Chapter 1 Structure and Function of Exercising Muscle Flashcards
What are the three main types of muscle?
Smooth, Skeletal, Cardiac
Smooth muscle and cardiac muscle are under what type of control?
involuntary control
Skeletal muscle is under what type of control?
Voluntary control
The most external layer of a muscle is covered by what connective tissue?
Epimysium
What are specific bundles within a muscle called?
Fascicles
What are the connective tissues surrounding fascicles?
Perimysium
Once past the perimysium and inside of a fascicle there are?
Muscle fibers
The connective tissue surrounding muscle fibers is?
Endomysium
Each muscle fiber is surround by a plasma membrane called??
Plasmalemma
The plasmalemma and the basement membrane in the muscle fiber make up the?
Sarcolemma
The Plasmalemma has many functions including…
- having folds that keep the muscle from stretching too far and disrupting the plasmalemma
- assists in transmission of action potential from motor neuron to muscle fiber
Satellite cells are located between the? Their function is to?
Plasmalemma and the basement membrane. Involved in growth and development of skeletal muscle as well as adaptation to injury, immobilization, and training.
The fluid between muscle fibers is called the?
Sarcoplasm
The Sarcoplasm is composed of …
dissolved proteins, minerals, glycogen, fats, and organelles.
How does the Sarcoplasm differ from cytoplasm?
large amount of glycogen stores and myoglobin stores which is an oxygen binding protein.
extensions of the plasmalemma that pass through the muscle fiber are?
Transverse tubules
Transverse Tubules are? fxn?
interconnected and pass among the myofibrils. They allow for nerve impulses received by the plasmalemma to be transferred to individual myofibrils.
Tubules that run perpendicular to transfer tubules and run parallel to myofibrils are called?
sarcoplasmic reticulum
The sarcoplasmic reticulum fxn is?
To store calcium for muscle contraction
Each muscle fiber contains several thousand ?
myofibrils
The myofibrils contain the contractile unit of the muscle and the basic unit of the myofibril its is called the?
sarcomere
two protein filaments that are in the myofibrils and are considered the contractile units in the muscle
actin, myosin
The thin filaments are?
Actin, troponin, tropomyosin
The thick filaments are?
myosin
The I band is?
light, thin filaments
The A band is ?
Dark, thin and thick filaments
The H zone is?
In the center of the A band, only seen in a relaxed muscle, thick filaments
M-line is
in the middle of the H zone. composed of proteins for thick filaments to attach and stabilize the sarcomere
Z disk
where sarcomeres connect end to end. Made up of proteins. There are two additional proteins nebulin and titian which provide points of attachment and stability for thin filaments.
Titin
connects myosin from M-line to Z disk to stabilize it.
Each thin filament is composed up of?
actin, tropomyosin, troponin
Actin
Is the backbone of the thin filament. Made up by globular proteins and actin molecules that are in helical pattern.
Tropomyosin
tube shaped protein that twists around actin.
Troponin
attached to both tropomyosin and actin regularly.
Tropomyosin and troponin due what?
They work with calcium ions to either relax or contract myofibrils.
Nebulin
is an anchoring protein for actin, mediates myosin and actin interaction.
Alpha motor neuron
nerve cell that connects with and innervates many muscle fibers
Motor unit
all the muscle fibers that are signaled by one alpha motor neuron.
sliding filament theory
- action potential is sent from brain
- AP travels down an alpha motor neuron to the axon terminal.
- AP causes the release of ACh at the synaptic cleft via secretory vessicles.
- Ach attaches to receptors on the plasmalemma causing a depolarization that travels down the T-tubule. The terminal cisternae release Ca2+
- Ca2+ flows into the sarcoplasmic reticulum to the sarcomere.
- Ca2+ attaches to troponin and causes the release of tropomyosin and actin.
- Myosin attaches to actin and the cross bridge is formed.
- ATP is hydrolyzed into ADP+Pi causing the power stroke of myosin pulling actin in
- ATP resynthisizes and causes the release of the myosin head.
- Completion of contraction occurs when Ca2+ is returned to the Sarcoplasmic reticulum.
Type 1 fibers
are slowing to contraction, small muscle fiber, good aerobic endurance, produce a lot of ATP with oxygen, carbs, and fats, used in low intensity training
Type 2 fibers
are faster to contraction, large muscle fiber, poor aerobic endurance, produce a alot of force, ATP produced without oxygen, high intensity training.
ATPase
enzyme that breaks ATP bonds for energy.
Eccentric
muscle lengthens while exerting force, maximal force produced is fast
Concentric
muscle shortens while exerting force, maximal force production is slow
Isometric
muscle tension is same as outside force
motor recruitment order
Type I, Type IIa, Type IIx
