The Human Body. Introduction. Human body. Nervous system Musculoskeletal system. Cardiovascular system. Produces movements.

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2 Itroductio Huma body Nervous system Musculoskeletal system Muscular forces Muscle extesio ad cotractio Complex system of muscles ad boes Produces movemets Cardiovascular system Heart Blood vessels Respiratory system Freivalds A., (2009) Niebel s Methods, Stadards, ad Work Desig. McGraw-Hill

3 The Nervous System Cetral Nervous System Brai Spial Cord Peripheral erves Efferet erves: Motor erves Afferet erves: Sesory erves Somatic Nervous System Coects orgaism with outside world Kroemer, K.H.E.., Gradjea, E. (1997) Fittig the Task to the Huma. Taylor & Fracis

4 The Nervous System Neuro The structural ad fuctioal uit of all ervous tissue (erve cell) Fuctio Structure Nerve impulses trasmitted through erve cells Soma Cell body Axo Coduct erve impulses away from cell bodies Dedrites Mediate impulses from other euros to the soma Kroemer, K.H.E.., Gradjea, E. (1997) Fittig the Task to the Huma. Taylor & Fracis

5 The Nervous System Fuctio of erves Cotrol system Regulates exteral ad iteral activities Moitors a variety of sesatios Factors ifluecig the workig of a euro Sesitivity of stimuli Ability to trasmit a stimulus Stimulatio of erves Impulse travels alog erve fiber Kroemer, K.H.E.., Gradjea, E. (1997) Fittig the Task to the Huma. Taylor & Fracis

6 The Nervous System Muscle iervatio Every muscle is coected to the brai Efferet erves or motor erves Motor erves carry impulses to skeletal muscles Afferet erves or sesory erves Sesory erves coduct impulses back to the brai as sigals Each erve fiber serves to iervate several muscle fibers Motor uit Icludes motor euro ad the muscle fibers that it iervates Kroemer, K.H.E.., Gradjea, E. (1997) Fittig the Task to the Huma. Taylor & Fracis

7 The Nervous System Motor Uit Group of muscle fibers iervated by braches of same motoeuro Size depeds o fuctio of muscle - May vary betwee ad withi muscles - Small i size where precisio movemet is required Eye muscle à10 fiber i each motor uit - Larger i coarse actig muscles Limb muscleà sigle motoeuro ca supply more tha 1900 fibers Kroemer, K.H.E.., Gradjea, E. (1997) Fittig the Task to the Huma. Taylor & Fracis

8 The Nervous System Reflexes Cotrols movemet ad activity Reflex cosists of three parts 1. A impulse travellig alog sesory erve 2. Itermediate euros, passig impulse to motor erves 3. Fial impulse to activate muscle Blikig is a reflex used to protect the eye Stimulus: Uexpected movemet Impulse travels to the brai Message passed to motor erve Motor erve operates muscles of the eyelids Kroemer, K.H.E.., Gradjea, E. (1997) Fittig the Task to the Huma. Taylor & Fracis

9 The Nervous System Skilled Work Graspig Operatio 1. Use of visual iformatio to direct movemet toward object to be grasped 2. Iformatio from eye is trasferred to brai 3. O basis of visual iformatio - Brai decides the ext move 4. Whe object is grasped - Pressure sesitive erves sed ew sigals to the brai - Operator ca adjust figer pressure Kroemer, K.H.E.., Gradjea, E. (1997) Fittig the Task to the Huma. Taylor & Fracis

10 The Nervous System Coditioal Reflexes Practice of movemets for a log time Complete movemet patter becomes egraved i the brai Coordiatio ad delicate adjustmet of muscular movemets - Cotiuous stream of sesory iformatio reaches motor coordiatio ceters Skilled work - Learig elimiated coscious cotrol - Movemets are automatic Kroemer, K.H.E.., Gradjea, E. (1997) Fittig the Task to the Huma. Taylor & Fracis

11 The Musculoskeletal System Types of muscles Cardiac Muscle Heart muscle Skeletal Muscles Attached to the boe Smooth Muscles Iteral orgas ad walls of blood vessels Freivalds A., (2009) Niebel s Methods, Stadards, ad Work Desig. McGraw-Hill

12 The Musculoskeletal System Skeletal Muscles 400 muscles withi the body Costitute approximately 50% of total body weight Attached to the boe by tedos ad crosses oe or more joits Cotrolled by the volutary ervous system or somatic ervous system Fuctio Geerate movemet aroud a joit Freivalds A., (2009) Niebel s Methods, Stadards, ad Work Desig. McGraw-Hill

13 The Musculoskeletal System Structure of muscles Costitutes of large umber of muscle fibers - Number of fibers depeds o muscle size Coective tissues bid fibers to form budles Attached to the boe by tedos ad crosses oe or more joits Cotrolled by the volutary ervous system Fuctio Geerate movemet aroud a joit Freivalds A., (2009) Niebel s Methods, Stadards, ad Work Desig. McGraw-Hill

14 The Musculoskeletal System Structure of Muscle Group of muscle fibers costitute a muscle Muscle fibers subdivided ito compoets that provide the cotractile mechaisms Myofibrils Protei filamets Filamets Allows muscles to cotract Types Thick filamets Thi filamets Slidig filamet theory Filamets slide over each other Allows muscle legth to chage durig cotractio Kroemer, K.H.E., ad Gradjea, E., (1999). Fittig the task to the Huma. Taylor ad Fracis.

15 The Musculoskeletal System

16 The Musculoskeletal System Muscle cotractio The ability of a muscle to shorte to about half its ormal restig legth Work doe by a muscle i a complete cotractio icreases with its legth Each muscle fiber cotracts with a certai force Stregth of etire muscle depeds o sum of muscle fiber forces Kroemer, K.H.E., ad Gradjea, E., (1999). Fittig the task to the Huma. Taylor ad Fracis.

