Chapter 20 Flashcards
cell membrane
selectively permeable
Remember mass balance
amount comes in has to come out
what happens if GFR stops
no ability to regulate osmalarity
water loss that can be regulated
urine
what controles fluid and electrolyte balance
renal, respiratory, and cardiovascular systems
what controles fluid and electrolyte balance
renal, respiratory, and cardiovascular systems
behavioral mechanisms
thirst and salt craving
What effects cell volume
ECF osmolarity
solute in terstitial medulla
Urea
solute in terstitial medulla
Urea
The Medullary Osmotic Gradient
- Filtrate entering the descending limb becomes progressively more concentrated as it loses water.
- Blood in the vasa recta removes water leaving the loop of Henle.
- The ascending limb pumps out Na+, K+, and Cl-, and filtrate becomes hyposmotic. (lower osmotic pressure)
The Medullary Osmotic Gradient
- Filtrate entering the descending limb becomes progressively more concentrated as it loses water.
- Blood in the vasa recta removes water leaving the loop of Henle.
- The ascending limb pumps out Na+, K+, and Cl-, and filtrate becomes hyposmotic. (lower osmotic pressure)
Ascending loop of henle transport types
Cotransport
Active transport (Na)
Impermeability to Water (NO WATER)
Chemical Gradient (everything else)
Electrochemical balance
Ascending loop of henle transport types
Cotransport
Active transport (Na)
Impermeability to Water (NO WATER)
Chemical Gradient (everything else)
Electrochemical balance
h2o movement
driven by the osmotic gradient between the tubule and interstitial fluid
What is impermeable to ions
escending loop of henle
What reabsorbs water and ions
Vasa Recta
What reabsorbs water and ions
Vasa Recta
Osmolarity of Urine:
how much water is excreted in the urine by the kidneys (alters amount of Na and Water reabsorbed in nephron)
Diuresis
removing excess water in urine
Low osmolarity
High
Dilute urine (kidney reabsorb ions but not water)
H - Concentrated Urine (Kidney reabsorb water not solute)
Vasopressin
= water reabsorbtion
secreted by posterior pituitary
greater vasopressin = greater water conservation
acts on Collecting duct cells
In distal nephron does water follow Na?
NO, Vasopressin is required in distal nephron to make it permeable to H2o
more vasopressin effect on urine
causes high concentration of urine
No vasopressin
urine
diluted urine as water is not reabsorbed in the nephron
vasopressin effect on permiability
yes it has an effect to make collecting duct more permeable to water
Stimuli for vasopressin
Plasma osmolarity
Blood pressure
Blood volume
Stimuli for vasopressin
Plasma osmolarity
Blood pressure
Blood volume
Distal portion of nephron Na reabsorbtion
Reulated by aldosterone (steroid hormone)
Distal portion of nephron Na reabsorbtion
Reulated by aldosterone (steroid hormone)
Aldosteron
target is principle cells of Distal tubules and collecting ducts
Increases Na reabsorbtion and K secretion
Aldosteron
target is principle cells of Distal tubules and collecting ducts
Increases Na reabsorbtion and K secretion
Aldosteron is regulated by
Increased extracellular K+ concentrations.
- (hyperkalemia)
Decreased blood pressure
Angiotenssin 2 - stimulates aldosterone secretion.
Decreased plasma Na+.
Increased ECF osmolarity. Inhibits aldoterone
aldoterone response
early - Result is increased Na+ reabsorption and K+ secretion
slower - Allows for a quicker response and greater capacity for Na+ reabsorption
What inhibits renin
High fluid flow causes macula densa to release paracrine to inhibit renin
ANG II effects
- Stimulates the adrenal cortex to produce aldosterone
Increases blood pressure through these pathways: - ANG II increases vasopressin secretion
- ANG II stimulates thirst
- ANG II is one of the most potent vasoconstrictors
- Activation of ANG II receptors in the cardiovascular control center increases sympathetic output to the heart and blood vessels
- ANG II increases proximal tubule Na reabsorbtion (followed by water reabsorbtion)
Atrial Natriuretic peptide (ANP)
Promotes Na and water excretion
Does opposite of RAAS
RAAS vs ANP
RAAS wants to increase water and Na reabsorbtion
ANP increases water and Na excretion
RAAS vs ANP
RAAS wants to increase water and Na reabsorbtion
ANP increases water and Na excretion
pH
drops = increase acidity
normal plasma range = 7.38-7.42
Ph changes
Denature proteins
affect nervous system (acidosis = less excitable)(alkalosis=more excitable)
Ph changes
Denature proteins
affect nervous system (acidosis = less excitable)(alkalosis=more excitable)
How to regulate pH
Buffers (1st line of defense, and decreases effect of pH change, found in ICF and ECF) (eg - Bicarbonate/ Hb)
Molecule that moderates changes in pH by binding or releasing H+.
Ventilation
Rapid and reflexive control of pH by changes in ventilation.
Kidneys
Renal regulation of H+(direct) and HCO3- (indirect)(excrete or reabsorb)
How to regulate pH
Buffers (1st line of defense, and decreases effect of pH change, found in ICF and ECF) (eg - Bicarbonate/ Hb)
Molecule that moderates changes in pH by binding or releasing H+.
Ventilation
Rapid and reflexive control of pH by changes in ventilation.
Kidneys
Renal regulation of H+(direct) and HCO3- (indirect)(excrete or reabsorb)
High osmolarity effect on aldosterone
inhibits aldosterone
