What are the functions of the muscular system?
-Movement of the body -Maintaining posture -Generates body heat -Role in other body systems (respiration, digestion, urination)
Types of muscle tissues
Skeletal -> striated, voluntary Smooth -> involuntary (digestive) Cardiac -> heart
A muscle is composed of many muscle fibers arranged in bundles called
Fascicles
Fibers are found within muscle cells called
Myocytes
Individual muscles are separated by fascia, which also forms
Fascia
Three different layers of connective tissue:
-Epimysium -Perimysium -Endomysium
Epimysium
Outermost layer, surrounds entire muscle
Perimysium
Separated and surrounds the fascicles (bundles)
Endomysium
Surrounds each individual muscle fiber
What are muscle cells?
Myoctyes
Sarcolemma
Muscle fiber membrane
Sarcoplasm
Inner material surrounding fibers (like cytoplasm)
Sarcoplasmic Reticulum
Transport
Myofibrils
Parallel muscle fibers within sarcoplasm
Each myofibril is made of many...
Myofilaments
The two types of myofilaments
-Myosin -Actin
Myosin
-Think filaments -A bands -Dark
Actin
-Thin filaments -I bands -Light
Hierarchy:
-Muscles -Fascicles (bundles) -Myofibrils (fibers) -Myofilaments (filaments)
What is dystrophin?
A cohesive protien, that maintains the structure of the muscle fibers
How is dystrophin spread?
Sex linked disorder
Some disorders of the muscles relate to the signals between the muscle and nerves -
Neuromuscular junction
Neuromuscular Junction
Where a nerve and muscle fiber come together
Motor End Plate
Folded area where muscle and neuron communicate
Synapse
Gab between the neuron and motor end plate (Synaptic plate)
Synaptic Vesicles
Where neurotransmitters are stored (these are released into the cleft and tell the muscle to contract
The neurotansmitter that crosses the gap is ________ which is stored in vesicles, which is broken down by __________.
Acetycholine; Cholinesterase
The Sliding Filament Theory -
The theory of how contracts is the sliding filament theory. The contraction of a muscle occurs as the thin filaments slide past the thick filaments. The sliding filament theory involves five different molecules and calcium ions.
Energy Source -
Provided by ATP from cellular respiration which occurs in the mitochondria
Creatine phosphate increases ___
regeneration of ATP
Only 25% of energy produced is used in metabolic processes - The rest is in the form of ____
Heat
What is elevated in people who have suffered heart attacks and who have DMD.
Creatine Kinase
What is a biomarker?
Substances that indicate damage to muscles
Muscle Fatigue
Muscle loses ability to contract after prolonged use
Muscle Cramp
A sustained involuntary contraction
Oxygen Debt
Not have enough oxygen causes lactic acid to accumulate in the muscles -> soreness
Hypertrophy
Muscles enlarge
Atrophy
Muscles become small and weak due to disuse
What is rigor mortis?
After a person dies, the joints of the body stiffen and becomes locked in place
What are the two types of myofilaments?
Myosin and Actin
The membrane of the muscle fiber is called the:
Sarcolemma
What is defined as the region between two two Z-lines?
Sarcomeres
What sturcture is similar to the endoplasmic reticulum?
Sacroplasmic reticulum
Dark bands are made from
Myosin
Light bands are made from
Actin
Tetanus
Person's muscles contract instead of relaxing. Causes cholinesterase to not break down the acetylcholine in the synapse.
Myotonia
A delayed relaxation of the skeletal muscles after voluntary contraction, electrical stimulation, or even being started.
Myasthenia Gravis
Autoimmune disease that causes muscle weakness
ALS
A progressive neurodegenerative disease
Muscular Dystrophy
Weakening of muscles
Muscle Posions
-Botulism -Botox -Strychnine -Curare
What chemical helps to regenerate ATP?
Creatine Phosphate
Skeletal muscles are responsible for moving ...
your body/bones
Muscle fibers are made of individual fibers (not filaments) called ...
Myofybrils
Connective tissue that surrounds fascicles is ...
Perimysium
Poisons such as botulism that prevent the release of acetylcholine would cause muscles to
Relax
What type of muscles are primarily voluntary ... makes up the heart ... found in digestive tract ...
-Skeletal -Cardiac -Smooth
What neurotransmitter is associated with the muscles
acetycholine
What cell organelle provides the ATP needed for muscle activity?
Mitochondria
The gap between the nerve and the muscle is called the ...
Synapse/Synapse Cleft
What is hypertrophy?
Muscles enlarge
What is atrophy?
Muscle become small and weak
A person who has a disease that inhibits the production of cholinesterase would have what kind of symptoms?
Muscles would contract
Cholinesterase is an enzyme that breaks down
Acetycholine
During a muscle contraction, cross bridges from between what two structures?
Actin and Myosin
In a sarcomere, the I band is made of ____ and the A band is made of ____
Actin - Myosin
The dark and light fibers of the muscles give cells ______ appearance.
Striated
The energy source for muscle concentration is
ATP
Vesicles in the motor neuron store what substance?
Acetycholine
When recruitment occurs, the number of motor units being activated
Increases
Sustained contraction of individual fibers, even when muscle is at rest is known as
Muscle tone
The immovable ends of the muscle is the
Origin
The movable end of the muscle is the
Insertion
Muscle fatigue is likely due to a buildup of
Lactic acid
A sarcomere is defined as the region between two
Z-lines
The condition where a body becomes stiff after death is called
Rigor Mortis
When ATP has been used, it becomes
ADP and Phosphate
What is a motor unit?
Motor neuron and muscle fiber
Myofibrils are composed of
Actin and myosin
The muscle fiber membrane is specialized to form a ______ at the neuromuscular junction.
Motor end plate
Which type of connective tissue surrounds fascicles (bundles)?
Perimysium
What type of tissues surrounds the entire muscle?
Epimysium
The substance that crosses the gap between a neuron and a muscle fiber is the
Neurotransmitter
Tendons connect ____ to ____
Muscles to bones
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