Download Muscular System

Muscular System
Read Ch 6
Assignment: pp 198 M/C #3 – 8, S/A #2,
10, 15 Clinic #2, 6
Types of Muscles
 Skeletal—
voluntary—
connects to
bones
■Cardiac—
involuntary—found in
heart only~!
■Smooth;
involuntary,
found in
hollow
organs
Functions of the Muscular
System
 Movement of body
parts—by pulling on
bones. Bones act as
levers, joints as the
fulcrum.
 Guard entrances and
exits
 Posture
 Stabilizing joints
 Create heat
Muscle Attachment Fibers
 Tendons—connect
muscle to bone
(cordlike)


Origin—fixed end
(proximal end of
bone)
Insertion—
moveable end
(distal end of bone)
 Aponeuroses—
connect muscles to
muscles (sheetlike)
Microscopic Muscle
Anatomy
 Plasma membrane
= sarcolemma
 Cytoplasm =
sarcoplasm
 ER = sarcoplasmic
reticulum
 Functions are
similar as in other
body cells, but the
name is different
•Lots of mitochondria
and several nuclei in
each cell
•Myofibril—fibers
extending lengthwise in
muscle cell, made up of
myosin and actin
Microscopic Anatomy
con’t:
 Myosin—thick filaments
 Actin—thin filaments
 Sarcomere—segment between 2 Z-lines
functioning as a contractile unit


A bands appear dark and thick
I bands are narrower and lighter
Video of sarcomere shortening
Muscle Physiology…
Reason for Motion
Brain
Motor Nerves
If enough Ach,
contraction occurs
Muscle
Cell
Energy necessary for all this to happen
comes from the generation of ATP
Acetylholine
(Ach) is the
Neurotransmitter
Stimulating
Muscle Cells
Muscle Physiology con’t:
 Nerve impulse arrives at muscle cell
 Ca+2 released from SR into sarcoplasm
 Ca+2 combines with troponin molecules in the
thick filaments of myofibrils (Myosin)

Troponin without Ca+2 doesn’t interact like this
 Myosin interacts with Actin and pulls toward
center
 Contraction of muscle


Video of contraction occuring…
Animation of entire process…
Muscle Physiology
 “All
or none”
law—a muscle
cell contracts all
the way or not at
all.
 It’s the number of
stimulated muscle
cells that decides
how much the
entire muscle will
contract…
You can sort of
contract your bicep or
you can really contract
your bicep…
Muscle Fatigue
 Definition: A muscle’s inability to
contract despite being stimulated
 Results from being unable to get
enough oxygen to muscle cells during
exercise

