Myology

Question 1

What kind of cell is a skeletal cell

Answer 1

Multinucleated

Question 2

Name the 3 types of muscles

Answer 2

Skeletal, cardiac, smooth

Question 3

Name the 3 types of connective tissue of skeletal muscle

Answer 3

Epimysium, perimysium, and endomysium

Question 4

What kind of muscle is a skeletal muscle (2)

Answer 4

Striated and voluntary

Question 5

What are the two types of filaments for muscle contraction

Answer 5

Thin (actin) filament, thick (myosin) filament

Question 6

What 3 important roles do skeletal muscles play other then movement

Answer 6

Maintains posture, stabalizes joints, generates heat

Question 7

Where is smooth muscle found

Answer 7

Hollow organs

Question 8

Why does the skeletal muscle generate heat

Answer 8

ATP is used to power muscle contractions, 3/4 of its energy escapes as heat

Question 9

What starts the muscle contraction

Answer 9

Calcium

Question 10

What is used to attach the myosin head to the actin creating a cross bridge

Answer 10

ATP

Question 11

What stores the calcium for release for muscle contraction

Answer 11

Sarcoplasmic reticulum which looks like a crochet sweater over the muscle

Question 12

What is a motor unit

Answer 12

A neuron and all the skeletal muscles it stimulates

Question 13

The thick filaments contains what?

Answer 13

the protein myosin and ATP enzymes which split ATP to generate power for muscle contraction

Question 14

the thin filament contains what?

Answer 14

The protein actin and some regulatory proteins

Question 15

What special functional properties allow muscle cells to perform their duty

Answer 15

Irritability: ability to receive and respond to stimulus
Contractility: ability to shorten (forcibly) when an adequate stimulus is received

Question 16

Explain the structure of a nerve going to a muscle cell

Answer 16

Neurons cell body contains a nucleus, and a cell body with dendrites. The axon is what goes to the muscle, covered by a myelin sheath. Axon seperates and goes to the muscle with several axon terminals which form junctions with the sarcolemma called neuromuscular junctions. Nerve endings to not touch muscle but creates gap called the synaptic cleft which is filled with interstitial fluid

Question 17

Explain the steps to make a muscle contract

Answer 17

Neurotransmitter is released called acetylcholine which diffuses across the synaptic cleft and attaches to receptors which is part of sarcolemma. If enough acetylcholine is released, the sarcolemma becomes temporarily permeable allowing and exchange of Sodium ions which rush into the muscle cell. this rush of sodium that upsets the sarcolemma will cause and electrical current called action potential which once started, can’t be stopped and the muscle contracts.

Question 18

Explain Direct phosphorylation of ATP by Creatine Phosphate (CP)

Answer 18

As ATP is being depleted, to make more, CP(which is found only in muscle fibers no other cell types) interacts with with ADP resulting in transfer of high-energy phosphate group from CP and ADP, thus regenerating more ATP.

Question 19

Explain Aerobic respiration to help regenerate ATP

Answer 19

During aerobic respiration, glucose is broken down completely to carbon dioxide and water (exhaling and sweat), and some of the energy released as the bonds ar broken is captured in the bonds of ATP molecules. May provide large ATP harvest, it’s fairly slow and requires continuous delivery of oxygen and nutrient to fuel muscle to keep it going.

Question 20

Explain Anaerobic glycolysis and lactic acid formation

Answer 20

The initial steps of glucose breakdown starts with glycolysis which doesn’t use oxygen. In glycolysis, glucose is broken down to pyruvic acid, and small amounts of energy is captured in ATP Bonds (2ATP per 1 glucose molecule). As long as enough oxygen is present, the pyruvic acid moves to the oxygen-requiring pathways that occur within mitochondira to produce more ATP as described above. During an intense workout, oxygen and glucose delivery is temporarily inadequate. In these circumstances, pyruvic acid made during glycolysis, is converted to lactic acid

Question 21

What is the main shortcoming of Anaerobic glycolysis

Answer 21

Uses huge amount of glucose for small ATP harvest, and accumulation of lactic acid promotes muscle fatigue nd muscle soreness

Question 22

Signs of dehydration in horses

Answer 22

Sweating to much, head drooping, pull skin and it takes time to come back: horse is hypersensitive-takes 3 days to rehydrate: muscle will feel like bubble wrap

Question 23

True or False: True muscle fatigue happens often. Explain

Answer 23

False, true muscle fatigue rarely happens because we fatigue long before the muscle is no longer able to be stimulated so we slow down or stop our activity long before.

Question 24

What happens during muscle fatigue

Answer 24

Muscle starts contracting weaker each time it’s being stimulated until if finally stops reacting at all (true muscle fatigue)

Question 25

What is the main cause of muscle fatigue

Answer 25

Oxygen debt. When muscles no longer are getting enough oxygen they need to work, lactic acid begins to accumulate (via anaerobic mechianism) and muscle starts running low on ATP and creatine stores causing muscle to eventually stop contracting. Oxygen must be payed back so when done and breathing deeply, muscles will take the amount of oxygen it needs to clear lactic acid, restore creatine phosphate and atp stores.

Question 26

Name the three types of muscle contractions and explain

Answer 26

Isotonic contractions (same tone or tension): myofilaments  are successful in sliding movements. Bending knee, rotating arm, smiling.
Isometric contractions (same measurement or length) myosin myofilaments are skidding their wheels. tension in muscle keep increasing, trying to slide but muscle is pitted against some more or less immovable object: straighten a bent elbow, when you push against a wall with bent elbows
Muscle Tone: Cannoto b consciously controlled, some fibers in a relaxed muscle are contracting. contraction not visible but muscle remains firm, healthy and constantly ready for action

Question 27

What is a prime mover

Answer 27

The muscle that has the major responsibility for causing a particular movement.

Question 28

What is an antagonist

Answer 28

Muscles that oppose or reverse a movement

Question 29

Explain how prime mover and antagonist work together

Answer 29

When the prime mover is active, the antagonist is stretched and relaxed and vice versa

Question 30

What is a synergist and how does it work

Answer 30

Synergists help prime movers by producing the same movement or by reducing undesirable or unnecessary movement. When a muscle crosses two or more joints, its contraction will cause movement in all the joints crossed unless synergists are there to stabilize them.

Question 31

What is a fixator and what does it do

Answer 31

Fixator is a specialized synergist. They hold a bone still or stabilize the origin of a prime mover so all the tension can be used to move the insertion bone

Question 32

What are the connective tissue coverings and what do they do

Answer 32

Myelin sheath, sarcolemma reticulum

They are important for support and storage of nutrients for contractive response