The Muscular System...The Muscular System ... the NERVOUS SYSTEM which is either voluntary or involuntary depending on whether we are consciously or unconsciously breathing. The phrenic

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

http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/19917.jpg

Types of Muscle:

Attached to bones

Voluntary

Allow 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.

http://www.uic.edu/classes/bios/bios100/labs/skeleta

l_muscle.jpg

Smooth Muscle Cardiac Muscle

No striations

Involuntary

Located in CVS and

hollow organs

(stomach, bladder,

etc.)

Striated

Involuntary

Located only in the

heart (pump blood)

http://www.victoriacollege.edu/dept/bio/Belltutorials/Histology%20Tutor

ial/Basic%20Tissues/imageFLL.JPG

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

http://chanteur.net/contribu/index.htm

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 have 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.ks.uiuc.edu/Research/telethonin/MuscleL1-t.jpg

http://www.easttroy.k12.wi.us/hs/dept/science/bottum/Adv

%20Biology/muscular/manatomy/images/muscle2.gif

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 neuro-transmitter).

The actin & myosin filaments slide past each other, shortening the muscle fiber (contraction).

Acetylcholine is the neurotransmitter responsible for skeletal muscle contraction.

This needs ATP and high [Ca++]

This 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 to do work Energy goes

into cycle (to

make ATP)

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?

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!

Facial muscles

Chewing Muscles

Frontalis

Occipitalis

Orbicularis Oculi

Orbicularis Oris

Buccinator

Zygomaticus

Masseter

Temporalis

Platysma

Sternocleidomastoid

Neck Muscles



Pectoralis Major: covers chest

Intercostal Muscles: between ribs

Rectus Abdominis: from pubis to rib cage

External oblique

Internal oblique

Transversus abdominus



Trapezius: kite-

shaped muscle over

neck & shoulder

Latissimus Dorsi

Erector Spinae (deep

back)

Quadratus Lumborum

Deltoid (triangular-

shaped muscle of

shoulder)



Biceps brachii

Brachialis

Brachioradialis

Triceps Brachii



Hip Joint Muscles: Knee Joint Muscles:

Gluteus Maximus (buttocks)

Gluteus Medius

Iliopsoas (p is silent; iliac crest to vertebrate)

Adductor Muscles

Hamstrings (includes

biceps femoris)

Sartorius

Quadriceps (includes

rectus femoris):

intramuscular

injections usually

occur here.



Ankle & Foot:

Extensor Digitorum Longus

Fibularis Muscles (fibula to metatarsals)

Gastrocnemius (calf)

Soleus



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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0ahUKEwjw_raA0tnKAhWHmx4KHd2fA8YQyjcIMQ&ei=MeywVrCiPIe3et2_jrAM#tbm=isch&q=muscle+movements+anatomy&imgdii=6G210TXx7_WGuM%3A%3B6G210TXx7_WGuM%

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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.

Documents

The Muscular System...The Muscular System ... the NERVOUS SYSTEM which is either voluntary or involuntary depending on whether we are consciously or unconsciously breathing. The phrenic