Lecture 2 - Body fluids Flashcards
4 aspects of body fluids (milieu intérieur comprises body fluids)
Volume, Distribution, Characteristics, Functions
Body water is the medium in which …
Solutes are dissolved, metabolic reactions take place
Interval of body water %
45 to 75%
What accounts for water content variations in individuals. (% of water in some parts of bady)
Skin 70% Muscle 70% Heart, Brain, Kidney and Liver 70-80% Bone 25% FAT 10%
Some functions of body water
Lubricates joints, transports nutrients and O2 to cells, Regulates body temperature, moistens tissues
2 body constituants that lower water % for an individual
Bone 25% water and mostly fat 10% water
Normal value of body water proportion and what is constant and what varies in individuals
60% water is normal. Solids and water quantity are constant but individuals have different amounts of fat.
what happens if body water is a fraction of lean body mass
water % in individuals would be constant
where do we find standard values
Physiological Reference Individual 21 year old, white male, 70 kg weight
Physiological Reference Individual value of body water and adjustments
60%. Adjustments for age, gender, weight, ethnic origin.
Variations in body water with age and gender (3 categories)
Baby : 75% Teen/Adult : F50% M60% Elderly : F45% M50%
Why less water % when puberty
Gain of fat
When difference in water % for M/F happens
Puberty
Why women smaller water proportion than males
More fat and less muscle
Why does water proportion in body get lower as we grow old
Tissues get drier
Calculation of body water
Body mass * water %
why body water significant for water-soluble medication and what field is it particularly important for
Dissolves in body water 100 mg / x L . Important in pediatrics
Body water is constant in health : Why
Dynamic steady state. Exchanges with external environment and individual and between different compartments within individuals
Water intake (3)
Oral fluid, oral intake as food, oxidative water from metabolism
Water output (5) (which ones are insensible)
Lungs (water exhaled) - insensible (we do not feel it), skin - insensible respiration, kidneys, stool (feeces) and extra water cleared out by kidneys
major homeostatic organ
Kidneys
Obligatory losses everyday
1,5 L of water : 1 L insensible 0,5 L urine + stool
Faultative losses of water everyday
Varies with intake (extra water will be in urine)
Insensible perspiration characteristics (4)
Pure water, Passive evaporation (humidity/temp.), Entire skin surface, Continuous
Swating
Electrolyte solution, Active secretion, Sweat glands, Activated by heavy work or high temp. (so not continuous)
Water turnover (ex : 20% would be 20% in 20% out everyday) of adults and baby and consequences for babies
Adults : 3-4%, Babies 10% –> less regulation capacities, sensible to hypothermia
Constant body water volume helps maintain … (2) and this allows
- Normal solute concentrations 2. Normal blood volume and pressure
Allows adequate supply of O2 to tissues
Negative water balance possible causes (5)
Reduced intake, Excessive loss from gut (throwing up)***, Excessive sweating, Excessive loss in expired air (ex high altitude), Excessive loss in urine (or also in stool - diarrhea)
Water intoxication possible causes (2)
Excessive intake, Renal system failure
what happens at high altitude for excessive water loss in expired air
We breath rapidly for oxygen so more water is expired
Water intoxication : how can the kidney failure happen
Kidneys unable to excrete the water (can put out almost 1L/hour if healthy)
