Anatomy and Physiology: Chapter 2 section 3 Water in the Body

Weak electrolytes

mostly molecular compounds and a few ions that ionizes/dissociates partially, which dissolves in water mostly as molecules. It's solution is a weak conductor of electricity

A ________________ solution contains equal numbers of hydrogen and hydroxide ions, while an acidic solution contains more hydrogen ions than hydroxide ions.

neutral

What is the difference between the pH number and pH scale?

pH number is an exponent pH scale is logarithmic (Hydrogen concentration goes up or down by 10s; 10 times more or 10 times less)

The hydrocarbon tail of a fatty acid is hydrophobic, thus imparting very limited ________________ of the molecule in water.

solubility

The concentrations of ions in body fluids are carefully regulated primarily by

the coordination of activities at the kidneys (ion excretion), the digestive tract (ion absorption), and the skeletal system (ion storage or release).

Solute

the dissolving substances

To change water from a liquid to a gas

water temperature must be high for individual molecules to develop enough kinetic energy to break all the hydrogen bonds, water carries (absorbs) heat with it when changing (e.g., evaporation of perspiration on the skin)

Changes in electrolytes in body fluids

will disturb almost every vital function. For example, declining potassium levels will lead to a general muscular paralysis, and rising potassium levels will cause weak and irregular heartbeats.

Salt

• Inorganic compound composed of any cation (except hydrogen) and any anion (except hydroxide) • Held together by ionic bonds • Many dissociate completely in water, releasing cations and anions - Example: NaCl NaCl → Na+ + Cl-

Acid

• Solute that dissociates and releases hydrogen ions (H+) • Often referred to as proton donors - After losing an electron, a hydrogen ion consists solely of a proton • Strong acids dissociate completely - Example: hydrochloric acid (HCl) HCl → H+ + Cl-

Base

• Solute that removes hydrogen ions (H+) from solution • Proton acceptor • May release a hydroxide ion (OH-) • Strong bases dissociate completely - Example: sodium hydroxide (NaOH) NaOH → Na+ + OH-

Colloid

A solution containing dispersed proteins or other large molecules (homogeneous mixture) - Remain in solution indefinitely (small enough to pass through a filter but too large to pass through semipermeable membranes) - Example: liquid Jell-O, protein in the blood plasma, the cytoplasm within a cell

Aqueous solutions

A solutions in which water is the solvent

Electrolytes

A substance that produces ions when dissolved in water; its solution conducts electricity. - 2 types: strong and weak electrolytes

Solution

A uniform mixture of two or more substances (solute and solvent)

Neutral pH

Has a balanced pH equal to 7 (Contains equal # of Hydrogen ions (H+) and Hydroxide ions (OH-)

Alkaline (basic) pH

Has a pH above 7 (Contains high # of Hydroxide ions (OH-), and lower # or Hydrogen ions (H+)

Acidic pH

Has pH below 7 (Contains high # of Hydrogen ions (H+), lower # if Hydroxide ions (OH-)

Why does water have a high heat capacity?

Waters ability to absorb and release heat very slowly, prevents sudden changes in temperature, which is very important to warm-blooded organisms, to help maintain homeostasis

7 Important Electrolytes that Dissociate in Body Fluids

1 - NaCl (sodium chloride) → Na+ + Cl- 2 - KCl (potassium chloride) → K+ + Cl- 3 - CaPO4 (calcium phosphate) → Ca^2+ + PO4^2- 4 - NaHCO3 (sodium bicarbonate) → Na+ + HCO3^- 5 - MgCl2 (magnesium chloride) → Mg^2+ + 2Cl- 6 - Na2HPO4 (sodium hydrogen phosphate) → 2Na+ + HPO4^2- 7 - Na2SO4 (sodium sulfate) → 2 Na+ + SO4^2-

4 Important properties of water, important to the functioning of the human body.

1 - lubrication 2 - chemical reactant 3 - high heat capacity 4 - solvent (Solubility)

3 negative effects of abnormal pH fluctuations in the human body.

1 cell and tissue damage (due to broken bonds) 2 - changes in the shapes of proteins 3 - altered cellular functions.

