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SKELETAL MUSCLES. ??  SKELETAL MUSCLE TISSUE  NERVOUS TISSUE  BLOOD  DENSE CONNECTIVE TISSUE.

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Presentation on theme: "SKELETAL MUSCLES. ??  SKELETAL MUSCLE TISSUE  NERVOUS TISSUE  BLOOD  DENSE CONNECTIVE TISSUE."— Presentation transcript:

1 SKELETAL MUSCLES

2 ??  SKELETAL MUSCLE TISSUE  NERVOUS TISSUE  BLOOD  DENSE CONNECTIVE TISSUE

3  TECHNICALLY, SKELETAL MUSCLE IS NOT AN INDIVIDUAL CELL BUT A FIBER FORMED BY THE FUSION OF MANY MYOBLASTS (EMBRYONIC MUSCLE CELLS).  MULTINUCLEATED  FIBER IS OFTEN CALLED A ‘CELL’  LENGTH: COULD BE MANY CENTIMETERS LONG: MUCH OF LENGTH OF THE SPECIFIC MUSCLE IT IS FOUND IN  DIAMETER: 50 µm

4  DENSE CONNECTIVE TISSUE  COVERS MUSCLE; A GROUP OF FIBERS AND INDIVIDUAL FIBERS ◦ EPIMYSIUM: MUSCLE ◦ PERIMYSIUM: FASCICLE ◦ ENDOMYSIUM: INDIVIDUAL FIBER  IF IT EXTENDS BEYOND THE MUSCLE FIBERS= TENDON  APONEUROSIS: FIBROUS SHEETS OF FASCIA THAT CONNECTS TO BONE OR THE FASCIA OF ANOTHER MUSCLE (ABDOMINAL MUSCLES)  ALLOWS INDIVIDUAL MOVEMENT, CARRIES BLOOD VESSELS AND NERVES

5 DDEEP FASCIA ◦A◦AROUND MUSCLE SSUBCUTANEOUS FASCIA ◦F◦FORMS SUBCUTANEOUS LAYER SSUBSEROUS FASCIA ◦C◦CONNECTIVE TISSUE LAYERCOVERING THE ORGANS OF AND LINING THE CAVITIES

6 CCELL MEMBRANE: SARCOLEMMA CCYTOPLASM: SARCOPLASM PPARTS: ◦I◦I BAND ◦Z◦Z LINE ◦A◦A BAND ◦M◦M LINE MMYOFIBRILS: ◦M◦MYOSIN ◦A◦ACTIN TROPONIN TROPOMYOSIN http://www.comprehensivephysiology.com/WileyCDA/CompPhysArticle/refId-c110050.html

7 http://jerrybruton.files.wordpress.com/2011/03/parts_of_a_muscle.jpg

8  TITIN  SARCOPLASMIC RETICULUM  TRANSVERSE (T) TUBULES  CISTERNAE

9  http://www.youtube.com/watch?v=EdHzKYD xrKc http://www.youtube.com/watch?v=EdHzKYD xrKc

10  ACTIN AND MYOSIN FILAMENTS SLIDE ON EACH OTHER SHORTENING THE SARCOMERE AND PULLING ON THE MUSCLES’ ATTACHMENTS

11 MMOTOR NEURON ◦C◦CARRY IMPULSE TO EFFECTOR (LIKE MUSCLE) SSYNAPSE ◦F◦FUNCTIONAL CONNECTION TO MUSCLE ◦G◦GAP/SPACE ◦R◦RELEASES NUEROTRANSMITTERS TO CROSS GAP MMOTOR END PLATE ◦S◦SPECIALIZED SECTION OF MUSCLE FIBER MEMBRANE ◦U◦USUALLY ONE PER MUSCLE FIBER MMOTOR UNIT ◦O◦ONE MOTOR NEURON AND ALL THE MUSCLE FIBERS IT CONNECTS TO ◦A◦ALL WORK TOGETHER

12  ACETYLCHOLINE (Ach)- NEUROTRANSMITTER FOR MUSCLE CONTRACTION  RELEASED AS NEUROTRANSMITTER FOR SKELETAL MUSCLE CONTRACTION  DIFFUSES ACROSS SYNAPTIC CLEFT BINDS TO RECEPTOR  STIMULATES MUSCLE CONTRACTION  SENDS IMPULSE ALONG MUSCLE

