Body fluids Flashcards
The total amount of fluid in the human body is approximately what percentage of body weight?
70%
Body fluid has two compartments namely?
Intracellular fluid(ICF){55%} and Extracellular fluid{ECF}(45%)
Extracellular fluid includes?
Interstitial fluid: present between the cells(80% of ECF)
Plasma: present in the blood(20% of ECF)
Also includes Lymph, synovial fluid, vitreous & aqueous humours, amniotic fluid etc.
Body fluids are composed of?
Organic substances: glucose, amino acids, fatty acids, hormones, enzymes.
Inorganic substances: sodium, potassium, calcium, chloride etc
Barrier separating ICF from interstitial fluid is?
Plasma membrane
Barrier separating interstitial fluid from plasma is
Blood vessel wall
Most abundant cation in ECF is
Sodium:
- muscle contraction
- impulse transmission
- fluid and electrolyte balance
Most abundant anion in ECF is
Chloride:
- regulates osmotic pressure
- forms HCL in gastric acid
Most abundant cation in ICF is
Potassium:
- resting membrane potential
- action potential
- maintains intracellular volume
- regulation of pH
Most abundant anion in ICF is
Proteins & phosphates
Sodium potassium pumps play a major role in
Keeping potassium high inside the cells and sodium high outside the cells
Second most prevalent cation in the ICF is
Magnesium:
- Cofactor for certain enzymes and sodium potassium pump
- essential for synaptic transmission
- normal neuromuscular activity
- myocardial function
List not less than four specialised fluids of the body
Lymph Milk Cerebrospinal fluid Sweat Tears Aqueous humour Vitreous humour
Give at least four functions of lymph(96% water & 4% solids)
- Transport lymphocytes
- Route for intestinal fat absorption
- Maintains structural and functional integrity of tissue.
- Redistribution of fluid
- Return protein from tissue spaces into blood
- Removal of bacteria and other foreign bodies from tissues
Give three functions of milk(83-87% water and 13-17% solids)
- milk provides galactose, a structural unit for growing infants
- It’s metabolized to lactic acid in the small intestine which eliminates harmful bacteria
- Source of protein, mineral and vitamins
Give two functions of amniotic fluid
Physical protection to the fetus
Medium for exchange of various chemical
- Sweat regulates body temp. by
- Insensible perspiration amounts to
- Volume of sweat produced during muscular exercise at elevated temperature per day
- Water content of sweat
- pH of sweat
- Non protein nitrogen (urea) in sweat
- Electrolyte in sweat
- Cooling and Evaporation
- 800-1200ml/day
- 10-14l
- 99.2-99.7%
- 4.7-7.5
- 0.07-1%
- Na: 12.6-127 meq/l
K: 5-32 meq/l
Cl: 8.5-85 meq/l
- Tears are produced by
- Tears pH is
- Tears protein content is
- ____ lyses the cells of microorganisms by breaking down the polysaccharides of their outer layer
- Lachrymal glands
- 7-7.6 due to loss of CO2
- 0.6-0.18g/dl
- Lysozyme
Give four functions of tears
Lysozyme protects eyes from microorganisms
Lubricates the surface of the cornea
Protects eyes from injury
Fill the irregularities of the cornea to improve optical properties
What is body water content and body solid content of
- Infants
- Adult males
- Adult females
- Old males and females
- 73-80% water, 20-27% solid
- 50-60% water, 40-50% solids
- 40-50% water, 50-60% solids
- 45% water, 55% solid
Water intake/water output is
2500ml/day
Osmolality is maintained at
~280-300 mOsm
Increase in osmolality
Stimulates thirst
ADH release
Decrease in osmolality
Thirst inhibition
ADH inhibition
NB: Large changes in blood volume or pressure also stimulates ADH
Give three principal abnormalities of water balance
Dehydration
Hypotonic hydration
Edema
Hypotonic hydration is also known as
Cellular overhydration or water intoxication
Hypotonic hydration occurs as a result of
Renal insufficiency
Rapid excess water ingestion
Hypotonic hydration is treated with
Hypertonic saline
Criterion for plasma indicator is
Substance should not cross capillaries
Indicators used for plasma are
Evans blue dye
Radioiodinated fibrinogen
Radioiodinated albumin
Criterion used for ECF indicators is
Substance should cross capillaries but not cross cell membranes
Indicators used in ECF are
Isotonic solutions of sucrose, inulin, NaCl etc
Criterion for Total body water indicators is
Substance should distribute evenly in ECF & ICF
Indicators used in TBW are
Heavy H2O
Antipyrine
Aminopyrine
Tritiated H2O
Give three criteria for a suitable dye
- Even mixing throughout the compartment
- The material should be relatively easy to measure
- No physiological activity
- Either it must be unchanged during the experiment or if it changes the amount changed must be known
What law is obeyed in measurement of TBW?
Law of Mass Conservation
Law of Mass Conservation is based on
Concentration in a well mixed substance that distributes itself only in the compartment of interest
What method is used in TBW measurement
Indicator (dye) dilution technique
Formula for calculating ICF volume is
ICF volume = Total body water - ECF volume
Formula for calculating interstitial fluid volume is
Interstitial fluid volume(ISFV) = ECFV - PV
ECFV: Extracellular fluid volume
PV: Plasma volume
Second most prevalent extracellular anion is
Bicarbonate (HCO3)
