APII RENAL Flashcards
What is the pH of ECF
7.35-7.45
PH varies based on what two compounds
HCO3-
Or partial pressures of CO2
What is a metabolic change in pH
When the pH changed is caused by HCO3
What is a respiratory change in pH
When the pH change is caused by PCO2
What is the first line of defense against acid-base abnormalities
In the ECF, the bicarbonate buffer system
In the ICF, when PCO2 increases, CO2 moves into the cell and combines to make H2CO3.
What is the bicarbonate buffer system
CO2 +H20=H2CO3= H*+HCO3-
What is the second line of defense for acid base balance
Respiratory center.
Blood PCO2 and pH are important regulators of ventilation rate.
Chemoreceptors send signals to compensate the RR for either acidosis or alkalosis
In acidosis the RR
Increases
In alkalosis RR
Decreases
What is the third line of defense in Acid Base Balance
Renal System
Tubules allow for secretion of H* that raise pH
Called renal net acid excretion (RNAE)
Tubules also allow for reabsorb of HCO3
Metabolic Acidosis
Ph< 7.35
Decrease HCO3-
metabolic alkalosis
Ph >7.45
Increase in HCO3-
respiratory acidosis
ph <7.35
Increase PCO2
Respiratory Alkolosis
PH above 7.45
Decrease pCO2
What is ammonia
Is nitrogenous waste when proteins are catabolized
Can be toxic if excess accumulation
Where is ammonia mostly converted to urea
Liver
What is urea
Less toxic than ammonia
Important in osmotic gradient in the tubules in the renal medulla
If you let urea sit what will happen
Converts back to ammonia
Why pees smells
What is Uremia
Excess build up of urea in the blood stream
Caused by kidney failure
What is the BUN
Blood Uria Nitrogen Levels
A marker of liver and kidney function
What part of the tubule get the biggest bang for the buck
THE PCT
What percentage of filtrate is reabsorbed in the tubules
99%
What is absorbed/ reabsorbed in the PCT
Largest amount o solute and water is reabsorption is in the PCT
100% of glucose, amino acids, and vitamins
50% of Cl-
80-90 of filtered HCO3
50 percent of Urea ( Urea recycling)
How is sodium transported out of the PCT
by active transport
What is cotransported with Na+
In the PCT
Glucose and a.a.
How do cl- ions pass in the PCT
passive movement created by Na*
What causes special permeability of water in the PCT and LoH
Aquaporin-1 channels
Protein water channels that increase the rate of water movement
What is solvent drag
The osmosis of water will often bring K* and Ca** with it in a motion called solvent drag
How does Urea move in the PCT
Passively moves out of the tubule into the interstitium
Can go into the peritubular capillaries, vasa recta, can stay in the interstitium
50% remains in the PCT
(Uria recycling creates osmotic movement)
What creates osmotic movement
Uria recycling
What areas of the PCT are impermeable to Urea
The thick ascending limb of the LoH and the Proximal DCT
What action does PTH have on PCT
Stimulates PCT to secrete phosphate
Stimulates production of calitriol to be made (released into blood)
**Stimulates the cells int he DCT to reabsorb more calcium ** (Not in the PCT)
How is reabsorption in the LoH
Solvent and water are independently regulated
15% of water is regulated in descending portion only
The descending limb of the LoH
Mostly water reabsorption and solute secretions (concentrates the filtrate)
Reabsorption in the ascending limb of LoH
No water reabsorption, but reabsorption of solutes are reabsorbed ( dilutes the filtrate)
Is the thin portion of the LoH permeable to water
No, has no Aquaporin channels
As water is held in, solutes move out and dilute the filtrate
Where is a lot of energy expenditure happen in the LoH
Thick portion
Active reabsorption of ions
As filtrate moves up the limb, filtrate becomes more dilute
(Contains macula densa cells)
What is the reabosbption in the DCT
By the late portion 90-95 percent of solutes/wate has be reabsorbed and returned to the interstitium/ blood stream
What are two specific cells found in the DCT
Principle cells
Intercalated cells
What effect does ADH have
Causes principle cells in the DCT to become more permeable to water via aquaporin II cells
How is the urine in the presence of ADH
Small amounts of highly concentrated urine
How much urine is produced at maximal ADH secretion
As little as 400-500 ml of very concentrated urine
Aquaporin II are only effect where
In the DCT in the presence of ADH
What effect does aldosterone have on the principle cells of the DCT
Causes sodium reabsorbtion ( brings h20 along)
And potassium secretion.
