Skeletal muscles

• Which division of the nervous system controlls skeletal muscle

  The somatic motor neurons
• How are bones connected to skeletal muscle

  Using tendons
• What are tendons made of

  Collagen
• What are the main functions of skeletal muscles

  Movement and maintenance of posture.

  Control of sphincters.

  Thermoregulation.

  Nutrients reserve.
• Where does skeletal muscle sit in the skin

  Below the subcutaneous tissue
• What is the epimysium made of

  Dense connective irregular tissue
• Waht is the perimysium made of

  Dense connective irregular tissue
• Label the skeletal muscle

  Muscle fibres are often referred to as myocytes.

  A) Bone

  B) tendon

  C) Epimysium

  D) Perimysium

  E) Fasicle

  F) Endomysium

  G) Muscle fiber

  
• What is a bundle of myocytes called

  A fascicle it is wrapped in a perimysium
• What is the role of the epimysium

  It covers the outside of the muscle
• What is the role of the perimysium 


  It holds the fascicles.
• What is the role of the endomysium

  It separates the individual myocytes.
• How is a myocyte formed

  Myoblasts fuse in embryonic development.
• What are the features of myocytes

  Multinucleated. The nuclei sit under the sarcolemma.

  Striated due to the alignment of the sacromeres.
• What is the plasma membrane of a muscle fibre

  Sarcolemma
• What are myofibrils

  They possess the contractile properties of a muscle fibre.
• Waht are myofibrils made of.

  Myofilamets which can be thick or thin. These are arranged into sacromeres
• Label this and state what it is

  This is a skeletal muscle fibre.

  A) Sacromere

  B) Mitochondria

  C) Motor neuron

  D) Synaptic terminal

  E) T tubule

  F) Sarcoplasmic reticulum

  G) Myofibril

  H) Sacrolemma

  I) Calcium

  
• What is stored in the sarcoplasmic reticulum when relaxed

  Calcium
• What are T-tubules

  The T stands for transverse. They transfer the action potential from the sarcolemma to the sarcoplasmic reticulum.
• How is oxygen transported to the mitochondria of a muscle fibre

  Using myoglobin
• What is the cytoplasm of a muscle fibre called

  The sarcoplasm
• What is a sarcomere

  The arrangement of thick and thin myofilaments.

  It extends from one Z line to the next.
• Label this and state what it is

  It is a myofibril.

  A) Sacromere

  B) A band

  C) Z line

  D) I band

  E) M Line

  F)

  
• What is the M line

  It is in the middle of the sarcomere and attaches thick filaments together.
• What is the A band

  Consits of thick and thin filaments
• What is the I band

  Consists of only thin filaments
• What is the H band

  Consists of only thick filaments
• What is the Z line

  It is made of alpha actinin, which binds actin and titin to join the sarcomeres together.
• What is the zone of overlap

  This is where the thick and thin fibres overlap
• What happens to the sacromere during contraction

  The Z line shortens
• What are thick filaments made of

  Myosin
• What does the head of myosin do

  Binds to actin and hydrolyses ATP to ADP.
• Where is titin found

  At the end of the thick filaments
• What is the role of titin

  To prevent over-extension of the sarcomere
• How do the myosin filaments work

  The myosin head moves [thick filaments] and pushes the actin [thin filaemnts] towards the M line.
• What are the thin filamets made of

  Actin
• What are the regulatory proteins in thin filaments

  Troponin and Tropomyosin.
• What does nebulin do

  It anchors the thin filaments to the Z line
• What does troponin do

  Regulates the position of tropomyosin