Body Solutions T H E C H E M I S T RY O F S O L U T I O N S I N Y O U R B O D Y

Transcription

1 Body Solutions T H E C H E M I S T RY O F S O L U T I O N S I N Y O U R B O D Y

2 The human body is composed mostly of water.

3 Approximately 60% of the body s total water content is contained inside cells. 20% of that is the liquid component of the blood and is present in the heart, our arteries, veins and capillaries. The remaining 20% include the fluids that bathe all the cells, spinal fluids, lymph, ocular fluid (eye), synovial fluid (joints), and various secretions such as saliva, bile, gastric juice and mucus.

4 The human brain is about 85% water and our bones are between 10 to 15% water. 70% of your muscle is water

5 Water is one of the very best diet aids and fat reducers. It: Suppresses your appetite, Reduces sodium buildup, Helps maintain muscle tone, Helps the body eliminate waste and toxins. Relieves fluid retention. (If you don t give your body water, it holds onto water) Reduces fat deposits in the body by helping the body metabolize the fat that is stored.

6 Water serves as a lubricant in digestion and almost all other body processes. The water in saliva facilitates chewing and swallowing, ensuring that foods will slide easily down the esophagus. Water in other digestive fluids sustains movement throughout the gastrointestinal system.

7 The watery fluid surrounding joints and eyeballs helps them move smoothly and is their only lubricant. Water carries oxygen and nutrients into all your cells.

8 Water is a perfect conductor of electricity. This becomes important for nerve impulses travel, for example. Water also helps regulate your body temperature.

9 Coffee, tea or soda pop that you drink don t count as part of your water intake, because if these products are caffeinated (and most of them are) it has just the opposite effect on our bodies. Caffeine acts as a diuretic and actually results in water reduction to our bodies.

10 By the time a person feels thirsty, his or her body has lost over 1 percent of its total water amount.

11 Is it possible to drink too much water? Drinking too much water too quickly can lead to water intoxication. Water intoxication occurs when water dilutes the sodium level in the bloodstream and causes an imbalance of water in the brain.

12 Does it make a difference what kind of water I drink? If you put either distilled or de-ionized waters into a bowl of gold fish they will die..there is no longer any oxygen in the water. Also, our bodies need the minerals that are in water. We can only adsorb minerals which are water soluble.

13 The chemistry that happens in solution is very important to the function of all your body s systems. Enzymes and hormones are all dissolved in watery body fluids and act on metabolites (amino acids, carbohydrates, vitamins and minerals) that are similarly dissolved. As a solvent containing these substances, water is necessary for transport to and from all cells of the body.

14 Nutrients begin their travels by entering the bloodstream, or circulation as water, which will carry them to where they are needed.

15 Electrolytes Substances that form ions in solutions are called electrolytes. When electrolytes such as sodium chloride dissolve in water, their ions will conduct electricity through the solution. (A substance such as table sugar will not form ions in solution and will not conduct electricity.)

16 Electrolytes are important because they are what your cells (especially nerve, heart, muscle) use to maintain voltages across their cell membranes and to carry electrical impulses to other cells. Your kidneys work to keep the electrolyte concentrations in your blood constant despite changes in your body.

17 example: Sodium (Na)+ Without sodium, the body will lack extracellular fluid and might affect blood pressure, leading to insufficient circulation of oxygen causing drowsiness, nausea etc. Most people s diet has much more sodium than the body needs.

18 example: Potassium (K)+ Potassium is extremely important in electrolyte function since 95% of your body's cells are made up of Potassium. Potassium deficiency in the human body is characterized by muscle weakness, fatigue, mental confusion, irritability, heart disturbances, and problems in nerve conduction and muscle contraction. This is caused by a low diet of fresh fruits and vegetables.

19 The chemistry of water Water forms the internal ocean that baths every cell of the human body. A water molecule is composed of one atom of oxygen and two atoms of hydrogen held together by covalent bonds.

20 Special Properties of Water. Polar: H bonding, adhesion and cohesion. High specific heat. Universal Solvent. High Surface Tension. Has capillary action.

