Quad 1: Cohort D
PSK 4U1
Kinesiology
___
Unit 7: Muscular Anatomy
Essential Question(s): What are the three types of muscle tissue in your body and what are their functions? How
are muscles named? How are muscles arranged in the human body and why? How does origin and insertion of a
muscle affect the way that muscle works? What are the basic parts of a muscle? How does a muscle contract from
brain to action? What are the most common muscle injuries? What is DOMS? How does the Sliding Filament
Theory of muscle contraction work?
Essential Vocabulary to Learn: Musculoskeletal System / Agonist / Antagonist / Stabilizers / Origin / Insertion /
Muscle Fibre / Sarcolemma / Sarcoplasm / Sarcomere / Sarcoplasmic Reticulum / Z-Line / A-Line / M-Line /
Neuromuscular System / Neuromuscular Junction / Motor Unit / All or None Principle / Acetylcholine (ACh) / ATP /
Myosin / Actin
Kinesiology
October 8th, 2020
Unit #7: Muscular Anatomy
Questions and Vocab:
Notes:
-> What are the three types
of muscle tissue in your
body? What are their
functions?
Types of Muscle Tissue
-
Skeletal
Smooth
Cardiac
They have various functions
and characteristics that help
them play their part.
-
-
-
Skeletal Muscle
- Elongated, cylindrical, striated
- Attached to skeleton
- Voluntary
Cardiac Muscle
- Elongated, cylindrical, striated
- Walls of heart
- Involuntary
Smooth Muscle
- Elongated, spindle-shaped, non-striated
- Walls of stomach
- Involuntary
2
-> What are the 5 major
properties of muscle
fibres?
-
ICEEC
-> What are the basic parts
of a muscle?
-
Multiple different
layers
SFMMS
Actin and myosin filaments cause striation; when randomly arranged, no striation
Fastest to slowest contraction: skeletal, cardiac, smooth
Shortest to longest contraction length: smooth, cardiac, skeleton
Properties of Muscle Fibres:
-
Irritability, or the ability to respond to stimuli
Contractibility, or the ability to shrink in length
Elasticity, or the ability to stretch and return to original position
Extensibility, or the ability get longer
Conductivity, or the ability to transmit impulses of the nerves
Parts of a Muscle:
- Muscle belly
- Epimysium (deep fascia)
- Muscle Fascicle
- Perimysium
- Muscle fibre
- Endomysium
- Sarcoplasmic Reticulum
- Sarcolemma
- Sarcomere
Basic:
Skeletal muscle -> muscle fascicle-> muscle fibres -> myofibrils -> sarcomere
Epimysium -> perimysium -> endomysium
3
Features of Sarcomere
-> What is the significance
of origin and insertion?
-
Transverse Tubule: stimulate and coordinate contractions
Sarcolemma: cell membrane of muscle fibres
Sarcoplasmic Reticulum: membrane network controlling individual myofibrils
Z-line: Denotes the end of a sarcomere
Zone of thick filament: has thick and thin filament
I-band: only thin filaments
H-band: only thick filaments
A-band: contains all thick filament, including H-band and overlap zone
-
Origin and insertion
- Origin: where muscles attached to axial skeleton (doesn’t move)
- Insertion: where muscle attaches to bone with most movement
Origin/ insertion help determine the functions of various muscles
-> How are muscles
named?
ADL DHSA
- 6 different naming
factors
Muscle naming:
1.
2.
3.
4.
5.
6.
Action: flexor, extensor
Direction of fibres: longitudinal fibres-> rectus, horizontal fibres-> transversus
Location of muscles: anterior, posterior, supra-infra
Divisions / heads: multiple origins- bi/ tri, multiple layers-> max/min
Shape: deltoid->looks like delta, trapezius-> looks like trapezoid
Attachment: attach at sternum, clavicle, mastoid-> sternocleidomastoid
4
-> How are muscles
arranged in the body?
-
Muscle arrangement:
-
Muscles must stay in opposing pairs, as they can only contract, not expand.
- Agonist: muscle that creates main movement
- Antagonist: muscle that opposes the agonist muscle: returns to normal
-
Few key pairs:
- Elbow flexion, Ag: Biceps brachii Ant: Triceps brachii
- Shoulder abduction, Ag: Deltoid Ant: Latissimus dorsi
- Knee extension, Ag: Quadriceps Ant: Hamstrings
- Trunk flexion, Ag: Rectus abdominis Ant: Erector spinae group
Stabilizers are muscles that support body during multi-plane movement
In antagonist pairs
-> What are types of
muscle contractions and
incorporated exercises?
