physiology Flashcards
what are the physiological functions of skeletal muscles? (5)
- maintenance of posture
- purposeful movement in relation to external environment
- respiratory movements
- heat production
- contribution to whole body metabolism
what is the largest type of tissue in the human body?
muscle
what are the 3 types of muscle tissue?
- skeletal muscles
- cardiac muscles
- smooth muscles
what muscle type is striated?
skeletal and cardiac
how does striation appear under a light microscope?
alternating dark bands and light bands
what causes the light/dark bands that can be seen in striated muscle?
light- actin thin filaments
dark- myosin thick filaments
what muscles are voluntary and what ones are involuntary ?
voluntary- skeletal muscle
involuntary- cardiac and smooth muscle
what nervous system controls skeletal muscle?
somatic nervous system
what nervous system control cardiac and smooth muscles?
autonomic nervous system
what type of muscle has a neurogenic initiation of contraction?
skeletal
what muscle has a myogenic initiation (initiated in muscle) of contraction?
cardiac muscle
what muscle has motor units?
skeletal muscle (the units are sarcomeres)
what muscle has neuromuscular junction present?
skeletal
what muscle has gap junctions present?
cardiac
how does calcium enter in cardiac muscle?
from ECF and sarcoplasmic reticulum
how does calcium enter in skeletal muscle?
entirely through the sarcoplasmic reticulum
what is the transmitted at the neuromuscular junctions in skeletal muscle?
acetylcholine
muscles which serve fine movements (external eye muscles, facial expressions, intrinsic hand muscles) have more or fewer fibres per motor unit?
fewer
what does the number of muscle fibres per motor unit depend on?
the function served by the muscle
how are skeletal muscles attached to the skeleton?
by tendons
how far do skeletal muscle fibres (cells) extend across the muscle?
they extend the entire length of the muscle
what are myofibrils?
specialised contractile intracellular structures
where are myofibrils found?
in skeletal muscle fibres (cells)
where are sarcomeres found?
in myofibrils