Intro to muscles (general myology)

Question 1

What are the 4 characteristics of muscle cells?

Answer 1

1. Irritability (“Electrical Excitability”)
2. Contractility
3. Extensibility
4. Elasticity

Question 2

What are the 3 types of muscle tissue (describe each)

Answer 2

1. Skeletal: striated, voluntary
2. Smooth: non-striated, involuntary, visceral
3. Cardiac: striated, specialized, involuntary

Question 3

What is muscle fascia?

Answer 3

• Dense irregular connective tissue
• completely surrounds muscle
• skeletal muscle found deep to it

Question 4

What are the extensions of the muscle fascia called?

Answer 4

Epimysium

Question 5

Muscle fiber =

Answer 5

Muscle cell

Question 6

Each muscle fiber is covered by:

Answer 6

endomysium

Question 7

Bundles of muscle fibers are called:

Answer 7

Fascicles

Question 8

Each fascicle is covered by

Answer 8

Perimysium

Question 9

Whole muscle is made up of:

Answer 9

a group of fascicles

Question 10

Whole muscle is covered by:

Answer 10

epimysium

Question 11

Each muscle fiber is made up of bundles of:

Answer 11

myofibrils

Question 12

Each myofibril is covered by:

Answer 12

sarcoplasmic reticulum

Question 13

Deep to endomysium, muscle fiber is covered by:

Answer 13

sarcolemma

Question 14

Each myofibril is made up of:

Answer 14

Myofilaments (proteins)

Question 15

Within each sarcomere, each myofibril has:

Answer 15

3000 actin (thin) myofilaments
1500 myosin (thick) myofilaments

Question 16

During contraction of muscle what happens to actin and myosin?

Answer 16

They overlap!

Question 17

What is a sarcomere?

Answer 17

The microfunctional unit of a muscle

Question 18

Describe a sarcomere

Answer 18

• Cross striations
• Dark (A) Bands: Actin+myosin
• Light (I) Bands: Actin ONLY
• middle: H zone + M Line (protein bands)
• Ends: Z discs
• Cross bridges (50 pairs)
• Surrounded by SR
• (Transverse) T-tubules: allow APs to spread quickly throughout muscle

Question 19

Motor Unit =

Answer 19

Gross Functional Unit of the muscle (motor neuron + muscle fiber)

Question 20

Motor unit is found at the:

Answer 20

myoneural junction

Question 21

skeletal muscle contraction principle:

Answer 21

all or none

Question 22

smooth muscle contraction principle

Answer 22

peristalsis

Question 23

Neuromuscular Junction (NMJ):

Answer 23

Synaptic end bulb + motor end plate

Question 24

Muscle Fiber Shapes:

Answer 24

• Longitudinal (Parallel): rectus abdominis
• Fusiform: Biceps
• Unipennate: flexor pollicis longus
• Bipennate: triceps
• Multipennate: deltoid
• Circular: around mouth, eyes
• Radiate (Triangular/Convergent): pec major

Question 25

How do you name a muscle?

Answer 25

- Action - Direction of fibers - Location - Size - # origins - Shape - origin/insertion

Question 26

Origin:

Answer 26

Proximal end (red)

Question 27

Insertion:

Answer 27

Distal end

Question 28

Belly (Head):

Answer 28

Fleshy or meaty part

Question 29

Aponeurosis:

Answer 29

Broad, flat, tendon

Question 30

Agonist:

Answer 30

Prime mover, Main action muscle

Question 31

Antagonist:

Answer 31

Opposing muscle

Question 32

Synergist:

Answer 32

helps action of agonist

Question 33

Synergist (Fixator):

Answer 33

Stabilizes to help agonistA

Question 34

Atrophy:

Answer 34

Decrease muscle size due to inactivity

Question 35

Hypertrophy:

Answer 35

Increase muscle due to activity

Question 36

Describe tendons.

Answer 36

- Extensions of muscle belly - Epimysium, perimysium and endomysium - Dense, regular connective tissue - Parallel bundles of collagenous fibers - attaches muscle to bone (at periosteum) - may/may not have synovial sheath

Question 37

Describe ligaments.

Answer 37

- attach bone to bone - dense regular (or irregular) connective tissue - mostly parallel collagenous fibers (some elastic) - attaches to bone's periosteum - important for jnt stability - jnt (fibrous) capsules: strength/stability - certain lvl of flexibility for mvmt

Question 38

What is isometric exercise?

Answer 38

- no jnt or functional mvmt (pulling an object attached to the ground)

Question 39

What is an isotonic exercise?

Answer 39

- fixed resistance, variable speeds (progressive resistive exercise: PRE) (at the gym, bicep curls)

Question 40

What is an isokinetic exercise?

Answer 40

- constant speed (degrees/sec) + accomodating resistance (max load at each point of jnt's ROM)

Question 41

What are the 2 types of contraction?

Answer 41

Concentric: muscle shortens Eccentric: muscle lengthens

Question 42

Muscle spindle function:

Answer 42

stretch + speed of stretch (in muscle belly)

Question 43

Golgi tendon organs function:

Answer 43

Tension