muscles and movement 3 Flashcards
myocytes
contractile cell unique to animals (muscle cells)
what are the contractile elements within myocytes?
thick and thin filaments
what makes up thick filaments
polymers of myosin
what makes up thin filaments
polymers of alpha actin
ends are capped by CapZ and tropomodulin
what are the two main types of muscle cells
striated -
skeletal and cardiac muscle
actin and myosin are arranged in parallel
Smooth -
actin and myosin are not arranged in any way
ex. Gi tract
what is a single cell in the skeletal and cardiac muscle called
skeletal - myofiber
heart - cardiomyocyte
made up of repeating sarcomeres
I band (sarcomere)
imisotropic
contains only thin filaments
A band (sarcomere)
anisotropic
occupied by thick filaments
Cap Z (sarcomere)
caps positive ends of actin
tropomodulin
caps negative ends of actin
titin
binds to thick filaments and connects to z disk
spring like structure
M-line (sarcomere)
opposing myosin fibres join together
what is the thick to thin filament ratio
each thick filament is surrounded by 6 thin
how long is the duty cycle of of myosin 2 and why?
duty cycle is 0.05 not 0.5 because it is tethered it doesn’t need to be in cross bridge at all times to stay attached, does not want to impede other myosins from pulling the thin filament
How is force related to length of sarcomere?
sarcomeres require the optimal length to be able to produce maximum force
the more overlap allows for more force, but too much will result in decreased force
not enough overlap will result in decreased force
