Muscular System Flashcards
What are smooth muscles associated with?
Internal organs
What are skeletal muscles associated with?
Muscles attached to the skeleton
What patterns does the heart contract?
Involuntary patterns
What is the muscle structure composed of?
Skeletal, nervous, and connective tissue, also blood
What separates skeletal muscles from adjacent muscles?
Connective tissue - fascia
What are fascicles?
A bundle of muscle fibers
What are muscle fibers composed of?
Nuclei, sarcoplasm surrounded by sarcolemma
What is within the sarcolemma?
Myofibrils
What are the 2 different protein molecules?
Myosin (thick filament) + Actin (thin filament)
What is a sarcomere?
The s-an between one Z line & the next Z line
What is a functional unit of muscle?
Each sarcomere
When muscles contract what happens to the H band?
Gets shorter
Cross bridges consist in which myofilament?
Myosin
What do cross bridges attach to?
Actin
What do cross bridges do once they attach?
Begin to pivot
What is the sliding filament theory?
Cross bridges cause myofilament to move towards another only when actin moves
What happens once cross bridges attach?
I and H zone get shorter, area of overlap (actin+myosin) increases, Z lines are closer together
What is muscle contraction?
Shortening of muscle sarcomere, insertion towards origin
What is muscle relaxation?
Cross bridges turn lose & actin myofilaments slide back
Where is the binding sites for cross bridges?
Actin filament
What 2 protein filaments block binding sites?
Troponin + tropomyosin
What do calcium ions do?
Cause molecules to move which exposes binding sites
What organelle stores calcium ions ?
Sarcoplasmic reticulum
What causes cross bridges to pivot & contract?
ATP
