Muscular System Notes
Muscular System
Muscles are responsible for ________________________________________________________________.
3 basic types that are found in the body

______________________________________

______________________________________

______________________________________
Skeletal Muscle

Attached to ___________________________________________

__________________________ controlled

Tissue appears ____________________________

Cells are ________________, ____________________________, and _______________________________.
Smooth Muscle

Makes up _____________________________________________________________.

__________________________ controlled

Tissue appears ____________________________

Cells are ________________, _____________________________, and have a single __________________

Tissue is extremely ______________________ while retaining its ability to __________________
Cardiac Muscle

Makes up _____________________________________________________________.

__________________________ controlled

Tissue appears ____________________________

Cells are ________________, _____________________________, and have a single __________________
Functions of the Muscular System
1.
2.
3.
4.
5.
Sites of Muscle Attachment

__________________________

__________________________

___________________________________________________
Muscle fibers blend into a connective tissue attachment

________________________ - ______________________________________________________________________

________________________ - ______________________________________________________________________
Characteristics of Muscle Tissue
1.
2.
3.
4.
Muscle Fiber Arrangement (Label and draw the arrangements below)
_______________
_______________
________________
_________________
________________
Skeletal Muscle Actions
Origin – _________________________________________________________________________________
Insertion – _____________________________________________________________________________
Action – ________________________________________________________________________________
Example:
Label the origin and insertion in the diagrams above.
Naming Muscles
1.
Example:
2.
Example:
3.
Example:
4.
Example:
5.
Example:
6.
Example:
In-class Quiz – How are the following muscles named?
1. Biceps femoris 2. Flexor carpi ulnaris 3. Gluteus maximus 4. Abductor magnus 5. Rhomboid major –
Structure of Skeletal Muscle
Connective Tissue

_________________________ - dense connective tissue that surrounds and separates
muscle
o Gives rise to _______________________________________.

_________________________ - fused to the ___________________________________________________,
therefore connecting _______________________________ to __________________________.

____________________________ - ____________________________________ of connective tissue that
connect _______________________________________ OR _______________________________________.

____________________________ - layer of connective tissue around ___________________________.

____________________________ - layer of connective tissue that surrounds individual
____________________________(______________________) within each whole muscle

____________________________ - layer of connective tissue that ________________________________
o Muscle cell = ______________________________________
Skeletal Muscle Flow Chart
Skeletal Muscle Fibers

Beneath the _____________________ (__________________________) is the _________________________
(_______________________) and ____________________________________________.
o The SR and T-tubules _______________________________________________________________
when the fiber is stimulated.

The sarcoplasm of each muscle fiber (muscle cell) contains _____________________________
which are ___________________________________________

_________________________ are separated into compartments called _________________________
that contain _________________ and _________________ filaments.
o _________________ filaments – made of ___________________________________________
o _________________ filaments – made of ___________________________________________

A sarcomere extends from Z line to Z line
o ______________________ (_____________ bands) are anchored to the Z lines are the
length of _______________________________
o ______________________ (______________ bands) are the length of ______________________.
Label the following diagram using: Sarcomere, Myofibril, Z line, I band, A band
Skeletal Muscle Contraction
Neuromuscular Junction
 ___________________________________ - ____________________________________________________________________
 The axon of the motor neuron extends outward from the brain or spinal cord. The
_________________________________ will only ________________________ when stimulated by the
_________________________________.
 The site where the ___________________________ and ______________________ meet is the
_______________________________________________________________.
 The muscle fiber membrane forms a ___________________________________________.
 The end of the ______________________________________ branches into the ____________________________.
The cytoplasm has abundant mitochondria and contains many tiny ___________________
________________________________ that store ____________________________________.
 A ______________________________________ and the _______________________________________________________
make up a ____________________________________.
Skeletal Muscle Contraction
Role of Myosin and Actin
_________________________ - consists of two twisted strands with cross-bridges projecting out
_________________________ - a protein with binding sites that the myosin cross-bridges attach to
Contains 2 proteins - _____________________________ and _________________________________.
Label the following diagram using: Cross-bridges, Myosin, Actin, Troponin, Tropomyosin
Sliding Filament Theory
 Myosin heads attach to __________________________________________________________________________
 Cross-bridge bend and ____________________________, causing the ___________________________________
______________________________________, toward the center of the sarcomere, causing it to shorten
 Myosin releases… ____________________________________________________________________________________
 Energy is provided from the conversion of _______________________________________.
o Releases a ton of __________________________________!!!!
o _______________________ is needed to properly position _________________________
so that it can ____________________________________________
 Cycle of “grab and release, grab and release” will continue as long as __________ is available
Steps of Skeletal Muscle Contraction
•
Nerve impulse travels down motor neuron to the neuromuscular junction
•
ACh is released from synaptic vesicles
•
ACh binds to Ach receptors on the motor end plate which generates a muscle
impulse
•
Muscle impulse travels down the T-tubule (through the muscle fiber) and eventually
reaches the sarcoplasmic reticulum
•
Muscle impulse causes the sarcoplasmic reticulum to release calcium ions
•
Calcium ions bind to troponin and change its shape
•
This causes the position of tropomyosin to be altered
•
Binding sites on actin are now exposed
•
Actin and myosin bind via the myosin cross-bridges
•
Myosin cross-bridge pulls the actin filament causing them to slide over the myosin
filament
•
Sarcomeres shorten in length
•
New ATP binds to myosin
•
Actin and myosin break apart
•
ATP splits which provides energy
•
Myosin cross-bridge goes back to original position
Steps of Skeletal Muscle Relaxation

