MUSCULAR SYSTEM GUIDED NOTES
Name: _____________________________ Class: _________
DO NOW
Which muscle “fact” is false?
1. It takes about 30 muscles to smile.
2. Your muscles generate enough heat each day to boil 2 pints of water for an hour.
3. There are 640 muscles in the body.
4. The longest muscle of the body is the gluteus maximus.
Which prefix doesn’t refer to muscles?
1.
2.
3.
4.
Myo Mus Mys Sarco –
Muscle Functions
 _________________________________________________
Muscle contraction allows movement
• Of the body
• For facial expression
• To move fluids, digesting food, and other substances through the body
• Maintain blood pressure
•
___________________________________________________
Muscles are constantly varying their contraction to maintain posture while we
are seated or standing.
•
___________________________________________________
Muscle contraction helps keep joints in position
•
___________________________________________________
• Muscle contraction requires an enormous amount of energy.
• When food is converted to ATP to power the muscles, nearly 75% of the energy is lost to heat.
• Remember: _________________________________________________________________
Gross Anatomy of Muscle Tissue
 A single muscle cell is called a _________________________________.
Muscle fibers are LONG (up to 1 ft).
 Each muscle fiber is wrapped in a delicate connective tissue called __________________________/
Remember: _____________________________
 Multiple fibers (cells!) are grouped together to form a _________________________________.
 Each ____________________ is wrapped up with a connective tissue called ______________________.
Remember: ______________________________
 ___________________________________ branch out between the fascicles.
 The whole muscle is covered by a thick, tough layer of connective tissue called
___________________________.
 The epimysia fuse to
 The __________________________(outer connective tissue) of bone
- or  The __________________________ (outer connective tissue)of cartilage
- or  _______________________ (rope like connective tissue that connects muscle to bone)
- or  ________________________(sheetlike connective tissue that attaches muscle to bones, cartilage, or
other muscles)
Identify:
Nuclei,
Muscle fibers,
Endomysium
Perimysium
Blood vessels
Comparison of Skeletal, Smooth, and Cardiac Muscle
Make a Venn Diagram comparing and contrasting skeletal, smooth, and cardiac muscle
MUSCLE CONTRACTION
Do Now:
1) The connective tissue covering that encloses the sarcolemma of an individual muscle fiber is called the
a) Epimysium
c) Endomysium
b) Perimysium
d) periosteum
2) A fascicle is
a) A muscle
b) A bundle of muscle fibers
3) Muscle tissue that is involuntary
a) cardiac muscle only
b) Smooth muscle only
c) Skeletal muscle only
c) A bundle of myofibrils
d) A group of myofilaments
d) Cardiac and smooth muscle
e) Cardiac and skeletal muscle
4) The muscle tissue that consists of single, very long, cylindrical, multinucleate cells with very
obvious striations is:
a) cardiac muscle only
d) Cardiac and smooth muscle
b) Smooth muscle only
e) Cardiac and skeletal muscle
c) Skeletal muscle only
5) Which of the following is NOT a function of the muscular system
a) Producing movement
d) Generating heat
b) Maintaining posture
e) Hematopoiesis
c) Stabilizing joints
Muscle Structure
Muscle  __________________________ (bundle of fibers)  _______________________ (single cell) 
____________________________  __________________________ (unit of contraction)
Microscope Anatomy of Skeletal Muscle
•
Each myofibril can be divided into
contractile units called
___________________________.
•
Sarcomeres consist of overlapping
protein filaments of ____________
and _________________.
•
Regular arrangement of dark and light
bands. Dark bands occur where
myosin is present.
•
The ______________ is where the
myosin attaches
•
__________________(a membrane)
mark the edge of each sarcomere;
serve as attachment site for actin
•
Use the picture to come up with a definition of the following:
I band
A band
H zone
Turn and Talk
First match the words …
actin
cell
myofibril
group of cells
sarcomere
cell membrane
fascicle
protein
muscle fiber
organelle
sarcolemma
contractile unit
Then, write a paragraph that uses all the words in both columns above and explains that structure of the
muscle
Contraction Overview
•
Globular heads of myosin filaments attach to actin
filaments.
•
Myosin pulls ________________________ :
“Sliding filament theory”
•
Causes _____________________ to shorten,
particularly the ______________________
Which one is
contracted?
How can you
tell?
Contraction Details
1. A motor neuron stimulates the muscle cell by releasing the ____________________________________
into the synaptic cleft between the neuron and muscle cell.
Note: A __________________________ is a single motor neuron and all the muscle fibers it activates
2. ACh causes an electric current called an _____________________________ to move through the muscle
cell.
3. The action potential causes the ________________________________________________________________.
4. ______________________________________________________________ on actin filaments.
5. Myosin heads (& ADP) attach to actin binding sites, ____________________________________.
6. Myosin heads release ADP, move the actin filament in “___________________________________”
7. ATP binds to myosin head. The crosslink between actin and myosin breaks.
8. ATP becomes ADP + P, readying the myosin head to reattach to actin.
•
If Ca2+ is still present, cycle will
repeat, with myosin heads
reattaching and contracting the
muscle even more.
•
Once the action potential is over,
the Ca2+ is reabsorbed into the
sarcoplasmic reticulum. Without
Ca2+, myosin cannot attach to
actin.
NOTE: ATP is required to break
cross-links, not to form them.
Explains rigor mortis
Why then do muscles need
ATP?
Muscle Stimulation and Exercise
Do Now
What sort of exercise is best for muscles? Why?
Response to Stimulation