1. Isotonic
2. Isometric
3. Isokinetic
-
Resistance training
helps with a variety of
body functions
-> What are some common
muscle injuries?
Muscle contractions and exercises:
1. Isotonic: controlled muscle shorten/lengthen- e.g dumbbells
2. Isometric: muscle fibres stay same length- e.g squat
3. Isokinetic: involves machines to control contraction speed- combines other two!
Resistance training helps with:
- Increased muscles
- Increase in muscle form (mitochondrial density, protein levels)
- Increased muscle efficiency
- Improved body composition
- Increased resting metabolic rate
- Increased motor unit recruits
- Body needs more efficiency on neuromuscular side, so more motor units
help out the cause
- Stronger connective and support tissue
- Boost in bone density, tendon strength, joint stability, eyc
- Increase fuel storage capacity of muscle fibres
- Greater glucose storage
- Increased fuel efficiency
- Body adaptations
- Joint, power, speed improvements
- More blood supply
- Increased O2 delivery and removal of waste
Common Muscle Injuries
-
Strain of muscles
Shin splints
ACL Tears
DOMS, or double onset muscle soreness, which occurs 1/2 days after a tough
workout
5
-> How does a muscle
contract from brain to
action
Key terms:
Acetylcholine (ACh): a
neurotransmitter
Actin: thin sliding filament
Myosin: thick sliding filament
-> What is the sliding
filament theory of muscle
contraction
-
A repeating cycle
Calcium and ATP
always needed
Myosin heads pull the
actin filament
together, causing
contraction
Muscle Contraction: Neurocontrol!
The neuromuscular system is responsible for the contraction of a muscle
1. A messages begins in the brain and moves through the central nervous system
2. The message goes to the axon branch, then terminal.
3. Acetylcholine (ACh) is a neurotransmitter that carries the message from the axon
terminals to the sarcolemma of the muscle fibres involved
4. ACh creates action potential which travels down the t-tubule and makes the
sarcoplasmic reticulum release calcium ions from the terminal cisternae
5. Calcium ions move to the actin filament’s tropomyosin, binding to attachment
sites on troponin
6. Tropomyosin pivots and causes the binding sections on the actin to be exposed
7. Myosin heads attach to the binding sections of the actin filament
8. ATP, which is a form of energy produced, is broken down by ATPas, which
induces the power stroke, and causes the actin to slide along the myosin
filament, as if being rowed
9. Actin and myosin with stay contracted until the brain sends signals to stop.
Calcium and ATP energy are needed as well, in order for the muscle to continue
to contract.
Sliding Filament Theory
1. Step 1: Active site exposure
a. Calcium is available
b. Calcium binds w/ troponin
c. Creates a troponin-tropo,ysin complex which moves from the active site
2. Step 2: Form a Crossbridge attachment between troponin and tropomyosin
3. Step 3: Myosin head pivots towards the sarcomere using ATP energy
4. Step 3: When the myosin gets anothers TP molecule to bind to, it detaches from
the first one
5. Step 5: The process repeats and the myosin is reactivated but only is:
a. Calcium is present
b. ATP is available to use
Helpful Video:
https://www.youtube.com/wat A motor unit is a term used to refer to a pair including a motor neuron and muscle
ch?v=nTZnBdeIb5c
fibres
The all or none principle states that the muscle will wither completely react to the
stimuli or will not at all
The Musculoskeletal system refers to connections between the bones and the
muscles of the body. Neuromuscular system refers to the muscles and nervous
system.
6
Summary
-
Study the muscle
anatomy diagrams
Study diagram on
Sliding Filament
Theory
-
There are three types of muscle tissues with different properties and abilities
Muscles are named based on a variety of factors. Study them all w/ examples
Understand how muscles are arranged and function(insertion and origin)
There are various parts of muscles when you look at all the layers. Know them
Study muscle injuries (you should be familiar with these, already)
Understand excitation-coupling, and how a message moves from the brain to
skeletal muscle -> sliding filament theory, too!
If you study these sheets, plus view the videos, you should be good!