Muscular System
Each muscle consists of a group of
fibers held together by connective
tissue, and enclosed in a fibrous
sheath or fascia (FASH ee ah).
Muscles cause movement, help to
maintain posture, and produce heat.
3 types of muscle
Parts of a muscle
Skeletal muscles are elastic and work
in pairs -one flexing while the other is Body– the main portion
extending. They are striated, with
Origin– the fixed attachment
horizontal markings, and are
stimulated to contract by electrical Insertion- the point of attachment to
impulses from the nervous system. the part of the body moved by this
muscle
Fast, white muscle fibers contract
rapidly, have poor blood supply, In this picture, the origin of the
operate without oxygen, and tire muscle is the scapula attachment; a
quickly. Slow, red muscle fibers tendon provides the insertion on the
contract more slowly, have better ulna and radius bones.
blood supplies, operate with oxygen,
and do not tire as easily. They are
used in ongoing movements, such as
maintaining posture.
Smooth muscles contract slower than
skeletal muscles, but can remain
contracted longer, and are not as
dependent on oxygen. They are
stimulated by electrical impulses or
hormones, and use carbohydrates for
energy.
Smooth muscle lines most hollow
organs of the body, such as the
intestines, stomach, and uterus. They
help move substances through
Tendon is a means of attachment,
tubular areas such as blood vessels
connecting the muscle to the bone.
and the small intestines, contracting
They vary in length, from less than an
automatically and rhythmically.
inch to more than a foot. A wide
Cardiac muscle or myocardium are sheet-like tendon is called an
striated like skeletal muscles, but are aponeurosis (ap ah nyu ROH siss).
smaller and shorter. They are
stimulated to contract by electrical
impulses sent out from small clumps major muscles
of specialized tissue in the heart…
the sinoatrial (sī-nō-Ā-trē-ul) and
atrioventricular node (ā-trē-ō-ven-trik-
y ə-lər) nodes.
Each muscle consists of a group of
fibers held together by connective
tissue, and enclosed in a fibrous
sheath or fascia (FASH ee ah).
Muscles cause movement, help to
maintain posture, and produce heat.
3 types of muscle
Parts of a muscle
Skeletal muscles are elastic and work
in pairs -one flexing while the other is Body– the main portion
extending. They are striated, with
Origin– the fixed attachment
horizontal markings, and are
stimulated to contract by electrical Insertion- the point of attachment to
impulses from the nervous system. the part of the body moved by this
muscle
Fast, white muscle fibers contract
rapidly, have poor blood supply, In this picture, the origin of the
operate without oxygen, and tire muscle is the scapula attachment; a
quickly. Slow, red muscle fibers tendon provides the insertion on the
contract more slowly, have better ulna and radius bones.
blood supplies, operate with oxygen,
and do not tire as easily. They are
used in ongoing movements, such as
maintaining posture.
Smooth muscles contract slower than
skeletal muscles, but can remain
contracted longer, and are not as
dependent on oxygen. They are
stimulated by electrical impulses or
hormones, and use carbohydrates for
energy.
Smooth muscle lines most hollow
organs of the body, such as the
intestines, stomach, and uterus. They
help move substances through
Tendon is a means of attachment,
tubular areas such as blood vessels
connecting the muscle to the bone.
and the small intestines, contracting
They vary in length, from less than an
automatically and rhythmically.
inch to more than a foot. A wide
Cardiac muscle or myocardium are sheet-like tendon is called an
striated like skeletal muscles, but are aponeurosis (ap ah nyu ROH siss).
smaller and shorter. They are
stimulated to contract by electrical
impulses sent out from small clumps major muscles
of specialized tissue in the heart…
the sinoatrial (sī-nō-Ā-trē-ul) and
atrioventricular node (ā-trē-ō-ven-trik-
y ə-lər) nodes.
