Transcript Chemistry of Muscle Contraction

Chemistry of Muscle Contraction
• _______ is the energy source for actin and myosin
to contract.
– Produced by the many _____________.
– ATP that has become ADP can recharge back to ATP when creatine
phosphate (CP) splits and donates a phosphate.
– Glucose and oxygen are also needed for contraction.
• Stored in form of glycogen and myoglobin for aerobic metabolism.
• Anaerobic metabolism produces __________ acid
Heat Production
• Muscular activity is one of the major heat-generating
mechanisms that the body uses to maintain its temperature.
• Shivering (small spasms of contraction) helps to prevent
hypothermia
Cardiac
Muscle
• Also known as ______________ due to lack of
conscious control ________________ and
_______________ due to microscopic
appearance
– Contain myofibrils
• Only found within the heart (walls)
• Much smaller than skeletal muscles cells and only
contain one nuclei per cell
• Are longer than wide and have multiple branches
forming a network of cells.
– Contain _________ _________- gap junctions
where cells attach one to another.
• Transmit impulses from cell to cell.
• This allows entire groups of cells to
contract together at the same time.
• Dark, transverse
Physiology of
Cardiac Muscle
• No external nerve stimulation
required to contract.
– Rate and rhythm of contraction is due to (SA
node) _______ ______ (pacemaker) of
heart located in the wall of the right atrium.
– Impulse follows a controlled path through
the conduction system of the heart.
• Groups of cardiac muscle cells
that touch adopt the
contraction rate of the most
rapid cell.
• Cardiac cells contract in rapid,
wavelike fashion down a
controlled path.
– This helps to squeeze blood out of chambers
of the heart
Nerve Supply of Heart
•
Heart rate is modified by Autonomic Nervous
System
– Sympathetic and Parasympathetic Nervous
Systems
1. Sympathetic fibers stimulate heart to beat
harder and faster as part of "fight or flight
response”
2. Parasympathetic fibers inhibit cardiac
function, causing heart to beat more slowly
and with less force, part of “feed or breed”
response.
Smooth Muscle
• Also known as ______________ due
to lack of conscious control
________________ and
_______________ due to lack of
striations.
• Found in two forms:
– _________________ smooth muscle
• Large sheets of cells in the walls of some hollow
organs
– _________________ smooth muscle
• Small, discrete groups of cells make delicate
movements.
Smooth microscopic muscle anatomy
• Small with single nucleus.
• Actin and myosin are present,
but are not arranged in
parallel.
– criss-cross cell and are
attached to __________ bodies
that are similar to Z lines of
skeletal muscle.
– Cell balls up as it contracts
Visceral Smooth Muscle
• Found in walls of many soft internal
organs that are known as viscera.
• Instead of fine movements, work in
waves of motion.
• Does not need external stimulation.
– If stretched, will contract more
strongly.
• __________ nervous system
decreases activity, __________
nervous system increases activity
Multiunit Smooth Muscle
• Individual cells or small groups of
cells that produce fine and
delicate movements
– Ex: blood vessel walls, within
the eye, small airways
• Also under influence of the
autonomic nervous system