Download Chapters 10 & 11 Notes - Decker

Muscle Tissue
Chapter 10
I.
A.
Skeletal Muscle Tissue &
The Muscular System
Three types of muscle tissue
1.
2.
3.
Skeletal
Cardiac
Smooth
B.
Skeletal Muscle Functions
1.
Produce skeletal movement
a.
b.
Contractions pull on tendons to move bones
Muscles always pull, never push
2.
Maintain posture & body position
3.
Support soft tissues (organs)
4.
Guard entrances & exits
5.
Maintain body temperature
II. Anatomy of Skeletal Muscle
A.
A skeletal muscle contains
1.
2.
3.
4.
Connective tissues
Blood vessels
Nerves
Skeletal muscle tissue
B.
Connective Tissue Organization
1.
Epimysium
a.
b.
c.
2.
Surrounds entire muscle
Makes up part of the deep fascia
Made of dense connective tissue
Perimysium
a.
b.
Divides skeletal muscle into bundles of muscle
fibers called fascicles
Contains blood vessels & nerves that go to each
fascicle
3.
Endomysium
a.
b.
4.
Surrounds individual skeletal muscle fibers &
bind adjacent fibers together
Contains satellite cells (muscle stem cells),
which function in muscle repair
Tendons & Aponeurosis (tendinous sheet)
a.
b.
c.
d.
Composed of collagen fibers of the above
membranes
Connect muscles to bones
Interwoven with the periosteum & extend into
the bone matrix
VERY STRONG!
C.
Blood Vessels & Nerves
1.
Muscle contraction requires large amounts
of energy
2.
Muscles are very vascular
a.
b.
c.
Nutrients
Oxygen
Wastes
D.
Microanatomy of Skeletal Muscle Fibers
1.
Muscle Fiber- muscle cell
2.
Sarcolemma- cell membrane of a muscle
fiber
3.
Sarcoplasm- muscle fiber cytoplasm
4.
Transverse Tubules (T Tubules)
a.
b.
Narrow tubes that connect to the sarcolemma and
extend into the sarcoplasm
Carry electrical impulses that are conducted by
the sarcolemma
5.
Myofibrils
a.
Cylinders inside the muscle fiber that run the
entire length of the fiber
b.
Each muscle fiber contains 100s to 1,000s
c.
Attached to the sarcolemma
d.
As they shorten, muscles contract
e.
Consist of bundles of myofilaments
i.
ii.
Protein filaments
Composed of:
» Actin- thin filaments
» Myosin- thick filaments
6.
Sarcomeres
a)
b)
c)
d)
Repeating units of myofilaments
Smallest functional unit of a muscle fiber
10,000 end-to-end per myofibril
Interactions between thick & thin filaments =
muscle contraction
* See diagram for labeling
7.
Sliding Filament Theory - thin filaments
slide toward the center of the sarcomere,
alongside the thick filaments. (The filaments
themselves do not actually shorten.)
Video 1
Video 2
Put it all together!
Concept Check
1.
How would severing the tendon attached
to a muscle affect the muscle’s ability to
move a body part?
2.
Why does skeletal muscle appear striated
when viewed through a microscope?
The Muscular System
Chapter 11
I. Organization of Skeletal Muscle Fibers
A. Factors that determine the effects of a
muscle contraction:
1. The anatomical arrangement of the
muscle fibers
2. The way the muscle attaches to the bones
of the skeletal system
B. Fascicles- bundles of muscle fibers within a
skeletal muscle.
C. 4 Patterns of Fascicle Organization
1. Parallel Muscles- fascicles are
parallel to the long axis of the muscle.
a. Most common type.
b. Some are flat bands.
c. Some are spindle-shaped w/ a central
body (aka belly or gaster)
d. Ex. biceps brachii
2. Convergent Muscles- fascicles are based
over a broad area, but unite at a common
attachment site.
a. Fan- or triangle-shaped
b. Ex. pectoralis group (chest muscles)
3. Pennate Muscles- fascicles form a
common angle with the tendon.
a. Unipennate- Fibers go off in one direction
Ex. extensor digitorum
b. Bipennate- Fibers go off in two directions
Ex. rectus femoris
c. Multipennate- Fibers go off in many
directions
Ex. deltoid
4. Circular Muscles (aka sphincter)- fibers
are concentrically arranged around an
opening or recess.
a. Contracting decreases the diameter of the
opening.
b. Guard entrances and exits of internal
passageways.
c. Ex. orbicularis oris (mouth)
(a review from physical science…)
Levers are:
1.
simple machines
2.
structures that
move on a fixed
point called a
fulcrum.
3.
When effort
force is applied, a
lever moves
about the
fulcrum,
overcoming the
resistance.
II. 3 Classes of Levers in the Body
A. First Class Levers
1. The fulcrum lies
between the applied
force (AF) and the
resistance (R)
R
F
E
2. Ex.
a. Teeter-totter
b. scissors
B. Second Class Levers
E
1. The resistance is located
between the applied
force and the fulcrum.
R
2. Ex.
a. Wheelbarrow
b. Hinged doors
F
C. Third Class Levers
1. The applied force is between the resistance and
the fulcrum.
2. This is the most common type of lever in the
body.
R
3. Ex.
a. Sweeping
b. Shoveling
R
F E