Fluid Balance and Total Body Water PDF

Fluid balance and Total body water Dr.Noha Osama Lecturer of physiology Faculty of medicine Helwan University 1  Objectives -By the end of this lecture...

Fluid balance and Total body water Dr.Noha Osama Lecturer of physiology Faculty of medicine Helwan University 1  Objectives -By the end of this lecture, you should be able to: 1. Know the distribution of total body water. 2. Distinguish the difference between the composition of the ECF & ICF. 3. Outline the factors affecting water balance. 2  What is Normal body composition?!!  In adult male, body weight is 90 kilograms: 18 % of his body weight proteins 15 % of his body weight fats 7 % of his body weight minerals 60 % of his body weight water 3 Factors affecting total body water 1- Physiological 1- Age 2- Sex 3- Body weight 4- Race Factors affecting total body water 2- Pathological A- Dehydration (Vomiting, Diarhea) B- Overhydation ( Iatrogenic man made )  Distribution Of Body Water (Fluids) 60% of body weight is water 40% of body weight is ICF (intracellular). 20% of body weight is ECF (extracellular).  What is the difference between Intracellular fluid (ICF)& Extracellular fluid(ECF) ?  So we have….. ECF contains large quantities of Na+ & Cl-. ECF have low amounts of protein And on other hand ICF have large quantities of K+ & proteins  How do we do Water Balance ? Water balance means water gain = water loss What will happen if there is Imbalance If water gain > water loss (Overhydration) If water loss > water gain (Dehydration) What are the symptoms of Dehydration? 1- Thirst sensation ( Homeostasis action) 2- Dry mouth ( decrease salivation) 3- Decrease elasticity of skin 4- Decrease urination 5- Rapid Heart beats ( tachycardia/palpitations) 6- Headache Over hydration (Iatrogenic) Sweating is initiated in response to a rise in body temperature that occurs on exposure to a hot environment. Evaporation of the sweat cools the body. This is an example of a. negative feedback b. positive feedback c. feedforward mechanism d. local control mechanism A 28 year old pregnant woman completes her 3rd trimester with no obvious signs of labor. Her physician gives her a hormone to increase the uterine contractions to facilitate the delivery. Which mechanism is responsible for completing the normal labour? a) Feedforward mechanism b) Negative feedback mechanism c) Positive feedback mechanism d) Cellular homeostasis A 69 year old man was discharged from the hospital after being treated from dehydration. His physician asks him to drink more water and avoid hot weather due to age- disturbed thermoregulatory homeostasis. Which one is the most correct definition of homeostasis? A. excessive changes according to the surrounding conditions. B. having variable composition of extracellular fluid. C. keeping in hand with external environment changes. D. limited chance to survive. E. maintenance of a constant internal environment. References Please drink water , You need it