Week 1 - Salt & Water Handling Flashcards
What determines extracellular fluid volume?
Sodium content (total body sodium content)
What determines intracellular fluid volume?
Sodium concentration
What are some effectors of Na+ regulation?
RAAS PGs (PGI2) Renal sympathetic nerves ANP NO
What is an example of ANP?
Uroguanylin
What does increased Na+ content cause?
edema
What does decreased Na+ content cause?
Hypovolemia or shock
–> Can lead to low Na+ concentration (via ADH induced H2O retention)
What does increased water content cause?
Intracellular edema (due to hyponatremia?)
What does decreased water content cause?
This is the least common of Na+/water imbalances
Sudden drop in water content can cause osmotic demyelination (don’t need to know the details of this yet)
What is being sensed in Volume Regulation?
Effective circulating volume
What is being sensed in Osmoregulation?
Plasma osmolarity - intracellular osmolarity
What are the sensors for Volume Regulation? (3)
Carotid sinus
Atria
Renal Circulation
What is the sensor for Osmoregulation?
Hypothalamus
What are some effectors of Volume Regulation?
Sympathetic Nerves RAAS ANP Pressure Natriuresis ADH
What is the main effector of Osmoregulation?
ADH
What is effected in Volume Regulation?
Sodium excretion
What is effected in Osmoregulation?
Water excretion (via ADH) Water intake (thirst)
What is the concentrating segment of the nephron? Why?
The descending limb (because water is reabsorbed here)
What is the diluting segment of the nephron? Why?
The ascending limb (because Na+ & K+ & Cl- are all being reabsorbed)
Where does ADH act?
What does it do?
Collecting duct
Either permits or does not permit reabsorption of water
What would cause ADH release to be inhibited?
Drinking a big glass of water
What is the sympathetic innervation to the kidneys?
Afferents from T10-L1
What is the parasympathetic innervation to the kidneys?
Vagus (CN X)
Where is referred kidney pain usually felt?
Dermatomes T10-T12 on the back, “flank pain”
Where are the venous sensors for Na+ regulation?
What do they detect?
Right Atrium (detect stretch) & Pulmonary Receptors (sense early pulm edema)
What happens after the right atrial stretch receptors are activated?
- stimulates release of ANP
- inhibits ADH
- decrease in vascular resistance
What are the pulmonary receptors?
What happens when they are activated?
Nerves adjacent to the pulmonary capillaries.
- inhibit SNS
What is tonicity?
the effective osmolality
What is osmolality?
The amount of osmotically active particles in solution divided by mass of solvent (water)
What are effective osmoles?
solutes that cannot move across cell membranes
At any given time, what percent of the body’s blood volume is located in the venous system?
70%
What are 4 causes of metabolic acidosis?
Ketoacidosis
Lactic acidosis
Renal Failure
Toxins/OD
