Chapter 6 Chapter 6

The Muscular SystemThe Muscular System

Disclaimer: Included in this presentation are pictures you will not find in your book, make note of the information and move on. Working smarter is not working harder.

Muscle Lecture 2 Muscle Lecture 2

Motor Neuron pathways and Body Motor Neuron pathways and Body MovementsMovements

Motor Unit: BasicMotor Unit: Basic

A Motor Unit is basically:

The combination of Nerve + Muscle bundle.

But what about the BRAIN?

I’m so glad you asked…

Motor Unit + Brain (CNS)Motor Unit + Brain (CNS)

So here we have added the BRAIN.

It tells the Muscle to “React”

REACT= Contract

So what Tells the Brain to React?

I’m so glad you asked…

Motor Unit: Sensory neuron Motor Unit: Sensory neuron + Brain + Motor Neuron+ Brain + Motor Neuron

Sensory Neurons tell the Brain to react.

Which then tell the Motor Neuron to go into action

So how fast is the stimulus that triggers a Motor Unit?

I’m so glad you ask…

Motor Unit: Nerve Motor Unit: Nerve ImpulseImpulse

Nerve impulses travel at 170 mph or 200 m/s 170 mph or 200 m/s

Meaning: Things happen quickquick

Motor Unit: NowMotor Unit: Now

Sensory neurons are triggeredSensory neurons are triggered Impulse is sent to the BrainImpulse is sent to the Brain Brain sends impulses to the Motor UnitBrain sends impulses to the Motor Unit Then…Then…

Motor Unit: Motor Unit: Neurotransmitters Neurotransmitters

The Nerve Impulse reaches the Neuromuscular junctionNeuromuscular junction (where the nerve meets the muscle).

Ach = acetylcholine is released

This crosses the space called “synaptic cleft”

Hits the muscle fiber receptors and causes a CONTRACTION

Then Ach is broken down and the muscle RELAXES

Motor Unit: Motor Unit: Action PotentialAction Potential

Ok so this is …what?!?!?!

In real terms the Action Potential is simply:

The amount of The amount of stimulus to trigger stimulus to trigger a Sensory a Sensory Motor ResponseMotor Response

It is all-or-nothingall-or-nothing

Motor Unit:Motor Unit:Action Potential Action Potential

In action….

Hold please while I get out the needle.

Just Kidding…

Motor Unit: SummationMotor Unit: Summation1.1. Sensory neuron is tripped Sensory neuron is tripped

2.2. Sends a signal to the CNS Sends a signal to the CNS

3.3. Nerve impulse's are sent to Muscle FibersNerve impulse's are sent to Muscle Fibers

4.4. Action Potential is reached Action Potential is reached

5.5. Ach is releasedAch is released

6.6. Muscle ContractionMuscle Contraction

7.7. Ach is Broken downAch is Broken down

8.8. Muscle Relaxes Muscle Relaxes

9.9. Heavy Breathing occurs and High fives are Heavy Breathing occurs and High fives are ExchangedExchanged

Body Movements: FlexionBody Movements: FlexionDedicated to all my Twilighters Dedicated to all my Twilighters

Flexion:Flexion:

Closing the angle of a joint

|closed|

Body Movements: Body Movements: ExtensionExtension

Extension:Extension:

The act of straightening or extending a limb. Personally I don’t like definitions that have the word their defining in them, but…I think you get the point.

Ways I say “Hello”Ways I say “Hello”

Body Movements: Body Movements: RotationRotationTurn your head left

Turn your head right

=ROTATION=ROTATION

Ok now I’m going to do something alittle extreme now…

Hold please.Hold please.

Body Movements: Body Movements: AdductionAdduction

Adduction:

Movement towardtoward the midline of the body

Body Movements: Body Movements: AbductionAbduction

Abduction: Abduction:

The act of moving a body away from the planet to be anally probed by curious aliens.

Wait…WHAT?!?!?!Wait…WHAT?!?!?!NEXT SLIDE!!!!NEXT SLIDE!!!!

Body Movements: Body Movements: AbductionAbduction

Abduction:Abduction:

The movement of a limb awayaway from the midline of the body.

Body Movements: Body Movements: CircumductionCircumduction

Circumduction:Circumduction:

Moving a limb in a circular motion

~still attached to the body~

Summation: if you need to Summation: if you need to write this down, you write this down, you weren’t paying attention.weren’t paying attention.

Nerve impulses are received and then sent to Nerve impulses are received and then sent to Motor Units Motor Units

If a strong enough signal is sent (Action If a strong enough signal is sent (Action Potential is reached)Potential is reached)

Neurotransmitters are released (Ach) Neurotransmitters are released (Ach) “Contraction” occurs and then broken down “Contraction” occurs and then broken down “Relaxation” occurs“Relaxation” occurs

Body movements I am holding you responsible Body movements I am holding you responsible for knowing: Flexion, Extension, Rotation, for knowing: Flexion, Extension, Rotation, Abduction, Adduction and CircumductionAbduction, Adduction and Circumduction

Chapter 6 Chapter 6

If you are not done with your labs finish If you are not done with your labs finish them. them.

If you are done, start learning the If you are done, start learning the muscles so you are not stalled for time muscles so you are not stalled for time during the test. during the test.

If you know all the muscles, help your If you know all the muscles, help your classmates to learn them. classmates to learn them.