HNF 462 1stdition Lecture 17Outline of Last LectureI. Sodiuma. Sources b. Intestinal Absorptionc. BioavailabilityII. Potassiuma. Sourcesb. Intestinal and Cellular Absorptionc. BioavailabilityIII. Chloridea. Sourcesb. Intestinal Absorptionc. Bioavailability IV. Transport, Storage, and Excretiona. Sodiumb. Potassiumc. ChlorideV. Balancing Electrolytesa. ControlOutline of Current LectureI. Osmotic PressureII. Maintenance of Fluid Balancea. Hydrostatic Pressureb. ISF Colloid Osmotic Pressurec. Negative ISF Hydrostatic Pressured. Plasma Osmotic PressureThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.III. Regulation of Extracellular Water Osmolarity and Volumea. Renin-Angiotensin-Aldosterone b. Atrial Natriuretic PeptideIV. HypertensionV. Water, Electrolytes, and Muscle FunctionCurrent Lecture: Water and Electrolytes Pt 21. Osmotic Pressurea. The pressure that causes the movement of water across a semipermeable membrane that separates water with two different solute concentrations (from high water concentration to low water concentration)b. Movement of water is caused by concentration differences2. Maintenance of Fluid Balancea. Hydrostatic Pressurei. Dominant force that controls water movement from the blood to the ISFii. Created by the heart pumpingb. ISF Colloid Osmotic Pressurei. Weak force (due to low protein concentration) that controls water movementfrom the blood to the ISFc. Negative ISF Hydrostatic Pressurei. Weak force that controls water movement from the blood to the ISFd. Plasma Osmotic Pressurei. Force that controls water movement from the ISF to the bloodii. Caused by protein/other macromoleculese. At the arteriolar end of a capillary, blood is moving out of the blood. Water carries nutrients to cellsf. At the venule end of a capillary, blood is moving into the blood because hydrostatic pressure is weak due to the increase in distance and the higher concentration of proteins in the blood. Water moves wastes out of the cells into the bloodg. Electrolytes do not effect movement of water in between blood and the ISF3. Regulation of Extracellular Water Osmolarity and Volumea. Extracellular water: collection of liquid in the blood and in the ISFb. Controlled by smaller atoms (ex. potassium and sodium) because they effect osmoticpressurec. Renin-Angiotensin-Aldosterone regulates osmolarity and volumei. Kidney senses low blood pressure and produces renin (protein)ii. Renin cleaves angiotensinogen angiotensin Iiii. Angiotensin I is converted to angiotensin II (hormone that can increase blood pressure)1. Angiotensin-converting enzyme is produced by the lungsiv. Angiotensin II Increases BP1. Signals production of aldosterone = sodium/water retention increases blood volume = increased blood pressure2. Increases Vasopressin: signals water retention and thirst = increase in blood volumea. Produced by the hypothalamus in response to increased extracellular water osmolarity and decreased intravascular volumeb. Increases thirstc. Increases kidney water reabsorption (water retention)d. Increases kidney sodium absorptione. Net effect is a decrease in extracellular water osmolarity3. Promotes vascular constriction (narrows blood vessels)v. Regulates Na and K: increases sodium absorption (increases extracellular fluidosmolarity, which promotes fluid retention) and potassium excretiond. Atrial Natriuretic Peptide (ANP)i. Counteracts systems that increase blood pressure, works to decrease BPii. ANP is made by the heart when blood pressure is highiii. Heart muscle fibers are stretched when BP is high release ANPiv. Promotes NA excretion and water loss through urinev. Inhibits aldosterone production and renin release4. Hypertensiona. Defined by blood pressure >140/90b. Correlation between high sodium intake and high BP; reduction of sodium intake willdecrease BPc. DASH Trial: promotes low sodium and high potassium diet; shown to decrease BP5. Water, Electrolytes, and Muscle Functiona. Excitation of neurons relies on the correct cellular ratio of sodium and potassiumb. Water and electrolyte imbalance alters excitability of neurons and muscle cellsi. Overhydration lowers sodium concentration in bloodii. Dehydration pulls fluids out of