Muscles Part 2 Fitz

Question 1

Isotonic twitch contractions

Answer 1

Generate force by changing the length of the muscle.

Question 2

Tension differences are based on

Answer 2

The recruitment of more muscle fibers (more sarcomeres). With each sarcomere recruited, tension is increased.

Question 3

Unfused tetanus

Answer 3

Spastic muscle movement. Action potentials causing a lot of contractions. Ex: working out in reps. Taking breaks.

Question 4

Fused tetanus

Answer 4

Fully contracted muscle and stays contracted. This is what happens when a muscle cramps.

Why we get tetanus shots.

Question 5

Optimal length of a fiber

Answer 5

The length at which the fiber develops the greatest isometric active tension.

Question 6

Passive vs active tension

Answer 6

Passive (elastic) is due to titan elastic filament. Can be stretched and springs back into place.As you stretch it, passive tension increases.

Active tension of a muscle fibers develops during contraction and can be altered by changing the muscle length. As you stretch it, it reaches isometric, then decreases in tension due to too much overlap.

Question 7

Fatigue resistant fibers vs fatigue prone

Answer 7

Fatigue resistant- oxidative fibers

Fatigue prone- glycolytic.

Question 8

Three ways a muscle fiber can form ATP

Answer 8

1. Create ATP from creatine phosphate (reserve ATP source)
2. Oxidative phosphorylation of ADP in mitochondria
3. Substrate level phosphorylation of ADP in the cytosol via glycolysis

Question 9

Fast twitch fibers

Answer 9

Rapid contraction but short lived. Extra ocular muscles.

Question 10

Slow twitch fibers

Answer 10

Very slow to reach max tension, but doesn’t fatigue as quickly.

Question 11

Diameters to determine slow oxidative, fast oxidative and fast glycolytic

Answer 11

Slow oxidative- small and dark
Fast oxidative- medium size and lighter
Fast glycolytic- largest and lightest

Larger diameter= faster signal

Question 12

Rates of fatigue for slow oxidative, fast oxidative and fast glycolytic

Answer 12

Rates of fatigue from fastest fatigue to slowest fatigue
Fastest- fast glycolytic
Fast oxidative
Slowest- Slow glycolytic

Question 13

What gives oxidative fibers its red color

Answer 13

Myoglobin, which is only seen in lives muscles. Due to a higher need for blood supply.

Question 14

4 parts of twitch contraction

Answer 14

1. Latent period (2m sec when ca2+ is being released froM SR)
2. Contraction period. Filaments slide past each other.
3. Relaxation period. Active transport of Ca2+ back in SR
4. Refractory period. Muscles cannot respond until it can reset.

Question 15

Isotonic contraction

Answer 15

A load is moved by changing the length of a muscle.

Question 16

Two types of isotonic contraction

Answer 16

Concentric- a muscle shortens to produce force and movement. Lifting book towards chest.

Eccentric- a muscle lengthens while maintaining force and movement. Lowering book towards legs with arms extended.

Question 17

Isometric

Answer 17

No movement occurs. Tension is generated without muscle shortening. Holding a book out straight. Arms not bent.

Question 18

Myogram measures

Answer 18

Muscle fibers

Question 19

Summation

Answer 19

When a new contraction occurs before the muscle had fully relaxed, tension will add which is called summation.

Question 20

Sensory feedback from the muscle is by

Answer 20

Muscle spindles (Activated by stretch) and golgi tendon organ (activated by tension)

Question 21

A muscle spindle consists of ___

Answer 21

of a collection of specialized fibers that lie within a connective tissue capsule.

Question 22

The muscle spindle is innervated by

Answer 22

Its own gamma motor neuron and is supplied by 2 afferent sensory terminals- primary and secondary. Both are activated by stretch.

Question 23

The golgi tendon organ

Answer 23

Monitors change in muscle tension.

Located where muscle attaches to bone.

Question 24

Patellar tendon reflex (stretch reflex)

Answer 24

Tapping on the tendon causes extension response from the golgi tendon and muscle spindles.

Question 25

Atrophy

Answer 25

Happens primarily from not using a msuscle.

Question 26

Which virus destroys motor neurons

Answer 26

Polio

Question 27

ALS

Answer 27

Excitotixic disease- too much calcium in the cytoplasm results in the cell killing itself. In ALS, the neurons that have paravalbumin die last. Makes sense since paravalbumin is a calcium regulator.

Stephen hawking

Question 28

Muscular dystrophy is more present in males or females

Answer 28

Males.

Question 29

Muscular dystrophy is a disorder in which

Answer 29

Costamers (which hold the myofibrils to the sarcomere) rip and no longer support the muscle. Death usually occurs because the diaphragm can’t contract.

Question 30

Dystrophin

Answer 30

A type of costumer, which is a protein that holds the myofibrils to the sarcomere.

Question 31

Myasthenia graves

Answer 31

Body attacks ach receptors in muscles. Patient has diplopia- should use neostigmine to increase muscle contractions.

Question 32

Muscular sclerosis is related to which polyneuropathy syndrome?

Answer 32

Guillaian barre- body attacks nerves. weakness and tingly.

Question 33

Myofibrils of smooth muscles interact with ___, instead of Z, M lines

Answer 33

Dense bodies.

Question 34

Is there a solid NMJ in smooth muscle

Answer 34

No

Question 35

Receptors on smooth muscles

Answer 35

Variscocities. Little beads. Chemicals from nervous system can bind anywhere on the varicosities.

They are attached to the axon of the postganglionic autonomic neuron.

Question 36

In smooth muscle, calcium binds to ___

In skeletal muscle, calcium binds to ___

Answer 36

Calmodulin

Troponin

Question 37

What type of cell communication occurs in smooth muscle

Answer 37

Gap junctions/connexons. Wave of contractions. Systolic Ca2+ from extracellular fluid stimulates the smooth muscles.

Question 38

Gap junctions are found in which two muscles

Answer 38

Cardiac and smooth

Question 39

action potentials in cardiac muscles have a long plateau period due to which channel

Answer 39

The L calcium channel