Normal pH of blood

7.35-7.45 Outside this range damages cells and tissues by: - Breaking chemical bonds - Changing shapes of proteins - Altering cellular functions

Match the solute or compound to its characteristic: Acid A. A solute that dissociates in solution and releases hydrogen ions B. A solute that removes hydrogen ions from a solution C. Reversibly dissociates into a hydrogen ion and a bicarbonate ion D. An ionic compound consisting of any cation except a hydrogen ion and any anion except a hydroxide ion E. A compound that stabilizes the pH of a solution by removing or replacing hydrogen ions

A

Sort the states of water by density, from least dense, to most dense. A. Water vapor, Ice, liquid B. Ice, Liquid, Water vapor C. Water vapor, Liquid, Ice D. Liquid, Ice, Water vapor

A

Which of the following best describes why ice has a lower density than liquid water? A. Hydrogen bonding causes water to crystallize with more empty space between molecules than in the liquid state. B. Because water changes from its polar form as a liquid to its nonpolar form as a solid. C. The water molecules have less atomic motion than ice. D. There is more space between individual atoms at lower temperatures, which means colder water has a lower density.

A

Which properties of water allow the water strider (insects) to walk across the surface of water? A. Surface tension B. Aqueous solutions C. Thermal inertia D. Specific heat

A

Which property is exemplified by the fact that a large mass of water changes temperature very slowly? A. thermal inertia B. hydrolysis C. lubrication D solubility

A

Which property of water is directly responsible for lowering body heat with sweat? A. Heat of vaporization B. Heat capacity C. Surface tension D. Cohesion

A

Why does liquid water have such a high heat capacity? A. Water molecules are good at forming and breaking hydrogen bonds. B. Water is a linear molecule which makes absorbing heat easier. C. Water molecules are packed very closely together. D. Water is a nonpolar molecule.

A

Hydration spheres

A layer/sheath of water molecules that form around an ion in solution - In Ionic bonds and Polar Covalent bonds

Dissociation/Ionization

A process in which ionic bonds are broken as the individual ions interact with the positive or negative poles of polar water molecules. - Such as "NaCl in H2O" (Aqueous solution)

Alkalosis

Abnormal physiological state caused by high blood pH (above 7.45) - pH above 7.8 causes uncontrollable, sustained skeletal muscle contractions

Acidosis

Abnormal physiological state caused by low blood pH (below 7.35) - Below 7 produces a coma

Match the solute or compound to its characteristic: Base A. A solute that dissociates in solution and releases hydrogen ions B. A solute that removes hydrogen ions from a solution C. Reversibly dissociates into a hydrogen ion and a bicarbonate ion D. An ionic compound consisting of any cation except a hydrogen ion and any anion except a hydroxide ion E. A compound that stabilizes the pH of a solution by removing or replacing hydrogen ions

B

Solutes that remove hydrogen ions from a solution are called ______. A. buffers B. bases C. acids D. salts

B

Which of the following explains why water is a good solvent for polar and ionic compounds? A. Water is an ionic compound. B. Water is a polar molecule. C. Water is a hydrophobic molecule. D. Water is a non-covalent molecule.

B

Which substance is the most alkaline, meaning it has more hydroxide ions (OH-) than hydrogen ions (H+)? A. eggs (pH=7.8) B. household ammonia (pH=11) C. wine (pH=3) D. pure water (pH=7)

B

Why is water so effective at hydrogen bonding? A. There are two hydrogens, doubling the positive charge on the water molecule. B. Oxygen is very electronegative and strongly attracts hydrogen's electron. C. Hydrogen is more electronegative than oxygen, so it is more likely to donate its electrons to oxygen. D. The hydrogens in water are ionically bonded to the oxygen.

B

In body fluids, sodium chloride functions as an important ______. A. enzyme B. hydration sphere C. source of electrolytes D. colloid

C

In body fluids, the production of Na+ and HCO3− from NaHCO3 (sodium bicarbonate) is which type of chemical process? A. hydrolysis B. hydration C. dissociation D. dehydration

C

Match the solute or compound to its characteristic: Carbonic acid A. A solute that dissociates in solution and releases hydrogen ions B. A solute that removes hydrogen ions from a solution C. Reversibly dissociates into a hydrogen ion and a bicarbonate ion D. An ionic compound consisting of any cation except a hydrogen ion and any anion except a hydroxide ion E. A compound that stabilizes the pH of a solution by removing or replacing hydrogen ions

C

The polarity of water is due to which characteristic? A. the asymmetrical positions of the oxygen atoms that are attached by polar covalent bonds B. the asymmetrical positions of the hydrogen atoms that are attached by nonpolar covalent bonds C. the asymmetrical positions of the hydrogen atoms that are attached by polar covalent bonds D. the asymmetrical positions of the hydrogen atoms that are attached by ionic bonds

C

Which of the following describes surface tension in water? A. Surface tension occurs due to ionic bonding. B. Surface tension is caused by water molecules repelling one another. C. Surface tension allows water to support small objects if they are placed carefully on its surface. D. Surface tension of water is weakened by hydrogen bonding.

