Muscular Random Flashcards
account for 40 to 50 percent of body mass
Muscles
when contracted, they shorten, pull their
ends & produce movement
Muscle
specialized for contraction
Muscles
Contraction of a muscle brings
about
Movement
study of muscle
structure & function
Myology
Types of Muscle Tissue
- Skeletal Muscle
- Cardiac Muscle
- Smooth Muscle
Functions of the Muscular System
1.) Body Movement
2.) Maintaining Posture
3.) Storing substances within the body
4.) Moving substances within the body
5.) Producing Heat
results
from alternating contraction &
relaxation of skeletal muscles
Body movement
results from sustained
contraction of some skeletal
muscles to stabilize body
positions.
Maintaining Posture
results
from sustained
contraction of ringlike
bands of smooth
muscle called
sphincters
Storing substances within the body
results
from contraction &
relaxation of smooth
muscles in the walls of
organs; also result from
contraction of cardiac
muscle to pump blood
Moving substances within body
maintains normal body temp.;
can also result from
involuntary contraction of
skeletal muscles called
shivering
Producing Heat
ability to respond to
electrical signals or
nerve impulses that
stimulate muscle cells
to contract
Electrical Excitability
ability of muscle cells
to shorten and
generate a strong
pulling force as they
contract
Contractility
ability to stretch,
within limits, without
being damaged
Extensibility
ability to return to its
original length &
shape after
contraction or
extension
Elasticity
Special Properties of
Muscles
- Electrical Excitability
- Contractility
- Extensibility
- Elasticity
Connective Tissue Components
1.)Subcutaneous Tissue
2.)Deep fascia
3.)Epimysium
4.)Perimysium
5.)Endomysium
• also called “superficial fascia”
• separates muscle from skin
Subcutaneous Tissue
• fibrous connective tissue sheet w/c
holds together individual muscles or
groups of muscles
Deep fascia
• wraps an individual muscle
Epimysium
• surrounds bundles of muscle fibers
called fascicles
Perimysium
• wraps each individual muscle fiber
Endomysium
• continuous w/ epimysium, perimysium &
endomysium
• rope-like structure made of fibrous
regular connective tissue
• merges w/ deep fascia & anchors
skeletal muscles to the periosteum of
bones
Tendon
• plural: aponeuroses
• a flat tendon
Aponeurosis
• abundant in each muscle
• capillaries carry blood to muscle cells &
supply them w/ O2 & nutrients
• also remove heat & waste products of
muscle metabolism
Blood vessels
• somatic motor neuron: the type of
neuron that excites skeletal muscles to
contract; carry electrical signals to the
muscles from the brain
• frontal lobe: area of brain where control
center for skeletal muscle movement is
located
Nerves
• synonymous w/ muscle cells
• named as such because they are cylindrical
& elongated (each is 10 to 30 cm long)
• thousands of them make up a single muscle
Muscle fibers
Parts of a Muscle Fiber
1.) Sacrolemma
2.)Transverse tubules
3.) Sarcoplasm
4.)Myoglobin
5.)Sarcoplasmic
reticulum (SR)
6.)Myofibrils
7.)Myofilaments
8.)Sarcomere
•Part of a muscle fiber
• the cell’s plasma
membrane
• contains receptor
sites for certain
substances
Sarcolemma
•Part of a muscle fiber
• or “T tubules”
• tiny inward folds of
the sarcolemma w/c
tunnel in from the
surface toward the
interior of each
muscle fiber
Transverse Tubules
•Part of a muscle fiber
• where electrical
signals travel
through along the
sarcolemma
Transverse Tubules
•Part of a muscle fiber
• ensure that nerve
impulses excite all
parts of the muscle
fiber at essentially
the same instant
Transverse Tubules
•Part of a muscle fiber
• the cell’s cytoplasm
• consists of myofibrils,
numerous
mitochondria,
glycogen granules, &
other cellular
organelles
Sacroplasm
•Part of a muscle fiber
• releases its bound
O2 when it is
needed by the
mitochondria for
ATP production
• the reddish
pigment of muscle
cells
• contains iron w/c
enables it to bind
w/ O2
Myoglobin
•Part of a muscle fiber
• the smooth ER of
muscle cells
• stores & releases
calcium ions,
needed for muscle
contraction
• surrounds the
myofibrils
Sarcoplasmic
reticulum (SR)
•part of a muscle fiber
• long, rod-shaped
structures that
extend from one
end of the muscle
fiber to the other
• make up most of
the sarcoplasm
• the contractile
organelles of
skeletal muscle
Myofibrils
•Part of a muscle fiber
• thin & thick filaments
w/c are contractile
proteins located
within myofibrils
• give the muscle fiber
its striated
appearance
• their unique & precise
arrangement w/in the
muscle fibers gives
the muscles their
contractility,
extensibility &
elasticity
Myofilaments
•Part of muscle fiber
•a compartment
formed from the
overlapping of
myofilaments in
specific patterns
• the basic unit of
contraction in
skeletal muscle
Sacromere
Parts of a Sarcomere
- Z lines
- Thick filaments
- Thin filaments
• part of a sacromere
• zigzagging lines
w/c are the end
boundaries of a
sarcomere
• separate one
sarcomere from
the other
Z lines
a contractile
protein w/c is
the main
component of
thick filaments.
shaped like two
golf clubs
twisted together
their heads bind
to the actin of
thin filaments to
contract muscle
myosin (thick filaments)
a spring-like
protein
molecule that
resists over-
stretching.
anchors the
thick filaments
to the Z lines
titin (thick filaments)
• part of a sacromere
• are also anchored
to the Z lines;
made of various
proteins
Thin filaments
• part of a thin filaments
• contractile
protein w/c is the
main component
of thin filaments
actin
•part of a thin filament
• protein strands
w/c cover the
myosin-binding
sites on actin in
a relaxed
muscle
tropomyosin
•part of a thin filament
•hold the
tropomyosin
strands in place &
are together
called, troponin-
tropomyosin
comple
•when bound to Ca++
ions, it changes
shape & moves
tropomyosin away
from myosin-
binding sites, to
contract muscle
troponin
Physiology of
Contraction &
Relaxation of
Skeletal
Muscle
Sliding Filament Mechanism
Types of Contraction
1.) Tonic
2.) Flaccid
3.) Spastic
4.) Isotonic
5.) Isometric
6.) Twitch
7.) Tetanic
