Download Muscular System

Muscular System
Human A & P
1/28/09
Intro

What causes movement of the human body?
– Contraction/Relaxation of muscles

How much body weight do muscles comprise?
– 40-50%

What is the scientific study of muscles called?
– Myology

What is the scientific study of movement called?
– Kinesiology
Types of Muscle Tissue
1. Skeletal—striated (light and dark bands),
attached to bones; voluntary
Types of Muscle Tissues
2. Cardiac—heart muscle, striated and has
intercalated disks, involuntary, cannot
regenerate
Types of Muscle Tissue
3. Smooth—lines blood vessels & airways and
digestive tract, non-striated, involuntary
Functions of Muscle Tissue
To produce _______________
 ____________body positions
ex) hold head up, posture, stand, sit
 To regulate organ _________

– Sphincters—mouth, stomach, and colon
Moving substances within the body
 To produce __________by contraction or
_____________

Characteristics of Muscle Tissue
Excitability-respond
to __________
 Extensibility—
stretch without
being damaged
 Elasticity—return to
its original shape
 Contractility—
shorten and thicken
when stimulated

Structure of Muscle Tissue






Skeletal Muscle
Fascicle
Fiber
Myofibril
Sarcomere
Filaments
Connective Tissue Components

Fascia—fibrous
connective tissue that lies
beneath the skin and
around muscle
– Superficial—sub Q
– Deep—holds and separates
muscles
 Rolfing story here



Epimyseum-wraps around
the entire muscle
Perimyseum-covers
fascicles (looks like tofu)
Endomyseum—wraps
around each muscle fiber
Cellular Components





Cellular components are located
in muscle fibers
Instead of cytoplasm, it has
____________________
Within this sarcoplasm are many
_________________, as you
recall as the “powerhouse” of
the cell
• Instead of endoplasmic
reticulum, it has
__________________reticulum,
which stores
___________________required
for muscular contraction
• Its plasma membrane is called
a _________________
Muscular Contraction

TO UNDERSTAND HOW MUSCLES
CONTRACT/RELAX, YOU MUST FIRST
IDENTIFY THE STRUCTURE OF
SARCOMERES

Each sarcomere is separated by zig
zags called _________

MYOFIBRILS are made up of several
______________, or compartments,
that contain the thick and thin protein
filaments _____________ and
_________________

______________are the thin filaments
– connected to z discs

_______________are the thick
filaments
– form
________________________,
which look like two golf clubs
twisted together. (myosin heads)
Muscular Contraction

For a muscle to contract, it must be
stimulated by electrical signal called a
______________ _____________
____________

Muscle nerve cells or ____________
______________ have long tails called
______________, which carry a chemical
neurotransmitter called
_____________________.

This nerve impulse must “jump” over a gap
called a_____________

Where this ‘jump’ takes place is called the
________________ _________________

_________________is constantly being
released and broken down to trigger muscle
action potential.

EX) _______________________-affects
events at NMJ. Bacteria which blocks release
of ACh, and may cause suffocation by
paralyzing the ________________
Muscle Contraction (cont)







After muscle action potential takes place, the ________________
____________________ _________________ as you viewed in the kickoff
video, occurs.
For this mechanism to take place, the body’s high energy molecule must be
available.
ATP structure review:
• adenine
• ribose
• 3 __________groups
Energy is made available when the bond between last two ____________ is
broken, creating _________. The constant cycle of ATP - ADP is what gives
us energy. Also, ______________ ions must be available. Recall, they are
stored in the___________ _________________.
Steps in Muscle Contraction

1. Muscle action potential (electrical impulse--_____ions) created by release
of_____________________

2. Stimulation of sarcoplasmic reticulum by ___________ions triggers release of
________into ______________

3. Calcium ions trigger _________________________ mechanism by binding to
troponin and tropomyosin on __________and changing the shape of proteins.

4. ATP splits, producing ____________needed to form ______________between
________ and _____________filaments.

5. Myosin heads swivel, actin (thin filaments) slides past _____________ thick
filaments toward center of sarcomere, causing contraction

6. Energy from ATP causes crossbridges to break, and the enzyme
_______________________ breaks down acetylcholine, _________________ions go
back to the sarcoplasmic reticulum.
Define the following
diseases/disorders






A. Charley horse
B. Hypertonia
C. Hypotonia
D. Muscular Dystropy
E. Myalgia
F. tremor






tic
spasm
I. cramp
J. paralysis
K. twitch
L. patellofemoral stress
syndrome
DIFFERENTIATE BETWEEN THE
THE PAIRS OF TERMS BELOW
– ISOMETRIC/ISOTONIC CONTRACTION
– ORIGIN/INSERTION OF MUSCLES
– SLOW TWITCH/FAST TWITCH FIBERS
– PRIME MOVER (AGONIST)/ANTAGONIST
Diagrams

Label the following:
–
–
–
–
–
–
H Zone
I band
Z-disks
A band
Actin
Myosin