Skeletal Muscle Physiology 1 Flashcards
Dr S Khogali
name the 3 types of muscle in the body
skeletal
cardiac
smooth
which 2 muscle types are striated?
skeletal and cardiac
what causes the dark bands in muscle under a microscope?
thick myosin filaments
what causes the light bands in muscle under a microscope?
thin actin filaments
what muscle type does not have striation?
smooth muscle
skeletal muscle are innervated by _______ nervous system so are _________ wheres cardiac and smooth are innervated by the ___ and are so ___________
skeletal muscle are innervated by somatic nervous system so are voluntary wheres cardiac and smooth are innervated by the ANS and are so involuntary
in which muscle type are there neuromuscular junctions present?
skeletal
are gap junctions present in skeletal muscle?
no - only in cardiac muscle
excitation contraction of skeletal muscle is due to what? from where?
Ca2+ from sarcoplasmic reticulum
name the chemical transmitter at the neuromuscular junction
acetylcholine
define the motor unit
a single alpha motor neuron and all the skeletal muscle fibres it innervates
muscles which serve fine movements have _____ fibres per motor unit
fewer
muscle fibre > _________ > sarcomere > myosin and _____
muscle fibre > myofibril > sarcomere > myosin and actin
each muscle fibre contain many what?
myofibrils
actin and myosin are arranged into what?
sarcomeres - the functional units of muscle
define the functional unit
the smallest component capable of performing all the functions of that organ
the sarcomere is found between 2 what?
Z lines
name the 4 comes of the sarcomere
A-band
H-zone
M-line
I-band
the A-band is…
Made up of thick filaments along with portions of thin filaments that overlap in both ends of thick filaments
the H-zone is…
Lighter area within middle of A-band where thin filaments don’t reach
the M-line…
Extends vertically down middle of A-band within the centre of H-zone
the I band…
Consists of remaining portion of thin filaments that do not project in A-band
the force generation in muscle depends upon what?
ATP-dependent interaction
ATP is required for both contraction & relaxation
true or false?
true
In skeletal muscle fibres, Ca2+ is released from the lateral sacs of the sarcoplasmic reticulum when the surface action
potential spreads down
the __________ _ _______
transverse (T)-tubules
what is required to switch on cross bridge formation?
Ca2+
the muscle fibre is relaxed when the binding site is physically covered by the what?
troponin-
tropomyosin complex
the muscle fibre becomes excited when Ca2+ binds with what?
troponin
the thin filament is pulled inward during contraction
true or false?
true
What’s the difference between Luiseach Mathers and a vampire?
source: http://www.jokes4us.com/dirtyjokes/gingerjokes.html
One is a pale, bloodsucking creature that avoids the sun. The other is a vampire.
