Unit 7 Flashcards
BLOOD FILTRATION: location and function
Location: glomerulus
Remove waste products from blood
REABSORPTION: location and function
Location: nephron
Recover nutrients, ions, H2O
SECRETION: location and function
Location: nephron
Assists filtration by removing waste products directly from blood
ACTIVATION: Vitamin D
- Dehydrocholesterol → vitamin D3 by ultraviolet (UV) light @skin
- Vitamin D3 → calcitriol @kidney
Location where Calcitriol ↑Ca++ deposition
@bone
Location where Calcitriol ↑Ca++ reabsorption
@kidneys
Location where Calcitriol ↑Ca++ absorption
@small intestines
ENZYME RELEASE: Renin
location what does renin converts to
- Location: kidneys
- Renin converts Angiotensinogen → Angiotensin I → Angiotensin II
Function of Angiotensin II
- vasoconstricts (↑blood pressure)
- Causes aldosterone (hormone) release (adrenal cortex) which stimulates DCT to reabsorb salt, H2O follows the salt
AUTOREGULATORY LIPID RELEASE: Prostaglandins
location and function
- Location: kidneys
- Prostaglandins: vasodilate (↓blood pressure)
H+ SECRETION:
- Eliminates excess hydrogen ions
- Controls acid/base (pH) balance
HCO3– REABSORPTION:
- Recovers bicarbonate ions
- Controls acid/base (pH) balance
HORMONE RELEASE: Erythropoietin (EPO) (location and function)
Location: kidneys
EPO ↑RBC production (bone marrow)
Function of Renal Artery:
Transports ↑O2 blood from aorta → kidney (filtration)
Function of Renal Vein:
Transports filtered ↓O2 blood from kidney → inferior vena cava
Function of Renal Column:
- Area between renal pyramids (medulla)
- Site for blood vessel passage to the cortex
Function of Nephron:
- Kidney FUNCTIONAL UNIT
- Filtration, reabsorption, & secretion
Function of Capsule:
- Thick outer membrane
- Surround & protect
Function of Cortex:
- Outer layer
- Contains most of the nephron
- Filtration, reabsorption & secretion
Function of Medulla:
- Inner layer
- Nephron structures not located in cortex
- Salt, water & urea reabsorption
Function of Renal Pyramids:
- Triangle-shape
- Loops of Henle, collecting ducts, & counter-current multiplier system (concentrates salt & saves water)
Function of Renal Papilla:
- Renal pyramid apex
- Releases urine → minor calyx
Function of Minor Calyx:
- Collecting sac surrounding papilla
- Transports urine from papilla → major calyx
Function of Major Calyx:
- Collecting sac
- Transport urine from minor calyces → pelvis
Function of Renal Pelvis
Collects urine from major calyces → ureter
Function of Ureter
Transport urine from renal pelvis → bladder
Function of Urinary bladder:
- Stores urine from ureter
- Releases urine → urethra
Function of Urethra:
Releases urine → outside
Function of Afferent Arteriole:
Transports arterial blood → glomerulus (filtration)
Function of Efferent Arteriole:
Transports filtered blood from glomerulus → peritubular capillaries & vasa recta → renal venous system
Function of Glomerulus:
- Blood filtration
- Nonspecific filter
- Removes both useful & non-useful materials into filtrate
Function of Bowman’s Capsule:
- Sac that encloses glomerulus
- Transfers filtrate from glomerulus → Proximal Convoluted Tubule (PCT)
Function of Proximal Convoluted Tubule (PCT):
- Reabsorbs most of the useful substances in the filtrate: Na+ (65%), H2O (65%), HCO3– (90%), Cl– (50%), glucose (100%)
- Primary site for secretion of toxins, wastes & hydrogen ions (H+)
Function of Descending Limb of the Loop of Henle (DLLH):
- Counter-current multiplier system
- Permeable to H2O
- Impermeable to solutes (salts)
- Receives filtrate from the PCT; allows H2O to be reabsorbed; sends “salty” filtrate to ALLH; “Saves water & passes salt”
Ascending Limb of the Loop of Henle (ALLH):
- Counter-current multiplier system
- Impermeable to H2O
- Permeable to salts
- Actively transports (reabsorbs) salts (NaCl) into the interstitial fluid of the medulla; “Saves salt & passes water”
- Filtrate becomes dilute; interstitial fluid of medulla becomes hyperosmotic (salty)
Function of Distal Convoluted Tubule (DCT):
- Receives dilute fluid from ALLH
- If Aldosterone (hormone) is present, sodium is reabsorbed, (Cl– & H2O follow Na+); Potassium (K+) is se
Function Collecting Duct:
- Receives fluid from DCT
- If antidiuretic hormone (ADH) is present, collecting duct becomes porous to water
- Collecting duct H2O moves (osmosis) to the “salty” (hyperosmotic) medulla
Where is the LAST CHANCE to save water?