C

Which of the following statements is true regarding water as a substance? A. Ionic substances are insoluble in water. B. All solutes dissolve easily in water. C. A water solution is also known as an aqueous solution. D. Water is a non-polar solvent.

C

Which statement is correct regarding the relationship of the pH of hydrochloric acid in the human stomach (pH = 1) and the pH of pure water (pH = 7)? A. Hydrochloric acid is ten thousand times more acidic than pure water. B. Hydrochloric acid is approximately one million times more alkaline than pure water. C. Pure water is approximately one million times less acidic than hydrochloric acid. D. Pure water is approximately six times more alkaline than hydrochloric acid.

C

Why is water unable to dissolve substances like oil? A. Water is nonpolar and oil is polar. B. Both water and oil are nonpolar. C. Water is polar and oil is nonpolar. D. Both water and oil are polar.

C

Within the human body, carbonic acid (H2CO3) and sodium bicarbonate (NaHCO3) act as which of the following? A. bases B. acids C. buffers D. salts

C

Buffers

Compounds that stabilize the pH of a solution by removing or replacing hydrogen ions (H+) - Help to maintain normal pH of body fluids

Match the solute or compound to its characteristic: Salt A. A solute that dissociates in solution and releases hydrogen ions B. A solute that removes hydrogen ions from a solution C. Reversibly dissociates into a hydrogen ion and a bicarbonate ion D. An ionic compound consisting of any cation except a hydrogen ion and any anion except a hydroxide ion E. A compound that stabilizes the pH of a solution by removing or replacing hydrogen ions

D

Weak acids and bases

Dissociate partially in water - Have less of an impact on pH than strong acids and bases Example: carbonic acid (H2CO3) • H2CO3 ↔ H+ + HCO3 - In body fluids, carbonic acid reversibly dissociates to hydrogen ion and bicarbonate ion

Match the solute or compound to its characteristic: Buffer A. A solute that dissociates in solution and releases hydrogen ions B. A solute that removes hydrogen ions from a solution C. Reversibly dissociates into a hydrogen ion and a bicarbonate ion D. An ionic compound consisting of any cation except a hydrogen ion and any anion except a hydroxide ion E. A compound that stabilizes the pH of a solution by removing or replacing hydrogen ions

E

Important properties of water: Chemical reactant

In our bodies, ________________________ occur in water, and water molecules are also participants in some reactions, including hydrolysis and dehydration synthesis.

strong electrolytes are

Ionic compound that ionizes/dissociates completely (100%) when it dissolves in water. Its solution is a good conductor of electricity,

Water

Is Most important component of your body, that makes up about 2/3 of total body weight and affects all physiological systems

Important properties of water: High heat capacity (Specific Heat)

Is the amount of heat required to raise the temperature of a unit mas (one gram) of a substance by 1ºC

How does the high heat capacity of water help support life?

It allows animals to have highly regulated internal body temperatures.

Thermal inertia

Large mass of water changing temperature very slowly.

pH

Measurement of Hydrogen ions (H+) concentration in body fluids (negative logarithm in mol/L) - pH ranges from 0 to 14

Hydrophobic

Non-polar molecules that do not react readily with water. (Do not dissolve in water) - Examples: fats and oils

Hydrophilic

Polar molecules that interact readily with water molecules (Dissolve in water) - Examples: glucose (an important soluble sugar)

Explain how the ionic compound sodium chloride dissolves in water (aqueous solution).

Sodium chloride (NaCl) dissociates (dissolves) in water as the positive poles of water (H2O) molecules are attracted to the negatively charged chloride ions, and the negative poles of water molecules are attracted to the positively charged sodium ions. - The ions stay dissolved in solution because a layer of surrounding water molecules (a hydration sphere) separates them from each other.

Suspension

Solution containing larger particles - Particles will settle out if undisturbed (trapped by filters and semipermeable membranes) - Example: whole blood (cells)

Solvent

The liquid substance in which other atoms, ions, or molecules are distributed.

Buffer systems

Usually involve a weak acid and its related salt, which functions as a weak base. - Help maintain pH within normal limits - Minimize pH shifts Examples: • Carbonic acid (H2CO3) • Sodium bicarbonate (NaHCO3)

Important properties of water: Lubrication

Water is an effective _____________ because there is little friction between water molecules, so a thin layer of water between tow opposing surfaces will greatly reduces friction between them - reduces friction within joints and in body cavities.