Muscles have ________________________________ – they contract to different degrees, depending
upon the __________________ and _________________________________________________

If a nerve fires once (unusual), the muscle contracts and relaxes. This is called a __________________.

If the nerve fires rapidly in succession, then the muscle
__________________________________________ in between impulses – resulting in
________________________________ (a smooth, prolonged contraction)


The strength of contraction also depends on _____________________________________ are
stimulated.

The more muscle fibers stimulated, the ________________________________ of the muscle
Quick Review
What vocab word describes the fact that muscles may contract to different degrees?
What two factors determine the extent to which a muscle contracts?
Muscle Metabolism
Muscle contraction requires enormous amounts of energy in the
form of ______.
The amount of ATP stored in the cell only lasts for ~5 seconds!
The rest of the ATP must be regenerated, using one of three
pathways.
Pathway 1: ______________________________________________________________

___________________________

___________________________

___________________________

___________________________
Pathway 2: __________________________________________________________________

_____________________________

_____________________________

_____________________________

_____________________________

______________________________
Misconception alert!

Lactic acid build-up is not responsible for muscle soreness the day after exercise
(that’s due to ___________________________________).

Lactic acid build-up is responsible for the _____________________________________.

Also, lactic acid build-up increases ____________________________ (inability of muscle to contract
when stimulated)
Pathway 3:_____________________________________________________________________

___________________________

___________________________

___________________________

___________________________
Which energy pathway is better?

CP and anaerobic supply
energy at a____________________
(for __________________________)
but for a __________________ only.
Examples:

_______________________

Any sport with bursts of
energy & quick changes
(e.g. ___________________,
______________________)

________________________
Aerobic can provide energy _______________________________________________.
But, muscles are not working at peak levels
Examples: __________________________, __________________________
Oxygen Debt
All _______________________________________________________ causes changes in the muscle that need
to be reversed after the exercise is over

________, ____________, _________________, and ________________ reserves need
to be replenished

_________________________ needs be broken down
Oxygen debt is the __________________________________________________________
___________________________________________________________________________. This is why you
breathe deeply for a while after intense exercise.
Think, Pair, Share

Name the reactants and products of each energy system.

Which two energy systems are only used in muscles?

Which two energy systems lead to oxygen debt?