What causes secretion of aldosterone
Hyperkalemia
Angiotensin II
What are two types of Intercalated cells
Type A: causes secretion oh H*
Reabsorb bicarbonate
Reabsorbed potassium
Type B: does the exact opposite
How does ANP effect the DCT and collecting DUCTS
Inhibits the reabsorption of sodium and water,
Meaning dieresis/ diuretics
inhibits Renin-angiotensin-aldosterone syndrome.
What is the function of the kidney
Regulate Blood Ionic Composition Regulate Blood pH Regulate Blood Volume and Pressure Maintain Blood Osmolarity Produce Hormones Regulate Blood Glucose Levels Excrete Waste and foreign substances
How does the kidney regulate blood pH
Secrets H* and retains HCO3-
What enzyme/ hormone does the kidney secretes
Renin
EPO
Caltriol
What are the wastes secreted in the kidney
Urea/ Ammonia Bilirubin Creatine Uric Acid Hormone Metabolites
Where is Urea/ Ammonia from
Deamination of a.a.
What is bilirubin from
catabolism of hemoglobin
what is Creatinine from
Break down of creatine phosphate in muscles
Where is uric acid from
Catabolism of nucleic acids
Where is the Kidneys located
Anatomically between the last thoracic and the 3rd lumbar vertebrae
Partially protected by the 11th and 12 ribs
Approx 4-5 in long, 2-3 in wide, 1 in thick
What is the concave border of the kidney called
Hilum
What are the three external layers of the kidney
Renal fascia
Adipose capsule
renal capsule
What it’s the renal fascia
Outermost layer of the kidney
Dense C.T. That anchors the kidney and adrenal gland to the retro peritoneal wall
What is the adipose capsule of the kidney
Middle External layer
Called the renal fat pad
What is the renal capsule
The innermost layer of the external anatomy of the kidney
Smooth transparent C.T. That is continuos with the ureters
Maintains shape of kidney
What contains all of the glomeruli and convoluted tubules of the nephrons
-also makes the columns that lay between the pyramids
The Adrenal Cortex
Describe the Renal Medulla
Collection of all renal pyramids and contains all of the LoH and Collecting Ducts
Approx # of pyramids per kidney
8-18
What is the papilla
Narrow apex of the pyramid
-contains the papillary duct leading to the minor calyx
What makes up a renal lobe
Pyramid (medulla) the overlying cortex, and 1/2 of each adjacent column (cortex)
What is a minor calyx
Small chambers that collect urine directly from the papilla
What is a major calyx
Larger chambers that collect urine from the minor calyces
-2 to 3 per kidney, are extensions of the ureters
Describe the renal pelvis
Where Major calyces drain into one large chamber
- mixes and collects all urine in the entire kidney
- connects to the ureter
What is the renal sinus
3-d space that houses the blood vessels, adipose tissue and nerve supply to the kidney
What is the renal hilum
Indentation of the kidney where the ureters emerge along with the blood and lymph vessels, and nerves
Outline the blood flow from the Aorta to the Glomerulus
Aorta Renal Artery Segmental Artery Interlobar Artery Arcuate Artery Interlobular Artery (Radial Artery) Afferent Arteriole Glomerulus
Outline the blood from from the glomerulus back to the vena cava
Glomerulus Efferent Arteriole Peritubular Capillaries Vase Recta (Juxtamedullary Only) Interlobular Vein (Radial Vein) Arcuate Vein Interlobar Vein Segmental Vein Renal Vein Inferior Vena Cava
What is total renal blood flow?
