Skeletal Muscle Cells

Question 1

Sarcolemma

Answer 1

Cell membrane of a muscle fiber cell.

Question 2

Myofibrils

Answer 2

Long organelles that nearly fill the cytoplasm of a muscle cell.

Question 3

Sarcomeres

Answer 3

Chains of tiny contractile units that make up Myofibrils.

Question 4

Myofilaments

Answer 4

Produce the light (I) and dark (A) bending pattern.

Question 5

Thick/Myosin Filaments

Answer 5

Split ATP to generate muscle contraction.

Question 6

Myosin Heads

Answer 6

Part of thick filaments, they link the thick and thin filaments together during contraction.

Question 7

Thin/Actin filaments

Answer 7

Composed of the contractile protein actin and are anchored to the Z line.

Question 8

Sarcoplasmic reticulum

Answer 8

Stores calcium and releases it when the muscle fibre is stimulated to contract.

Question 9

Muscle Cell Irritability

Answer 9

The ability to receive and respond to stimulus.

Question 10

Muscle Cell Contractility

Answer 10

The ability to shorten when adequate stimulus is received.

Question 11

True or false:

Skeletal muscle cells must be stimulated by nerve impulses to contract

Answer 11

True

Question 12

Motor unit

Answer 12

One neutron and all the skeletal muscle cells that it stimulates.

Question 13

Nerve fibre/Axon

Answer 13

Long extension of a Neuron.

Question 14

Axonal terminals

Answer 14

Firms connections with the Sarcolemma of a different muscle cell. (Neuromuscular Junctions.)

Question 15

Synaptic cleft

Answer 15

The gap between the nerve endings and muscle cell membranes. Filled with interstitial fluid.

Question 16

Acetylcholine

Answer 16

The neurotransmitter that stimulates skeletal muscle cells.

Question 17

Action potential

Answer 17

Acetylcholine is released, the Sarcolemma allows entry of sodium ions. This gives the cell a sudden rush of positive ions causing a change to the electrical conditions - resulting in muscle contraction.

Question 18

The sliding filament theory

What causes filaments to slide?

Answer 18

Energized by ATP, Cross bridges attach to myosin binding sites on the thin filaments and sliding begins.

Question 19

True or false:

A skeletal cell is multinucleated

Answer 19

True

Question 20

What are 2 ways graded muscle contractions are produced?

Answer 20

1. By changing the speed of muscle stimulation.

2. By changing the amount of muscle cells being stimulated.

Question 21

Tetanic contraction

Answer 21

Muscle contractions are completely smooth and sustained.

Question 22

What are the 3 pathways for ATP regeneration?

Answer 22

1. Creatine phosphate
2. Aerobic respiration
3. Anaerobic glycolysis and lactic acid formation

Question 23

Creatine phosphate

Answer 23

High energy molecule found in muscle fibres, regenerates ATP.

Question 24

Aerobic respiration

Answer 24

ATP is regenerated by metabolic pathways that use oxygen. Produces CO2 and H2O.

Question 25

Anaerobic glycolysis and lactic acid formation

Answer 25

Anaerobic = Without oxygen. Glycolysis glucose is broken down to pyruvic acid, small amounts of energy are captured in ATP bonds. When muscle activity is too intense or there is not enough oxygen/glucose, pyruvic acid is converted to lactic acid.

Question 26

How many days does it take for a horse to recover from muscle fatigue?

Answer 26

3

Question 27

Muscle fatigue

Answer 27

A muscle us unable to contract even though it is still being stimulated.

Question 28

What are the types of muscle contractions?

Answer 28

Isotonic | Isometric

Question 29

Isotonic

Answer 29

The muscle shortens and movement occurs. Ex. Bending the knee and smiling.

Question 30

Isometric

Answer 30

No movement, muscle does not shorten.

Question 31

Every skeletal muscle is attached to at least 2 points, what are they?

Answer 31

Origin | Insertion

Question 32

Origin

Answer 32

Attached to the immovable bone (like the anchor).

Question 33

Insertion

Answer 33

Attached to the moveable bone, when muscle contracts the insertion moves toward the origin.

Question 34

Prime mover muscle

Answer 34

The muscle that has the most responsibility when several muscles are contracting.

Question 35

Antagonist muscle

Answer 35

Muscles that oppose or reverse movement.

Question 36

Synergist muscle

Answer 36

Help prime movers by producing same movement or reducing unnecessary movement.

Question 37

Fixator muscles

Answer 37

Hold bone still or stabilize the origin of a prime mover.