This will
eventually lead
to a muscle
contraction if
the stimulus is
above the
threshold.
What do we have in common?
Puffer
fish
Poison Arrow Frog
Blue-ringed Octopus
Neuromuscular Junction - The Real Thing!
Botulinum toxin binds to pre-synaptic membranes
at neuromuscular junctions, enters the neuron,
and then a component of the toxin interferes
with the release of neurotransmitter.
Release of acetylcholine is blocked.
No acetylcholine? No muscular contraction.
(flaccid paralysis)
The Transverse (T) Tubules work
with the sarcoplasmic reticulum
to rapidly concentrate and move
calcium ions throughout the
sarcoplasm
Ca2+ binds the troponin molecules on
the thin actin myofilaments.
This leads to the ability of the thick
myosin filaments to bind the actin.
The myosin heads pull the actin
molecules inward, causing the whole
fiber to shorten.
What is happening
when ATP binds
the myosin head?
The cross-bridge is
broken and the muscle
relaxes!
Body
Temperature
Rigor Mortis
Time since
death
Warm
Not yet stiff
Dead not more
than 3 hours
Warm
Stiffness
starting in head
Dead 3 to 8
hours
Cold
Stiff
A
Cold
Dead 9 to 36
hours
No longer stiff
Dead more than
36 hours
http://www.youtube.com/watch?v=9FF6
UKvDgeE
http://www.youtube.com/watch?v=pcay
ZjTKsm8&feature=related