0:00 Hello, in this video, we're going to talk about body fluid compartments and 0:11 also touch 0:11 on electrolytes. 0:13 The body can be divided into solids and water. 0:17 Solids make up about 40 to 50%, depending if you're male or female. 0:22 Water accounts for about 60% of the total body weight for an adult male and 50% 0:28 of that 0:29 for an adult female. 0:31 This difference between the sexes reflects the proportionality of larger mass, 0:36 of adipose 0:37 tissue and adult females, and the greater average muscle tissues in adult males 0:43 . 0:43 Solids are things such as protein, lipids, carbs, and minerals. 0:48 In this example, the total volume of water is that of an average adult male and 0:54 is about 0:55 40 liters. 0:56 The total body water is distributed into two fluid compartments. 1:01 The extra cellular fluid, ECF, and the intra cellular fluid, ICF. 1:08 ECF is about 1/3 of total body fluid, which means about 15 liters, let's just 1:17 say. 1:18 The ICF is 2/3 of total body fluid, which is about 25 liters. 1:26 ECF can be further divided into the plasma, which is fluid in the circulation. 1:33 Fluid in the circulation make up about 20% of the extra cellular fluid. 1:40 The remaining 80% is found in the interstitium, which is fluid found between 1:47 the cells. 1:48 The intra cellular fluid, ICF, is basically fluid that's inside the cell, and 1:54 as mentioned 1:55 is where most of the total body fluid is found. 1:59 Inside the cell means basically where the nucleus is, and again the nucleus, 2:05 holds the 2:05 cell's DNA. 2:09 We mainly get fluid from drinking water and eating food, and so the main fluid 2:16 input is 2:17 basically from the gastrointestinal tract. 2:19 We need roughly 2,500 ml per day, which is required to balance your average 2:31 water loss. 2:33 Of course, water enters firstly the extracellular fluid, first from the 2:41 gastrointestinal tract. 2:43 Water can then move between the different fluid compartments in the body like 2:48 so. 2:49 Intracellular fluid contains 2/3 of the total body water, and again, extrace 2:54 llular fluid 2:55 contains the rest only 1/3. 2:58 Really important to understand that water moves passively between fluid comp 3:02 artments, 3:03 either via channels or between cells. 3:05 No need for active transport, no need to spend energy to move water between 3:10 fluid compartments. 3:12 Movement of water occurs passively in response to osmotic gradients. 3:18 To demonstrate this concept, imagine a jaw like this represents your body. 3:22 A semi-permeable membrane separates the jaw into two compartments. 3:28 You have more solutes on the right compartment, and through osmotic gradients, 3:31 principal fluid 3:32 will shift to the area with more solutes, and this is osmosis. 3:37 We talked about fluid input through the gastrointestinal tract. 3:41 Fluid output occurs through other roots, the kidneys, the gastrointestinal 3:46 tract, the lungs 3:47 and the skin. 3:51 You lose about 2,500 ml of water each day. 3:56 Once fluid accumulates in the interstitium, for example due to disruption in 4:01 solute concentration 4:03 across the plasma and the interstitial space. 4:06 The body has ways to fix this, and this is through the lymphatics. 4:12 Fluid may also travel from the interstitium, from the interstitial space, to 4:16 the plasma 4:17 through the lymphatic vessels that drain into the venous circulation. 4:24 Let's now talk about electrolytes. 4:26 We have many electrolytes that are distributed throughout the body's comp 4:31 artments. 4:32 In the extracellular fluid, we can find sodium, potassium, calcium and chloride 4:38 , which can 4:39 move between the plasma and the interstitium via semi-permeable membranes. 4:45 The concentration of electrolytes in the plasma and the interstitium is about 4:52 the same. 4:53 For example, sodium in blood is about 145 millimoles per liter. 4:59 Potassium is 4, calcium is 2.5, and chloride is 115 on average. 5:06 Electrolytes can't just move through the lipid membrane between the extrace 5:11 llular fluid and 5:12 the intracellular fluid. 5:15 They often rely on transport channels. 5:18 For example, sodium and potassium move via sodium-potassium pumps, where 3 5:25 sodium is transported 5:26 out of the cell in exchange for 2 potassium inside the cell. 5:31 This type of channel requires ATP. 5:34 This sort of mechanism allows the different gradient of ions across the body 5:39 compartments. 5:40 Because inside your cell, you have 12 millimoles per liter of sodium and 5:46 potassium you have 5:47 155 millimoles per liter. 5:50 Interest cellular calcium is less than 0.5 and chloride is 4. 5:57 You can see straight away that the main cation in the extracellular fluid is 6:02 sodium. 6:03 The main cation in the intracellular fluid is potassium. 6:08 The main anion in the extracellular fluid is chloride and the main anion in the 6:15 intracellular 6:16 fluid are the negatively charged proteins, but the main electrolyte is 6:23 phosphorus. 6:24 Proteins are also found in the plasma, but not in the interstitium. 6:29 Not in the interstitial fluid. 6:31 The main protein found in plasma is albumin and albumin helps maintain the osm 6:36 otic gradient. 6:38 Those keep water in the blood vessels. 6:40 Phosphorus in the phosphate form is the main anion in the intracellular fluid. 6:46 Other important negatively charged ions are bicarbonate, which is very 6:52 important acid 6:53 base balance. 6:55 These electrolyte levels are very important to know and understand because if, 7:01 for example, 7:01 you have high concentrations of calcium or potassium in plasma or in the ext 7:07 racellular 7:08 fluid, cardiac arrhythmias can develop and death can result. 7:13 All the homostatic mechanisms that monitor and adjust the composition of body 7:18 fluids 7:18 responds to changes in the extracellular fluid, not the intracellular fluid. 7:26 In summary, sodium is the main extracellular fluid cation, chloride is the main 7:34 extracellular 7:34 fluid anion, potassium is the main intracellular fluid cation, phosphate or 7:40 phosphorus is the 7:41 main intracellular fluid anion, and bicarbonate is important in acid base 7:47 balance. 7:56 [BLANK_AUDIO]
