Introductory Nutrition Unit Five

- a covalently bonded, polar molecule Water - a covalently bonded, polar molecule aaaaaaaaaaaaa Molecules are said to be polar if they have slight opposite charges on either end

The slight attraction between the negative end of one molecule and the positive end of another results in a… aaaaaaaaaaaaaaaaa

Water - Polarity leads to adhesion and cohesion aaaaa - Polarity leads to adhesion and cohesion Adhesion and cohesion lead to capillary action and surface tension - High specific heat leads to temperature stability - High heat of vaporization leads to evaporative cooling

Water aaaaa - Spheres of hydration form electrostatic interactions, keeping ions from interacting with each other - This characteristic means water has a high degree of solvency and chemical reactivity

Water aaaaa - Water also ionizes into H+ and OH- which can be incorporated into other molecules or released from them

Water

Osmosis Solute - substance that is dissolved in a medium (solvent) Solvent - substance (usually liquid) that dissolves a solute Solution - mixture of solutes dissolved in a solvent Concentration - ratio of solute to solvent

Osmosis Diffusion - the movement of a substance from an area of high concentration to an area of low concentration Osmosis - the diffusion of water - the movement of water to an area of high solute concentration

Osmosis Isotonic solution *concentration of solutes outside the cell is equal to the concentration inside the cell Hypertonic solution *concentration of solutes outside the cell is greater than the concentration inside the cell

Osmosis Hypotonic solution *concentration of solutes outside the cell is less than the concentration inside the cell The selectively permeable character of the cell membrane functions to maintain isotonic conditions in the body

Animal Cell Osmosis Lysed Crenated Aaaaaaaaaaaaa Aaaaaaaaaaaaa

Electrolyte Functions The functions of electrolytes are varied and important: + chemically reactive and participate in metabolism + determine charge difference across cell membranes

Electrolyte Functions The functions of electrolytes are varied and important: + powerfully affect the osmolarity of body fluids and the body’s water content and distribution + form essential minerals + regulate acid/base balance

Electrolyte Concentrations Extracellular fluids (ECF) are fluids of the body found outside the cells Intracellular fluids (ICF) are fluids of the body found inside the cells (cytoplasm)

Electrolyte Concentrations HPO43- (Lo) Na+ (145mEq/L) Ca2+ (Hi) Mg2+ (Lo) K+ (4mEq/L) K+ (150mEq/L) Mg2+ (Hi) Ca2+ (Lo) Na+ (12mEq/L) HPO43- (Hi)

Electrolyte Concentrations Cl- (103mEq/L) OH- HCO3-(Hi) H+ HCO3- (Lo) Cl- (4mEq/L) H+ OH-

ICF vs. ECF ICF ECF 65% of body fluids Major electrolytes K+ Mg2+ HPO43- 35% of body fluids Major electrolytes Na+ Ca2+ Cl-

ICF vs. ECF 26L 40L total body fluid 10L 3.2L 0.8L Interstitial Fluids Blood Plasma Lymph How much fluid is found in the ICF and the ECF? Which one do you think has the most fluid? *ICF is the largest fluid compartment in the body. For the average person it will hold about 25 liters of fluid. *About 12 liters of the ECF are in the interstitial fluid. *The remaining ECF makes up the blood. It contains about 3 Liters. *The total amount of fluid in the body will be about 40 liters. 0.8L Other 40L total body fluid

Movement of Water Fluids are constantly exchanged between these compartments Osmosis occurs across capillary walls and plasma membranes

Movement of Water The movement of the water from one compartment to the other is determined by solute concentrations

Movement of Water

Fluid Balance Balance of body fluids means that fluid intake should equal fluid output In addition, the fluid gained or lost must be added to or taken from the right compartment (ICF or ECF)

Fluid Balance

Fluid Balance As has been seen, electrolyte concentrations in the different compartments must also be stringently maintained Electrolytes attract water through osmosis, therefore a loss of fluids results in the loss of electrolytes

