1B.3 MUSCLE BASICS Flashcards
What are the 3 types of muscle
Skeletal
Cardiac
Smooth
What muscle type is found in skeletal muscles, striated (myosin + actin), voluntary control, multi-nucleated?
Skeletal
What type of muscle cell is found in the heart, striated, has involuntary control (autorhythmicity) and has a single nucleus
Cardiac
what type of muscle cell is found in the viscera + blood vessels+ skin, not striated, involuntary control, and has a single nucleus?
Smooth
What are the 4 functions of muscle tissue (hint: PSPS)
- Produce body movements
- attached to bone via tendons - Stabilizing body positions
- Producing heat (thermogenesis)
- Storing + moving substances in the body
- Sphincters, peristalsis, blood vessel tone
What are the 4 properties of muscle tissue (Hint: ECEC)
- Electrical Excitability
- able to respond to stimuli
> Electrical signals = autorhythmicity in the heart
> chemical signals = action potentials signals received at neuromuscular cleft - Contractility
- attached to bone via tendons, Cells physically contract to generate force - Elasticity
- returns to original length after contraction extension - Extensibility
- can stretch within limits, without being damaged
-Greatest in smooth muscle (food in stomach) & heart (blood in chambers)
Muscle organization (Hint: PTEFPEM)
-Periosteum (lines bone)
-Tendon
-Epimysium (encases muscle)
-Fascicle (bundle of myofibres)
-Perimysium (encases fascicle)
-Endomysium (covers myofibre)
-Myofibre (muscle cell)
Organization of Myofibre (Hint: EMMT)
-Endomysium
-Myofibre
-Myofibril (repeating units of saromeres)
-Thick and thin filaments
What are the 3 types of skeletal fiber types
TYPE 1: slow oxidative
TYPE 2A: Fast oxidative-glycolytic
TYPE 2B: Fast Glycolytic
ALL MUSCLES CONTAIIN A COMBINATION OF ALL FIBER TYPES BUT THEIR PROPORTIONS VARY
CAN TRAIN SPECIFIC FIBER TYPES
What are the 5 stages of the sliding filament theory
- Bound State
- Power Stroke
- Rigor State
- Relaxed Sate
- Binding State
What do ATP and Calcium do in muscle contraction
ATP:
-Necessary for myosin to bind to actin and for power stroke
Calcium:
-Binding sites on actin are usually covered by tropomyosin
- When calcium binds to the troponin complex, tropmyosin rolls away
-Contraction can occur
Strain: Tendon/muscle injury TRIATS
Grading
G1 = overstretching
G2 = Partial Tear
G3 = Complete Tear
Symptoms:
- Swelling/bruising or redness
- pain at rest
- inability to use muscle, or weakness
First Aid: Protection, Rest, Ice, Compression, Elevation (PRICE)
How does Aging affect the muscle?
Progressive muscle loss (age 30 onwards)
Muscle mass is replaced by fibrous connective tissue + adipose
Causes:
- Decreased voluntary neural control of muscle (motor neuron loss + decreased sensory feedback)
- Slower nerve conduction speed
- Muscle fibre loss (particularly type 2 = more oxidative metabolism, less force)
OVERALL: LESS POWER & STRENGTH
What does exercise do for the muscle?
- effective to improve muscle mass at any age
- Aerobic + Strength - based activates are effective at both slowing, and even reversing age - related muscular decline
- Benefits:
> Increased Bone Density
> Increased Motor Neuron Firing Rate
> Hypertrophy of muscle fibers