1B.3 MUSCLE BASICS

Question 1

What are the 3 types of muscle

Answer 1

Skeletal
Cardiac
Smooth

Question 2

What muscle type is found in skeletal muscles, striated (myosin + actin), voluntary control, multi-nucleated?

Answer 2

Skeletal

Question 3

What type of muscle cell is found in the heart, striated, has involuntary control (autorhythmicity) and has a single nucleus

Answer 3

Cardiac

Question 4

what type of muscle cell is found in the viscera + blood vessels+ skin, not striated, involuntary control, and has a single nucleus?

Answer 4

Smooth

Question 5

What are the 4 functions of muscle tissue (hint: PSPS)

Answer 5

1. Produce body movements
   - attached to bone via tendons
2. Stabilizing body positions
3. Producing heat (thermogenesis)
4. Storing + moving substances in the body
   - Sphincters, peristalsis, blood vessel tone

Question 6

What are the 4 properties of muscle tissue (Hint: ECEC)

Answer 6

1. Electrical Excitability
   - able to respond to stimuli
   > Electrical signals = autorhythmicity in the heart
   > chemical signals = action potentials signals received at neuromuscular cleft
2. Contractility
   - attached to bone via tendons, Cells physically contract to generate force
3. Elasticity
   - returns to original length after contraction extension
4. Extensibility
   - can stretch within limits, without being damaged
   -Greatest in smooth muscle (food in stomach) & heart (blood in chambers)

Question 7

Muscle organization (Hint: PTEFPEM)

Answer 7

-Periosteum (lines bone)
-Tendon
-Epimysium (encases muscle)
-Fascicle (bundle of myofibres)
-Perimysium (encases fascicle)
-Endomysium (covers myofibre)
-Myofibre (muscle cell)

Question 8

Organization of Myofibre (Hint: EMMT)

Answer 8

-Endomysium
-Myofibre
-Myofibril (repeating units of saromeres)
-Thick and thin filaments

Question 9

What are the 3 types of skeletal fiber types

Answer 9

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

Question 10

What are the 5 stages of the sliding filament theory

Answer 10

1. Bound State
2. Power Stroke
3. Rigor State
4. Relaxed Sate
5. Binding State

Question 11

What do ATP and Calcium do in muscle contraction

Answer 11

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

Question 12

Strain: Tendon/muscle injury TRIATS

Answer 12

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)

Question 13

How does Aging affect the muscle?

Answer 13

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

Question 14

What does exercise do for the muscle?

Answer 14

• 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