Muscles Flashcards
The 4 unique characteristics of muscle tissue
Excitability: respond to input from stimuli
Contractility: muscle fibres can contract and shorten
Elasticity: when tension is removed muscle cells return to their original length
Extensibility: muscle fibres can be stretched beyond their resting length
Why are muscles considered organs
they contain all 4 tissue types
Characteristics of Skeletal Muscle Tissue
striated
usually attached to bone (bar most facial muscles)
multi-nulcei
voluntary control
functions of skeletal muscle tissue
for body movement
maitain posture
regulate temperature
storage and movement of materials
support
composition of muscles
muscle fibres (muscle cells)
blood vessels
nerves
organisation of muscles
muscle
fascicle
muscle fibre (muscle cells)
myofibrils
myofilaments (actin and myosin)
how many layers of CT do muscles have
3 layers composed of collagen and elastic fibres
what is the purpose of the CT in muscles
provides protection
site for blood vessels and nerve distribution
means for attachment to the skeleton
What are the 3 CT layers
Endomysium
Perimysium
Epimysium
The location and tissue type of each CT layer
Endomysium - surrounds and electrically insulates each muscle fibre, Areolar CT
Perimysium - surrounds the fascicles, dense irregular CT
Epimysium - surrounds the entire muscle, dense irregular CT
what are the names for muscle-specific plasma membrane, cytoplasm and smooth ER
sarcolemma
sarcoplasm
sarcoplasmic reticulum (regulates Ca2+)
name the thick and thin filaments
thick - Myosin
thin - Actin
what is sliding filament theory
the mechanism for contraction where the myosin heads ‘walk’ along the binding sites of the Actin
cardiac muscle fibre features
striated
y-shaped
one/two nuclei
joined by intercalated discs (gap junctions for communication)
autorhythmic
under involuntary control
Smooth muscle fibre features
short fusiform cells (tear drop)
single central nucleus
no striations
thin filaments attached to Dense Bodies
under involuntary control