Body Composition Flashcards
Order the body components by their relative weight in the body
- Water
- Proteins
- Fats
- Minerals
What factors affect total body water?
Format: Factor (Effect on total body water)
Sex (Male > Female)
Age (Young > Old)
Amount of body fat (Low > High)
Total body water percentage of adult male
60%
Total body water percentage of adult females
50%
Why do males have a higher total body water than females?
Greater proportion of fat making up female body weight
Adipose tissue has low water content
Total body water percentage of infants
75%
Why are infants prone to dehydration?
Low total body water could be lost from diarrhea and vomiting
Water content of lean body tissue (fat free tissue)
71-72ml/100g-tissue
Which tissues have the highest and the lowest body water percentage?
Highest - Grey matter = 85%
Lowest - Dentin = 10%
What regions are body water present in?
Extracellular Fluid (ECF) - Fluid outside the cells
Intracellular Fluid (ICF) - Fluid inside the cells
What fraction of water forms ECF?
1/3 total body water (c.14L)
What fraction of water forms ICF?
2/3 total body water (c.28L)
What are the components of ECF?
Plasma = c.3L
Interstitial fluid (between cells) = c.11L
How can water exit the body?
Kidneys
Lungs
Feces
Sweat
Skin
How does water move between the different regions of the body?
What constitutes the body’s internal environment?
ECF
What are electrolytes?
Substances which are naturally charged when dissolved in water
What are cations?
Positively charged ions
What are anions?
Negatively charged ions
What electrolytes are present in ECF?
Large amounts of Na+ and Cl-
Small amounts of K+, protein and phosphate
What electrolytes are present in ICF?
Large amounts of K+, protein and phosphate
Small amounts of Na+ and Cl-
What is the importance of Na+ balance?
Osmosis depends on Na+ reabsorption
If water or Na+ is disturbed, regulation of the other is affected