Fluid Balance The three structures that play the major role in fluid and electrolyte balance are: * brain (hypothalamus) * kidneys * adrenal glands

Regulation of Fluid Intake Decreased volume of ECF or Increased osmolarity of ECF Hypothalamus Decrease saliva Creates thirst Increased volume of ECF which decreases osmolarity of ECF Drink fluids

Hypothalamic and Kidney Regulation of Fluids and Electrolytes

Adrenal Gland Regulation of Fluids and Electrolytes

Minerals Minerals can be classified into two groups: ~major minerals (macrominerals) >100mg/day ~ trace minerals (microminerals) <20mg/day

Minerals Sodium (major mineral) * chemical symbol - Na * functions - primary cation of ECF - maintains fluid balance - necessary for nerve impulses and muscle contractions

Minerals Sodium (major mineral) * found naturally in most foods & as an additive for taste and preservation

Minerals Sodium (major mineral) * deficiencies lead to muscle cramps, fatigue, nausea, vomiting, dizziness & confusion * toxicity leads to hypertension and edema (water retention)

Minerals Potassium (major mineral) * chemical symbol - K * functions - primary cation of ICF - maintains fluid balance - necessary for nerve impulses and muscle contractions

Minerals Potassium (major mineral) * found in most fresh foods, especially fruits, vegetables and meat

Minerals Potassium (major mineral) * deficiencies lead to muscle weakness & irregular heart beat * toxicity leads to muscle

Minerals Chloride (major mineral) * chemical symbol - Cl * functions - major anion of the ECF - assists in maintaining fluid balance - necessary for digestion - needed for nerve activity

Minerals Chloride (major mineral) * major food source is salt * deficiencies are rare but lead to vomiting and dehydration * toxicity leads to hypertension and edema (water retention)

Minerals Phosphorus (major mineral) * chemical symbol - P * functions - major anion of the ICF - assists in maintaining fluid balance - necessary for DNA, RNA & ATP production - needed to activate some enzymes

Minerals Phosphorus (major mineral) * food sources are high protein foods * deficiencies are rare but lead to dizziness and muscle weakness * toxicity leads to muscle spasms and convulsions

Minerals Selenium (trace mineral) * chemical symbol - Se * functions - antioxidant system - immune function - necessary for thyroid hormone production

Minerals Selenium (trace mineral) * food sources are organ meats, pork, wheat & rice * deficiencies lead to heart disease, arthritis, muscle wasting & impaired immune function * toxicity leads to nausea, vomiting, liver disease & impaired immunity

Minerals Copper (trace mineral) * chemical symbol - Cu * functions - cofactor (enzyme activity) - immune function

Minerals Copper (trace mineral) * food sources are liver, legumes, grains & cereals * deficiencies lead to anemia and poor immune response * toxicity leads to vomiting, impaired nerve function & impaired immunity

Minerals Iron (trace mineral) * chemical symbol - Fe * functions - cofactor (enzyme activity) - immune function - hemoglobin formation

Minerals Iron (trace mineral) * food sources are liver, red meat, legumes, leafy greens & seafood * deficiencies lead to anemia and poor immune response * toxicity leads to liver damage & impaired immunity

Minerals Zinc (trace mineral) * chemical symbol - Zn * functions - cofactor (enzyme activity) - DNA & protein metabolism - immune function

Minerals Zinc (trace mineral) * food sources protein rich foods * deficiencies lead to hair loss, diarrhea & poor immune response * toxicity leads to diarrhea & impaired immunity

Minerals Manganese (trace mineral) * chemical symbol - Mn * functions - cofactor (enzyme activity) - immune function

Minerals Manganese (trace mineral) * food sources are legumes, grains & cereals * deficiencies lead to poor immune response * toxicity leads to impaired immunity

Chapter Nine Objective Seven Read the last section in the text (pgs 374-379) and able to define, identify and discuss