Muscle Histology Flashcards
What is a skeletal muscle fiber?
Single, long, multinucleated cell with flattened nuclei on the periphery
What is a cardiac muscle fiber?
Indeterminate number of cells joined end to end, each with 1 or 2 rounded nuclei
What is a smooth muscle fiber?
Single cell with single nucleus in the center
Speckled hot dog central nucleus, looks small and circular
What are myofibrils?
Groups of actin and myosin filaments
What is the sarcoplasmic reticulum?
Smooth ER that is closely associated with groups of myofibrils
What is endo-,peri-, and epimysium?
Endomysium - surrounds muscle fibers
Perimysium - Surrounds fasicles
Epimysium - surrounds the whole muscle
What type of collagen is associated with the connective tissue layers of the muscle?
Type 1 Collagen
What is a sarcomere?
Basic functional unit of a myofibril
Repeating units along the length of the muscle fiber
Composed of actin and myosin filaments
Overlapping filaments create the banding pattern of the striations
What is the Z line?
Point of attachment for thin filaments (actin)
What is the I band?
Z line and thin filaments (actin)
What is the A band?
Represents the full length of the thick filaments (myosin
Thin filaments overlap
Where are the T-tubules located in skeletal muscle?
Between the dark band and the light band
A-I junction
What is a muscle triad?
Two sections of sarcoplasmic reticulum and a T-tubule
Skeletal muscle
Where are the T-tubules located in cardiac muscle?
Z -line
Form diads with sarcoplasmic reticulum
What are Purkinje fibers?
Carry signal in cardiac muscle from nodes
Allow synchronized contraction of the heart
