Muscles

Question 1

Functions of Muscular System

Answer 1

produce movement
maintain posture
generate heat
stabilize joints

Question 2

Three Types of Muscle Tissue

Answer 2

Skeletal/Voluntary/Striated
Smooth/Involuntary/Non-striated
Cardiac

Question 3

muscles attached to the skeletal system and constitutes approx. 40% of body weight

Answer 3

Skeletal Muscle

Question 4

arranged in 2 layers, one running circularly and the other longitudinally

Answer 4

Smooth Muscle

Question 5

found only in the heart

Answer 5

Cardiac

Question 6

Chemical Composition of Muscle Tissues

Answer 6

70% water
20% protein
5% carbohydrate, lipid, inorganic salts

Question 7

Connective Tissue Sheathes Which Surround the Skeletal Muscles

Answer 7

Epimysium
Perimysium
Endomysium

Question 8

tougher coat of connective tissue that bound many fascicle

Answer 8

Epimysium (fascia)

Question 9

coarser fibrous membrane that covers bundle of fibers called fascicles

Answer 9

Perimysium

Question 10

bundle of muscle fibers

Answer 10

fascicle

Question 11

a delicate loose connective tissue that surrounds each muscle fiber

Answer 11

Endomysium

Question 12

• cytoplasm of each muscle cell

- contains numerous myofibrils

Answer 12

Sarcoplasm

Question 13

• a threadlike structure that extends from one end of the muscle fiber to the other
• consists of myofilaments (proteins) myosin and actin

Answer 13

Myofibrils

Question 14

• comprises the larger thick filaments that are made mostly of bundled molecules of the protein myosin
• resemble like minute golf clubs
• extends the entire length of a dark A band and the mid parts of the filaments are smooth but their ends are studded with small projections

Answer 14

Myosin filaments

Question 15

• part that attaches to exposed sites on the actin and - —– known as cross bridge when they link the thick and thin filaments together during contraction

Answer 15

myosin heads

Question 16

myosin heads when they link the thick and thin filaments together during contraction

Answer 16

cross bridge

Question 17

comprises the tin filaments/myofilaments which resemble 2 minute strands of pearls twisted together
anchored to the Z disc (disc-like membrane)

Answer 17

Actin filaments

Question 18

calcium-binding sites attached at specific intervals along actin filaments

Answer 18

Troponin

Question 19

• expose attachment sites on the actin myofilaments when calcium binds to troponin
• cover attachment sites when calcium is not bound to troponin

Answer 19

Tropomyosin

Question 20

• highly ordered arrangement of myosin and actin
• basic structural and functional unit of a skeletal muscle
• contractile unit of muscle
• extends from on Z-disc to another Z-dic

Answer 20

Sarcomere

Question 21

• darker, central region of the sarcomere

- extends the length of myosin filaments

Answer 21

A band

Question 22

• a network of protein fibers for the attachment of actin

- attachment point of actin

Answer 22

Z line

Question 23

• a light band which consist only of actin

- spans each Z disk and ends at the myosin filaments

Answer 23

I band

Question 24

• light zone which contains only of myosin

- disappears during contraction

Answer 24

H zone

Question 25

- dark, straining band at the center of the sarcomere where myosin is anchored - attachment point of myosin

Answer 25

M line

Question 26

cell membrane of the muscle fiber

Answer 26

Sarcolemma

Question 27

- tube-like invagination located along the surface of sarcolemma - arranged at regular intervals along the muscle fiber and wrap around sarcomeres where the myosin and actin filaments overlap - connect the sarcolemma to the sarcoplasmic reticulum

Answer 27

Transverse/T-tubules

Question 28

nerve cells along which action potentials travel to skeletal muscle fibers

Answer 28

Motor Neuron

Question 29

consist of a single motor neuron and all the skeletal muscle fiber it innervates

Answer 29

Motor Unit

Question 30

- junction between a branch of an axon and a muscle - - --- fiber function is to release Ach in response to an action potential at the neuromuscular junction

Answer 30

Neuromuscular Junction or Synapse

Question 31

axon terminal

Answer 31

Presynaptic terminal

Question 32

- space between the presynaptic terminal and the muscle fiber membrane - Na is abundant

Answer 32

Synaptic Cleft

Question 33

muscle membrane fiber

Answer 33

Postsynaptic Membrane

Question 34

small vesicles in the presynaptic terminal which contain acetylcholine

Answer 34

Synaptic Vesicles

Question 35

- a molecule released by the presynaptic nerve cell that stimulates or inhibit a post synaptic cell - neurotransmitter

Answer 35

acetylcholine

Question 36

enzyme that breaks down acetylcholine

Answer 36

Acetylcholinesterase

Question 37

- the sliding of actin myofilaments past myosin ------------ - myofilaments during contraction

Answer 37

Sliding Filament Model

Question 38

Types of Muscle Contraction

Answer 38

Isotonic | Isometric

Question 39

- myofilaments are successful in their sliding movements | - muscle shortens and movement occurs

Answer 39

Isotonic

Question 40

- contraction in which muscles do not shorten; no net movement - myofilaments are trying to slide but muscle is pitted against some immovable object

Answer 40

Isometric

Question 41

Physiologic Properties of Muscle

Answer 41

``` Excitability Contractility Tonus Extensibility Elasticity ```

Question 42

the capacity of the skeletal muscle to respond to stimulus

Answer 42

Excitability

Question 43

the ability of skeletal muscle to shorten with force

Answer 43

Contractility

Question 44

the ability of the skeletal muscle to sustain partial contraction in response to stretch receptors

Answer 44

Tonus

Question 45

skeletal muscle can be stretch

Answer 45

Extensibility

Question 46

the ability of the skeletal muscle to recoil to their original resting length after they have been stretched

Answer 46

Elasticity

Question 47

Types of Muscles

Answer 47

Prime mover/ Agonist Antagonist Synergists Fixators

Question 48

- muscle that has major responsibility for causing a particular movement - produces flexion

Answer 48

Agonist/Prime Mover

Question 49

- muscles that oppose or reverse a movement | - for muscles with opposing action

Answer 49

Antagonist

Question 50

- muscles that help prime movers by producing the same movement or by reducing undesirable movements - group of muscles working together to produce a movement

Answer 50

Synergists

Question 51

- specialized synergist that hold a bone still or stabilize the origin of a prime mover - postural muscles that stabilize the vertebral column, muscles that anchor the scapula to the thorax

Answer 51

Fixators

Question 52

- the head - fixed - attached to the immovable or less immovable bone

Answer 52

Origin

Question 53

- end of the muscle attached to the movable bone - when muscles contract, itmoves toward the origin - mobile

Answer 53

insertion

Question 54

longest muscle in the body

Answer 54

Sartorius

Question 55

nuclei in skeletal muscle

Answer 55

sarcolemma

Question 56

- smooth endoplasmic reticulum | - has a high concentration of calcium ions

Answer 56

Sarcoplasmic Reticulum

Question 57

provides the final go signal for contractions

Answer 57

Calcium`=

Question 58

long, threadlike extension of a neuron

Answer 58

nerve fiber or axon

Question 59

Potassium diffuses from this

Answer 59

sarcolemma

Question 60

products of breakdown of acetylcholine

Answer 60

acetic acid | choline (goes back to axon terminal)

Question 61

acetylcholine receptors are present in these folds

Answer 61

sarcolemma