Download The Muscle System

Notes
The Muscular System
Chapter 36
Section 2
Muscle System Functions
 Provides voluntary
movement of body
 Enables breathing,
blinking, and smiling
 Allows you to hop,
skip, jump, or do
push-ups
 Maintains posture
 Produces heat
Functions Continued
 Causes heart beat
 Directs circulation
of blood
 Regulates
blood
pressure
 Sends blood to
different areas of
the body
Functions Continued
 Provides movement of
internal organs
 Moves food through
digestive tract
 Enables bladder control
 Causes involuntary actions
 Reflex actions
 Adjusts opening of pupils
 Causes hair to stand on
end (
)
Muscle Tissue
Characteristics
 Is made up of contractile
fibers
 Provides movement
 Controlled by the
nervous system
 Voluntary- consciously
controlled
 Involuntary- not under
conscious control
 Examples
 Skeletal
 Smooth
 Cardiac
Skeletal
Smooth
Cardiac
Types of Muscle Tissue
 There are
three main
types of
muscle tissue
 Skeletal
(striated)
 Cardiac
(heart)
 Smooth
(visceral)
Comparison of Muscle Types
Muscle Type
Skeletal
Cardiac
Smooth
Location
Attached to
bone
Heart
Walls of internal
organs + in skin
Function
Movement of
bone
Beating of heart
Movement of
internal organs
Control Mode
Voluntary
Involuntary
Involuntary
Shape
Characteristics
Long + slender
Branching
Spindle shape
Striated- light
and dark bands
Many nuclei
Striated
One or two
nuclei
Non-striated
One nucleus
(visceral)
Frontalis
Location
of Muscles
 Skeletal
Muscles
 Anterior
view
Masseter
Deltoid
biceps
Pectoralisbrachii
Major
Brachioradialis
External Obliques
Rectus abdominis
Quadriceps Group
Quadriceps
group
Tibialis Anterior
Location
of Muscles
Trapezius
Triceps brachii
 Skeletal
Muscles
Latissimus dorsi
 Posterior
view
Gastrocnemius
Hamstring
Hamstring
group
group
Gluteus
maximus
Muscles You Need to Know
















1. brachioradialis
2. biceps brachii
3. deltoid
4. external oblique
5. frontalis
6. gastrocnemius
7. gluteus maximus
8. hamstring group
9. latissimus dorsi
10. masseter
11. pectoralis major
12. quadriceps group
13. rectus abdominis
14. tibialis anterior
15. trapezius
16. triceps brachii
A
5
F10
15K
B
3
G11
L16
C
2
H13
D
4
O
9
1I
M7
12E
P8
14
J
N
6
Location of Muscles
 Involuntary
Muscles






Diaphragm
Digestive organs
Arrector pili
Heart
Urinary bladder
Muscles around
blood vessels
Muscle Tissue Anatomy
bundle of muscle
fibers – fascicle
M
u
s
c
l
e

