generate osmotic pressure
In the descending limb of the loop of henle what is the osmolarity in side the limb when compared to the intersticial fluid?
It is lower inside the limb so water moves out to the intersticial fluid
What is countercurrent multiplication?
The thing in the loop of henle in the descending limb causes the opposite effect in the ascending limb
Which statement about physiology at the loop of Henle is true?
Na+ is reabsorbed passively at the descending limb
B Water is reabsorbed down an osmolarity gradient (low to high osmolarity)
CI nterstitial osmolarity decreases as you move deeper into the medulla
D Distal tubule fluid is hypertonic to insterstitium
B Water is reabsorbed down an osmolarity gradient (low to high osmolarity)
What are the triggers to produce ADH?
Low volume (Osmoreceptors detect shrinking) and Low pressure (Baroreceptors detect Pressure)
what is the PRIMARY determinent of the release ADH?
Osmoreceptor response
What is the response in the late distal tubule and collecting duct to ADH release?
- Increase expression of aquaporins in the luminal membrane of the late distal tubule and entire collecting duct so water can be reabsorbed.2. Increase number of urea transporters in the luminal membrane of the medullary collecting duct so urea it is permeable to urea
What is the other word for ADH?
Vasopressin
Does ADH affect filteration in the nephron?
no
What happens when there is low ADH?
Diuresis and water is trapped in the distal tubule and collecting duct. A high volume of dilute urine is produced
What happens when ADH is high?
Antidiuresis-Water is reabsorbed and urine is concentrated
What is urea?
By product of protein metalbolism
Is urea an effective osmole in the collecting duct?
no just in the loop of henle
During diuresis, which of the following is true?AUrea reabsorption in medullary collecting duct is highBCollecting duct permeability to water is lowCWater reabsorption at loop is increasedDA small volume of urine is produced
BCollecting duct permeability to water is low
What is the vasa recta?
A group of capillaries around the late distal tubule and collecting duct
What is the function of the vasa recta?
To preserve medullary hyperosmolarity by keeping solutes
What is the main ECF ion?
Na+
What is changed by changing the amount of Na+?
ECF volume
What is changed by changing the concentration of Na+?
ECF osmolarity
What needs to be regulated to control the osmolarity and volume of the extracellular fluid?
ECF Na+
Where is most of the Na+ located in the body?
Extracellular (ECF)
Where does most of the K+ live in the body?
intracellularly
What do you find in the cell
Mg++,K+ , PO4, protein
Where do you find most Cl- in the body?
Extracellularly
Where do you find most bicarbonate?
Extracellularly
What is the derterminant of ECF osmolarity?
Na+ concentration
High ECF Concentration is called
Hypernatremia
What are the signs of hypernatremia?
Rupture of cerebral vesselsMuscle weaknessAtaxia,behavioral changeComa to death
What is low Na+ ECF Concentration called?
Hyponatremia
What are the signs of Hyponatremia?
Incoordination and seizures
What is concentration?
The amount of a specified substance (Na+) in a unit amount of another substance (water)
What detects change in ECF osmolarity
osmoreceptors in the pituitary gland
When there is high ECF osmolarity what do the osmoreceptors do?
Shrink
What are the effects of osmoreceptor shrinkage
ADH release and Thirst Body, ADH is released and aquaporins are made thus reabsorption of water takes place and ECF osmolarity decreases
What occurs when there is more ECF in volume?
Hypervolemia (ascites and pulmonary edema)
What happens when ECF volume is too low?
Hypovolemia-Hypovolemic shock, organ damage
What can cause a volume change in ECF?
Na+, Blood loss, vomiting, liver failure
What do kidneys do to when it detects a volume change of ECF.
Regardless of cause, they change the amount of ECF Na+ to correct the volume
Does the kidney regulate protein?
no, the liver
What will be the effect of increasing extracellular fluid sodium concentration?AECF volume will go downBECF volume will go upCECF osmolarity will go downDECF osmolarity will go up
DECF osmolarity will go up
Where is the thirst center in the brain?
Hypothalamus
Which statement about hyponatremia is most accurate?AA hyponatremic individual will have high ECF Na+ concentrationBThere will likely be translocation of fluid from ECF into ICFCOsmoreceptors in hypothalamus will shrinkDADH release will be increasedEThe individual will feel thirsty
BThere will likely be translocation of fluid from ECF into ICF
What is more serious hypervolemia or hypovolemia?
Hypovolemia
How does the kidney detect volume change in the ECF?
- Baroreceptors2. Juxtaglomerular Apparatus
Where are baroreceptors located?
Heart (mostly right side), aorta, carotid sinus
What do baroreceptors sense?
Stretch (increase in volume)
When the baroreceptors stretch what is the response?
Sympathetic nervous system and natriuretic peptide release(decreases a high ECF volume)
How does the juxtaglomerular Apparatus regulate ECF volume?
It has stretch receptors that stretch when ECF volume goes up.
Where is the juxtoglomerular apparatus located?
By the afferant arterioles
How does the juxtoglomerular apparatus increase a low ECF fluid?
The Renin-Angiotensin system
How do we increase ECF volume?
When low ecf is detected the 1. sympathetic nervous system increases Na+ reabsorption ECF volume2. Increases GFR and Pic and Pc is reduced of the peritubular capillaries of the proximal tubule to increase rebsorbtion
What does the sympathetic nervous system specifically do in when ecf volume is low?
norepinephrine constricts the efferant arteriole which builds capilary hydrostatic pressure within the glomerulus and the GFR increases promoting the movement of sodium back into the bloodstream
What triggers the renin -angiotensin mechanism?
The afferant arteriole detects stretch and Low ECF volume triggers the release of renin from the juxtaglomerular cells
What happens when renin is released?
Angiotensin II is increased and Na+ reabsorbtion is increased
Describe the renin angiotensin mechanism
- Angiotensinogen is produced in the liver and enters the blood stream2. When it encounters renin, renin cleaves angiotensenogen to angiotensin I 3. Angiotensin I sits in the blood stream until it encounters Angiotensen converting enzyme4. This enzyme cleaves it to angiotensin II
Where is angiotensin converting enzyme produced?
In the lungs
What does angiotensin II do?
- Potent vasoconstrictor that changes starlings forces in peritubular capillaries2. Stimulate Aldosterone which increases Na+ reabsorbtion via NaK+Atpase
Where is aldosterone found?
Adrenal gland
How is ECF Volume decreased?
Natriuretic peptides inhibit the ways sodium can be reabsorbed and it promotes Na excretion through the urine
What is the mechanism of natriuretic peptide release?
it inhibits renin-angiotensin II, aldosterone and Na+ channels in the collecting duct all decreasing renal Na+ reabsorption
Which statement about hypovolemia is accurate?AIt is defined as high ECF volumeBIt is caused by low ECF Na+ concentrationCIn response, sympathetic flow to the kidneys is increasedDTo correct it, the Renin-Angiotensin system will be inhibitedSubmit
In response, sympathetic flow to the kidneys is increased
Increased sodium_______ECF Volume
Increases
