How Does Rigor Mortis Work?

November 9th, 2009

Do Now

1. What is rigor mortis? 2. How do your muscles contract?

(what do you remember from Living Environment?)

Aim Why does rigor mortis occur?

Learning Target: I can...

Agenda Do Now Mini Lesson – Muscle Contractions,

Mechanism behind Rigor Mortis Practice – Graphic organizer with diagrams

& descriptions

Share out How do your muscles contract? When muscle contraction stops

working, rigor mortis occurs

What makes up muscles

Thin filiment - actin Thick filiment - myosin

When you want to pick something up...

Your brain sends a signal for the myosin to stick to the actin

How does the myosin stick to the actin?

Myosin heads bind to actin

Myosin heads form little “cross-bridges”

What’s the purpose of forming crossbridges?

the thick myosin bands pull the thin actin bands closer muscle contraction.

Works because of the cross bridges.

myosin

actin

How do your mucles lose the contraction?Remeber ATP from Living

Environment???ATP = Adenosine

Triphosphate

ATP Product of cellular respiration. What’s the purpose of cellular

respiration? (dust off those cob-webs) body converts glucose energy

What does ATP do? Breaks these

connections between mysin and actin

Allows muscle to relax

Cellular Respiration ATP Production Stops muscle contraction

What do you think happens when cellular respiration stops?

Cellular Respiration ATP Production Stops muscle contraction

Stop and jot

What do you think happens when cellular respiration stops?Cellular Respiration ATP Production Stops muscle

contraction

If there is no ATP, muscles stay contracted. Why, then, would rigor mortis go

away after 36 hours?? Stop and jot!!!

If there is no ATP, muscles stay contracted. Why, then, would rigor mortis go

away after 36 hours?? Autolysis - cells start breaking down.

Cell wall breaks down cell contents leak out.

Muscles do not relax, but are broken down

Autolysis causes...

Muscles to become softMuscles don’t relax, but break

down. – important distinction!

Lets practice this! Make a graphic organizer explaining the process

of muscle contraction what goes wrong to cause rigor mortis

What is a graphic organizer?