What is it per kidney
1200 ml per minute
600 ml per kidney per minute
The glomerulus allows for ________ but not _______
Filtration
Not reabsorbtion
What is the fluid in the nephron called
Filtrate
When does filtrate become Urine
After leaving the collecting duct
What are the two parts of the nephron
Renal Corpuscle
Renal Tubule
What comprises the renal corpuscle
Glomerulus
And Bowmans Capsule
What comprises the renal tubules
PCT
LoH
DCT
Are the collecting ducts part of the nephron
NO
What are the two types of Nephrons
Coritcal nephrons ( most abundant) Juxztamedullary Nephons
What is the most abundant type of nephron
Cortical nephrons
Describe a cortical nephron
Renal Corpuscle lies int he outer renal cortex
Has a short LoH
Pertibular Capillaries only
Describe Juxtamedullary Nephrons
- Renal Corpuscles lie deep in the renal cortex
- Long LoH
- Peritubular Capillaries give rise to the vasa recta
What type of nephron lies in the outer cortex
Cortical Nephrons
What is signifigant about the afferent Arteriole
It brings blood TO the glomerulus
Has a wide thick lumen
What is significant about the efferent Arteriole
Is the Arteriole LEAVING the glomerulus
Smaller and thinner lumen
What is tubular reabsorption
Movement from the tubule to the capillaries
What is tubular secretion
Movement from the capillaries to the tubules
What percent of filtrate gets reabsorbed
99%
What is the GFR
Is the sum of all filtration rates of all functioning nephrons
How much filtrate do adults make a day , how much is reabsorbed , how much is made into urine
- 150 to 180 Liters of Filtrate a day
- 99% reabsorbed
- 1 to 2 liters of urine a day
What makes up the “leaky” barrier in the capsule/ glomerulus
Capillaries and Podocytes
What are the three layers of the filtration membrane
Fenestrations of endothelial cells
Basal lamina
Slit membranes between podcytes
What stops blood from passing into the Capsule
Fenestrated endothelial cells
What stops proteins from entering the capsule
Basal Lamina and podocytes/ pedícles
What regulates the surface area in the filtration membrane
Mesangial cells
Mesangial cells when relaxed ____________
When contracted
__________
- increase surface area
- reduce surface area
Where is capillary pressure highest in the body
In the glomerulus
Describe Glomerular Blood Hydrostatic pressure
GBHP
Pressure in the glomerulus pushing outward into the capsular space
~55mmhg
Describe Capsular Hydrostatic Pressue
CHP
Pressure exerted by the filtrate in the capsular space that pushes inward on the visceral glomerulus
Aka back pressue
~15 mmhg
Describe Blood Colloid Osmotic Pressure
BCOP
Pressure from proteins in blood plasma (MAINLY ALBUMIN)
Gravity
-opposes filtration-
~30mmhg
What is the FP equation
GBHP-CHP-BCOP
~55mmhg-15mmhg-30mmhg
=10mmg
When postive then filtration occurs
What is nephrolithiasis
Kidney Stone
What is hydronephrosis
Fluid retention in the kidneys
Pathologically caused by kidney stones
What is the GFR
Glomerular Filtration Rate
-the amount of blood filtered by the glomerulus into the capsular space per unit time
~90-140ml/ min in males
~80-125 ml/min in females
What happens is GFR is too fast
Filtrate passes to quickly and required substances may not get reabsorbed
What happens if GFR is too slow
Nearly all filtrate will be reabsorbed and certain wastes may not be secreted efficiently
Constriction of the afferent Arteriole….
Decrease glomerular pressure
-decrease RBF and GFR
Constriction of the efferent Arteriole
Increase glomerulus pressure
- decrease RBF
- increase GFR
Dilation of the efferent Arteriole
Decreases glomerular pressure
- increase RBF
- decreases GFR
Binational of the afferent Arteriole
increases glomerular pressure
-increases both RBF and GFR
What product is used to estimate GFR
Creatine clearance
What are mechanisms that regulate GFR
Renal Auto regulation (innate)
Neural Regulation (symp. NS)
Hormonal Regulation
(Angiotesin II and ANP)
What is the myogenic mechanism
Acute increase in BP stretches the afferent Arteriole
Causes smooth muscle contraction of the afferent Arteriole (reducing RBF)
(reduces GFR) initially
-protects the nephron from rapid changes in BP
When does myogenic mechanism occur naturally
In Systolic BP of 90-180
Immediate increase in BP causes …
Myogenic vasoconstriction and then compensatory vasodilation
What is tubuloglomerular feedback
Responds to changes in NaCL and H2O
Macula densa cells detect increase levels in the filtrate (GFR too fast)
- release ATP and adenosine
- causes both Afferent and Efferent Art to contract
- Decreases the GFR
What is the JGA
The juxtaglomerular apparatus
- A complex structure that has the ability to affect systemic BP through auto regulation of the tubuloglomerular feedback system
- one for every nephron
What are the three components of the JGA
-juxtaglomerular cells
(granular cells)
-Macula densa cells
-Lacis Cells
Where are Macula densa cells found
In the walls of the late thick ascending LoH
Where are Lacis Cells found
Between the Afferent, efferent, and DCT
What is another name from lacis cells
Extraglomerular mesangial cells
What are the two functions of the juxtaglomerular cells
Aka granular cells - Detect when BP is too low (Sensing stretch in the afferent arteriole) -Synth and secrete Renin (Helps to increases BP)
What are the two functions of macula densa cells
-detect increase NaCL in the filtrate
-release ATP and Adenosine
(Triggers contraction of afferent arteriole and lacis cells)
(Reduces GFR)
When a person is at rest
- how is sympathetic stimulation of the kidney
- how are the afferent and efferent Arteriole
Stimulation is low and the Arteriole are both dilated
What happens to ECF during the flight or flight response
Begins to be reduced due to metabolism
- triggers release of Epi/Norepi
- causes constriction of Afferent arteriole
What does Angiotensin II do
Ultimately reduces GFR -very potent vasoconstrictor (Effects both afferent and efferent0 (Effects efferent first) Cause a brief increase in GFR and then a reduction.
