Muscular System Flashcards
It provides movements and maintain body posture.
Muscles
3 Types of muscle.
Skeletal muscle, Cardiac muscle, Smooth muscle
A type of muscle that makes up 40% of body weight and is attached to bone.
Skeletal muscle
Connective tissue that surrounds entire skeletal muscle.
Epimysium
Bundle of muscle fibers.
Muscle fasciculus/ fasciculi
Connective tissue around each muscle fasciculi.
Perimysium
Skeletal muscle cells.
Muscle Fiber
Connective Tissue that surrounds each muscle fiber.
Endomysium
Threadlike proteins that make up muscle fibers.
Myofibril
Proteins that make up myofibrils. E.g. Actin and Myosin
Myofilament
Cytoplasm of Muscle fiber.
Sarcoplasm
Cell membrane of Muscle fiber that contains T-tubules.
Sarcolemma
A specialized type of SER occurs in muscle cells where calcium ions are stored. It surrounds myosin.
Sarcoplasmic Reticulum
It is wrapped around sacromers.
T- tubules (transverse)
It is the smallest portion of myofibril capable of contraction.
Sacromere
Thin myofilament
Actin
Thick myofilament
Myosin
Attachment site on actin for Ca2+.
Troponin
Attachment site on actin for myosin.
Tropomyosin
Contains actin and myosin.
Sacromere
Protein fiber that forms attachment site for actin.
Z disk
Center of sacromere that contains only myosin.
H zone
Contains only actin.
I band
Where actin and myosin overlap.
A band
Where myosin are anchored.
M line
Stimulus that causes rapid depolarization and repolarization.
Action Potential
Change in charges where in the inside becomes more + (positive) and - (negative) on the outside. This is where Na+ channels open.
Depolarization
Changes back to resting potential. Na+ channels closes.
Repolarization
Restores balance and pumps Na+ out of cell and transport K+ into cell.
Sodium-Potassium (Na+-K+)
Nerve cells that carry action potentials to muscle fibers.
Motor neuron
This is where nerve cell and fiber meet.
Neuromuscular Junction (synapse)
End of nerve cell.
Presynaptic terminal (axon)
Muscle fiber membrane.
Postsynaptic membrane