Download What make up the bulk of the body and account for about one

Prefixes and Suffixes
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blast = budding or germ
clast = break
myo- = muscle
sarco – flesh
- algia or alg(i)o = pain
arthr(o) = pertaining to the joints or limbs
- ase = enzyme
fibr(o) = fiber
What make up the bulk of the
body and account for about 30 –
40% of its weight?
MUSCULAR SYSTEM
• a muscle is a tissue composed of fibers
capable of contracting to effect bodily
movement
Cardiac Muscle
• makes up the walls of the
heart
• cells are striated; one central nucleus
• involuntary – cannot be controlled
• contractions propel blood
throughout the body
Smooth Muscle
• found in the walls of hollow organs
– ex: stomach, intestines, blood
vessels
• no striations; one central nucleus
• involuntary
• moves substances along
internal passageways
Skeletal Muscle
• Provides movement for body parts
• Made up of muscle tissue, nervous tissue,
blood and connective tissue
– attached to bones, cartilage, tendons or skin
• have striations, dark bands or stripes
– results from the presence of two types of
protein filaments
• voluntary control
• cells have multiple
nuclei
MUSCLE STRUCTURE
• muscle cells are called muscle fibers
• contract in response to stimuli
• each muscle fiber (cell) is made up of
many myofibrils
–
myofibrils
• a rod-like structure that
contracts when stimulated
• made up of two
types of filament:
actin (thin) and myosin
(thick).
– Filaments are made up
of proteins
• consist of sections called
sarcomeres
Sarcomeres
• functional unit of
skeletal muscle
• Extends from one Z
line to the next Z line
• Z line – location
where actin filaments
are anchored at their
endpoints
http://videos.howstuffworks.com/hsw/6100-the-cellmuscle-cells-video.htm
Contracting a Muscle
• Myosin and actin interact to
shorten the length of a sarcomere
• myosin attaches to the actin
• The myosin head bends inward,
pulling the actin with them
• This action shortens the length of
the sarcromere
http://highered.mcgrawhill.com/sites/0072437316/student_view0/chapter42/animations.
html#
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter10/animation__
myofilament_contraction.html
During contraction, the thin filaments slide past the thick
During contraction, the thin filaments slide
past the thick filaments, shortening the
sarcomere
–all sarcomere
shorten
simultaneously,
causing the
entire muscle
fiber and the
muscle to
contract
Motor Units
• The trigger for a muscle contraction
is an electrical impulse.
–signals sent from the central
nervous system. (brain and spinal
cord)
• A motor neuron (nerve cell) and all
the muscle fibers that it stimulates
are known as the motor unit.
Neuromuscular Junction
• Connection between the motor neuron and
muscle fiber
O2 Supply and Cellular Respiration
• Blood carries O2 from the lungs to body
cells
• Myoglobin stores O2 in muscle tissue,
reducing need of blood supply
• O2 required for cellular respiration
– C6H12O6 + O2
CO2+ H2O + ATP
O2 Debt
• During strenuous activity muscle fibers
have an increase need for energy
• Not enough O2 leads to anaerobic (without
O2) respiration
– Results in build a up of lactic acid in the
muscles
- Lactic acid can be converted back to glucose by
the liver
• active muscles use a lot of energy and
require a continuous supply of oxygen and
nutrients (how is this supplied?)
• Muscle fatigue
– Inability of a muscle to contract
– Results as a depletion of ATP
– During rigorous activity the blood cannot
transport enough Oxygen to function properly
• Cellular Respiration
– Lactic acid is produced as a waste product
• presence of waste results in soarness
• MUSCLES THAT ARE EXERCISED
REGULARLY form more cappilaries and
mitochondria
• When the triceps muscle (extensor)
contracts, it opens, or extends, the elbow
joint.
Hw:
• What is the relationship between cellular
respiration and heat production?
• Why are steroids considered unhealty?
HOW MUSCLES AND
BONES INTERACT
• muscles generate force and produce movement by
contracting or pulling on body parts
–
individual muscles can only pull; they cannot push
• skeleton muscles are attached to bone, stretch
across a joint, and are attached to the end of
another bone
– tendons connect muscle to bone
• one bones is usually more stationary than
the other
• The point where the muscle attaches to the
stationary bone is called the origin
• The point where the muscle attaches to the
more moveable bone is the insertion
– A muscle’s insertion bone moves toward
its origin bone
• Most skeletal muscles work in pairs
• When one muscle or set of muscles contracts, the
other relaxes.
• Flexor, a muscle that bends a joint. Extensor, a
muscle that straightens a joint
• When the biceps muscle (flexor) contracts,
it bends or flexes the elbow joint
• A controlled movement requires
contraction by both muscles
•
A muscle pulls when it contracts, but exerts no force when it relaxes and CANNOT PUSH. When one muscle Pulls a bone in one direction, another muscle is needed to PULL the bone in the other
direction.