increases systemic blood pressure
What is the role of ANP/BNP
Secreted by the atria Detects over stretching in the heart Causes a reduction in BP (Dilates afferent but constricts efferent arteriole) (Increases GFR)
What role do prostaglandins play in hormonal regulation of GFR
Activated locally during hemorrhage or reduced ECF
- attempts to counteract the effects of angiotesin II
- helps prevent renal ischemia
How does N.O. Effect hormonal regulation of GFR
Endothelium derived relaxing factor
- helps conteract Angiotensin II
- Increases GFR
Causes vasodilation at aff and efferent Arteriole
( much more at aff)
What is the role of bradykinin
vasodilator that stimulates the release of NO and prostaglandins
-increases GFR
What is the role of adenosine
Produced within the kidneys
Causes vasoconstriction in tubuloglomerular feedback at the afferent arteriole
-reduces GFR
What is ACE
Angiotensin Converting Enzyme
- Located on the surface of afferent arteriole, glomerular capillaries, and lungs
- Converts Angiotensin I to II
- Reduces GFR
How is the RAAS activated
- In response to low afferent arteriole pressure, renin gets released
- stimulation of beta-1 In juxtaglomerular cells, renin gets released
- by decrease in NaCL detected by macula densa cells, renin gets released
What does renin interact with
Angiotensinogen, released by hepatocytes (liver)
Renin cleaves of a 10-amino acid peptid and creates Angiotensin I
Where is angiotensin I converted to II
Lung endothelium containing ACE
Kidney endothelium containing ACE
What are the specific functions of Angiotensin II
Decreases GFR
Enhances Na and Cl and H20 reabsoption in the PCT
(Increases blood pressure and volume)
-stimulates the adrenal cortex to secrete aldosterone
(Increases reabosption of Na and CL and to secrete more K* in the collecting ducts)
(Action on principle cells of the Collecting duct)
-Stimulates Post. Pituitary to release ADH
(Causes more H20 retention in the DCT and collecting ducts)
What structures are responsible for the plasma osmolartiy and volume
LoH
DCT
Collecting Ducts
where is the filtrate first “concentrated”
In the descending LoH
Permeable to water
Where is the filtrate initially “diluted”
The Ascending LoH
Impermeable to water
Where does final dilation/concentration occur
In the DCT and Collecting Duct
Where ADH as its actions
In the absence of ADH urine should be
Diluted
In the presence of ADH urine should be..
Concentrated
What are 6 characteristics of Urinalysis
Volume Color Turbidity Odor pH Spec. Gravity
What is normal urine production in a 24 hr period
1-2 liters
What is turbidity
When urine is clear when voided, becomes cloudy with time
What is the normal pH of Urine
4.6-8.0
Average~6.0
What does pyridium do to urine
Change its color (RED)
What is the specific gravity of urine
Density of urine
~1.001 to 1.035
The high the solutes the higher the value
What is a marker for bacterial pathogens in a UA
Nitrite
What is a marker for WBC in a UA
Leukocyte Esterase
What is the protein concentration in urine ?
