5.3 Flashcards
(23 cards)
What must a muscle do to make a movement?
Cross a joint
What are the muscle attachment sites?
Original: muscle start that does not move
Insertion: uncle end that is pulled towards the origin
What are muscles functions?
Motion
Stabilising body position
Regulation of organ volumes
Support of soft tissue
Maintain body temp
Storage of nutrients
How are the compartment groups in a muscle coordinates in flexing the elbow?
Anterior compartment in contracting = agonist
Posterior compartment is relaxing = antagonist
What are the key characteristics of muscles?
Extensibility: stretch without damage
Elasticity: return to original shape
Contractility: shorten when stimulated
Excitability: respond to stimuli (action potential)
What are the three types of muscles?
Skeletal muscle (attaches to bone)
Cardiac muscle (forms the heart)
Smooth muscle (located within walls of hollow organs)
Describe skeletal muscle
- attaches to bone
Muscle appear “striated”
Multinucleated; cells on edge
Voluntary control
Describe the cardiac muscle
The muscle of the heart
Muscle appears “striated”
One, central nucleus
Involuntary control; autorhythmic
Describe smooth muscle
Atttched to hair follicles and walls of hollow organs
Non-striated
One, central nucleus Involuntary
Involuntary control
What are features of skeletal muscle?
- long, cylindrical multinucleated
- cannot divide
- Muscle cell membrane = sarcolemma
- Muscle cell cytoplasm = sarcoplasm
What is a fascicle?
When many muscle cells bundle together
What is endomysium?
A thin areolar connective tissue covering each muscle cell
What is perimysium?
A fibrous connective tissues covering each fascicle
What is the epimysium?
A fibrous connective tissue that covers the entire muscle
This is connected to the deep fascia (dense CT) and attaches to tendons
what are myofibril?
Hundred in the sacroplasm
Contains bundles of protein filaments that interlock (myofilaments, actin=thin and myosin=thick)
Contain repeating contractile units (sarcomeres)
What is myosin?
A thick filament that binds to actin (thin filament)
Actin slides inwards
What are features of cardiac muscles cells?
Striated , short, branched
Single centrally located nucleus
Individual cells connected by intercalated discs
Same arrangement of actin and myosin as skeletal muscle
Why is the cardiac muscle autorhythmic cells?
Contract without stimulation from nervous system
What are features of visceral smooth muscle tissue?
Multiple smooth muscles to form one muscle unit
Gap junctions allow unison contraction
Found in most blood vessels, walls of hollow organs
What are features of multi unit smooth muscle tissue?
Individual, independent smooth muscles cells have their own nerve endings
Contract independently
Found in airways, Arrector pili muscles, iris
What are features of skeletal muscle regeneration?
No division as 1st year
Growth via enlargement of existing cells
Repair: satellite cells can replace damaged cell, fibrosis if not enough (most common)
What are features of cardiac muscle regeneration?
Cannot divide or regenerate; healing via fibrosis (scar formation)
What are features of smooth muscle regeneration?
Regeneration is possible
Cells can grow in size (hypertrophy) or number (hyperplasia)
