Download muscular system

MUSCULAR SYSTEM
(pp. 813-817)
I. Purpose
The primary function of the muscular system is to produce ___________________. The contraction of
muscle tissue requires _______, so muscles are constantly carrying out ________________________
and require a large number of ____________________________.
II. Description
A. Muscle Fibers
Individual muscle cells are called muscle _________________. All humans have the __________
number of fibers. Muscle bulk occurs because of ________________________ of muscle fibers,
not an increase in the number of muscle cells.
B. Muscle Types
1. Skeletal Muscle - ________________, ___________ muscle cells that fuse together to form a
__________________________ muscle fiber. Muscle fibers are arranged end-to-end to produce
strong contractions. If the oxygen supply to muscle cells is depleted, they can switch to
___________________________ for energy production.
2. Cardiac Muscle - _____________________, ____________________ muscle cells found
only in the ______________, with each cell having its own nucleus. Cardiac muscle cells are
arranged in chains that lattice together. When the muscle contracts, the entire lattice of cells
contracts together producing a powerful contraction.
3. Smooth Muscle - ________________, ___________ muscle cells. Smooth muscle contractions
are slow and prolonged. Found in the ______________________________________________
C. Muscle Contraction
Each muscle fiber contains thousands of contracting units called ___________________.
Sarcomeres are made up of two types of protein filaments:
1. Actin - ___________filaments that form the border of each sarcomere.
2. Myosin - _______________ filaments found in the _______________ of the sarcomere.
Actin and myosin overlap to produce the _________________ pattern seen in ________________
and __________________ muscle. When a muscle contracts, the actin and myosin filaments slide
over each other and the sarcomere ________________________. Every sarcomere within a
single muscle fiber contracts as a unit, thereby shortening the entire __________________. The
number of fibers that can contract at one time determine an individual’s _________________. The
length of the contraction time is known as __________________________.
III. Skeletal Muscle
A. Anatomy - Skeletal muscles are attached to bones by tough bands of tissue called ____________.
Every muscle has at least 2 tendons, each attached to a different bone:
1. Origin – Muscle attachment site(s) that ______________________________________
2. Insertion – Bone that is ___________________________________________. For example,
the ______________________________ has __________________ attaching it to the
____________________ and __________________. The origin is the ____________________
and the insertion is the _____________________.
B. Movement - Skeletal muscles attached to the bones of the __________________ skeleton work in
opposing pairs.
1. Flexor – muscle that causes limb to _____________ at ____________.
2. Extensor – muscle that causes limb to ___________________ at ___________. For example,
contraction of the biceps brachii _____________ the arm so it acts as a _____________, while
contraction of the triceps brachii __________________ the arm so it is the ________________.