Body Fluids Homeostasis & Membrane Transport

1. Body Fluids Homeostasis&Membrane Transport

2. Objectives • Describe the distribution of water in the body. • Define & describe the different body fluid compartments and their composition. • Know & identify signs of dehydration. • Define & explain “Homeostasis”. • Function of the Cell and its organelles • Describe the basic structure of the cell membrane. • List & explain the different transport mechanisms that occur across the cell membrane.

3. Section one: Body Fluids

4. Body Composition Water= 60% TBW 60%

5. Distribution of Body Fluids Inside Outside Plasma Intracellular Interstitial Extracellular

7. Distribution of Body Fluids Body Fluids ⅔ ICF ⅓ ECF 1% Transcellular Fluid ¾ IF ¼ Plasma Fluid in body spaces: (pleural, pericardial, peritoneal, synovial, & intraocular)

8. Example • In a healthy adult man whose weight is 70 Kg, calculate the volume of: • ICF • ECF • Plasma • IF

9. Body Fluid Compartments An average 70 kg body wt adult 60% water = 42 l (decreases with age, lesser in female and varies with obesity) Extra cellular: 1/3 (14 L) = 20% body wt (plasma; interstitial) intravascular =3L (plasma) (1/4 ECF) interstitial =11 L( 3/4 ECF)) transcellular CSF, Intraocular, pleural, peritoneal, synovial, digestive secretion Intracellular: 2/3 ( 28L) or 40% of body wt

10. Body Fluids and Fluid Compartments • The percentage of total body water: 45-75% • Intracellular compartment • 2/3 of body water (40% body weight) • Extracellular compartment • 1/3 of body water (20% body weight) • the blood plasma (water=4.5% body weight) • interstitial fluid and lymph (water=15% body weight) • transcellular fluids: e.g. cerebrospinal fluid, aqueous humor (1.5% BW) • Distribution of substances within the body is NOTHOMOGENEOUS.

11. VOLUME OF BODY FLUIDS IN 70 kg MAN TOTAL VOLUME 42 L INTRA CELLUAR FLUID 28 L(ROUGHLY 2/3 OF TBW) EXTRA CELLULAR FLUID 14 L(ROUGHLY 1/3 OF TBW) PLASMA 4 L(ROUGHLY ¼ OF ECF)

12. What are the factors affecting TBW? • Physiological: • Age. • Sex (♀ < ♂). • % of Body fat. • Pathological: • Vomiting. • Diarrhea.

13. Is there a difference between ICF & ECF? Yes In composition

15. Differences Between ICF and ECF? Intracellular Fluid (ICF) Extracellular Fluid (ECF) • ↑↑ Potassium (K+). • ↑↑ Magnesium (Mg+). • ↑↑ Phosphate ion (PO4-). • ↑↑ Sodium (Na+). • ↑↑ Chloride (Cl-). • ↑↑ Bicarbonate ions (HCO3-). • Nutrients: • Oxygen, glucose, fatty acids, & amino acids.

17. How does the body keep its fluid content constant?

18. Fluid Balance in the body Input = output • Water intake: • Fluids ingested (2100 ml). • From metabolism (200ml) • Daily loss: • Insensible loss (700 ml). • Sweat (100 ml). • Feces (100 ml). • Urine (1400 ml). Total intake = 2300 ml Total loss = 2300 ml

20. Causes of Increased loss of Fluids Dehydration ↑↑ Sweating (hot weather). Vomiting. Diarrhea. ↑↑ urine output (Diabetes).

21. Section two: Homeostasis

22. The Internal Environment • All body cells live in the same environment (ECF). • The skin separates this environment from the outside world (external environment). ECF = Internal environment.

23. The Internal Environment • ECF contains the proper concentration of substances (O2, glucose, ions, amino acids, and fatty acids) needed for proper functioning of the cell. • The internal environment must be kept constant. • The process by which the body keeps the internal environment constant despite changes in the external environment is known as “Homeostasis”.

24. Homeostasis A state of balance in the body

25. Homeostasis Maintenance of relatively stable internal environment (ECF) .

28. Control Mechanisms • The body has thousands of control systems. • They function to restore balance when it is lost. How? By feedback mechanisms

29. Feedback Mechanisms • Most control systems act by negative feedback. • Negative feedback = the high concentration causes decreased concentration which is negative to the initiating stimulus. Controller Effector Sensor ↑↑ CO2 ↓↓ CO2

30. Controlling Glucose levels • Your cells need an exact level of glucose in the blood. • Excess glucose gets turned into glycogen in the liver • This is regulated by 2 hormones (chemicals) from the pancreas called: Insulin Glucagon

31. Glycogen If there is too much glucose in the blood, Insulin converts some of it to glycogen Insulin Glucose in the blood

32. Glycogen If there is not enough glucose in the blood, Glucagon converts some glycogen into glucose. Glucagon Glucose in the blood

33. Feedback Mechanisms • A Positive feedback = the initiating stimulus causes more of the same effect. • Very few: • Blood coagulation. • Childbirth. • Generation of nerve signals.

34. Cell Structures and Functions

35. Contents • Functions of the cell membrane. • Structure of the cell membrane. • Lipid bilayer. • Membrane proteins. • Types of membrane proteins. • Mechanisms of cell membrane transport. • Passive transport. • Active transport.

36. The Cell Membrane • In order to keep the composition of the ICF & ECF constant, there should be a barrier. • This barrier is the cell membrane. • The cell membrane does not only function as a sac that encloses cellular organelles but it also controls the movement of substances in and out of the cell.

37. Types of cell in our body Cell that connect Fibroplast RBC Cells that cover Epithelial cells Cells that moves parts Skeletal muscle Smooth muscle

38. Types of cells Cell that store nutrients Fat cells macrophages Cell that gather information Nerve cells

39. Types of cells Cells of reproduction Ovum sperm

40. Cell structure Cells are different but have same basic structure Nucleus Cytoplasm Plasma membrane (cell membrane)

41. General Cell Structure Nuclus Cytoplasm Rough endoplasmic reticulum Smooth endoplasmic reticulum Golgi apparatus Mitochondria lysosomes Cell membrane

42. Section three: Cell transport

43. Cell membrane Plasma membrane (outer cell membrane) Structure Lipid bilayer (tail to tail) phospholipid Protein (float) Carbohydrate branching sugar attach to protein

44. Structure of The Cell Membrane

45. Structure of the cell membrane The cell membrane consists almost entirely of a lipid bilayer with large number of protein molecules, many of these penetrating all the way through the membrane.

46. Cell membrane cont. Lipid bilayer Barrier flexibility Protein Channel Carriers Receptors for hormones enzymes Sugar (glycoprotein) Blood type Cell to cell interaction

47. Many Functions of Membrane Proteins Outside Plasma membrane Inside Transporter Enzymeactivity Cell surfacereceptor Cell adhesion Cell surface identity marker Attachment to thecytoskeleton

48. fat-soluble substances (O2, CO2, & alcohol) Water-soluble substances (ions, glucose) Outside Inside

49. Membrane Proteins

50. Cont. membrane proteins • Integral proteins = proteins that protrude all the way through the membrane. • Peripheral proteins= proteins attached only to one surface of the membrane and do not penetrate.