Yoga Anatomy

56 Yoga anatomY

E5267/Kaminoff/fig4.3/417613/alw/pulled-r3

Connective

tissue fibers

Muscle fibers

Bone Tendon

Muscle belly

Skeletal muscle is generally attached to bones
and creates movement at the joints. It has alter-
nating bands of light and dark fibers that give the
tissue its striated appearance. Skeletal muscle is
controlled by the somatic portion of the nervous
system, which makes many of its functions volun-
tary, or under our conscious control. Cardiac muscle
is in the heart, and smooth muscle is in the blood
vessels, airways, and visceral organs. Cardiac tissue
is also striated but is controlled by the autonomic
nervous system and hormones from the endocrine
system. Smooth muscle is not striated and, like car-
diac muscle, is controlled by the autonomic nervous
system and the endocrine system.
The skeletal muscle tissue that we see with the naked eye is made up of bundles of fas-
cicles. The fascicles are made up of bundles of muscle fibers, which are the actual muscle
cells. Inside the muscle cells are bundles of myofibrils (or myofilaments; see figure 4.2).
Each of these bundles of myofibrils, muscle cells, and fascicles are wrapped in a layer of
connective tissue, and all these layers of connective tissue come together at the ends of the
muscles to create the tendons and other tissues that connect muscles to bones (figure 4.3).
The myofibrils are made up of thick and thin filaments that lie alongside each other and
overlap. These filaments are twisted strands of molecules that create contractions.

E5267/Kaminoff/fig4.1/417611/alw/pulled-r3

Nerve axonMuscle fiber

Capillary Fascia

Figure 4.1 Muscles are composed of
several tissues working together: muscle
fibers, nerves, capillaries (blood vessels),
and fascia (connective tissue).

E5267/Kaminoff/fig4.2/417612/alw/pulled-r3

Fascicle

Muscle belly

Muscle fiber

Myofibril

Figure 4.2 The muscle belly is
made up of bundles of fascicles that
are made up of bundles of fibers
(muscle cells) containing bundles of
myofibrils.

Figure 4.3 Fibers of connec-
tive tissue (white) run through
the muscle (red). At either end of
the muscle, the connective tissue
comes together to create tendons,
which connect to bone.