CHAPTER 19Musculoskeletal System
1. THE SKELETAL SYSTEM•  A skeleton has many functions:  – Supports body  – Protects soft body parts  – Produces blood cel...
– The axial skeleton • Supports the axis of the body and   includes the skull, vertebral column,   and rib cage.– The appe...
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Axial skeleton            Skul...
The Vertebral Column   Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 7 cerv...
JOINTS        There are 3 types of joints:1.  FIBROUS– immovable   – Sutures between bones of skull2.  CARTILOGENOUS– slig...
TYPES OF SYNOVIAL JOINTS Synovial which means they are freely movable   –  Bones are separated by a cavity   –  Tendons he...
Bone StructureBones are complex organs consisting of several kinds oftissues.Bones  –  Are covered with a connective tissu...
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.                       cartila...
– The central cavity of a long bone (or  diaphysis)   • Contains yellow bone marrow, which     is mostly stored fat.– The ...
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.          central canal       ...
Compact Vs Spongy Bones•  COMPACT BONE –  HARD MATERIAL of the bone –  Highly organized•  SPONGY BONE –  Unorganized appea...
Skeletal Diseases and InjuriesThe human skeleton is quite strong andprovides reliable support, but it is susceptible todis...
A. Fracture•  If a force applied to a bone exceeds its capacity to   bend, the result is a broken bone or fracture.•  The ...
SOME TYPICAL BONE FRACTURES  LINEAR            SPIRAL COMMINUTED TRANSVERSE COMPOUNDThe fracture is   At least one    The ...
B. Osteoporosis•  Bones lose mass and mineral content•  Leads to an increase risk of fractures
C. Arthritis•  Osteoarthritis  –  Degenerative joint disease     (cartilage)•  Rheumatoid arthritis  –  Autoimmune disease...
2. THE MUSCULAR SYSTEM
2. THE MUSCULAR SYSTEM•  Pull on bones to produce movements•  Skeletal muscles = voluntary   movements•  Attached to the b...
Antagonistic pairs of muscles bring aboutmovement in opposite directions
a. Anterior view                                                                                             frontalis    ...
b. Posterior view                                                                                          occipitalis    ...
Muscle structure                            • The skeletal muscle consists of                            bundles of parall...
MUSCLE FIBER•  One muscle fiber has many myofibrils•  Is called striated, because the myofibrils   exhibit alternating lig...
How does a muscle contract?•  A myofibril is composed of 2 kinds of filaments: –  Thin filaments, made mostly of the prote...
Figure 27.33
The sliding-filament modelMyosin heads in the thick filaments binds to specificsites on actin molecules in the thin filame...
Muscle contractrion videos•  http://www.youtube.com/watch?   v=CepeYFvqmk4•  http://www.youtube.com/watch?   v=v71ZP8_RoOU...
Control of muscle contractionMotor neurons    •  Stimulate muscles to contract.    •  Can branch to a number of muscle    ...
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.                              ...
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.                              ...
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.                              ...
Whole Muscle Contraction•  In the Body    – A motor unit is a nerve fiber together with      all the muscle fibers it inne...
Athletics and Muscle Contraction•  Exercise and Size of Muscles  –  Muscles that are not used decrease in size     (atroph...
Are all your muscle fibers the same?•  What types of exercises can you do?      •  Aerobic such as running      •  Anaerob...
Different fibers for different types of exercises: Slow-Twitch and Fast-Twitch Muscle Fibersslow-twitch                   ...
Chapter 19
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Chapter 19

  1. 1. CHAPTER 19Musculoskeletal System
  2. 2. 1. THE SKELETAL SYSTEM•  A skeleton has many functions: – Supports body – Protects soft body parts – Produces blood cells – Stores mineral and fat – Along with muscles, permits flexible body movement•  The human endoskeleton is composed of cartilage and bones
  3. 3. – The axial skeleton • Supports the axis of the body and includes the skull, vertebral column, and rib cage.– The appendicular skeleton • Is made up of the bones of the limbs, shoulders, and pelvis.