The collecting duct
Function of Peritubular Capillaries:
Transport reabsorbed materials from PCT & DCT → renal veins
Function of Vasa recta:
- Blood vessels of the peritubular capillary network
- Surround descending & ascending loops of Henle
Filtration Structures of Glomerulus:
-Filtration site
Screen-like:
-Fenestrated glomerular capillaries (podocytes w/ pedicels)
-Allows passage of H2O & solutes smaller than plasma proteins
Net filtration pressure of blood hydrostatic pressure (BHP)
60 mm Hg (out)
Net filtration of colloid osmotic pressure (COP)
-32 mm Hg (in)
Net filtration of capsular pressure (CP)
-18 mm Hg (in)
Total net filtration pressure (NFP)
10 mm Hg
What does the Juxtaglomerular Apparatus (JGA) contain?
- Macula densa cells (DCT)
- Granular cells (afferent arteriole)
Function of Juxtaglomerular Apparatus (JGA)
maintain blood pressure
What does Granular cells detect and release?
detect ↓pressure; release renin
What does Renin convert?
Renin converts angiotensinogen → angiotensin I → angiotensin II
What does Macula dense monitors?
blood salt
What does macula dense do when high blood salt content occurs?
- macula densa inhibits granular cells
- Inhibits renin release, which
- Inhibits Angiotensin II (causing vasodilation & ↓blood pressure)
- Aldosterone inhibited (↓blood volume & ↓blood pressure)
Summary of Granular cells
↑Blood volume & ↑BP
Summary of Macula Densa
(inhibit granular cells)
↓Blood volume & ↓BP
Ascending limb of loop of Henle (ALLH): (counter-current mechanism)
- Reabsorbs salt (active transport) → interstitial tissue of the medulla
- Makes medulla hyperosmotic (salty)
What leaves Ascending limb of loop of Henle (ALLH) during counter-current mechanism
Salt (NaCl)
Osmolarity of Ascending limb of loop of Henle (ALLH) fluids
Osmolality of ALLH fluid decreases from 1200 to 100 milliosmoles/L (mOsm/L)
- ALLH is impermeable to H2O
- Remove salt from filtrate
- Accumulate salt in medulla
Accumulated salt in medulla is used to “draw-out” water (osmosis) from:
1) DLLH (H2O permeable, salt impermeable)
2) Collecting duct
Is DLLH permeable to H20?
- DLLH is H2O permeable & loses H2O to the medullary interstitial tissue
- H2O is reabsorbed by medullary blood vessels
- Osmolality of DLLH fluid changes from 300 to 1200 mOsm/L
- Saves H2O
Where does ALLH transfer salt into?
- ALLH actively transfers salt into medulla
- Medullary salts attract H2O out of DLLH
Hyperosmotic (salty) medulla
- Hyperosmotic (salty) medulla will also “pull-out” H2O from the collecting duct if ADH (hormone) is present
- H2O moves out of collecting duct (urea follows)
- Urea contributes to ↑osmolality of the medulla
What makes ADH?
Hypothalamus
Where is ADH stored and causes?
- ADH stored in posterior pituitary & released (if dehydration)
- ADH causes collecting duct “pores” to open
- H2O moves from collecting duct → medulla
As H2O leaves the collecting duct:
- Collecting duct fluid becomes more concentrated (↑osmolality of collecting duct fluid 100 to 1200 mOsm/L)
- If ADH is not present, H2O is lost in dilute collecting duct fluid (100 mOsm/L)
Vasa recta is permeable to:
salts and water
How does vasa recta vessels flow?
- flow counter-current to loop of Henle fluid (counter-current exchange)
- Blood flowing through vasa recta absorbs H2O (not salts)
- Vasa recta return H2O back to body & leave salts (maintain hyperosmotic medulla)
Equation of excretion and why does the difference mean?
