Muscle Physiology Flashcards
(32 cards)
Functions of the muscular system
Body movement
Maintenance of posture
Respiration
Production of body heat
Communication
Constriction of organs and vessels
Heartbeat and blood circulation
Four properties of muscle cells
Contract ability
Excitability
Extensibility
Elasticity
Contract ability
Ability to shorten
Excitability
Capacity to respond to stimulus (contracts)
Extensibility
Can be stretched Beyond normal resting length
Elasticity
Recoil after stretching
Three types of muscle cells
Smooth
Skeletal
Cardiac
Smooth muscle
Most widely distributed throughout the body greatest variety of functions
controlled by the nervous and endocrine system
Skeletal muscle
40% of body weight
Muscle fiber
Multi peripheral nuclei
Hypertrophy
Enlargement of muscles which results from an increase in size of each muscle fiber not from a substantial increase in number of muscle fibers
Hyperplasia
the enlargement of an organ or tissue caused by an increase in the reproduction rate of its cells, often as an initial stage in the development of cancer. (Motosis)
Connective tissue layer surrounding muscle fibers
External lamina endomysium perimysium epimysium Fascia
Actin
Thin myofilament
Myosin
Thick myofilament
Myosin heads
Bind to active sites on actin molecules cross; Bridges
ATPase
Enzyme that breaks down ATP releasing energy
Sarcomere
Repeating working units within individual muscle fibers
Z discs
At each end of sarcomere (acting attachment)
I band
Either side of Z band to end of myosin filament
A band
Length of myosin filament
H Zone
In the center of a band no overlap and only myosin is present
M line
Middle of H zone - filaments that attach to center of myosin myofilaments A and I bands of parallel myofibrils are aligned (striations)
How many skeletal muscles are there?
640