  4. 4. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.Axial skeleton Skull:Appendicular skeleton cranium mandible clavicle Thoracic cage: scapula sternum ribs humerus Costal cartilages Vertebral column ulna Pelvic girdle radius sacrum carpals coccyx metacarpals phalanges femur patella fibula tibia tarsals metatarsals phalanges
  5. 5. The Vertebral Column Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 7 cervical vertebrae in Neck region 12 thoracic vertebrae Ribs attach here. 5 lumbar vertebrae in small of back Sacrum: 5 fused vertebrae Coccyx: usually 3–5 fused vertebrae "tailbone".
  6. 6. JOINTS There are 3 types of joints:1.  FIBROUS– immovable – Sutures between bones of skull2.  CARTILOGENOUS– slightly movable – Connected by hyaline cartilage – Ribs / sternum – Connected by fibrocartilage – Intervertebral discs3.  SYNOVIAL – freely movable
  7. 7. TYPES OF SYNOVIAL JOINTS Synovial which means they are freely movable –  Bones are separated by a cavity –  Tendons help to stabilize the joint –  Synovial membrane produces synovial fluid 3 types:permit movement in permit movement in permit onlyall planes one direction only rotationalEx: shoulder joint Ex: elbow movement
  8. 8. Bone StructureBones are complex organs consisting of several kinds oftissues.Bones –  Are covered with a connective tissue membrane. –  Have cartilage at the ends that cushions the joints. –  Are served by blood vessels and nerves.
  9. 9. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. cartilage spongy bone epiphysis (contains red bone marrow) compact bone Central cavity(contains yellow bone marrow) diaphysis Fibrous connective tissue blood vessel epiphysis
  10. 10. – The central cavity of a long bone (or diaphysis) • Contains yellow bone marrow, which is mostly stored fat.– The end of a long bone (or epiphysis) • Contains red bone marrow, a specialized tissue that produces blood cells.
  11. 11. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. central canal osteoncompact bone spongy bone Blood vessels
  12. 12. Compact Vs Spongy Bones•  COMPACT BONE –  HARD MATERIAL of the bone –  Highly organized•  SPONGY BONE –  Unorganized appearance (but plates follow lines of stress so spongy bone is strong) –  Spaces filled with red bone marrow
  13. 13. Skeletal Diseases and InjuriesThe human skeleton is quite strong andprovides reliable support, but it is susceptible todisease and injury, such as: A.  Fracture B.  Osteoporosis C.  Arthritis
  14. 14. A. Fracture•  If a force applied to a bone exceeds its capacity to bend, the result is a broken bone or fracture.•  The treatment of a fracture involves 2 steps: 1.  Putting the bone back into its natural shape 2.  Immobilizing it until the body can repair the fracture –  In severe cases, a fracture can be repaired surgically by inserting plates, rods, and/or screws to hold the broken pieces together.