Acetylcholinesterase – rapidly decomposes Ach remaining in the synapse

Muscle impulse stops

Stimulus to sarcolemma and muscle fiber membrane ceases

Calcium moves back into sarcoplasmic reticulum

Myosin and actin binding prevented

Muscle fiber relaxes
Energy Sources for Contraction

Energy for contraction comes from ___________________________________ which is limited
in muscle cells

_________________________________________ stores excess energy released by the
_______________________________. It can transfer the phosphate to ADP to make __________.
Oxygen Supply and Cellular Respiration

Cells create _______ by using ________________________ to break down __________________.

Muscle cells require ______________________________________________________ in order to
completely breakdown glucose.

Oxygen is carried to the muscle by ________________________________________________________

Oxygen is stored in muscle by _____________________________________________.
Oxygen Debt

During rest or moderate activity, there is enough oxygen to supply the muscle
o Cells can use __________________________________ to produce energy

During strenuous activity, __________________________________ may develop.
o Cells have to use _________________________________ to produce energy
Oxygen Debt continued

The liver converts lactic acid back to glucose

During strenuous activity, ________________________________________ is being created than
the liver can convert to glucose

As a result, ___________________________________________________________________________________.

Following strenuous exercise, the liver continues to work, however, it requires a lot
of oxygen. The amount of oxygen requires is the ________________________________________.
Muscle Fatigue

When a muscle loses its ability to contract during strenuous exercise, it is referred
to as ________________________________,

Muscle fatigue usually arises from ________________________________________________________.
o Prevents the muscle from responding to stimulation
Types of Muscle Fibers
Slow Twitch (Type 1)
Fast Twitch (Type 2)
Muscle Fiber Types and Performance

Power Athletes
o ____________________________________
o Have a __________________ of fast fibers

Endurance Athletes
o ____________________________________
o Have a __________________ of slow fibers

Others
o _____________________________________
o __________ slow fibers and __________ fast fibers
Types of Muscle Contractions

When skeletal muscles contract, they may produce two types of contractions:
o ____________________________________________________
o ____________________________________________________
Isotonic Contraction

Length of muscle ___________________, usually resulting in __________________________________

The __________________ (load) on a muscle stays _______________________

Two types
o ______________________ - _________________________________________________
o ______________________ - _________________________________________________
Isometric Contraction

Length of muscle ________________________________, even as tension increases.
o Example:

Necessary in everyday life to counteract the effects of gravity
o Example:
Muscle Growth and Size

___________________________ - ____________________________________________
o Due to strenuous activity
o More ________________ and ___________________ filaments are formed

___________________________ - ____________________________________________
o With lack of exercise
o Loss of ___________________ and ________________ filaments
Muscles Working Together

For muscle to create movement, they can ______________________________!

A muscle that contracts to perform the desired actions is known as an
______________________ or ______________________________________.

A muscle that helps the agonist is a ___________________________________.

A muscle that opposes the action of the agonist, therefore undoing the desired
action is an ____________________________________.