Chapter 10 Flashcards
Function of Water in the body
- medium for chemical reactions
- transports nutrients and wastes
- provides protection
- helps regulate temperature
- participates in chemical reactions
- maintains acid-base balance
- removes carbon dioxide and waste products
- blood=90% water
Solvent
Solute
A fluid in which one or more substances dissolve
Dissolved substances
Polar
Used to describe a molecule that has a positive charge at one end and a negative charge at the other
-water (oxygen atom has electrons around it more so negative charge)
Ions
An atom or group of atoms that Carrie’s an electrical charge
Dissociate
To separate two charged ions
-ex: when positively charged sodium ion bound to negatively charged chloride ion is placed in water, the sodium ions move apart or dissociate because positive sodium is attracted to the negative pole of water molecule and negative chloride is attracted to positive pole of water.
Hydrolysis reaction
A type of chemical reaction in which a large molecule is broken into two smaller molecules by the addition of water
-ex: breaking maltose into two glucoses
Condensation reaction
A type of chemical reaction in which two molecules are joined to form a larger molecule and water is released
-ex: formation of the disaccharide maltose from two glucose molecules
Proper body pH for chemical reactions to take place is
7.4-neutral basic
Intracellular fluid
Extracellular fluid
The fluid located inside cells
2/3 of body water
-highest concentration of protein
-potassium, but low sodium and chloride
-Fluid located outside cells. It includes fluid found in the blood, lymph, gastrointestinal tract, spinal column, eyes, joints, and that found between cells and tissues
-highest concentration of sodium and chloride but low potassium
1/3 of body water
Intestinal fluid
The portion of the extracellular fluid located in the spaces between cells in body tissues
- lymph, blood plasma and extracellular fluid
- lowest concentration of protein
Blood pressure
The amount of force exerted by the blood against the artery walls
-due to combination of minerals in each fluid
Water intake levels from food and beverages
Fluids-75-80% of water
Food-20-25%
Where is water lost to
Urine, feces, sweat, evaporation from lungs
Insensible losses
Fluid losses that are not perceived by the senses, such as evaporation of water through the skin and lungs (1L/day)
What causes the desire to drink
Triggered by a decrease in the amount of water in the blood, which is senses by the thirst center in the hypothalamus of the brain. A decrease in saliva secretion, which causes a dry mouth, also stimulates thirst
Antidiuretic hormone
A hormone secreted by the pituitary gland that increased the amount of water reabsorbed by the kidney and therefore retained in the body
- prevents solute concentration on the blood from increasing further when blood solute levels are high
- when solute concentration is low, levels decrease so less water is reabsorbed and more is excreted in urine
- Stimulated thrust and secretion of ADH from the brain
- ADH stimulates the kidneys to reabsorbed water
Dietary reference intake of water for men and women per day
Men: 3.7L
Women: 2.7L
Dehydration
A condition that results when not enough water is present to meet the body’s needs (1-2%)
-caused reduction in blood volume, impairs ability to deliver oxygen and nutrients to cells and remove waste products
Early symptoms: thirst, headache, fatigue, loss of appetite, dry eyes, dry mouth, dark-coloured urine
Water intoxication
A condition that occurs when a person drinks enough water to significant lower the concentration of sodium in the blood
Hyponatremia
Abnormally low concentration of sodium in the blood due to water intoxication
/water moves by osmosis from the blood into the tissues to try to dilute the higher concentration of solutes causing tissue swelling or edema
Electrolytes
Positively and negatively charged ions that conduct an electrical current in solution. Commonly refers to sodium, potassium and chloride
- essential for life
- distribution of these affects distribution of water throughout the body
Hypertension
Blood pressure that is consistently elevated to 140/90mm Hg or greater
- too much salt puts your at risk
- 20%+ adults in Canada
- if sodium intake is reduced to less than 2300 mg per day, it is estimated that hypertension would be reduced by 30% and cardiovascular disease by 13%
Cell membranes keep the majority of sodium _____ the cell and potassium _____ the cell
Outside
Inside
Renin
An enzyme produced by the kidneys that converts angiotensinogen to angiotensin 1
Angiotensin 2
A compound that causes blood vessel walls to constrict and stimulates the release of the hormone aldosterone
Aldosterone
A hormone that increases dokie reabsorption by the kidneys and therefore enhances water retention
-increases blood pressure
Deficiencies in any of the electrolytes leads to
Acid-base balance disruption, poor appetite, muscle cramps, confusion, apathy, constipation and irregular heartbeat
Optimal blood pressure
Less than 120mm Hg of systolic pressure and less than 80mg Hg of diastolic pressure or 120/80
Lifestyle choices to keep blood pressure in the normal range
- eat plenty of fruits and veggies
- chose and prepare foods with less salt
- aim for a healthy weight
- increase activity
- drink alcohol in moderation
- no smoking
- low stress
Where do you want blood pH to be?
7.34-7.45
How do we absorb water
GI tract by osmosis
Balancing concentration in and out of cells
Water balance
- not stored
- water in must equal water out
In: consumption of water, fluid, food and production during cellular respiration
Out: excretion in urine and feces, evaporation from doing and lungs and sweating
Regulating water loss: the kidneys
- kidneys function as a filter
- water moved from the blood into kidney tubules
- blood cells and proteins are too large and remain in the blood
- needed substances are reabsorbed back into the blood
- unneeded substances are excreted in urine
When do you need to increase intake of water
- increased activity
- increased temperature
- decreased temperature
- high protein diet
- low calorie diet
- high salt diet
- high fibre diet
- caffeine intake
- alcohol intake
Canadians and electrolyte levels
High in NaCl, low in K
Electrolyte functions
- regulate fluid balance
- nerve conduction
- muscle contraction
- blood pressure balance
Deficient of electrolytes
Acid-base imbalances, poor appetite, muscle cramps, confusion, constipation, irregular heartbeat
Toxicity of electrolytes
Rare
- only in absence of water
- K=stop heart
- NA=increase Ca output
DASH diet
Dietary approach to stop hypertension : developed to reduce high blood pressure
- more fruits and veggies
- low fat milk
- low red meat
- low sweets and sugar drinks
- high in K, Ca, Mg, Fibre
Lowered blood pressure in 2 weeks significantly!
Sodium sensitive
bring in lots of sodium and increase blood sodium level and bring in lots of water; This increases blood volume and pressure, kidneys fix sodium and water levels (normal)
Bring in sodium and water which increase volume and pressure of blood. But they are slow to sodium excretion, and sodium prevents dilation of blood vessels and cause high blood pressure to consist
Sodium free
Salt free
Less than 5 my of sodium per serving
Same as sodium free
Low sodium
Contains 140 mg or less of sodium per serving
Lightly salted
Reduced sodium
Contains 50% less added sodium per serving than usual
Contains 25% less sodium per serving than usual
Sodium UL
2300 mg/ day
1500mg/day for pre hypertension
3440 mg/day is normal consumption…
