Structure of Skeletal Muscle
Muscles contain:
o Muscle tissue
o Connective tissue (epimysium, endomysium and perimysium)to bind it together
o Nerves carry information to and from the muscle (brain/spinal cord)
o Blood vessels to bring oxygen, remove waste produces, supply nutrition and energy
and maintain fluid levels.
In general, muscle consists of a muscle belly with a fibrous tendon at either end which is
attached to the bone by the tendon.
Q: What is the purpose of connective tissue?
A: Anything which gives the body form, binds it together or protects it from
mechanical damage…it surrounds and supports the muscle tissue. It therefore:
o Transmit the force of the muscle to the bones
o Protect muscle tissue from damage
o Binds muscle fibres together
A muscle is an extremely complex structure but it is relatively easy to understand because
it is highly organised into small, identical units (see section of muscle diagram which
shows the organisation of muscle fibres and connective tissue).
Q: Are all muscle fibres the same size?
o No as there are large differences in both length and widths
Task:











Label muscle diagram and learn the following: How muscles move:
Blood vessels
Bone
Tendon
Muscle Fibre (*)
Epimysium (*)
Endomysium (*)
Perimysium (*)
Myofibril (*)
Sarcomere (*)
Actin (*)
Myosin (*)
Structure of the Body
Characteristics common to muscle
 Make notes on the general characteristics common to muscle tissue and limit this
to: contractility, extensibility, elasticity, atrophy, hypertrophy, controlled by nerve
stimuli and fed by capillaries.
533583499
Skeletal Muscle Section
Structure
o
Bone
o
o
Epimysium
(connective tissue)
Endomysium
(connective tissue)
Perimysium
(connective tissue)
Muscle Fibre or Muscle cells
Blood Vessel
Tendon
533583499
Each individual muscle (eg bicep) is
surrounded by a connective tissue
sheet called the epimysium
Each individual muscle fibre is
surrounded by the endomysium
Is a sheath of connective tissue fibers,
that divides the skeletal muscle into a
series of compartments, each
containing a bundle of muscle fibers
called a fascicle.
o Basic cellular unit of muscle and
contains several nuclei outside of
the cell
o Nucleus is the control centre of
the cell
Form the vascular system
White
flexible
connective tissue.
cord/strap
of
o
o
o
Description
Starts off as cartilage, then turns
into bone through ossification
process
Rigid Connective tissue that
makes up the skeleton
Smooth external layer of moist
connective tissue
The epimysium separates the
muscle from surrounding tissues
and organs.
Function
o
o
o
o
Support
Movement
Blood production
Protection
o
o
Gives muscles its shape
Provides
smooth
surface
against which other muscles
can glide
Binds muscle together
o
Very thin layer of connective
tissue which surrounds individual
muscle fibres (total envelope)
Wraps around fibres and binds
them together to form bundles
White fibrous connective tissue
containing collagen and elastic fibres
Binding together fasciculi which
are bundles of fibres
o
Consists of smaller units called
myofibrils
(Further discussion in A2)
o
o
o
Arteries
Veins
Capillaries
o
Very tough and very strong
Movement eg.
Slow twitch/ fast twitch
To bring oxygen, remove waste
produces, supply nutrition and
energy and maintain fluid levels
o Attach muscle to bone
o Helps
production
of
movement around a joint.
All 3 connective tissue layers (epimysium, endomysium and perimysium) are connected to each other so that when the muscle fibres
contract, they are ultimately linked to the tendons which are attached to bones across joints, thus creating voluntary movement.
Skeletal Muscle Section continued………..
Task: Fill in the gaps
Structure
Myofibril
Sacromere
Actin
Mysoin
533583499
Description
Function
Made of myofilaments called thin
filaments and thick filaments.
• Thin and thick filaments are
made mainly of the proteins actin
and myosin.
One of the slender threads of a
muscle fiber in skeletal and
cardiac muscle cells.
Contractile units within muscle
cells.
Contains
the
contractile
filaments within the skeletal
muscle cell.
Sacromeres give striated muscles their
banded appearance.
Within the Myofibril. The
smallest contractile unit of a
striated muscle cell.
Muscle Contraction
The protein component of
microfilaments that forms thin
filaments in skeletal muscles and
produces contractions of all
muscles through interaction with
thick (myosin) filaments;
A thin, contractile protein
filament, containing 'active' or
'binding' sites. It slides past
myosin casing contractions.
The protein component of thick
filaments.
A thick, contractile protein
filament,
with
protusions
known as Myosin Heads. Pulls
action filaments towards one
another by means of cross
bridges
Actin is a round protein shaped
roughly like a ball.
Myosin is a long thin protein with a
head on it. Many of these myosin
proteins are linked together in a
bundle, also forming a filament, with
the heads pointing out.
533583499