Transcript Mechanism of muscle contraction The sliding filament Theory The

Mechanism of muscle
contraction
The sliding filament Theory
•
The way that muscles
actually contract and
shorten is a theory called
the sliding filament theory
•
This theory involves the
movement of the
microscopic thin (actin)
and thick (myosin)
filaments
the Sliding Filament Theory
•
In this theory we need to
look at the relationship
between the actin
filament and the myosin
filament
•
These filaments are
going to work together in
order to cause the
contraction
the Sliding Filament Theory
•
All over the thick
filaments there are small
heads that protrude from
the body of the filament
called myosin heads
•
They myosin heads will
attach themselves to
binding sites on the thin
actin filament.
the Sliding Filament Theory
•
The binding sites are
exposed and activated
when calcium ions are
present
•
This allows myosin to
bind temporarily to the
actin filament
•
The myosin then acts as
oars to “row” in the thin
filament
Energy for Muscle
Contraction
• Muscles always need
energy for muscle
contraction
•
Muscles can only use
energy stored in the form
ATP
(Adenosinetriphosphate)
•
Muscles only store 4-6
seconds worth of ATP
therefore ATP needs to
me made constantly
ATP creation
•
There are three ways in
which ATP is created in
the body
•
Direct Phosphorylation of
ADP
•
Aerobic respiration
•
Anaerobic respiration
Direct Phosphorylation of
ADP
•
The body can directly
Phosphorylate ADP
•
This means that ADP and
Creatine phosphate
come together to set off a
reaction that will create
ATP and Creatine
Aerobic Respiration
•
Aerobic respiration is
how ATP is generated
through cellular
respiration in the
presence of oxygen
•
Aerobic respiration
involves glycolysis, the
Krebs cycle, and the
electron transport chain.
Anaerobic respiration
•
The human body can
also get ATP from
Anaerobic Respiration
•
The method of Anaerobic
Respiration is the
fermentation of lactic acid