Muscle Contraction Part 1

Muscle Contraction Part 1

Parts of a muscle

• Dense connective tissue called fascia, surround and separate each muscle

  
  

  
  

• Fascia extends beyond the ends of the muscle and gives rise to tendons that are fused to the periosteum of bones   (tendons connect muscle to bones)

  
  

• Some muscles are connected to each other by broad sheets of connective tissue called aponeuroses

Multiple Choice

Dense connective tissue called _______, surround and separate each muscle

• aponeuroses

• fascia

• tendons

Multiple Choice

Some muscles are connected to each other by broad sheets of connective tissue called __________.

• fascia

• aponeuroses

• tendons

Parts of a muscle

• Fascia blends with the epimysium, the layer of connective tissue around each skeletal muscle

  
  

• The perimysium extends inward from the epimysium; it surrounds bundles of skeletal muscle fibers, called fascicles, with each muscle 

  
  

• Each muscle cell (fiber) is covered by a connective tissue layer called endomysium.

  
  

Multiple Choice

Fascia blends with the ______, the layer of connective tissue around each skeletal muscle

• epimysium

• perimysium

• endomysium

Multiple Choice

The ________extends inward from the epimysium; it surrounds bundles of skeletal muscle fibers.

• epimysium

• perimysium

• endomysium

Multiple Choice

Each muscle cell (fiber) is covered by a connective tissue layer called __________.

• epimysium

• perimysium

• endomysium

Multiple Choice

bundles of skeletal muscle fibers

• fascia

• fascicles

• perimysium

Skeletal Muscle Fibers

• Each muscle fiber is a single, long, cylindrical muscle cell.

• Fibers respond to stimulation by contracting

• The cell membrane of a muscle fiber is the sarcolemma

• The cytoplasm of a muscle cell is the sarcoplasm ; it contains many mitochondria and nuclei

  
  

Skeletal Muscle Fibers

• The sarcoplasm contains parallel myofibrils , which are active in muscle contraction:

  
  

• Thick filaments in myofibrils consist of the protein myosin

  
  

• Thin filaments in myofibrils are mainly composed of the protein actin, but also contain troponin and tropomyosin

  
  

  
  

• The organization of these filaments produces bands called striations

  
  

Multiple Choice

The cell membrane of a muscle fiber is the

• sarcolemma

• sarcoplasm

• myofibril

Multiple Choice

The cytoplasm of a muscle cell is the _____ ; it contains many mitochondria and nuclei

• myofibril

• sarcolemma

• sarcoplasm

Multiple Choice

The sarcoplasm contains parallel ______ , which are active in muscle contraction:

• muscle fibers

• myosin

• myofibrils

Multiple Choice

Thick filaments in myofibrils consist of the protein

• troponin

• myosin

• actin

Multiple Choice

Thin filaments in myofibrils are mainly composed of the protein

• actin

• myosin

• fascia

Multiple Choice

The organization of these filaments produces bands called

• myofibrils

• striations

• sarcomeres

The Sarcomeres of Myofibrils

• Myofibrils are made up of many units called sarcomeres , joined end-to-end

• A sarcomere extends from one Z line to the next

• Striations consist of an alternating pattern of light and dark bands

• I bands (light bands) are made up of actin filaments, which are anchored to the Z lines

• A bands(dark bands) are made up of overlapping thick and thin filaments

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The Sarcomeres of Myofibrils

• In the center of the A band is the H zone , which consists of myosin filaments only

• The M line , in the center of the H zone, consists of proteins that hold the myosin filaments in place

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• 
  

• 
  

• 
  

• 
  

Multiple Choice

Myofibrils are made up of many units called

• sarcolemmas

• sarcoplasms

• sarcomeres

Multiple Choice

These bands are made up of actin filaments.

• I bands

• A bands

• striations

Multiple Choice

These are made up of overlapping thick and thin filaments

• I bands

• A bands

• striations

Multiple Choice

Thick filaments are also known as ________.

• actin filaments

• myosin filaments

Multiple Choice

Thin filaments are also known as ____.

• actin filaments

• myosin filaments