13 http://emedicine.medscape.com/article/1171206-media

14  NO CONTRACTION/NO IMPULSE  TROPONIN-TROPOMYOSIN COMPLEX BLOCKS ACTIVE SITE OF ACTIN

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17  http://www.blackwellpublishing.com/matthe ws/myosin.html http://www.blackwellpublishing.com/matthe ws/myosin.html

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24  http://www.blackwellpublishing.com/matthe ws/myosin.html http://www.blackwellpublishing.com/matthe ws/myosin.html

25  IMPULSE TRAVELS ALONG MOTOR NEURON  REACHES AXON TERMINAL CAUSING NEUROTRANSMITTERS TO RELEASE ACh  Ach BINDS TO RECEPTOR ON MOTOR END PLATE  DEPOLARIZES MUSCLE FIBER MEMBRANE  MUSCLE IMPULSE/ACTION POTENTIAL MOVES ALONG SARCOLEMMA IN ALL DIRECTIONS TO T-TUBULES  CAUSING CISTERNAE OF SARCOPLASMIC RETICULUM TO RELEASE CALCIUM

26 CCISTERNAE HOLDS A HIGHER CONCENTRATION OF CALCIUM THAN CYTOPLASM (?) ◦C◦CALCIUM PUMP IN MEMBRANE OF SR CCALCIUM BINDS TO TROPONIN (WHAT HAPPENS WHEN SOMETHING FORMS A BOND?) SSHAPE CHANGES (?) EEXPOSES ACTIVE SITES OF ACTIN AND MYOSIN CROSSBRIDGES CAN BIND TO ACTIVE SITE

27  MYOSIN CROSSBRIDGE BINDS WITH ACTIN AND BENDS PULLING ACTIN FIBER CLOSER  THEN IT RELEASES, STRAIGHTENS (USING ATP) AND CAN BIND WITH ANOTHER ACTIVE SITE

28 UUSING ATPase THE CROSSBRIDGES USE ATP TO GET INTO A COCKED POSITION TO BIND TO ACTIN AND PULL IT CLOSER SHORTENING THE SARCOMERE AND THUS THE MUSCLE UUSING ANOTHER ATP THE CROSSBRIDGE RELEASES FROM ACTIN AND THEN GETTING INTO THE COCKED POSITION ONCE AGAIN CCONTINUES: ? ◦ AS LONG AS NERVE IMPULSES RELEASES ACh

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30 http://www.lab.anhb.uwa.edu.au/mb140/addons/copyright.htm

31  NERVE IMPULSE CEASES  ACh? ◦ ACETYLCHOLINESTERASE DECOMPOSES ACh  Ca? ◦ NOT RELEASED BY CISTERNAE SO PUMP TAKES OVER  CROSSBRIDGE LINKS BREAK & TROPOMYOSIN REFORMS SHAPE BLOCKING ACTIVE SITE  MUSCLE FIBER RELAXES

32  THICK  2/3 OF PROTEIN  200+ GLOBULAR PROTEINS 

33  THIN FILAMENT  ¼ OF ALL PROTEINS  GLOBULAR PROTEIN

34  TROPOMYOSIN ◦ ROD-SHAPED ◦ FILLS IN GROOVE OF ACTIN, BLOCKING ACTIVE SITE  TROPONIN ◦ ATTACHED TO TROPOMYOSIN ◦ CALCIUM BINDS HERE  DYSTROPHIN ◦ ATTACHED TO INSIDE OF CELL MEMBRANE ◦ MAKES CELL MEMBRANE STRONGER TO WITHSTAND CONTRACTION

35  ATP ◦ DIRECTLY ◦ A SMALL AMOUNT  CREATINE PHOSPHATE ◦ 4-6X MORE ABUNDANT THAN ATP ◦ MUST BE CONVERTED TO ATP ◦ SYNTHESIS CONTROLLED BY CREATINE PHOSPHOKINASE  RELIES ON CELLULAR RESPIRATION ◦ ONLY A FEW SECONDS WORTH OF ENERGY IN ATP AND CREATINE PHOSPHATE

36 CCELLULAR RESPIRATION REQUIRES: ? ◦O◦OXYGEN CCARRIED TO CELLS BY: ? ◦R◦RBC: HEMOGLOBIN IIN MUSCLES: ◦M◦MYOGLOBIN AATTRACTS O 2 MORE RRED COLOR WWHY NEEDED? MMUSCLE CONTRACTION REDUCES BLOOD FLOW

37  AT REST: ENERGY SUPPLIED BY AEROBIC RESPIRATION  DURING EXERCISE: ◦ CAN CHANGE GLUCOSE TO: ?  PYRUVIC ACID  LACTIC ACID = ANAEROBIC THRESHOLD/ LACTIC ACID THRESHOLD  OXYGEN DEBT IS WHEN LACTIC ACID BUILDS UP  LIVER REFORMS LACTIC ACID INTO GLUCOSE BUT NEEDS TO HAVE THE OXYGEN REPLENISHED TO DO THAT  = THE AMOUNT OF OXYGEN NEEDED TO RECONVERT LACTIC ACID AND REPLACE THE ORIGINAL AMOUNT OF ATP AND CREATINE PHOSPHATE AND REPLACE OXYGEN LEVEL OF BLOOD AND TISSUE TO NORMAL

38  MUSCLE PRODUCES MORE GLYCOLYTIC ENZYMES MEANING ? ◦ MORE GLYCOLYSIS  MORE CAPILLARIES AND MORE MITOCHONDRIA = ? ◦ MORE AREOBIC RESPIRATION MORE BLOOD PRODUCTION OF LESS LACTIC ACID SO DOESN’T AFFECT pH

39  LOSES ABILITY TO CONTRACT AFTER PROLONGED EXERCISE DUE TO: ◦ LESS BLOOD FLOW ?  LESS ACh ◦ ION IMBALANCE ACROSS SARCOLEMMA ◦ FEELING TIRED ◦ ***MOSTLY FROM INCREASE OF LACTIC ACID WHICH LOWERS pH AND FIBERS CAN’T RESPOND CRAMP: SUSTAINED INVOLUNTARY CONTRACTION ◦ DUE TO DECREASED EXTRACELLULAR ELECTROLYTE CONCENTRATION ◦ CALCIUM PUMP DOESN’T WORK SO ACTIN & MYOSIN STAY LOCKED

40  FROM? ◦ CELLULAR RESPIRATION ESPECIALLY FROM?  MUSCLES  MORE THAN HALF THE ENERGY RELEASED  CARRIED THROUGHOUT BODY BY? ◦ BLOOD ◦ HOMEOSTASIS MECHANISMS

41  THRESHOLD STIMULUS: ◦ THE STRENGTH OF A STIMULUS THAT STARTS AN IMPULSE  TWITCH: ◦ PERIOD OF CONTRACTION AND RELAXATION  LATENT PERIOD: ◦ A PERIOD OF DELAY BEFORE CONTRACTION  MYOGRAM: ◦ A RECORD OF A CONTRACTION  LENGTH: ◦ TOO LONG OR TOO SHORT DECREASES CONTRACTION FORCE

42  WHOLE MUSCLE FORCE: DEPENDS ON THE FREQUENCY AT WHICH INDIVIDUAL MUSCLES ARE STIMULATED AND HOW MANY FIBERS ARE CONTRACTING

43  SUMMATION: ◦ WHEN THERE ARE MULTIPLE STIMULI OF INCREASING STIMULATION UNTIL MUSCLE CAN NOT RELAX  SUSTAINED CONTRACTION: ◦ MUSCLE CAN’T RELAX DUE TO SUMMATION  TETANIC CONTRACTION: ◦ SUSTAINED CONTRACTION WITH ABSOLUTELY NO RELAXATION

44 ??  THE MORE FIBERS IN ONE UNIT THE LESS PRECISE CONTROL  DIFFERENT MOTOR NEURONS HAVE DIFFERENT THRESHOLDS SO SOME ARE MORE EASILY STIMULATED THAN OTHERS  SO VARYING AMOUNT OF CONTRACTION OF WHOLE MUSCLE  MULTIPLE MOTOR UNIT SUMMATION OR RECRUITMENT= AN INCREASE IN THE NUMBER OF MOTOR UNITS INVOLVED IN THE CONTRACTION

45  DURING A SUSTAINED CONTRACTION SMALLER MOTOR UNITS ARE RECRUITED EARLIER AND LARGER RESPOND LATER BUT MORE FORCEFULLY (INCREASING STRENGTH)  CONTRACTION IS SMOOTH DUE TO DIFFERENT MOTOR UNITS BEING RECRUITED AT DIFFERENT TIMES  TETANIC CONTRACTIONS OCCUR IN SOME OF THE FIBERS DURING NORMAL CONTRACTIONS  MUSCLE TONE: EVEN AT REST THERE IS SOME CONTRACTION OF SOME FIBERS  IMPORTANCE: ◦ POSTURE

46 IISOTONIC ◦M◦MUSCLE SHORTENS ◦C◦CONCENTRIC: SHORTENS ◦E◦ECCENTRIC: DOESN’T SHORTEN: LESS FORCE (LAYING DOWN A BOOK) IISOMETRIC ◦E◦ENDS DON’T MOVE ◦T◦TENSION INCREASES ◦P◦POSTURE WHICH OCCURS MOST COMMONLY?

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48  SLOW TWITCH/ TYPE I ◦ RED FIBERS ?  MYOGLOBIN ◦ MANY MITOCHONDRIA ?  AEROBIC RESPIRATION ◦ HIGH RESPIRATORY CAPACITY  CAN GENERATE ATP AS FAST AS THEY NEED IT ◦ CONTRACT A LONG TIME/ DON’T FATIGUE  FAST TWITCH/ TYPE IIb ◦ GLYCOLYTIC FIBERS ◦ WHITE FIBERS  LESS MYOGLOBIN ◦ LESS MITHOCHONDRIA  LESS CELLULAR RESPIRATION ◦ MORE EXTENSIVE SR  INTERMEDIATE FIBERS/ TYPE IIa ◦ WHITE FIBERS ◦ FAST TWITCH FATIGUE RESISTANT ◦ FAST SPEED WITH HIGHER OXIDATIVE CAPACITY 5ksandcabernets.com/2012/05/fast_twitch-slow_twitch-muscle_fibers/

49 www.flickr.com/photos/thehappyrower/4083774365/ www.bing.com/images/search?q=fast+speed+muscles+&view www.examiner.com/article/us-olympic-trials-2012-men-s-and-women-s-5000m... behindtheworkout.com/2012/03/10/ slow-twitch-vs-fast-twitch-know-your -muscle-fibers/

50 http:/ iupucbio2.iupui.edu/anatomy/Outlines/Martini%204th%20Chapt%209.htm

51  BONE AND MUSCLE ACT AS LEVERS ◦ PARTS:  BAR  PIVOT/FULCRUM  OBJECT TO BE MOVED AGAINST RESISTANCE  FORCE FOR ENERGY FOR MOVEMENT

52  FULCRUM BETWEEN OBJECT AND FORCE ◦ SEE-SAW; SCISSORS ◦ RAISING HEAD: FACE IS OBJECT: ATLAS IS FULCRUM: MUSCLES AT BACK OF HEAD IS THE FORCE

53  FULCRUM THEN OBJECT THEN FORCE ◦ WHEELBARROW ◦ STANDING ON TOES: TOES = FULCRUM; BODY = OBJECT; LEG MUSCLES = FORCE

54  OBJECT THEN FORCE THEN FULCRUM ◦ TWEEZERS ◦ RAISING OBJECT IN HAND BY BICEPS: OBJECT IN HAND; BICEPS PULLS ONE RADIUS; ELBOW= FULCRUM

55 http://www.ichristianschool.org/anatomy/images/joints_bones/bonelevr.jpg

56 FIRST CLASS SECOND CLASS THIRD CLASS FIRST CLASS

57  ORIGIN ◦ IMMOVEABLE END OF MUSCLE  INSERTION ◦ THE END THAT MOVES http://www.equine-sports-massage.net/images/DeepDigFlexMusc.jpg

58  AGONIST/PRIME MOVER ◦ PRIMARY PRODUCER OF MOVEMENT  SYNERGIST ◦ CONTRACT TO ASSIST THE AGONIST  ANTAGONIST ◦ RESIST AGONIST’S MOVEMENT AND CAUSE OPPOSITE MOVEMENT IF BOTH CONTRACT THE STRUCTURE IS RIGID SMOOTH MOVEMENT DEPENDS ON RELAXATION OF ANTAGONISTS COORDINATED BY THE NERVOUS SYSTEM

