Unit 9 Flashcards
Where is the skeletal muscle located?
It is attached to bone
What are the characteristics of skeletal muscles?
Cells are long and striated, voluntary, multiple nuclei per cell
Where is the smooth muscle located?
In organs like the stomach, kidneys
What are the characteristics of smooth muscles?
Involuntary and non striated
Where is the cardiac muscle located?
Only in the heart
What are the characteristics of the cardiac muscle?
Long and branching and fit close together at junctions, involuntary, striated
What is the belly of the muscle?
Fleshy body of muscle between slender points of attachment
What is the fascia?
Layers of tough connective tissue surrounding large skeletal muscles
What is the endomysium?
A layer of connective tissue around the muscle fiber
What is the perimysium?
A layer of connective tissue that surrounds the the small bundles of fiber
What are fascicles?
Bundles of muscle fibers
What is the epimysium?
The outer layer of the fascia (outside of whole muscle)
What is the tendon?
A strong band of fibrous connective tissue that connects muscle to bone
What is the sarcolemma?
A cell membrane of a muscle fiber
What is the transverse tubules?
Point of a cell membrane that penetrate into a cell membrane for calcium to flow through
What is sarcoplasmic reticulum?
Specialized endoplasmic reticulum within the muscle fiber that release calcium ions during contraction and absorbing them during relaxation
What are myofibrils?
Long cylindrical structures in each muscle fiber containing actin and myosin
What are sarcomeres?
Contractile units formed of acting and myosin
What is the sliding filament theory?
Muscles contract because sarcomeres shorten. Sarcomeres shorten because actin and myosin filaments slide past each other.
How does myosin and actin cause contractions?
Myosin heads make contact with actin when stimulated. Cross bridges form. Myosin heads rotate, pulling actin towards the center of the sarcomere; causing the actin to slide past the myosin
How does the muscle contract and relax using energy?
ATP allows the actin and myosin to interact in the presence of calcium
Where is calcium stored?
In the endoplasmic reticulum, away from actin and myosin
What is a motor nerve?
A nerve that carries messages from the brain or spinal cord to a muscle
What is neuromuscular junction?
An area where a motor nerve meets a muscle fiber to send a message to relax or contract
What is motor unit?
One nerve and all of the skeletal muscle fibers it provides. Groups of motor units work together to coordinate the contractions of a single muscle
