Chapter 10 Flashcards
3 types of Muscles
- Skeletal - allows movement
- Cardiac - contracts heart
- Smooth - covers organs and passageways
Skeletal muscle functions
- produces movement of skeleton as muscles pull tendons
- maintains posture
- support soft tissue
- maintain body temp
- guards entrances and exits
Epimysium
- surrounds entire muscle
Perimysium
- surrounds each compartment called fascicle
- contains bundle of muscle fiber (pepperoni)
Endomysium
- surrounds individual muscle cells and interconnection adjacent muscle fibers
- between endomysium and muscle fibers
Sarcoplasmic reticulum
- stores and transfers calcium ions
tendon
- end of a muscle, collagen fibers of the epimysium, perimysium, and endomysium come together to form bundle called a tendon
Each muscle has two attachment sites
- origin- point of attachment to muscle to bone NON- MOVEABLE
- insertion- point of attachment to muscle to bone MOVEABLE
Skeletal muscle characteristics
- long
- embryonic stage- myoblasts form together to form single muscle fiber
- every nuclei in a muscle fiber represents a myoblast
- myoblast that do not fuse together differentiate into satellite cell
14 test questions
Skeletal muscle is surrounded by epimysium, containg muscle fascicles which are surrounded by perimysium that contains muscle fibers, that are surrounded by endomysium with calcium that contains myofibrils and those are surrounded by sarcoplasmic reticulum consisting of sarcomeres which contain thin and thick filaments
Sarcolemma
the cell membrane of the muscle fiber/cell that surrounds the sarcoplasm
Sarcoplasm
- cytoplasm of muscle cell/fibers (unequal charge across membrane)
- contains large amount of stored glycogen and myoglobin
Tendon
- connect muscle to bone
transverse tubules
- t- tubules
- passageways that carry electrical impulses from the sarcolemma into cell sarcoplasm
T- tubules surround what?
- myofibrils
Microfibrils
- responsible for skeletal muscle fiber contraction
Thin Filaments
- composed primarily of protein ACTIN
- composed of G-actin molecules, nebulin, in spiral pattern
- 3 tinged protein- Troponin holds Tropomyosin that cover Active sites
- every 7 pattern
Thick Filament
- composed primarily of protein myosin
- M-line - body of myosin
Sarcoplasmic Reticulum (SR)
- forms network around each myofibril
- muscles contract when stored calcium is released into cytosol
Sarcomeres
- smallest functional unit of muscle fiber cellular proteins of sarcomeres
- 
Titan
- proteins that stabilize thick and thin filaments
H zone
- contain only thick filaments
Zone of overlap
- where thick and thin filaments overlap
Calcium
- responsible for every muscle contracting
components of sarcomeres
- Z line marks ends of sarcomeres
- Z line consists protein called actin
- gives skeletal muscle striated look
Big step 1
- generate electricity (send down neuron)
Big step 2
- getting electricity to jump neuron to muscle fiber
Big step 3
- electricity to travel down muscle fiber (length And depth)
Big step 4
- getting muscle to contract
when contraction occurs the following happens
- H zones and I bands get smaller
- zones/areas overlap increases
- z lines move closer together
- width of A bands remain consistent
Area where necessary and muscles meet
neuromuscular junction
ACH
neurotransmitter
fascicle
- largest structural unit
Cross bridge
myosin grabs the actin when active site is exposed
Contraction cycle
step 1- expose of active site
step 2- formation of cross bridge
step 3- pivoting
step 4- detachment of across bridge
step 5- reactivation if myosin
Relaxed cycle
- ACH is broken down/destroyed by ACHE
- action potential stops
- SR reabsorbs the calcium
- troponin and tropomysion return to normal
- cross bridge broken
- contraction ends and muscles relax
3 ways muscle go back to original length
- gravity
- contraction of opposite muscle
- elastic nature of epimysium, endomysium, and perimysium
The amount of tension depends on..?
- frequency of simulation
- number of muscle fibers stimulated
Motor unit
- all the muscle fibers are controlled by single motor neuron
Size of motor unit
- how many fibers under control
wave simulation
- summation until maximum tension
Isotonic
- tension constant, there is movement
Isometric
- when muscle length does not change and tension does not exceed the resistance
Aerobic
- occurs in mitochondria
- provides 95% energy
- requires oxygen
Anaerobic
- occurs in cytoplasm
- does Not need oxygen
- provides < 5% energy
Myoglobin
Protein that transports and holds oxygen in muscle
Hypertrophy
When muscles are used when they become larger
Atrophy
When muscles are not used they become smaller
Four muscle types based on faciles form
- Parallel muscles
- Convergent muscles
- Pennate muscles
- Circular
Parallel Muscles
- parallel to long axis of muscle
- muscle contracts and becomes smaller and thicker
