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