Download These filaments are

Muscular System
Types of Muscle
Skeletal – striated & voluntary
Smooth – involuntary
Cardiac - heart
Muscles and
Muscle Fibers
Muscles are composed of many fibers that are
arranged in bundles called FASCICLES
Fascicle
Fascia
Individual muscles are separated by FASCIA,
which also forms tendons and aponeuroses
(sheet-like coverings)
Muscle Layers
Muscle cell or fiber
Endomysium – fascia around the
cell or fiber
Perimysium- fascia around a
group of fibers
Epimysium – fascia around the
entire muscle bundle
Lets get the hierarchy straight
Muscles
are made from a lot of
Muscle Fiber Bundles
which are made of
Individual Muscle Fibers (cells)
which are made of
Myofibrils
which are rows of
Sarcomeres
Muscles & Nervous System
Muscles receive their information from the nerve
cells at the Neuromuscular junction.
The means of contracting comes Sarcoplasmic
Reticulum. It is like the smooth and rough E.R. in
form and stores calcium .
When the signal comes from the nerves (acetylcholine), it
floods the cell with calcium which causes a chemical
reaction between the thin and thick filaments.
Myofibril – thick and thin filaments
These filaments are:
– ACTIN (thin) and MYOSIN (thick)
These filaments overlap to form dark and light
bands on the muscle fiber
 A band = dArk • thick (myosin)
 I band = lIght • thin (actin)
• In the middle of each I band are Z lines. A
sarcomere is one Z line to the other
What are the Thin and Thick
filaments?
Actin fibers bind to
make the thin filaments
Myosin fibers combine
to make the thick
filaments.
Together they
oppose each other to
form the “bands” of
the Sarcomere
SLIDING FILAMENT THEORY (MODEL)
The theory of how muscle contracts is the sliding
filament theory. The contraction of a muscle occurs as
the thin filament slide past the thick filaments.
DLC the anatomy of a skeletal muscle cell
from fiber to sarcomere.
Page 167 will be helpful
Where does the cell get it’s
energy?
Fibers contain
multiple
mitochondria for
energy
ATP is made here!
Energy Source
• Provided by ATP from cellular
respiration (mitochondria) Usually only
4-6 seconds worth is stored
•Aerobic respiration creates 36 ATP
molecules/Glucose – must have O2
•Anaerobic Respiration creates 2
ATP and Lactic Acid – absence of O2
Threshold Stimulus
Minimal strength required to cause a contraction
Motor neuron releases enough acetylcholine to
reach threshold
All-or-None Response
Fibers do not contract partially, they either do or don't.
Muscles and their movements:
Every one of the 600+ skeletal muscles is
connected to bone or connective tissue at
two points!
1. Origin – attachment to
immovable bone
2. Insertion – attachment
to a movable
bone
Naming Muscles
There are certain things used
when naming muscles.
1. Direction of the muscle fiber
Rectus– (straight ) Rectus
Femoris
2. Size of the muscle
Maximus –(largest) or
Minimus – (smallest)
Gluteus Maximus
3. Location of the muscle in the body
Frontalis – (in the front)
Frontalis muscle
4. The number of origins
Biceps – (two origins)
Triceps – (three origins)
Quadriceps – (four origins)
5. Location of the muscle’s
origin and/or insertion.
Sternocleidomastoid
(sternum-collar bone-mastoid
process of the Temporal bone)
6. Shape of the muscle.
Deltoid – (triangular muscle)
Deltoid muscle
7. Action of the muscle.
Flexor – (decrease bone
angle)
Extensor – (increases bone
angle)
Adductor – (brings bone
toward the median)
Flexor Carpi Radialis
Extensor Carpi Radialis
Adductor Magnus
Muscles perform different
types of movements:
All contract and relax, but these movements
are what it does to the body.
It all has to do with what the joint
does.
Flexion:
Decreases the joint angle.
Brings bones closer
together.
Extension:
Increases the Joint Angle.
Pushes bones farther apart.
Rotation:
Movement around the
longitudinal axis
Abduction:
Movement away from
the median plane.
Adduction:
Movement toward the
median plane.
Circumduction:
Combining Flexion,
Extension Abduction,
and adduction
(moving in a circle)
Dorsiflexion and
Plantar Flexion
Up and Down
movement of the foot
Inversion and
Eversion:
Face the sole of
the foot medially
or laterally.
Supination
and
Pronation:
Lateral or medial
rotation of a limb
Opposition:
Moving one finger
to oppose the
others.
Muscles of the Face and Skull (Front view):
Frontalis
Temporalis
Orbicularis Oculi
Zygomaticus
Orbicularis Oris
Platysma
Muscles of the Skull (side view):
Occipitalis
Sternocleidomastoid
Masseter
Trapezius
Muscles of the Chest and Shoulder
Trapezius
Deltoid
Pectoralis Major
Biceps Brachii
(long head)
Biceps Brachii
(short head)
Latisimus Dorsi
Serratus Anterior
External Obliques
Muscles of the abdomen (anterior)
Pectoralis Major
Rectus Abdominis
Transverse Abdominis
Internal Oblique
External Oblique
Linea Alba
Aponeurosis
Muscles of the abdomen (posterior)
Trapezius
Deltoid
Latissimus Dorsi
Rhomboid
Muscles of the Upper Leg (posterior)
Gluteus Medius
Gluteus Maximus
Adductor Magnus
Gracialis
Biceps Femoris
(long head)
Semitendonosis
Semimembranosis
Biceps Femoris
(short head)
Gastrocnemius
Muscles of the Upper Leg (posterior)
Sartorius
Adductor Group (groin)
Rectus Femoris
Vastus Lateralis
Vastus medialis
Fibular Longus
Tibialis Anterior
Soleus
Muscles of the lower arm and leg
The only muscles that are
important are the
highlighted ones
Muscle Review
Cardiac muscle
Fascicle
Perimysium
Sarcomere
Myosin
Aerobic respiration
Origin
Antagonist
Smooth muscle
Fascia
Epimysium
Sarcoplasmic reticulum
A-band
Anaerobic respiration
Insertion
Tendon
Skeletal muscle
Endomysium
Myofibril
Actin
I-band
Threshold stimulus
Prime mover
Questions:
1. What is the sliding filament theory?
2. List and describe the different types of muscle movements (flexion
extension, etc).
3. What are the different ways muscles are named?
4. Know all muscle names – Arm/Leg/Torso/Head