The Muscular System


Muscles are organs
They provide tone, move body fluids &
food, provide the heartbeat & distribute
heat.
There are 3 types of muscle:
1.
Skeletal Muscle
2.
Smooth Muscle
3.
Cardiac Muscle
Types of Muscle:
http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/19917.jpg
 Attached
to bones
 Voluntary
 Allow
http://www.uic.edu/classes/bios/bios100/labs/skeleta
l_muscle.jpg
movement
 Striated
(striped)
 Enclosed
in endomysium (connective tissue)
which forms fibers called fascicles.
 The
fascicles collectively form
aponeuroses, tendon-like structures which
attach to bones.
Smooth Muscle
No striations
 Involuntary
 Located in hollow
organs (stomach,
bladder, etc.)

http://www.victoriacollege.edu/dept/bio/Belltutorials/Histology%20Tutor
ial/Basic%20Tissues/imageFLL.JPG
Cardiac Muscle
Striated
 Involuntary
 Located only in the
heart (pump blood)

http://www.mccc.edu/~falkow/images/cardiac_001.jpg
 Movement
(contraction &
relaxation)
 Posture
 Joint
stabilization
 Heat
generation
http://chanteur.net/contribu/index.htm#http://chanteur.net/contribu/cJMdiaph.htm
Muscle type and innervation of the diaphragm
Type musculaire et innervation du diaphragme
© John Messmer 1998
[Re: Involuntary Diaphragm???]
There are three types of muscle in the body: skeletal, smooth and cardiac. Skeletal contracts in response to a nerve
impulse at the individual muscle cell's neural plate. It is not propogated to other muscles. Smooth muscle also uses a
stimulus to contract, though its type of contraction is less forceful than skeletal muscle and can propogate to other
smooth muscle cells. Smooth muscle is in intestines, for example. Cardiac muscle contracts spontaneously, but that's
a separate topic.
The diaphragm has ONLY skeletal muscle, not smooth muscle - none. It will not contract spontaneously as cardiac muscle.
It MUST have an impulse delivered to contract. That impulse can originate in the higher brain centers as when we
voluntarily inhale and exhale or in the lower brain as when low oxygen levels or high levels of acid or carbon dioxide
are present in the cerebrospinal fluid or blood. There are MANY sites of modulation of breathing in the brain too
complicated for this forum.
I will repeat what I have said before: the diaphragm muscle is skeletal and *not considered voluntary or involuntary* - it is
the NERVOUS SYSTEM which is either voluntary or involuntary depending on whether we are consciously or
unconsciously breathing. The phrenic nerve carries motor fibers that originate in the upper brain - the cortex which
serves voluntary actions, and lower brain - brainstem which serves involuntary actions. There are NO SYMPATHETIC
OR PARASYMPATHETIC nerves to the diaphragm. (Lungs, yes; diaphragm, no.)
We determine whether our diaphragms are at rest, contracted or forced up into our thoraces by the proprioceptive
(position) sensation in our abdominal and chest walls and the nociceptive (bad feeling) fibers in our intestines and
lungs. When it is contracted, our abdominal organs are pushed down and our abdominal walls are pushed out. When
relaxed, this reverses. To exhale fully, it requires us to contract the abdominal wall muscles and the intercostal
muscles (between the ribs) since our diaphragms can not move any higher than fully relaxed.
I hope this clears it up.
John
John Messmer, MD, Medical Director
Penn State Geisinger Health Group, Palmyra, PA
 Sarcolemma
is the plasma membrane.
 The
contractile unit in the muscle is the
sarcomere.
 Myofibrils
are the organelles.
 Myofilaments
are the proteins found
within the sarcomeres. These form
striations.

Actin are thin filaments.

Myosin are thick filaments.
Skeletal Muscle:
http://www.ivy-rose.co.uk/Topics/Muscles/Muscle_Cell_Close-up_1.jpg
These striations a pattern with 2 parts:
1. I bands (light) have actin
attached to Z lines.
2.
A bands (dark) are myosin
overlapping actin, contain an H
zone (central thick region) and
a M line.
 Within
the sarcoplasm is the
sarcoplasmic reticulum (just like
the ER of other cells). These are
membranous channels.
Skeletal Muscle Fiber:
http://www.cartage.org.lb/en/themes/sciences/LifeScience/GeneralBiology/Physiology/Muscular/SkeletalMuscle/muscle2.gif
http://www.easttroy.k12.wi.us/hs/dept/science/bottum/Adv
%20Biology/muscular/manatomy/images/muscle2.gif
http://www.ks.uiuc.edu/Research/telethonin/MuscleL1-t.jpg
 Motor
neurons (nervous system) connect to
each & every skeletal muscle fiber.
 The
connection between these two forms a
neuromuscular junction.
 This
is the reason skeletal muscles
contract.
 Motor
neurons branch; their ends contain a
lot of mitochondria & synaptic vesicles
(responsible for synapses).

They store neurotransmitters.
http://www.shelfieldpeonline.co.uk/assets/images/neuromuscular_junction.jpg
 The
basic movement of skeletal muscle
is a result of a stimulus (via a neurotransmitter).
 The
actin & myosin filaments slide past
each other, shortening the muscle fiber
(contraction).
 Acetylcholine
is the neurotransmitter
responsible for skeletal muscle
contraction.
 This
 This
needs ATP and high [Ca++]
is called the Sliding Filament
Theory.
http://www.dwm.ks.edu.tw/bio/activelearner/38/images/ch38summary.gif
 Aerobic
respiration: requires oxygen and
produces ATP, which is used by muscles.
 Creatine
phosphate: provides phosphate to
ADP to make ATP, which is then used by
muscles.
 Lactic
acid fermentation: this is anaerobic
respiration (no oxygen used).