T
I
s
s
u
e
Muscles are made up of bundles
of muscle fibers, called fascicles
 Fascicle is a bundle of muscle
fibers
 A muscle fiber is a muscle
cell….made up of many
small myofibrils
 Myofibrils
contain filaments
 Two types of
protein
filaments
A
n
a
t
o
m
y
Filaments
Muscle Fibers
Myofibrils
Muscle
Fascicle
Myofibril
Thin Filaments
 Contain two types of
protein filaments
 Actin- thin
protein
filaments
 Myosin- thick
protein filaments
 Z disc- point of
anchor of actin
 Sarcomerefunctional unit of a
myofibril, region
between Z discs,
Sarcomere
Sarcomere
Z Disc
Thick Filaments
Myosin Molecule
Actin
Molecule
Muscle Tissue
Anatomy
 What parts do you
remember?
1. Muscle
2. Fascicle
(bundle of fibers)
3. Muscle fiber
(muscle cell)
4. Myofibrils
1D
2C
3B
A
4
Muscle Tissue Anatomy Continued
What parts do you remember?....continued
C Muscle cell
F Actin
D Myofibrils
B Fascicle
A
G Myosin
E Filaments
B
H Sarcomere
C
A Muscle
I Z Disc
Myofibril
H
D
E
I
G
F
Mechanics of a Muscle
Contraction
 What stimulates a muscle to
contract?
 Your nervous system
 What cells are involved?
 Muscle cells and a motor neuron
 Motor neuron sends
impulse to muscle cells
 One neuron will form
synapses with many
muscle cells
 What is this called?
A
 A motor unit
 Let’s take a look under
theunit
microscope.…
motor
Mechanics of a Muscle
Contraction
 Where does stimulation occur?
 Neuromuscular junction
 How do motor neurons
communicate with
muscle cells?
 Neurotransmitters (typically
acetylcholine) carry
impulse signal across the gap
 What happens when a
muscle cell is stimulated?
 Calcium ions are released into the muscle cell
Myofibrils are
surrounded by
calciumcontaining
sarcoplasmic
reticulum.
Neurotransmitters
Mechanics of a Muscle
Contraction
 What do calcium ions do?
 Cause interaction between actin and myosin
 How do actin and myosin interact?
 Actin filaments slide over the myosin filaments.
 What model explains this?
 Sliding Filament Model
Mechanics of a Muscle
Contraction
 What causes actin to slide over
myosin?
 The head of myosin connects
to actin and pivots.
 What is this connection called?
 cross-bridge
 The binding of the myosin
heads throughout the
sarcomere occur
asynchronously…
 some myosin heads are
binding while other heads are
releasing the actin filaments.
 This process must be
performed repeatedly during a
single muscle contraction so
that the muscle is able to
generate a smooth force
Mechanics of a Muscle
Contraction
 What provides the energy to swivel the head of
ATP
myosin? _____
 How exactly does the sliding filament model work?
 In the sliding filament model of muscle contraction, the
(thin) actin filaments
[red] (that are attached
to the Z-line) slide (are
actually pulled) inward
along the (thick)
myosin filaments
[blue], and the
sarcomere (measured
from one Z line to the
next) is shortened.
Mechanics of a Muscle
Contraction
 When each sarcomere becomes shorter it
causes each myofibril to become shorter.
 When each
myofibril becomes
shorter it causes
the muscle fibers
to become shorter
 When each
muscle fiber
shortens the
Sarcomere
overall muscle
contracts.
Control of a Muscle
Contraction
 How long does a muscle cell
remain contracted?
 Until the release of acetylcholine
stops.
 How strongly does a muscle fiber contract?
 To it’s fullest extent.
 All-or-none response
 So what controls the
strength of a contraction?
 Number of muscle cells recruited
 To get a stronger contraction, more
cells are stimulated
 A single cell can’t contract harder
A Closer Look at Muscle Contraction
“hot”
guy
Muscle
Fiber
Deltoid
muscle
Myofibril
Actin
sarcomere
Myosin
Macroscopic Structure
of Muscle
Tendon attaches
 _________muscle to bone
Origin attachment
 _______of muscle to
immovable (fixed)
bone (anchors muscle)
 ________Insertion attachment
to bone that moves
when muscle contracts
Belly bulging middle
 _____part of the muscle
Belly of
Biceps
Muscle Movement
 Muscles originate on a _____bone
in our body,
fixed
cross over a ______,
______
joint and insert onto a moving
bone.
 It is important to understand that all muscles
move from the ________
insertion point
going toward the __________
origination
point.
 It is because of the placement
of the muscles that we can
move.
Muscle Movement
 Tendons
 attach _________
muscle to bone
 are inelastic
 don’t stretch when the force of
the muscle acts on them
 When muscle contracts,
it pulls on the _______
bone
 Individual muscles can
only ____
pull in ____
one direction
 Muscles work in
pairs
opposing ______
Muscle Movement
 ______Flexor Muscle that bends the joint when
contracted.
 Extensor
________- Muscle that straightens the joint
when contracted.
 Contracted
__________ muscle
is short, firm, tight
and thicker around.
 Relaxed
_______ muscle is
stretched, long, loose
and thinner around.
Muscle Movement
 When the biceps in the arm contracts the triceps
relaxes causing ________
________
bending of the arm.
contracts the biceps
 When the triceps in the arm _________
relaxes causing straightening
____________ of the arm.
 ______
Pairs of muscles are
needed because the
only active movement
_________
of a muscle is to
contract
_______, to lengthen it
must be _________
stretched by
the action of an
muscle
opposing _______.
I am
getting
motion
sicknes
s
Muscle Movement
Warning: This illusion
 The muscles, bones, and ligaments work
to control
body motion.
cantogether
make
you
feel very
dizzy, especially if you
are prone to motion
sickness
Muscles In Action
HYPERMUSCLE: MUSCLES IN ACTION
 Click above to get to this multimedia interactive HTML
document which will help you learn the muscle actions
of the human body.
Muscle + Bone Interaction
 Let’s review the structures involved in
movement at a joint.
B
C
F
A
D 
C
G
E
D
C
B
F
B
F
Ligament
Tendon
Cartilage
Body (Belly)
Origin
Insertion
Contracted muscle
Relaxed muscle
Flexor
Extensor
Muscle Disorders
Sprain
 A sprain is a wrenching, twisting or stretching
injury to a ligament.
Sprains often affect the
ankles, knees, or wrists.
Result in pain, swelling, redness, bruising, and
difficulty using injured joint.
Muscle Disorders
Strain
 A strain is an injury to a muscle or
tendon, and is often caused by
overuse, force, or stretching.
 Injured area
experiences:
 pain and
soreness
 swelling
 warmth, bruising,
or redness
 difficulty using or
moving the
injured area in a
normal manner
Muscle Disorders
Muscle Ruptures



