Dr. Taqey AlMosawey

 A bone joint composed from synovial membrane in cased two bone ends and synovial fluids (fig.5).the surfaces of the joint are articular cartilage. the surface of the cartilage is rough which plays an useful role in joint lubrication by trapping some of the synovial fluid. this fluid squeezed in the joint according to the stress applied on the joint.the amount and the viscosity of synovial fluid change according to the applied stress. when a continues stress applied on the knee joint, synovial fluid in continually squeezed in the joint which cause a swollen in the joint.

 i: rheumatoid arthritis which result in over production of synovial fluid in the joint and causes swollen joints and  ii: ostpoarthrosis a disease of the joint it self. threads squeeze synovial fluid from the porosi, of bone low viscosity means good lubrication the coefficient of friction reduced between the bones in the knee by synovial fluid to less than 0.01 where that of steel blade on ice s about 0.03.

 energy of the body:  all activities of the body include energy changes. the energy converted to work e.g. climbing a hill, lifting a weight ….  The potential energy can be change to a kinetic energy.  At based rest condition,the energy conserved by the body in nearly follows:   2770 used by liver and spleen  25% used by skeletal muscle and the heart.

 19% used by brain.  10% used by kidney.  19% digestive system, heat loosen … etc.  The body uses food …………..  The food n changed to molecules by the digestive system to combine with oxygen to produce the energy.  There are continuous changes in the energy of the body when it is doing work or not.

 The conservation of energy in the body can be given by the first law of thermodynamics:  ΔU=ΔQ-ΔW…..(1) where  ΔU=change in stored energy (-ve or +ve)  ΔQ=heat loose or gained  ΔW=work done by the body  When the change of ΔU,ΔQ and ΔW in a short interval of time Δt,thus the  Rate of change of ΔU,ΔQ and ΔW is given by: is the mechanical power.

 The unit of these are :_  Food energy : kcal or cal  Energy: joul/sec or watt or erg  Energy (English unit) : foot – pound.  Energy change in the body :  Food is oxidized by the cells of the body after the food digested to molecules of glucose the oxidation of one mole.  C 6 H 12 O 6 +6O 2 →6H 2 0+6CO kcal  This means that:  One mole of glucose (180gm) + 6 moles of O 2 (192gm) → 6 moles of H 2 O (108gm) + 6 moles of CO 2 (264gm) kcal of heat.

 Note thate one mole of a gas at normal conditions (normal temperature and normal pressure) has a volume of 22.4 liters.  Q1/ calculate the energy released per 1 gm of fuel and 1 lit of O 2 used ?  Q2/ calculate the volume in liters of each O 2 and CO 2 used per/gm of fuel ?  The basal metabolic rate BMR is the lowest rate of energy can consumption needed to perform minimal body function under resting condition when the body  The typical person consumes energy when completely at rest at a rate of about 92 kcal/hr or 107 w which is called 1 met.

 BMR is affected by the thyroid activity, it is higher for the persons having over active thyroid.  The chemical activity of the body is increasing or decreasing rapidly with the increase or decrease of the body temperature e.g. increase of body temperature will result in the increase of the chemical activity by 10%, and 2C˚ increase cause increasing of chemical activity by 20%. 3C˚ increase in the temperature causes 30% increase of 30% of the chemical activity. the decrease in the body temperature with result in decreasing the chemical activity of the body in the same rates an above. internal body temperature change in body

C˚C˚ Temperature % 3810% more 3920% more 4030% more 3610% less 3520% less 3430% less Note that the increase in food more than the consumption of energy will result in increasing of the weight and vice visa. hence to keep your weight steady you have to get food

 The conserved energy is converted to external work and life preserving functions. The external work is given by :  ΔW=FΔX …..(3)  Where :  F= the force moved a distance  ΔX and in its direction the power is the rate of doing work :  Where v= velocity =

 The external work is done when person is climbing a hill or walking up stairs which is equal weight of the body x vertical distance h I.e. ΔW=mgh…. (5)  Energy of 4.8 to 5 kcal is produced by consuming each liter of O 2.  The efficiency of the body is given by :

 The body is consider a good efficient machine its efficiency can be up to about 20% is cycling and heavy exercises..with external power production of 370w (0.5) and metabolic rate of 1850w  If you are riding a bicycle on level ground with constant speed there is no change in kinetic or potential energy and the power supplied is used to overcome friction and wind resistance long term power is proportional to the maximum rate of O 2 consumption in the working muscles for a healthy man this consumption = 50 ml/(kg.min).

 Pressure is defined as the force per unit area   For solid the force per unit area = stress the pressure for liquid column:  p=ρgh……..(2)  where ρ= density of liquid, g= gravity acceleration and h= high of liquid.

 measurement of pressure in the body :  part of the body normal pressure (mmHg) pressure instrument  Blood systole: sphygmomanometer  Skull diastole : (mercury colomn ) aneroidsealed container with needle or digital.