Lactic acid is produced (and a small amount of
ATP).
Energy goes
into cycle (to
make ATP) 
 Energy to do work
http://library.thinkquest.org/C006669/media/Biol/img/atp_cycle.gif
 Active
muscles tend to become O2 deficient.
 An
accumulation of lactic acid in muscles
causes fatigue, cramping and pain.
 Repaying
an oxygen debt (after strenuous
exercise) may take several hours.
 Even
at rest, muscle tone exists. This is the
sustained contraction of muscles. This is
important in maintaining posture.
 Muscles
move according to their location &
position.
 The
immovable end of a muscle is called
the origin (head) while the movable end is
called its insertion.
 Insertion
is pulled towards its origin.
 Some
muscles have more than 1 origin or
insertion.
 Ex:
biceps brachii (in arm) has 2 origins
(biceps=2 heads)
http://www.google.com/imgres?
 Flexion
means decreasing an angle
 Extension
means increasing an angle
 Muscle
name usually indicates info about
it: its location, size, # of attachments,
shape or action.
Examples:
deltoid (shaped like a delta or triangle)
biceps brachii (2 heads in the brachium, or
arm)
pectoralis major (large in size, located in
pectoral, or chest, region)
Look up labeled diagram of muscle system in text or online.
Know this diagram!
Chewing Muscles
Frontalis
 Occipitalis
 Orbicularis Oculi
 Orbicularis Oris
 Buccinator
 Zygomaticus

Facial muscles
Masseter
 Temporalis

Neck Muscles
Platysma
 Sternocleidomastoid

http://www.google.com/imgres?
Pectoralis Major:
covers chest
 Intercostal Muscles:
between ribs
 Rectus Abdominis:
from pubis to rib
cage

External oblique
 Internal oblique
 Transversus
abdominus

http://www.google.com/imgres?
 Trapezius:
kiteshaped muscle over
neck & shoulder
 Erector
Spinae (deep
back)
 Quadratus
 Latissimus
Lumborum
Dorsi
 Deltoid
(triangularshaped muscle of
shoulder)
http://www.google.com/imgres?
 Biceps
brachii
 Brachialis
 Brachioradialis
 Triceps
http://www.google.com/imgres?
Brachii
Hip Joint Muscles:
Knee Joint Muscles:

Gluteus Maximus
(buttocks)

Hamstrings (includes
biceps femoris)

Gluteus Medius

Sartorius

Iliopsoas (p is silent;
iliac crest to
vertebrate)


Adductor Muscles
Quadriceps (includes
rectus femoris):
intramuscular
injections usually
occur here.
http://www.google.com/imgres?
Ankle & Foot:

Extensor Digitorum
Longus

Fibularis Muscles
(fibula to
metatarsals)

Gastrocnemius (calf)

Soleus
http://www.google.com/imgres?
https://www.google.com/search?q=muscle+movements&biw=1280&bih=891&tbm=isch&imgil=U4L2lBW3OyOKgM%253A%253BMvE4OtsTvZ9tRM%253Bhttps%25253A%25252F%25
252Fwww.studyblue.com%25252Fnotes%25252Fnote%25252Fn%25252Fchapter-22musculoskeletal%25252Fdeck%25252F9470025&source=iu&pf=m&fir=U4L2lBW3OyOKgM%253A%252CMvE4OtsTvZ9tRM%252C_&usg=__dE7IhzVheZIDED3Em2Snz6XhqDc%3D&ved=
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https://www.google.com/search?q=muscle+movements&biw=1280&bih=891&tbm=isch&imgil=U4L2lBW3OyOKgM%253A%253BMvE4OtsTvZ9tRM%253Bhttps%25253A%25252F%25
252Fwww.studyblue.com%25252Fnotes%25252Fnote%25252Fn%25252Fchapter-22musculoskeletal%25252Fdeck%25252F9470025&source=iu&pf=m&fir=U4L2lBW3OyOKgM%253A%252CMvE4OtsTvZ9tRM%252C_&usg=__dE7IhzVheZIDED3Em2Snz6XhqDc%3D&ved=
0ahUKEwjw_raA0tnKAhWHmx4KHd2fA8YQyjcIMQ&ei=MeywVrCiPIe3et2_jrAM#tbm=isch&q=muscle+movements+anatomy&imgdii=6G210TXx7_WGuM%3A%3B6G210TXx7_WGuM%
3A%3BkQM3r4Zo3x_-2M%3A&imgrc=6G210TXx7_WGuM%3A
https://www.google.com/search?q=muscle+movements&biw=1280&bih=891&tbm=isch&imgil=U4L2lBW3OyOKgM%253A%253BMvE4OtsTvZ9tRM%253Bhttps%25253A%25252F%25
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 Look
up in text or online!
 Know the following:
Atrophy, rotation, abduction, adduction,
circumduction, dorsiflexion, plantar flexion,
inversion, eversion, supination, pronation,
opposition, prime mover, antagonists,
synergists, fixators, muscular dystrophy,
Duchene’s muscular dystrophy, and
mysthenia gravis

This slide show was developed by Dana Halloran,

Cardinal Mooney High School, Sarasota, FL.

Used with her personal permission,

adapted and amended by Rosa Whiting,

Manatee School for the Arts, Palmetto, FL.