14.1 POJA-L6233 Electron micrograph of skeletal muscle (human)
14.1 POJA-L6233 Electron micrograph of skeletal muscle (human)
Title: Electron micrograph of skeletal muscle (human)
Description:
Ultrastructure of striated muscle. (1) Sarcomere unit running from Z- to Z-line (or disc). (2) I-band (isotropic). (3) H-band with M-line. (4) A-band (anisotropic). (5) M-line. (6) Glycogen particles. Between the bundles of myofilaments small profiles of cross sectioned mitochondria (*) are localised. Some swollen mitochondria are present too.
The dark centre line in the H-zone is where cross-linking of the myosin filaments occurs.
The thicker myosin filaments form the A-band of the myofibril. All sarcomeres are aligned parallelly and are well organised in register.
Background:
The sarcomere (1) as the smallest functional unit has a length that cannot be measured accurately, however depending on type of muscle and on the degree of stretch it is assumed that the sarcomere length is between 1.5 to 4 micrometers long. Based on geometrical assumptions the sarcomere force should be maximal at a sarcomere length of 2.0 micrometer, because then a maximal overlap between actin and myosin occurs at twice the actin length (=1.9 micrometer) + width Z-line (= 0.1 micrometer).
Keywords /Mesh: locomotor system, skeletal muscle, striated muscle, myofibril, sarcomere, myosin, actin, A-band, I-band, H-band, M-band, Z-line, myofilament, electron microscopy, POJA collection
Title: Electron micrograph of skeletal muscle (human)
Description:
Ultrastructure of striated muscle. (1) Sarcomere unit running from Z- to Z-line (or disc). (2) I-band (isotropic). (3) H-band with M-line. (4) A-band (anisotropic). (5) M-line. (6) Glycogen particles. Between the bundles of myofilaments small profiles of cross sectioned mitochondria (*) are localised. Some swollen mitochondria are present too.
The dark centre line in the H-zone is where cross-linking of the myosin filaments occurs.
The thicker myosin filaments form the A-band of the myofibril. All sarcomeres are aligned parallelly and are well organised in register.
Background:
The sarcomere (1) as the smallest functional unit has a length that cannot be measured accurately, however depending on type of muscle and on the degree of stretch it is assumed that the sarcomere length is between 1.5 to 4 micrometers long. Based on geometrical assumptions the sarcomere force should be maximal at a sarcomere length of 2.0 micrometer, because then a maximal overlap between actin and myosin occurs at twice the actin length (=1.9 micrometer) + width Z-line (= 0.1 micrometer).
Keywords /Mesh: locomotor system, skeletal muscle, striated muscle, myofibril, sarcomere, myosin, actin, A-band, I-band, H-band, M-band, Z-line, myofilament, electron microscopy, POJA collection