Download Outline: Muscular System

Date: _________________
Notes: The Muscular System
Overview

Muscles are able to do their jobs because they are made of
____________________.
o
have a specialized cell membrane and cytoskeleton that allows it to
change; have _______________________

Muscles cells move by ________________: muscle cell ____________________
(muscles _______, never ___________)


Blood provides the necessary _____________________ to the muscle for proper functioning.
o
ion capable of conducting an _________________________ in a solution
o
examples: sodium, potassium, ________________, etc.
Body mass index (BMI): an indirect measurement of body density (The leaner you are, the more muscle mass
you have; a degree of leanness reduces heart disease & metabolic disorders).
Muscle

Appearance: grouped as _______________ and ____________________. The striped appearance is due to the
arrangement of cytoskeleton proteins

o
________________________: the cytoskeleton proteins involved in muscle contraction
o
nonstriated muscles provide ____________________________ than striated ones do
Control: characterized is by the type of control a person has over the function of the muscle
___________________: have a large degree of control; conscious.
___________________: contract without conscious control
Types of Muscle Tissue

develop from a process called ___________________; starts when a group of
o
stem cells in the ________________ turn into ________________.
o
____________________ provide the signal for the start of cell division and differentiation of muscle
types.
Physiology
Ms. Pastor
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Date: _________________

Cardiac:
o
______________ and _______________ muscle;
o
provides ____________ contraction;
o
each cell has two nuclei; communicate with one another
by ________________________ -- helps synchronize beat
o
Have a natural contraction cycle called the
_______________________

Smooth: produce weak involuntary contractions that can last for a long period of time.
o
Assist with ___________________ and ___________________ of blood vessels and tubular structures
of respiratory system
o

Pulsating contractions in digestive system is called ___________________ -- move food thru
Skeletal: provides movement of the __________ and _____________
o
Each skeletal muscle cell is composed of several __________________ that fuse together into a
_________________
o
Nerves that control the muscle fibers are called __________________________
Muscle Cell Structure:
Covered with an excitable membrane (called the ____________________) filled with specialized cytoskeleton (called
______________________)

Types of filaments
o
_________ myofilaments are composed of _____________.
o
_________ myofilaments are made up of three proteins
o

__________________- forms the core of the fiber, provides binding sites for myosin

__________________- reinforces the actin core

__________________- blocks the binding sites on actin during relaxed state
__________ filament: runs vertically; considered an elastic myofilament

Contractile unit of muscle is called _________________. Chains of sarcomeres form __________________

Thin myofilaments of the sarcomere are attached to a protein structure called a _________________.
Physiology
Ms. Pastor
Page 2 of 4
Date: _________________
o
Z-line marks the _______________ between each ____________________

Keeps thick and thin filaments aligned

helps control the _______________ and ______________ limits in a muscle; anchors the
sarcomeres to the sarcolemma.

_______________________________ stores and transports large amounts of the ______________ needed for
muscle contraction
Muscle Cell Function
Occurs in the following steps:

neural stimulation: takes place at the __________________________.
o
Nerve cells _____________________________ from the body to a muscle cell through the junction
o
Contraction is initiated when the nerve cells release a chemical signal called a ____________________.

__________________ binds to _________________ located on the ________________ and
then excites it.

This causes the ___________________________ to open, creating an _________________ of
sodium and potassium ions.
Physiology
Ms. Pastor

This, in turn, allows ______________ (Ca2+) ions to diffuse through the membrane.

The calcium travels to the ____________________, which initiates the contraction phase.
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Date: _________________

muscle cell contraction: begins when the ______________ released by the sarcoplasmic reticulum
___________________________.
o
Calcium causes the ______________ to ___________________
o
This then changes the shape of the
___________.
o
_____________________ of the actin are
exposed
o
_______________ (heads) are able to bind to them
o
Troponin _____________________________ so that energy is provided for the myosin heads to
pull/slide the thick myofilament across the thin myofilament.

muscle cell relaxation occurs when:

no more ____________________________ are exciting the ____________________

the __________________________ levels are restored

sarcoplasmic reticulum restores _______
o
________________ heads release from __________ binding sites and sarcomeres have no tension
o
Muscle remains in a contracted, but pliable, state.
_____________________ is common after death because ____________________________ into the sarcomere;
known as ______________________
Proper Functioning

_________________________ stores the ATP needed for muscle cells to function.

___________________ is a red-colored chemical that ______________________ for certain muscle cells.
Physiology
Ms. Pastor
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