Homeostasis & Body Fluids PDF

 At the end of the topic, the students should be able to: 1. Explain the principles of homeostasis. 2.Explain the characteristics and components of homeostatic control systems. 3.Name the different body fluid compartments. 4.Differentiate the general composition of extracellular and intrac...

 At the end of the topic, the students should be able to: 1. Explain the principles of homeostasis. 2.Explain the characteristics and components of homeostatic control systems. 3.Name the different body fluid compartments. 4.Differentiate the general composition of extracellular and intracellular compartments. 5.Outline the principles of measurement of body fluids. 6.Discuss the principles of osmolarity and tonicity in specific conditions. 1. Guyton A.C. & Hall, J.E. 2021. Textbook of Medical Physiology. 14thth Edition. Elsevier. 2.Sherwood, L. 2016. Human Physiology: From Cells to Systems. 9th Edition. Cengage Learning. 3.Costanzo L.S. 2018. Physiology. 6th Edition. Elsevier. 4.. 26th Edition. McGraw-Hill. 5.Widmaier EP, Raff H, Strang KT. 2019. Vander’s Human Physiology – The Mechanisms of Body Function. 15th Edition. McGraw- Hill.  Human Physiology The study of how human body function – mechanisms Include study of molecules to complex integration of different body systems The objective is to understand the function as a whole body  The cell is the basic living unit of the body - around 100 trillion cells performing specialized functions to maintain the body's function and structure. Organs are aggregates of many different cells held together by intercellular supporting structures. Body systems Body systems Body systems  Intracellular fluid (ICF): Fluid inside cells Extracellular fluid (ECF): Fluid outside the cells - consisting of plasma and interstitial fluid Cells are surrounded by fluid – from which = The internal environment they make exchanges (O2, nutrients, waste products) in order to live and maintain survival Total body water (TBW): Makes up 50% to 70% of body weight 2/ 1/ 3 3 1/4 3/4  ECF = ICF The “Internal High in potassium (K+), Environment” magnesium (Mg2+), High in sodium (Na+), and phosphate (PO4³-) chloride (Cl-), and ions. bicarbonate (HCO3-) Contains much less ions. sodium and chloride Contains nutrients like compared to ECF. oxygen, glucose, fatty Ion concentration acids, and amino acids. differences are Carries carbon dioxide maintained by special and other waste transport mechanisms products for excretion across cell membranes. (lungs and kidneys). Organization of electrolytes into compartments  Imagine you are outside on a hot day, and your body temperature starts to rise above the normal 37°C. Your body recognizes this change and responds to maintain homeostasis by initiating mechanisms to cool down.  homeo means “similar” stasis means “to stand or stay” What is internal environment? = Maintenance of nearly constant conditions in the internal environment All organs and tissues of the body perform functions that help maintain these constant conditions.  Homeostasis is essential for the survival of each cell, and each cell, through its specialised activities as part of a body system, helps maintain the internal environment shared by all cells Interdependent relationship of cells, body systems, and homeostasis. What factors in the Concentration of Waste product internal nutrients levels environment (ECF) (e.g., glucose, fatty (e.g., urea, CO2) acids, amino acids) need to be homeostatically maintained? O2 and CO2 levels Water balance pH balance Temperature Ion concentrations (e.g., sodium, chloride, potassium)  The homeostatic control system maintains a relatively constant body temperature when room temperature decreases.  The normal range for each constituent is narrow, and deviations typically indicate illness Body temperature: A rise of 11°F (7°C) above normal can trigger a vicious cycle of increased cellular metabolism, leading to cell destruction. Acid-base balance: Normal pH is 7.4, with lethal values only 0.5 pH units on either side.  Potassium ion concentration: