Presentation on theme: "Muscular and Skeletal System"— Presentation transcript:
1Muscular and Skeletal System Nestor T. Hilvano, M.D., M.P.H.(Images Copyright Discover Biology, 5th ed., Singh-Cundy and Cain, Textbook, 2012.)
2Learning ObjectivesExplain how muscle and skeleton interact to cause movement.Describe the structure and arrangement of filaments in a muscle cell.Explain how a muscle cell contracts.Give the functions of skeletal system.Describe the 3 main types of skeletons and give examples of each.Distinguish between axial and appendicular skeletons in human.Describe the 3 main types of joints and provide examples of each.Describe the complex structure of a long bone.Explain why bones break and how we can help them heal.
3Word stem endo- within hydro- water myo- muscle fibro- fiber sarco- fleshmere- a part
4Figure 31.7 Specialized Types of Muscles for Different Types of Movement (a) Muscles associated with the skeleton have a banded, or striated, appearance. (b) Cardiac muscle is also banded, and its muscle fibers are branched. (c) Smooth muscle does not have bands.
5Introduction: Muscle Contraction Movement is a fundamentalcharacteristicMuscle Cells capable ofshortening (it pull)Converting the chemicalenergy of ATP intomechanical energySkeleton provides a rigid structure to which muscles attachMovements require antagonistic pair of muscles
6The structure of Skeletal Muscle Skeletal muscle cell (fiber) is composed of myofibrils (fibrils)Each fibril consists of myofilamentsMyofilaments of contractile proteins= actin (thin) filaments and myosin (thick) filamentsTroponin (binds w/ Ca++), tropomyosin (covers active site of actin) = regulatory proteinsSarcomere – is a functional unit , bordered by Z lines (discs); A band (dark), I band (pale), H band (zone), M line,Sarcoplasmic reticulum – releases Ca++
7Sliding-Filament Model of Muscle Contraction FigSarcomere0.5 µmZMZRelaxed muscleContracting muscleFully contracted muscleContracted SarcomereMyosin-binding sites on the thin filament are blocked by the regulatory protein tropomyosin at rest; For a muscle fiber to contract, myosin-binding sites must be uncovered when calcium ions (Ca2+) bind to troponin, remove tropomyosin, active actin site open, myosin-actin slides. ATP needed.
8Myosin-binding sites blocked Figure 30.10BMyosin-binding sites blockedTropomyosinCa2-binding sitesActinTroponin complexCa2 floods thecytoplasmicfluidFigure 30.10B Thin filament, showing the interactions among actin, regulatory proteins, and Ca2+Myosin-binding sites exposedMyosin-binding site8
9Sarcomere Dark band Z Z Relaxed muscle Contracting muscle Figure 30.9ASarcomereDark bandZZRelaxed muscleContractingmuscleFigure 30.9A The sliding-filament model of muscle contractionFully contractedmuscleContracted sarcomere9
10Motor Neuron, Motor Unit, and NMJ Motor neuron stimulates muscle contractionMotor unit – consists of a motor neuron and all the muscle fibers it controls.Neuromuscular junction – a region between motor nerve fiber and muscle fiber.Action potential is transmitted to the fiber
11Functions of Skeletal System SupportProtectionMovementMineral storageBlood cell formation
12Skeletal System: Subdivisions I – Axial skeletonSkullThoracic (rib) cage- sternum- rib- thoracic vertebraec) Vertebral columnII – Appendicular skeletonUpper limbs and pectoral (shoulder) girdleb) Lower limbs and pelvic (hip)girdleExercises:What subdivision of skeletal system provides movements? Protects vital organs (brain, heart, lungs)?a. Axial skeleton b. Appendicular skeleton
13Axial Skeleton Skull – cranial bones and facial bones: Thoracic cage: cranial bones= Frontal (bone of forehead), parietal, temporal and occipital bonesfacial bones= Zygomatic bone (cheek bone); Nasal bone (bridge of nose); Maxillae (upper jaw), and Mandible (lower jaw)Thoracic cage:Sternum: manubrium, body, & xiphoid processRibs (12 pairs): 1st to 7th pairs (true ribs), 8th to 10th ribs (false ribs), 11th to 12th pairs (floating ribs)Vertebrae – cervical (neck), thoracic (chest), lumbar & sacral (back), and coccyx (tail bone)
15Joints Bones meet together; lever for movement Ball and socket joints – allow movement in all directions;ex. Shoulder joint, hip jointHinge joints – movement in single plane;ex. Elbow joint, knee jointPivot joints – rotate (spin) in its longitudinal axis;ex. Radio-ulnar joint
16Figure 31.4 Joints Combine Rigidity and Flexibility to Enable Movement The human knee illustrates how rigidity and flexibility together enable movement. Fluid-containing synovial sacs are shown in purple; cartilage, in gray.
17Structure of Long BoneDiaphysis – shaft/middle part; compact bone covered by periosteum; medullary cavity with yellow BMEpiphysis - ends of long bone; outer layer of compact bone and inner layerof spongy bone (red BM)Articular cartilage on joint surfaceBone is composed of collagen proteinsand calcium phosphatesGrowth of long bone occurs atepiphysis (epiphyseal plate of cartilage)Osteocytes (mature bone cells)Osteoblasts (bone forming cells)Osteoclasts (bone destroying cells)
18Fracture Break in the continuity of bone. Bone healing by: - immobilization- surgical interventionReplacement
19Osteoporosis Softening of bone Factors – changes in diet, lack of weight bearing exercise, lifestyle habits (smoking) and diseases (DM)Treatment – calcium, vitamin D, and drug therapy
20HomeworkDefine terms: motor neuron, motor unit, neuromuscular junction, sarcoplasmic reticulum, actin filament, myosin filament, troponin, tropomyosin, axial skeleton, appendicular skeleton, joint, fracture, osteoporosis, diaphysis, epiphysis, tendon, osteocyte, osteoblast, and ligament.Describe the structure of sarcomere (components).Discuss the mechanism of contraction of skeletal muscle (sliding theory of myofilaments).Compare and contrast the 3 types of muscles.Describe the movement of the following joints and give an example for each: ball and socket, hinge, pivot jointsIdentify the bones of human skeleton as described: bone of forehead, bone that protects the brain, cheek bone, upper jaw, lower jaw, breast bone, shoulder blade, collar bone, bone of the arm, bones of the forearm, wrist bones, bones of the palm, hipbone, knee cap, thigh bone, leg bones, ankle bones, bones of digits (fingers and toes).