  15. 15. SOME TYPICAL BONE FRACTURES LINEAR SPIRAL COMMINUTED TRANSVERSE COMPOUNDThe fracture is At least one The bone has The fractured is or OPENparallel to the part of the fractured into a at a right angle The skin isbone long axis bone is twisted number of pieces with the bone broken, the axis bone sticks out
  16. 16. B. Osteoporosis•  Bones lose mass and mineral content•  Leads to an increase risk of fractures
  17. 17. C. Arthritis•  Osteoarthritis –  Degenerative joint disease (cartilage)•  Rheumatoid arthritis –  Autoimmune disease –  Joints and other tissues are attacked
  18. 18. 2. THE MUSCULAR SYSTEM
  19. 19. 2. THE MUSCULAR SYSTEM•  Pull on bones to produce movements•  Skeletal muscles = voluntary movements•  Attached to the bone by tendons•  650 human skeletal muscles
  20. 20. Antagonistic pairs of muscles bring aboutmovement in opposite directions
  21. 21. a. Anterior view frontalis trapezius deltoid pectoralis major biceps brachii rectus abdominis external oblique adductor longus sartorius quadriceps femoris group peroneus longus gastrocnemius tibialis anterior extensor digitorum longus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  22. 22. b. Posterior view occipitalis trapezius deltoid Latissimus dorsi triceps brachii External oblique Gluteus medius Extensor digitorum Gluteus maximus Hamstring group gastrocnemius Peroneus longus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  23. 23. Muscle structure • The skeletal muscle consists of bundles of parallel muscle fibers • One muscle fiber is a muscle cell bundle of muscle fibers One muscle fiber/cell myofibrilsCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  24. 24. MUSCLE FIBER•  One muscle fiber has many myofibrils•  Is called striated, because the myofibrils exhibit alternating light and dark bands when viewed with a light microscope.•  A sarcomere is the region between two dark, narrow lines called Z lines. It is the unit of contraction
  25. 25. How does a muscle contract?•  A myofibril is composed of 2 kinds of filaments: –  Thin filaments, made mostly of the protein actin –  Thick filaments, made mostly of the protein myosin•  A sarcomere contracts –  When its thin filaments slide across its thick filaments.
  26. 26. Figure 27.33
  27. 27. The sliding-filament modelMyosin heads in the thick filaments binds to specificsites on actin molecules in the thin filaments.
  28. 28. Muscle contractrion videos•  http://www.youtube.com/watch? v=CepeYFvqmk4•  http://www.youtube.com/watch? v=v71ZP8_RoOU&feature=related•  http://www.youtube.com/watch? v=0kFmbrRJq4w&NR=1
  29. 29. Control of muscle contractionMotor neurons •  Stimulate muscles to contract. •  Can branch to a number of muscle fibers.A motor unit consists of a neuron and allthe muscle fibers it controls.
  30. 30. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Skeletal muscle fiber Axon branch Axon terminal myofibril neuromuscular junction a. One motor axon causes several muscle fibers to contract.
  31. 31. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Victor B. Eichler, Ph.D.
  32. 32. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. synaptic vesicle synaptic cleft acetyl choline (ACh) Na+ folded sarcolemma ACh receptorThe release of a neurotransmitter (ACh) causesreceptors to open and Na+ to enter a muscle fiber.
  33. 33. Whole Muscle Contraction•  In the Body – A motor unit is a nerve fiber together with all the muscle fibers it innervates – As the intensity of nervous stimulation increases, more motor units are activated – Some muscle fibers are contracting while others are relaxing – Even when muscles appear to be at rest, some fibers are always contracting (muscle tone)
  34. 34. Athletics and Muscle Contraction•  Exercise and Size of Muscles –  Muscles that are not used decrease in size (atrophy) –  If stimulation is not restored, muscle fibers are gradually replaced by fat and fibrous tissue –  Forceful activity over prolonged period causes muscle to increase in size •  Hypertrophy occurs only if muscle contracts to at least 75% of maximum tension •  Increase in number of myofibrils within fibers causes hypertrophy
  35. 35. Are all your muscle fibers the same?•  What types of exercises can you do? •  Aerobic such as running •  Anaerobic such as lifting weight•  Are their requirements in oxygen the same? NO •  Aerobic such as running needs lots of oxygen •  Anaerobic doesn’t•  They will need different amount of : –  mitochondria (remember turns oxygen into energy) –  myoglobin (protein that binds oxygen and iron)
  36. 36. Different fibers for different types of exercises: Slow-Twitch and Fast-Twitch Muscle Fibersslow-twitch fast-twitchfibers fibers Slow-twitch muscle fiber: Fast-twitch muscle fiber: • Is dark in appearance • Is light in appearance (Contains lots of mitochondria • is anaerobic and myoglobin) has explosive power •  is aerobic • Fatigues easily has steady power • has endurance © G.W. Willis/Visuals Unlimited Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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