muscle: intro and skeletal muscle 1

Question 1

types of muscle

Answer 1

skeletal muscle
cardiac muscle

Question 2

structure of skeletal muscle

Answer 2

striated
single long cylindrical cells
multiple peripheral nuclei
attatched to bones via tendons
- made of myofibrils with the contractile unit, the sarcomere

Question 3

cardiac muscle

Answer 3

only in heart
striated
branched with 1-3 central nuclei
connected via intercalated discs
involuntary control

Question 4

smooth muscle

Answer 4

involuntary control
found in wall of internal organs
spindle shaped, uninucleated
not striated

Question 5

role of calcium

Answer 5

calcium binds with troponin and the tropomysosin moves the mysosin binding sites on actin
cross bridge cycle continues so long as calcium levels remain above critical threshold (o.001-0.01mM)

Question 6

sliding filament theory

Answer 6

sarcomere shorten as thin filaments are pulled over thick filaments
z line is pulled toward m line
t band and h zone become narrower

Question 7

isotonic

Answer 7

shortening
tension constant
velocity variable

Question 8

isometric

Answer 8

no shortening
length constant
tension variable

Question 9

calciu regulation

Answer 9

1. in skeletal muscle, Ca channels open in SR and calcium ions are able to move into cytosol
2. active transport Ca ATPase constantly moving calcium from cytoplasm back to SR