muscular system anaphy Flashcards
Functions of Muscular System
- Movement
- Maintain posture
- Respiration
- Production of body heat
- Communication
- Heart beat
- Contraction of organs
and vessels
Types of Muscles
- Skeletal
- Cardiac
- Smooth
are muscle cell
Fibers
Abilities of Skeletal Muscles
- Contractility:
ability to shorten - Excitability:
respond to stimulus - Extensibility:
can stretch - Elasticity:
recoil
is cytoplasm
Sarcoplasm
- Contraction and shortening of muscles are due to the movement of
microfilaments
- Skeletal and smooth muscle cells are elongated (muscle cell =
muscle fiber
Skeletal Muscle Characteristics
- Makes up 40% of body weight
- Named because attached to bones (skeleton)
- Many nuclei per cell (near periphery)
- Striated
- Longest of muscle types
plasma membrane
Sarcolemma
endoplasmic reticulum of muscle
Sarcoplasmic reticulum
= contracting structures within a myofibrils; a section of the myofibrils
= joined end to end like train carriages, forms myofibril
=contain microfilaments that slide past
Sarcomeres
long thread-like proteins inside the muscle cell that make up muscle fibers
= contains many microfilaments
Myofibril
sheet or membrane around the cell.
Lemma
refers to flesh or muscle
Sarco
major component of a thin filaments
Actin
is a malignant tumor
Sarcoma
is a molecule that make up a thick micro filaments
Myosin
is a bundle of muscle fiber( cells)
Fascicle
connective tissue that surrounds
entire skeletal muscle (outside)
covers the entire skeletal muscle (protects the muscles from friction against other muscles and bones
- Epimysium
connective tissue around each muscle fasciculus
- Perimysium:
- skeletal muscle cells
Muscle fiber
bundle of muscle fibers
- Muscle fasciculus
thread-like proteins that make up muscle fibers
* long organelles inside muscle cell (cylindrical organelles)
- Myofibril:
connective tissue that surrounds each muscle fiber
- Endomysium
cell membrane
- contains T-tubules
- specialized plasma membrane
Sarcolemma
it is a muscle fiber membrane that contains nuclei which are pushed aside by long ribbon like
organelles called
myofibrils
give the muscle its striated (banded) appearance
Light (I) bands and dark (A)
- proteins that make up myofibrils
- Myofilament
- Thick filaments =
- Thin filaments =
Thick filaments = myosin filaments
Thin filaments = actin filaments
- contractile unit
- contains actin and myosin
- Sarcomere:
contractile unit of a muscle fiber
- Sarcomere
– Myofilaments produce banding (striped) pattern
- Organization of the sarcomere
– Composed of the protein myosin
– Contain ATPase enzymes to split ATP to release energy for muscle contractions
- Thick filaments
– Thick filaments Possess projections known as
myosin heads
are known as cross bridges when they link thick and thin filaments during contraction
– Myosin heads
– Myosin heads are known as
cross bridges
– Composed of the contractile protein actin
– Actin is anchored to the Z disc
- Thin filaments
- At rest, within the A band there is a zone that lacks actin filaments called the
the H zone
- thin myofilament
- resemble 2 strands of pearls
- Actin:
- thick myofilament
- resemble golf clubs
Myosin
- wrap around sarcomeres at A band
- associated with sarcoplasmic reticulum
-transports
- T-tubules (transverse)
- type of SER
- surrounds myofibril, myosin
- stores and releases Ca2+
- Sarcoplasmic reticulum
protein fibers that form attachment site for actin
- Z disk
- center of sarcomere
- contains only myosin
- H zone:
contains only actin
- I band
where actin and myosin overlap
- A band:
where myosin are anchored
- M line:
- cell membrane
- contains T-tubules
Sarcolemma
cytoplasm of muscle fiber (cell)
- Sarcoplasm:
- filament on grooves of actin
- attachment site on actin for myosin
- Tropomyosin:
attachment site on actin for Ca2+
Troponin
These are the long, thread-like structures that run the length of the muscle fiber and are responsible for contraction.
Myofibrils:
The basic contractile unit of muscle fibers, made up of actin (thin filaments) and myosin (thick filaments) proteins
Sarcomere
- Why is the inside of cell negative if K+ is positive?
K+ is able to diffuse out of cell freely but other larger negative molecules cannot.