Which energy system(s) predominate in the following activities: running for your life, hiking, lifting
heavy furniture
Critical Thinking 1
The graph below indicates the amount of lactic acid produced by muscle cells as a function of power (energy /
time).
1) Describe how lactic acid production varies with power.
2) Explain the shape of the graph using your knowledge of energy systems
Isotonic vs Isometric Contractions

_______________________ contractions occur whenever the muscles ____________, causing
movement
(e.g. ________________________________________________________________

_______________________________ contractions occur whenever the muscle’s
_____________________________________________________________________. This happens
when you try to move an immovable object.
(e.g. ___________________________; _____________________________, etc.)
Aerobic vs Resistance Exercise

Aerobic exercise (aka endurance or cardiovascular) – builds the
_____________________________________________ of muscles

Examples: _______________________, _____________________

Increases ____________________________________________;
____________________________________, &
______________________________________


Benefits

Greater resistance to fatigue

Better heart and lung function

Improved digestion

Improved bone density

Reduced risk of metabolic disorder

Increased immune system function
Resistance exercise (aka weight training) – focuses on ____________________________
_______________________________________________________________________

Examples: weights, some yoga exercises, pushups, situps,

Increases the ______________________________________________,
_________________________________________________

Benefits

Greater strength

Greater muscle mass = greater metabolism

Increased bone density
Muscle tone and muscle wasting

Muscles quickly deteriorate when not used

Lose 5-10% muscle mass per week with bed rest

Lose 20% muscle strength in one week of bed rest

Muscle strength plateaus at ~30% original strength after ~6 weeks of bed rest

Our body maintains muscle tone by systematically stimulating and partially contracting muscles
around the body

Electrical muscle stimulators can also help prevent muscle atrophy following a stroke, injury, or
surgery
Think, Pair, Share

Compare and contrast isotonic and isometric exercises, and provide an example of each

Compare and contrast resistance and aerobic exercise, and provide an example of each

Why is exercise necessary for our muscles?

How does exercise help our body function?
Muscle Names and Movement
Rules of Muscle Movement
1. All muscles have at least two _______________________________________________.
•
The ______________ is attached to the less movable bone
•
The _______________ is attached to the more moveable bone.
2. Muscles can only ____________________________. They cannot push.
3. During contraction, the muscle _____________________________________________.
If muscles can’t push, how do we do the
opposite movement?
How do we extend the arm?
Movements
•
_____________________________ – a movement that decreases the angle between two bones,
bringing them closer together.
•
_____________________________ – a movement that increases the angle between two bones,
putting them farther apart.
•
_____________________________ – extension of a joint beyond its normal range of motion
•
______________________________ – movement of a limb away from the midline of the body.
•
_____________________________ – movement of a limb towards the midline of the body
•
______________________________ – movement of a bone raround its longitudinal axis
•
______________________________ – the proximal end of a limb is stationary while the distal end
moves in a circle
•
_____________________________– lifting the foot so that its superior surface approaches the shin
•
_____________________________ – pointing the toes
•
_____________________________ – turning sole medially
•
_____________________________ – turning sole laterally
•
______________________________ – turning the palm so that it faces anteriorly
mnemonic: cupping a bowl of soup in your palm
•
______________________________– turning the palm so that it faces posteriorly
Examples
Work with a partner to come up with 5 ways to do each of the following movements:
•
Flexion
•
Extension
•
Hyperextension
•
Abduction
•
Adduction
•
circumduction
Types of Muscles
•
_________________________ – muscle that has the major responsibility for a movement
•
_________________________ – muscle that opposes / reverse a movement
Muscles can be both a prime mover and an antagonist – of different motions.
Movement
mover
Elbow flexion
Elbow extension
•
_________________________ – muscles that assist movement by also producing the motion or
stabilizing joints and reducing unwanted movements.
Ex: ________________________ and ___________________________ are synergists of elbow
flexion because they help the biceps
•
_________________________ – a type of synergist that stabilizes the origin of the prime mover, so
that only the insertion moves.
Example: the rotator cuff muscles of scapula are fixators for elbow flexion.
Practice 1
•
Find as many examples as you can of prime mover – antagonist pairs in the muscles just listed
•
Find as many synergist muscles as you can in the muscles just listed
Practice 2 – fill in diagrams