Blood isn’t reaching muscle cells fast enough
 Lactic acid (a waste product of
anaerobic respiration) builds up causing
poor muscle contraction
 Once you get enough O2 and ATP back
into body, lactic acid is removed.
Types of Contractions
Twitch—quick jerky response to
a stimulus
Tetanic—more sustained and
steady than a twitch. A series
of stimuli—contractions melt
together to produce a sustained
contraction.
Types of Contractions con’t:
 Isotonic—usually produces movement at
a joint. Muscle shortens and insertion
end moves toward the origin. Eg.,
walking, breathing, lifting and twisting
 Isometric—increase tension of muscle by
NOT shortening it. No movement, so the
muscle remains the same length.
Repeated isometric exercise will result in
larger and stronger muscles. eg.,
pushing against a wall.
Muscles and Exercise--Benefits
 Endurance exercise—Aerobic activity
 Stronger,
more flexible muscles, but no
increase in size of muscles.
 More blood is circulated to muscles so
muscles increase number of
mitochondria…making them more
efficient. More efficiency = less lactic
acid produced
 Other benefits: better digestion, better
elimination, bigger heart and better gas
exchange
Muscles and Exercise--Benefits
 Resistance exercise—strength
training
 Bigger,
stronger muscles, less flexibility
though and no improvement in
endurance
 If
you want ideas of types of strength
training available…talk to your coaches
or see me after class.
Recovery of muscles
Body needs to replenish ATP
and CP and get rid of LA—cool
down exercises will speed this
along.
LA removal with exercise—1/2
to 1 1/3 hour
LA removal without exercise—1
– 3 hours
Recovery of muscles con’t:
 Recovery of ATP— ~70% within 30
seconds, 100% within 3 – 5 minutes of
activity
 Recovery of glycogen depends on the
type of exercise and the amount of
carbs used during recovery—could take
2 – 8 days!
 Within
first 10 hours, 60% glycogen is
recovered…make sure to take in carbs
during first 48 hours of recovery!
Recovery of muscles
During hours 1 – 10, eat simple
and complex sugars…after 10
hours, complex carbs only!
If you only have 30 minutes
between events, only consume
simple sugars…no complex
carbs!
Body Movements
 Flexion—
decreasing the
angle of the joint by
bringing the bones
closer together
 Extension—
extends a joint by
increasing the
angle between the
bones
Body Movements
 Rotation—movement
around an axis
(partway around)
 Circumduction—a
combination of
flexion, extension,
rotation and
abduction. Eg.,
throwing a ball
Body Movements
 Abduction—
moving away
from the midline
 Adduction—
moving toward
the midline
Special Movements
 Pronation—motion
of palm from
anterior position to
posterior position
 Supination—palm
moves from
posterior position
to anterior position
Special Movements
Inversion—
turning the sole of
your foot medially
Eversion—turning
the sole of your
foot laterally
Special Movements
 Dorsiflexion—
pointing your
toes up toward
your shin
 Plantar
Flexion—
pointing your
toes downward
Factors used in naming muscles
 Direction of muscle fibers
 Rectus
= straight, oblique =
slanted
 Muscle size
 Maximus, minimus, longus
 Location of muscle
 Temporalis, frontalis, zygomaticus
Factors used in naming muscles
 Number of origins
 Biceps
(2), triceps (3), quadriceps (4)
 Location of origin and insertion
 Sternocleidomastoid
 Shape of muscle
 Trapezius
= trapezoid shaped
 Action of muscle
 Flexor,
extensor, adductor
Steroids—read page 180 and
handout
Drug
Human Growth
hormone (hGH)
Erythropoietin
(EPO)
What does it do?
Break down fat
for energy use
Risks
Disfigure bones and muscles,
jutting of forehead, heart
issues and metabolism
Increase RBC #
Thickens blood
and causes clots
Testosterone
Build muscle, quicker
recovery, aggressive
Heart disease, liver
cancer, impotence
Steroids/
androstenedione
Artificial testosterone
(see above)
See above
Stimulants
Delays muscle
fatigue
Overrides the “stop” message
…this is dangerous
Overall impressions of
steroids/drugs
Positives
■Increases muscle
mass
■More Oxygen
carried
■More aggressive
Negatives
■Distortion of breast tissue
■Bloated facial features
■Small repro organs
(testes and ovaries)
■Infertility
■Liver damage
■Retain more cholesterol
■Mental disorders
Muscle Show
and Tell
Head Muscles
Frontali
s
Orbicularis
Oris
www.slackbooks.com
Orbicula
ris Oculi
www.grendahl.com
daphne.palomar.edu
Head Muscles
en.wikipedia.org
Buccinator
Zygomaticu
s
www.ivy-rose.co.uk
Masseter
www.deltadental.com
Head/Neck Muscles
www.answers.com
Temporalis
sternocleidomast
oid
en.wikipedia.org
Abdomen/Chest
Muscles
Pectoralis
Major
fr.wikipedia.org
Abdomen/Chest
Muscles
Intercostals
www.courses.vcu.edu
Rectus Abdominus
summit.stanford.edu
Abdomen/Chest
Muscles
Obliques
Diaphragm
www.easyvigour.net.nz
www.getbodysmart.com
Transverse
Abdominus
www.swamij.com
Back Muscles
www.answers.com
Trapezius
Deltoid
Latissimus Dorsi
www.fotosearch.com
www.fitnessnet.nl
Arm Muscles
Biceps
Brachii
Brachioradialis
www.waynesburg.edu
Triceps brachii
www.iemily.com
Arm Muscles
www.rad.washington.edu
Arm Muscles
Extenso
r
Digitoru
m
www.dubinchiro.com
Arm Muscles
Flexor
Digitorum
Superficiali
s
www.rad.washington.edu
Arm Muscles
www.waynesburg.edu
Leg Muscles
www.answers.com
Leg Muscles
courses.washington.edu
Leg Muscles
Adductor Group
www.vancouveryoga.com
Leg Muscles
www.waynesburg.edu
Leg Muscles
www.octc.kctcs.edu
Leg Muscles
www.octc.kctcs.edu
Leg Muscles—Hamstrings
www.memorial.ecasd.k12.wi.us
Leg
Muscles
www.answers.com
en.wikipedia.org
Leg Muscles
www.courses.vcu.edu
www.octc.kctcs.edu
Extensor
Hallucis Longus
Leg Muscles
education.yahoo.com
Leg Muscles
www.memorial.ecasd.k12.wi.us
www.arthroscopy.com