There are three degrees of muscle ruptures
A muscle tear may be partial or complete and caused either by
a direct blow or by overexertion.
A first-degree strain involves less than 5 percent of the muscle.



A second-degree tear is a greater rupture that stops short of a
complete tear.




mild pain and not much loss of strength or range of motion.
Mild tears referred to as pulled muscles.
Any contraction of the torn muscle will cause pain.
There may be a defect of the muscle - a bump or an indentation - at
the site of the most pain.
You should be able to partially contract the muscle, but not without
pain
A third-degree rupture is a complete tear across the width of
the muscle




You will be unable to contract the muscle.
This is what happens when someone suddenly drops while
sprinting.
The torn end of the muscle may ball up and form a large lump
under the skin, and a great deal of internal bleeding occurs.
Severely torn muscles may require surgery to heal properly.
Muscle Disorders
Muscle Pull
Muscle Tear
 Muscle pull- very slight tear
 Chronic tear- gradual onset of pain
 Acute tear- sudden dramatic pain
Muscle
Tears
Muscle Disorders
Shin splints
 Shin splints is pain
resulting from damage to
the muscles along the shin.
Pain is felt in different areas,
depending on which muscles
are affected.
Shin splints represent an
"overuse injury" and occur
most commonly in runners.
Muscle Disorders
Treatment for Muscle Injuries
 R.I.C.E.
 Rest: Stop all activities which
cause pain.
 Ice: Helps reduce swelling.
Never ice more than 10-15 min.
at a time. Protect the skin.
 Compression: Wrap the strained
area to reduce swelling.
 Elevation: Keep the strained area as
close to the level of the heart as is
conveniently possible to keep blood
from pooling in the injured area.
Muscle Disorders
Spasms
Cramps
 Muscle spasm- when A muscle (or even a few
fibers of a muscle) involuntarily contract
 Muscle cramp- involuntarily + forcibly
contracted muscle that does not relax
 A forceful + sustained spasm
 Nick named charley horse
 Muscle feels tied up in knots
 Can last anywhere from a few
seconds to a quarter of an hour
 Caused by strain or injury