Ch 9 Test

Question 0

Perimysium

Answer 0

Bundles of muscle fibers are sheathed

Question 1

Epimysium

Answer 1

Entire muscle is covered by it

Question 2

Endomysium

Answer 2

Muscle fiber surrounded by endomysium

Question 3

Perimysium and endomysium

Answer 3

They both contain blood vessels and nerves that supply muscle fibers

Question 4

Skeletal muscle fibers features

Answer 4

Sarcolemma, sarcoplsm, and sr, transverse tubules and myofibrils aid in contraction

Question 5

Myofibrils

Answer 5

Contain myofilaments called thin filaments and thick filaments

Question 6

Thin filaments

Answer 6

Contain f-actin, nebulin, tropomyosin and troponin

Question 7

Thick filaments

Answer 7

Consists bundles of myosin molecules around a titin core, myosin molecule has a long tail and globular

Question 8

Excitation-contraction coupling

Answer 8

Action potential releases ACh in synaptic cleft, it diffuses to motor end, binding into receptors which opens sodium ion channels producing action potential in sarcolemma: start of muscle contraction

Question 9

Neuromuscular junction

Answer 9

Skeletal muscle fiber contracts when stimulated by a motor neuron at neuromuscular junction, a stimulus arrives in form of action potential. (Communication between nervous system and skeletal muscle fiber)

Question 10

Isotonic contractions

Answer 10

Tension in muscle roses and the length of muscle changes, two types concentric and eccentric

Question 11

Isometric contractions

Answer 11

Tension rises but the length of the muscle stays the same

Question 12

Creatin phosphate

Answer 12

Can release stored energy to convert adp to ATP

Question 13

Aerobic metabolism

Answer 13

Can provide most of the ATP needed to support muscle contractions, mitochondria absorb oxygen, adp, phosphate ions and organic substrates from cytoplasm, 17 ATP molecules

Question 14

Anaerobic metabolism

Answer 14

Muscle cell relies on it to generate ATP

Question 15

Lactic acid

Answer 15

The exhaustion of energy resources or other factors

Question 16

Skeletal muscles

Answer 16

Produce skeletal movement, maintain posture and body position, support soft tissues, guard entrances and exits, maintain body temperature, store nutrients

Question 17

Myosatellite cells

Answer 17

Stem cells that take part in repair damaged muscle tissue,

Question 18

Tendon, aponeurosis

Answer 18

Epimysium, perimysium, and endo come tog to form it

Question 19

Myoblasts

Answer 19

Fuse forming individual multinucleate skeletal muscle fibers, unfused cells remain in adult skeletal muscle tissue

Question 20

Myofibrils

Answer 20

Shorten and are responsible for skeletal muscle fiber contraction, consist of myofilaments which are bundles of proteins

Question 21

Sarcoplasmic reticulum

Answer 21

Forms a tubular network around each myofibril

Question 22

The M line

Answer 22

Proteins of m line connect the central portion of each thick filament to neighboring thick filaments

Question 23

The H band

Answer 23

Lighter region on either side of m line

Question 24

The zone of overlap

Answer 24

Is a dark region where thin filaments are located between thick filaments

Question 25

Filamentous actin

Answer 25

Is a twisted strand composed of two rows of 300-400 individual globular molecules of g actin

Question 26

Nebulin

Answer 26

Extends along f actin in the cleft between the rows of g actin

Question 27

Active site

Answer 27

Can bind to myosin much as a substrate molecule binds to active site of enzyme

Question 28

Tropomyosin

Answer 28

Cover active site on g actin and prevent actin myosin interaction

Question 29

Cross bridges

Answer 29

Myosin heads interact with thin filaments during contraction

Question 30

Tension

Answer 30

When muscle cells contract they pull on the attached tendon and energy is needed to produce it

Question 31

Muscle fiber contraction

Answer 31

The interaction between thick and thin filaments result in fiber contraction and consumption of ATP

Question 32

Tension production

Answer 32

Filaments interaction produce active tensions

Question 33

Calcium

Answer 33

When it binds it changes the shape of troponin molecule and weakens the bond between troponin and actin, the contraction cycle begins

Question 34

Twitches

Answer 34

Single stimulus-contraction-relaxation sequence in a muscle fiber, they vary in durations depending on type of muscle, location internal and external environment

Question 35

Glycolysis

Answer 35

Breakdown of glucose to pyruvate, net gain of 2 ATP molecules and generates 2 pyruvate molecules, provide substrate for aerobic metabolism

Question 36

Muscle fatigue

Answer 36

Depletion of metabolic reserves within muscle fibers, damage to sarcolemma and sarcoplasmic reticulum, a decline in pH

Question 37

Skeletal muscle fibers

Answer 37

Fast fibers, slow fibers, intermediate fibers

Question 38

Cardiac muscle tissue

Answer 38

Found only at heart, cardiac muscle cells are relatively small, single central placed nucleus, t tubules short and broad, sr lacks terminal cristernae, dependent on aerobic metabolism for energy,

Question 39

Intercalated discs

Answer 39

The sarcolemmas of two adjacent cardiac muscle cells are intertwined and blind by gap junctions and desmosomes