NUTR100 Lecture Notes - Lecture 15: Synovial Fluid, Amniotic Fluid, Cerebrospinal Fluid
13 Jun 2018
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Chapter 10 Water and Electrolytes
- 50-70% of adult’s body is water
- about 66% is within body cells and is called intracellular fluid
• The remaining 1/3 is extracellular fluid
o Between the cells within tissues and organs
o Blood(90% water) transports oxygen and nutrients to cells and removes CO2 and
waste products
- Body fluid composition of tissue varies by
o Tissue type: lean tissues (muscles) have higher fluid content than fat tissues
o Gender: males have more lean tissue and therefore more body fluid
o Age: lean tissue is lost with age and body fluid is lost with it
- Functions of fluids:
o Transport substances (blood, urine)
o Regulate blood volume and pressure
o Help maintain body temp
o Protect and lubricate body tissues
▪ Cerebrospinal fluid
▪ Amniotic fluid
▪ Synovial fluid
▪ Digestive secretions
- Water balance is important
- Body fluid is composed of
o Water
o Proteins
o Electrolytes: mineral salts dissolved in water that carry charges
▪ Extracellular: Sodium (Na+), chloride (Cl-)
▪ Intracellular: Potassium (K+), phosphate (HPO4^2-)
▪ The distribution of these affect the distribution of water in different parts
of the body
- To maintain water balance: intake has to equal output
o Increasing nutrients and the amount of solutes it contains decreases water
absorption
o 80-100% of beverages is retained
o also retained from fruits and vegetables
o metabolic water
- Water losses: urine, feces, lungs, sweat
o Factors that affect loss: environment, exercise, illness/injury, pregnancy,
breastfeeding, diuretics
- Fluid intake from meals and thirst is enough to maintain homeostasis
o Body responds to dryness in the mouth or throat, increased concertation of
sodium in blood, decrease in blood volume or pressure
o Response includes:
▪ Thirst mechanism,
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Document Summary
Functions of fluids: transport substances (blood, urine, regulate blood volume and pressure, help maintain body temp, protect and lubricate body tissues, cerebrospinal fluid, amniotic fluid, synovial fluid, digestive secretions. Body fluid is composed of: water, proteins, electrolytes: mineral salts dissolved in water that carry charges, extracellular: sodium (na+), chloride (cl-, the distribution of these affect the distribution of water in different parts. To maintain water balance: intake has to equal output of the body. Increasing nutrients and the amount of solutes it contains decreases water absorption: 80-100% of beverages is retained, also retained from fruits and vegetables, metabolic water. Water losses: urine, feces, lungs, sweat: factors that affect loss: environment, exercise, illness/injury, pregnancy, breastfeeding, diuretics. Recommendations for water intake: men 19 y and older is 3. 7l a day, women is 2. 7 liters per day, varies with climate, activity and body size.