21 Polar covalent bonds Consider, carbon (C) and chlorine (Cl). Chlorine can bond with carbon in an attempt to reach its octet. Electrons in a bond between these two elements are shared (covalent), but they are not shared equally. The shared electrons (one from Cl, one from C) would spend more of their time under the influence of chlorine, being farther right, but are not completely lost to carbon.

22 The electrons being shared are held closer to the Cl than to the C giving the molecules slightly charged areas.

23 The result of this pattern of unequal electron association is a charge separation in the molecule, where one part of the molecule has a partial negative charge and the other has a partial positive charge. (You should note this molecule is not an ion because there is no exchange of electrons, but there is a simple charge separation in this electrically neutral molecule.)

24 Polar and non-polar covalent bonds This type of covalent bond is called a polar covalent bond. In human body systems, polar covalent bonds are important because of the unique properties exhibited by molecules with these kinds of bonds.

25 The shape of the water molecule and the atoms in it give water this special property of polarity. This means that one end of the molecule is slightly positive while the other end is slightly negative.

26 H O H

27 Universal Solvent Water is so effective at dissolving substances that it is referred to as the universal solvent. Notice how the negative ends of water attract sodium and the positive ends attract chloride.

28 Hydrogen Bonding The dipole forces are attracted. A low-energy bond forms. This attractive force is what gives water its cohesive and adhesive properties.

29 Cohesion Water attracted to other water. This is caused by hydrogen bonds that form between the slightly positive and negative ends of neighboring molecules. This is the reason why water is found in drops; perfect spheres.

30 Surface Tension Surface tension is the name we give to the cohesion of water molecules at the surface of a body of water. Water Strider

31 Water can also be attracted to other materials. This is called adhesion. (Remember Adhesive tape picks up things) adhesion

32 Specific Heat Water has a high heat capacity. Specific heat (a measure of heat capacity), is the heat required to raise the temperature of 1 gram of water 1 C. Water, with its high heat capacity, changes temperature more slowly than other compounds that gain or lose energy.

33 Water is an active participant in Hydrolysis, which is a major chemical process of the body used to break down nutrients into usable molecules. During this process water molecules separate into hydrogen (H+) and hydroxyl (OH-) groups, each of which reacts with other substances. (H)+ and OH- ions also represent another important class of molecules

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35 The Chemistry of Acids and Bases *Usually, but not always Taste Feel (choose slippery or not slippery) ph (# from the key) Litmus (blue or red) Phenolphthalein Bromothymol Magnesium Baking soda NaOH(aq) Bitter Slippery 14 Blue *Pink *Blue NR NR HCl(aq) Sour not slippery 1 Red *Cloudy/ white *Yellow Bubbles Bubbles Holt Chapter 19

36 Acids

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38 Bases Almonds contain Amygdalin which, under certain conditions can produce hydrogen cyanide. In fact, cyanide gas has an almond scent.

39 Acidity matters to the human body because it affects the rate of most chemical reactions. The body maintains proper acidity by the use of buffers.

40 Some Properties of Acids : Produce H + ions in water Taste sharp or sour React with bases to form a salt and water ph is less than 7

41 Some Properties of Bases: Produce OH - ions in water Taste bitter and feel slippery Are electrolytes React with acids to form salts and water (neutralize) ph greater than 7

42 Some Common acids citric acid citrus fruit juice HCl hydrochloric acid stomach acid

43 Some Common Bases NH 3 hydrogen nitride ammonia KOH potassium hydroxide liquid soap Mg(OH) 2 magnesium hydroxide Milk of magnesia Al(OH) 3 aluminum hydroxide Maalox (antacid)

44 Acids and Bases in Water When an acid is poured into water, it gives up H + (hydrogen) to the water. When a base is poured into water, it gives up OH - (hydroxide) to the water.