- Excretion = Filtration – Reabsorption
- Difference between filtration & reabsorption determines how much of a substance kidneys eliminate per unit of time
Filtration: 16 grams of NaCl per day Reabsorption: 14 grams of NaCl per day
WHAT IS THE EXCRETION?
Excretion: 2 grams of NaCl per day
Amount Excreted =
Amount Filtered – Amount Reabsorbed
2g NaCl/day =
16g NaCl/day – 14g NaCl/day_______________ = 100g of glucose – 100g of glucose
Find the missing value
0.0g
100g of glucose = _____________ – 300g of glucose
Find the missing value
400g
200g of glucose = 400g of glucose – _____________
Find the missing value
200g
Renal Plasma Clearance Rate (RPCR) definition
amount of plasma cleared of a substance per minute
Kidneys conduct clearance through:
- Filtration
- Reabsorption
- Secretion
How does filtration affect clearance?
- Filtration directly affects clearance
- ↑Filtration → ↑material removed from blood plasma
How does reabsorption affect clearance
- Reabsorption indirectly affects clearance
- ↑Reabsorption → ↓material removed from blood plasma
How does secretion affect clearance
- Secretion directly affects clearance
- ↑Secretion → ↑material removed from blood plasma
C = (V x U) ÷ P
What does the C mean?
C = clearance rate (mL/min)
C = (V x U) ÷ P
What does the V mean?
V = urine production rate (mL/min)
C = (V x U) ÷ P
What does the U mean?
U = substance conc. in urine (mg/mL)
C = (V x U) ÷ P
What does the P mean?
P = substance conc. in plasma (mg/mL)
After a dose of inulin, urine has 30 mg/mL & plasma has 0.5 mg/mL of inulin (urine production rate (V) is 2.0 mL/min)
What is inulin clearance rate?
C = (V x U) ÷ P
120 mL/min of inulin
120 mL/min = (2 mL/min x 30 mg/mL) ÷ 0.5 mg/mL
Renal calculi (kidney stones) cause and effect:
- Cause: crystallization of calcium (Ca++), magnesium (Mg++), uric acid salts
- Precipitate w/in renal pelvis
- Calculi become large & travel down the ureter
- Effect: intense pain radiates from lower back to anterior abdominal wall (same side as renal calculus)
Cystitis (bladder infection) cause and effect:
- Cause: bacteria from anal region, sexually transmitted disease (STD), & chemicals
- Effect: inflammation, pain, fever, ↑urination
Glomerulonephritis (Bright’s Disease) cause and effect
- Cause: abnormal immune response (autoimmune)
- Inflammation of glomeruli
- Streptococcal antibody complexes
- Effect: abnormal filtration, renal failure
Incontinence cause and effect:
- Cause: old age, emotions (laughing), pregnancy, nerve damage, stress, excessive coughing
- Effect: loss of voluntary micturition
Gout (Gouty Arthritis) cause and effect:
- Cause: uric acid crystals in the soft tissues of joints (base of great toe)
- ↑Uric acid intake
- ↓Uric acid excretion (genetic)
- Effect: bone ends fuse & immobilize the joint
- **Note: humans, apes, dalmatians lack enzyme uricase (breaks down uric acid)
Gouty Arthritis Treatment
- Nonsteroidal anti-inflammatory drugs (NSAIDs)
- Glucocorticoids (cortisol)
- Avoid foods rich in organ tissue (liver, kidney, etc.)
- Recommendation: avoid processed meats, & organ meats rich in nucleic acids (purines)
Hemodialysis uses a ________ to transfer a patient’s blood plasma through a _____________ tube (permeable to selected substances)
machine, semi-permeable
Dialysis machine contains a dialysis fluid that produces a ________ gradient (↑ to ↓)
diffusion
Gradient allows abnormal substances to diffuse from blood plasma (produces a “________” effect)
cleansing
Def of dialysis
process to artificially remove metabolic wastes from blood plasma
What does dialysis therapy compensate for renal failure lead to?
- ↑Nitrogenous wastes (urea & ammonia)
- Ion imbalances
- pH imbalances
- Breathing imbalances
- Convulsions
- Coma
- Death
Key Aspects of dialysis therapy
- Blood is transferred from an artery (arm)
- Blood returns to a vein
- Blood is heparinized (prevent clotting)
- Dialysis sessions 3 times/week
- Each session = 4-8hrs
- Can lead to thrombosis (blood clots), infection & death of tissue (necrosis) around a shunt (access site in arm)