17 The Musculoskeletal System Muscle cotractio Maximum stregth of huma muscle Muscle cross sectio of 100 mm 2 ca develop a force of 30 to 40 Newtos Iheret muscle stregth depeds o the muscle cross-sectios Maximum muscle stregth At the midrage of the motio Kroemer, K.H.E., ad Gradjea, E., (1999). Fittig the task to the Huma. Taylor ad Fracis.

18 The Musculoskeletal System Regulatio of muscular effort Muscle fiber made to cotract by icomig ervous impulses Amout of muscle stregth depeds o umber of ervous impulses Excitatio of the umber of motor erve cells Speed of muscle cotractio Speed at which force is developed durig a give iterval of time Kroemer, K.H.E., ad Gradjea, E., (1999). Fittig the task to the Huma. Taylor ad Fracis.

19 The Cardiovascular System Heavy work Activity that requires physical exertio Characteristics - High eergy cosumptio - Severe stresses o the cardiovascular system Eergy cosumptio ad cardiac effort - Set limits to performace of heavy work - Used to assess severity of physical task Kroemer, K.H.E., ad Gradjea, E., (1999). Fittig the task to the Huma. Taylor ad Fracis.

20 The Cardiovascular System Physiological Measures Heart rate - Normal beats per miute (bpm) Oxyge cosumptio - Average restig liters per mi (L/mi) Respiratio (vetilatio) rate Metabolites cocetratio i saliva Body temperature - Normal 98.6º F Blood pressure - Normal 120/80 mm Hg (systolic/diastolic) Blood Urie

21 The Cardiovascular System Metabolism Coversio of chemical eergy (food eergy) to mechaical eergy ad heat Kroemer, K.H.E., ad Gradjea, E., (1999). Fittig the task to the Huma. Taylor ad Fracis.

22 The Cardiovascular System Basal Metabolism The rate of metabolic activity of a subject after 12 h fastig ad 8 h restig is called Basal Metabolic Rate (BMR) Eergy cosumed at rest Steady eergy cosumptio All chemical eergy from utriets is coverted ito heat Factors ifluecig basal metabolism Geder Size Weight BMR maitais 1) Body Temperature 2) Body Fuctios 3) Blood circulatio Kroemer, K.H.E., ad Gradjea, E., (1999). Fittig the task to the Huma. Taylor ad Fracis.

23 The Cardiovascular System Eergy expediture Eergy expediture is required for the muscle cotractio process Uit of measuremet: Kilojoules (kj) Assessmet Direct method Measuremet of heat (eergy) geerated by a perso i a calorimeter Idirect method Recordig oxyge uptake required for oxidatio of utriets 1 liter of oxyge cosumed = 20 kj (5kcal) eergy released Kroemer, K.H.E., ad Gradjea, E., (1999). Fittig the task to the Huma. Taylor ad Fracis.

24 The Cardiovascular System Eergy Expediture Two basic types of metabolism Aerobic More efficiet, but very slow Sustaied for a log duratio Example: Distace Ruig Aaerobic Very iefficiet, but is much quicker Work performed for o more tha few miutes Example: Spritig Kroemer, K.H.E., ad Gradjea, E., (1999). Fittig the task to the Huma. Taylor ad Fracis.

25 The Cardiovascular System Eergy Expediture Sub Maximal - Oxyge Cosumptio Vs. Time miut e s

26 The Cardiovascular System Heart Ratig Guidelies Measuremet of oxyge cosumptio ad eergy expediture is very expesive A alterate ad idirect method of measurig eergy expediture is heart rate The heart pumps the blood carryig oxyge to the workig muscles, thus the higher the level of eergy expediture, the higher the heart rate level Istrumetatio: heart rate moitor, $100, easy to use %HR max = (HR ave - RHR) / (Est. HR max - RHR) * 100% Est. Hr max = age for females Est. Hr max = age/2 for males Guidelie: Never exceed 1/3 of a idividuals max HR or max oxyge cosumptio!! Freivalds A., (2009) Niebel s Methods, Stadards, ad Work Desig. McGraw-Hill

27 Subjective Ratigs Subjective Ratigs of Perceived Exertio (RPE) A eve easier way of ratig workload, replacig the expesive machiery Borg 10 & 20 Scales Borg s 1967 RPE Scale with Verbal Achors (20 Scale) Freivalds A., (2009) Niebel s Methods, Stadards, ad Work Desig. McGraw-Hill Ratig Verbal Achor 6 No exertio at all 7 extremely light 8 9 very light light somewhat hard hard very hard extremely hard 20 maximal exertio

28 Measure Heart rate Blood pressure O2 cosumptio CO2 productio Respiratory quotiet (RQ) Tidal volume Miute vetilatio (Ve) Breath/mi - Heart rate moitor - Blood pressure moitor - Beckma Metabolic Cart (MMC) Equipmet Electromyogram (EMG) - Physiograph - Preamplified surface electrodes coected to a PC (via hardware ad software) Electrocardiogram (ECG/EKG) Lug capacities - FEV 1.0, FVC Static stregth - Grip stregth - Pich stregth - Back, composite stregth Dyamic stregth - Isokietic - Isoiertial - Electrocardiograph (5 lead, 9 lead) - Spirometer - Had grip dyamometer - Pich gauge - Load cell - Cybex, LIDO - Air Force 6 ft icremetal lift Rage of motio - Goiometer - Flexometer Temperature (oral, ski) - Thermometer, temp probes