45 Basic Acid/Base definition* Acids increase [H + ] in aqueous solutions (H 3 O + ) Bases produce OH - ions in solution OR react with water to remove a H leaving OH - *Arrhenius (traditional)

46 acids are measured by [H+] bases are measured by [OH - ]

47 Acid-Base Interactions in the body. Heme group The heme group in hemoglobin can interact with O 2 and CO 2. The Fe ion in hemoglobin is an acid O 2 and CO 2 act as bases

48 Neutralization Reactions Acidic compounds react with basic compounds and neutralize each other producing a salt (and usually gas and water too!) NaHCO 3 + HCl Base Acid Salt NaCl + H 2 (g) + H 2 O Neutralization is the reaction?! Huh?! of hydronium ions and hydroxide ions to form water.

49 ph another way to indicate [H + ] from French pouvoir hydrogene meaning hydrogen power

50 [H + ] is critical in many biological reactions. A quick method of denoting [H + ] is via ph. The ph scale describes a wide range of values The ph scale condenses possible values of [H + ] to a 14 point scale

51 The ph scale is a way of expressing the strength of acids and bases. Under 7 = acid 7 = neutral Over 7 = base

52 As acids get stronger, A ph of 1 is a very strong acid. As bases get stronger, A ph of 14 is a very strong base. NOTE: this is an inverse relationship:

53 ph of Common Substances

54 Why is ph important? Humans depend on water. The ph of water must be within a range of 5 to 9 in order for body cells to survive. Liquids with a ph less than about 5 are too acidic for humans to drink. Waters that are too basic can also be harmful. Water with a ph of greater that 9 can dissolve materials and tissues such as bone and skin.

55 ph testing There are many ways to test ph Litmus paper (red = acid) Red litmus paper (blue = basic) Blue litmus paper (red = acid) ph paper (multi-colored) ph meter (7 is neutral, <7 acid, >7 base) Universal indicator (multi-colored) Chemical Indicators like phenolphthalein Organic (natural) indicators like red cabbage, radishes

56 Paper testing - litmus Paper tests like litmus paper and ph paper Put a stirring rod into the solution and stir. Take the stirring rod out, and place a drop of the solution from the end of the stirring rod onto a piece of the paper Read and record the color change. Note what the color indicates. You should only use a small portion of the paper. You can use one piece of paper for several tests.

57 Paper Testing ph paper Put a toothpick into the solution. Take the toothpick out, and place a drop of the solution from the end of the toothpick onto a piece of the paper Compare the color to the color chart and note what ph the color indicates. You should only use a small portion of the paper. You can use one piece of paper for several tests.

58 ph meter Tests the voltage of the electrolyte Converts the voltage to ph Very cheap, accurate Must be calibrated with a buffer solution

59 indicators Indicators are dyes that can be added that will change color in the presence of an acid or base. Some indicators only work in a specific range of ph Once the drops are added, the sample changes color. Some dyes are natural, like radish skin or red cabbage

60 Biological Buffers* Every life form is extremely sensitive to slight ph changes. Human blood for example needs to remain within the ph range of 7.38 to *A buffer resists changes in ph when small quantities of an acid or base are added to it.

61 How do buffer solutions work? A buffer solution has to contain things which will remove any hydrogen ions or hydroxide ions that you might add to it - otherwise the ph will change. They do not react with each other or the water A buffer contains a weak acid and a weak base. But will react with strong acids or bases

62 If a strong base is added to a buffer, the weak acid part of the buffer will give up its H + in order to transform the base into water (H 2 O). Since the base is consumed by this reaction, the ph will change only slightly.

63 If a strong acid is added to a buffer, the weak base (in the buffer) will react with the H +. The H + gets absorbed, so the ph changes only slightly.

64 Living systems have built in biological buffers. Two especially important biological buffers are the phosphate and bicarbonate systems. H 2 CO 3 H + + HCO - 3 Carbonic acid bicarbonate ion

65 You can also find chemical (artificial) buffers.

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67 Molecules with a polar/ionized region at one end and a non-polar region at the other end are called amphipathic, as the molecule has both hydrophilic and hydrophobic characteristics. If amphipathic molecules are mixed with water, the molecules form clusters with the polar (hydrophilic) regions at the surface, where they will come into contact with water, and the non-polar (hydrophobic) regions nestled in the center of the cluster away from contact with water. The arrangement will increase the overall solubility in water.