Fluid compartments fall into these two categories. (What fraction is in each?)
1. Intracellular 2/3
2. Extracellular 1/3
Extracellular fluid is further broken down into...
Interstitial Fluid- 3/4
Other: blood, lymph, adipose, digestive tract
Which hormones regulate Na+ and Cl-?
- Angiotensin II (dehydration)
- Aldosterone (dehydration)
- Atrial natriuretic peptide (ANP) (overhydration)
Angiotensin II and Aldosterone cause:
- Increased tubular reabsorption of Na+ & Cl-
- Increased water by osmosis
- Increase BV
- Decrease GFR
Atrial natriuretic peptide ANP promotes:
- Increased secretion of Na+ & Cl-
- Decreased water by osmosis
- Decreased BV
- Increase GFR
Which hormone also regulates water loss directly? & how?
Antidiuretic hormone (ADH)- by increasing the permeability of the collecting ducts to water by promoting insertion of aquaporin-2 into the principle cells
What are the four functions of ions?
1. Control osmosis among fluid compartments
2. Conduct electricity
3. Serve as cofactors
Osmotic pressure by proteins on either side of the capillary membrane is called...? What other force is involved?
- Oncotic pressure
- hydrostatic forces
How do you determine the net movement of fluids?
Forces favoring flitration - Forces opposing filtration
What are the most important causes of edema?
- High BP (excess ions)
- Blockage of lymph flow
- Decreased plasma protein concentration
- Increased capillary permeability
What helps regulate the pH of the systemic arterial blood, in a healthy person? = 7.35-7.45
- Chemical buffers
How do chemical buffers, lungs and kidneys regulate pH?
Chemical buffers- act quickly to temporarily bind excess H+ or OH-
Lungs- change the rate and depth of breathing, CO2 is exhaled or retained & blood pH is corrected
Kidneys- excretion/reabsorption of acidic ions or basic ions, slowest mechanism, but only way to eliminate acids
What is it called and what happens when too CO2 is accumulated (Hypoventilation)?
"Respiratory acidosis" - when the blood is too acidic, causes shortness of breath, asthma, bronchitis
What causes metabolic acidosis?
ketoacidosis (diabetic, starvation diet), aspirin overdose; blood is too acidic