Should be zero
What is a normal BUN
7-20 mg/dL
What does a BUN measure
Urea/ Uremia
Catabolism of proteins in the liver
When GFR reduces in renal disease, the BUN,,..
Increases
What are the two blood tests to test kidney function
Plasma Creatine
BUN
What does plasma creatinine measure
Catabolism of creatine phosphate
What is a normal SERUM creatinine level
Anything below 1.6 mg/dL
What is renal plasma clearance and why is it important
The volume of plasma (ml) that can be completely cleared of a substance per unit time (min)
Drugs like penicillin have high clearance rates, which means dosages must be high to be effective
What is a great measure of True GFR
Inulin Clearance
What are the lab values needed for complete UA
24hr urine collection
Urinary Creatinine
Plasma Creatinine
What is the path of urine from the Collecting Ducts to the toilet
Collecting Ducts Papilla Papillary Ducts Minor Calyces Major Calyces Renal Pelvis Ureters Urinary Bladder Urethra Toilet
What mechanical mechanism move urine out of the body
Peristalsis along with hydro-static pressure and gravity
Are ureters intro or retro peritoneal
RETRO
What is the anti-reflux mechanism of the bladder
When bladder fills with urine, it pulls the bladder down which closes the ureters and stops urine back flow
What are the three layers of the ureter
The adventitia
Muscularis
Mucosa
What is the Ureter Adventitia
Anchors the ureters to the surrounding tissues, contains the blood vessels, nerves, and lymphatic vessels
What is the muscularis of the ureter
Provides peristalsis
-outer circular, inner longitudinal smooth muscle
What is the ureter mucosa
Transitional epithelium with goblet cells that secrete mucus
(To protect from acidity of urine)
What is the capacity of the Urinary Bladder
700-800 ml
Where is the anatomical location of the Urinary Bladder
Posterior to the pues symphysis
Immediately anterior to the rectum in males
Inferior and slightly anterior to the uterus in females
HELD IN PLACE BY PERITONEAL FOLDS
What is the serosa
Visceral peritoneum
Covers superior surface of the bladder
What are the three layers of the
Muscularis
Inner longitudinal
Middle Circular
Outer Longitudinal
What is the detrusor muscle
The muscularis of the urinary bladder.
When contracts it forces urine into the urethra
What are the two parts of the mucosa of mucosa
Rugae- Folds which allow filing/ stretching
Trigone- Smooth triangular area of the bladder floor
The posterior corners is the uretal openings
The anterior corner feeds to the urethral sphincter
Describe the urethral sphincter
Smooth muscle (Circular)
(Extension of the detrusor muscle)
Involuntary
just above the prostate in males
Describe the external urethral sphincter
Skeletal muslce,
Deep perineal muscles/ pelvic floor
What are the three sections of the male urethra
- Prostatic
- Membranous
- Spongy
What is the shortest portion of the male urethra
Membranous portion
forms the urethral sphincter
What are cowpers glands
Bulbourethral Glands that help neutralize the acidity of the urine
What is the micturition reflex
Parasympathetic reflex initiatives mechanism for urination which causes
- involuntary contractions of the detrusor muscle
- internal sphincter to open
What stimulates the pituitary gland to release ADH
Angiotensin II
What are ACE inhibitors used to treat
Primary Hypertension
What does ACE inhibitors do
Inhibit conversion of angiotensin I to angio II
Also increase bradykinin, Increase RBF and GFR
Why do people on ACE inhibitor cough often
Bradykinin
What are ARBs
Angiotensin II receptor blockers
Block Angio II at the afferent arteriole
Increases RBF and GFR
What is the apical membrane of the tubules
The lumen side of the cell
What is the basolateral membrane of the tubules
The interstitial side of the cell
What segments of the Tubule is always permeable to water
The PCT and th descending LoH
What type of cells make up the PCT
Simple cubodial cells with microvilli
What type of cells make up the LoH thin descending and thin ascending
Simple squamous cells
What type of cells make up the thick walls of the LoH
Subodial to low columnar
What type of cells make up the DCT
Most of the DCT is simple cubodial cells
The last part of the DCT is contain principle cells and tntercalated disks
What do principle cells do
Have receptors for ADH and aldosterone
What do intercalated disks do
Play a role in blood pH
What kind of cells are in the Collecting Duct
Simple cuboidal cells
Also contain principle cells and intercalated disks