59 http://www.deanza.edu/faculty/mccauley/6a-labs-tissues-01.htm

60 http://medcell.med.yale.edu/systems_cell_biology/muscle.php

61  SHORTER  SINGLE NUCLEUS IN CENTER  ELONGATED, TAPERING ENDS  ACTIN AND MYOSIN FIBERS ARE RANDOMLY ARRANGED (NOT STRIATED)  LESS DEVELOPED SR

62  MULTIUNIT ◦ LESS ORGANIZED ◦ ACT AS SINGLE CELLS ◦ IN IRIS AND BLOOD VESSELS  VISCERAL/SINGLE UNIT ◦ SHEETS OF SPINDLE SHAPED CELLS ◦ GAP JUNCTIONS ◦ THICK END IS NEAR ANOTHER CELL’S THIN END ◦ WORK AS A UNIT ◦ SOME HAVE RYTHMICITY: A PATTERN OF SPONTANEOUS REPEATED CONTRACTIONS ◦ EX: PERISTALSIS: CONTRACTION OF LOONGITUDINAL AND CIRCULAR MUSCLES ◦ FOUND IN HOLLOW ORGANS: OUTER COATS: LONGITUDINAL; INNER COATS: CIRCULAR

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64  SIMILARITIES TO SKELETAL  HAS CALMODULIN NOT TROPONIN  CALCIUM COMES MORE FROM EXTRACELLULAR FLUID  NUEROTRANSMITTERS ACETYLCHOLINE AND NOREPINEPHRINE AFFECT CONTRACTION: THEY EACH STIMULATE SOME AND INHIBIT OTHERS

65  WHERE ?  STRIATED  JOINED END TO END  INTERTWINED, 3-D NETWORK ??  SINGLE NUCLEUS  CISTERNAE LESS DEVELOPED =? ◦ STORE LESS Ca  LARGER T TUBULES ◦ RELEASES MORE CALCIUM MORE QUICKLY  RELIES MORE ON EXTRACELLULAR CALCIUM ◦ SO CAN CONTRACT LONGER THAN SKELETAL

66  INTERCALATED DISCS ◦ GAP JUNCTIONS  SYNCYTIUM  SELF EXCITING  RHYTHMIC  REFRACTORY PERIOD IS LONGER- AS LONG AS CONTRACTION = NO SUSTAINED OR TETANIC CONTRACTIONS

67 http://biol251.wikispaces.com/Ch4-Tissues CARDIAC MUSCLE

68 http://howtoloosebellyfatfast.net/tag/smooth-muscle-cells

69 http://classes.midlandstech.edu/carterp/Courses/bio110/chap07/chap07.html

70  STARTING IN 40’S DECLINES IN: ◦ MYOGLOBIN ◦ ATP ◦ CREATINE PHOSPHATE  DIAMETERS OF SOME MUSCLE FIBERS SHRINK  WALLS OF VEINS THICKEN  BECOME SMALLER, HAVE LESS WATER, LOSE STRENGTH  CONNECTIVE TISSUE AND ADIPOSE TISSUE REPLACE SOME MUSCLE TISSUE  BY 80 ½ OF MUSCLE MASS LOST: DUE TO LESS MOTOR NEURON ACTIVITY  SO REFLEXES SLOW

71  EXERCISE HELPS: ◦ COUNTERS THE LESS EFFICIENT O2 DELIVERY ◦ CAN GROW NEW MUSCLE  RELEASES INTERLEUKIN-6 STIMULATES SATELLITLE CELLS (STEM CELLS); DIVIDE AND MIGRATE MAINTAINS FLEXIBILITY OF BLOOD VESSELS KEEPING BLOOD PRESSURE NORMAL STRETCHING BEFORE AND AFTER, STRENGTH TRIANING AND AEROBIC EXERCISE STRENGTH TRAINING INCREASES MUSCLE MASS DECREASING FORCE ON JOINTS AEROBICS IMPROVES O2 USE AND ENDURANCE STRETCHING INCREASES FLEXIBILITY, DECREASES MUSCLE STRAIN, IMPROVES BLOOD FLOW LESS DEPRESSION IN OLDER PATIENTS

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