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1 Sports and Nutrition Exam 3 guide1. Describe the average fluid distribution, functions of water, relative tissue content and daily water balance both under normal and exercise conditions.- The average male is composed of 60% water, and a female is 55% water. Out of that 60%, 2/3 of it is intracellular fluid (ICF) and 1/3 is extracellular (ECF), and breaking the EFC down further is 80% interstitial (between cells) and 20% composes the plasma- Water has many essential functions, such as thermal heat capacity, many reactions, lubrication, transport, and an ionization medium for electrolytes. Basically any questioninvolving the function of water is “all of the above”.- If you want to look at the content is the tissues, the skin, organs, blood, and muscle (themost content) all are 75% or more water. Adipose is only 10% water, unless the person is really really really fat- Under normal conditions, water intake is around 2500ml and is mostly from ingested liquid. Output is mostly through the urine. In exercising conditions, intake is obviously greater at 5000ml and is from an increases ingested liquid (water from food is the same). Urine output is decreases substantially, because the body wants to hold onto the water, most is lost through the skin.2. Know the body content, functions, daily intake and concentrations of electrolytes discussed in class.- The two important electrolytes are sodium and potassium.  Sodium is present in the extracellular fluid at about 65g, and is involved mainly in the conduction of action potentials and maintaining the electrical gradient. It also controls the osmolality and acid-base balance as you will see later. Sinceit is an extracellular electrolyte, large amounts can be found in the sweat and Tony Berardi2plasma. The AI is 1500mg/d and the UL is 2500mg/d, but of course most Americas consume 1500-5000mg/d (big factor to cause hypertension and cardiac problems if interested) Potassium is an intracellular electrolyte and has the same functions as sodium, content of about 180g in the body. Most is thus in the cell. The AI is 4700 mg/d and most people don’t actually meet this number, and it is readily lost in the body. Some things to know that are extra information is that hypercalemia(huge excess potassium) can cause dangerous arrhythmias and be life threatening; it fucks up membrane conduction by lowering the resting potential of the heart, and this makes it harder to generate contractions. An injection of potassium can kill a person in seconds (lethal injection)3. Understand the equation to determine Net Filtration Pressure and be able to use this equation to solve a problem.- This equation will let you know if the fluid will be filtered (leave capillary) or absorbed (enter capillary). Blood always flows from the heart, to artery, to arteriols, then capillarys, and based on pressures, the water will act accordingly On the arterial end of the capillary, the hydrostatic pressure is greater (water pressure in capillary) and the osmotic pressure is lower (proteins and such) so it will have a net of water being filtrated (with the net filtration pressure heading out of the capillary). On the venous end, the reverse is true. Blood osmotic is high, thus net filtration pressure will be going into the cell.  Now to the formula, just plug in the numbers into the formula. He will give you the blood hydrostatic pressure, the blood osmotic pressure, interstitial fluid and interstitial osmotic pressure. Those last two are just numbers you willneed to determine the net filtration pressure. The formula is (Hydrostatic + Tony Berardi3interstitial osmotic)-(Osmotic + interstitial fluid). If the final value is positive, then you have filtration, and negative is reabsorption. 4. Identify which factors regulate fluid balance. Describe how each factor influences fluid balance.Which is primary response, long term, etc.- Fluid balance is regulated in the body by several precise mechanisms.  The first mechanism is actually dehydration. When an individual is dehydrated, several things happen: their plasma volume drops, which decreases their blood pressure, this response initiates the rennin system, rennin cascades to activate angiotensin 2, this stimulates thirst recepetors in the hypothamus, then one drinks and returns fluid level back to normal. This is a quick response (happens whenever one gets thirsty). Now to explain the hormones in detail One thing you that will help you understand is to realize that EVERYTHING in the body happens through a cascade/cause and effect; one thing always causes another. The first hormone is ADH, which is released from the posterior pituitary. This hormone increase water reabsorption from the collecting ducts in the kidney, increasing ones plasma volume. So one first gets an increase in osmolarity (because water content decreases, so it is more concentrated), this stimulates osmorereceptors in the hypothalamus, they stimulate the posterior pituitary to release ADH, ADH then helps reabsorb water in the collecting ducts. This will result in concentrated urine (super yellow) because you are absorbing the water from the kidneys and its osmolarity is increasing. More importantly, plasma volume is increased/osmolarity drops in the blood. The second mechanism accomplishes the same end result, to increase plasma volume, but does it through a different mechanism. The rennin-aldosterone mechanism works to increase the Na absorption in the collecting ducts, and water follows Na (because of osmosis), thus the end effect is the same to increase plasma volume. This is stimulate when plasma volume decrease, and this stimulates the JX cells of the kidney, this releases rennin, rennin cleaves Tony Berardi4angiotensinogen (inactive protein) to angiotensin 1, then in the lungs angiotensin 1 is cleaved to angiotensin 2 (ACE does this, and this is what ACE inhibitors stop), angiotensin 2 now acts on the adrenal gland to release aldosterone, aldosterone then acts the reabsorb Na/vasoconsticts the blood vessels. This will result in an increases plasma volume.  Aldosterone also increases potassium secretion to help maintain that electrolyte balance. So through these two mechanisms, fluid volume is regulated. ADH is more of a short term mechanism, and rennin-aldosterone is more long-term acting/slow acting. 5. Describe physiologically how dehydration affects fluid balance in the different


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FSU PET 3361 - Sports and Nutrition Exam 3 guide

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