Chp 9: Muscles

Question 1

What percentage of person’s body mass is muscle tisuse?

Answer 1

40%

Question 2

Skeletal Muscle

Answer 2

Attached to bones or (some facial muscles) skin
Facial expression, movement, heat, posture
Multinucleate cells, cylindrical, obvious striations, fibers parallel
Voluntary control

Question 3

Cardiac Muscle

Answer 3

Walls of the heart
Pumps blood continuously
Branching chains of cells, uni or bi-nucleate, striations, intercalated discs
Involuntary

Question 4

Smooth muscle

Answer 4

GI tract, uterus, eye, blood vessels
Peristalsis, blood pressure, pupil size, erects hair
One central nucleus, no striations

Question 5

Direct attachment to bone

Answer 5

Aka fleshy

Epimysium of muscle is fused to periosteum of bone or perichondrium of cartilage

Question 6

Indirect attachment to bone

Answer 6

Muscle’s connective tissue wrappings extend beyond muscle as ropelike tendon or sheetlike aponeurosis
Indirect attachments more common b/c of durability and small size

Question 7

Sarcolemma

Answer 7

Plasma membrane of muscle cell

Question 8

Epimysium

Answer 8

Overcoat of connective tissue that covers whole muscle

Question 9

Perimysium

Answer 9

Connective tissue of collagen and elastic fibers that surrounds each fascicle

Question 10

Endomysium

Answer 10

Connective tissue that surrounds each individual muscle fiber

Question 11

Muscle tissue organization at tissue level

Answer 11

Each muscle fiber (muscle cell) is wrapped in endomysium
Each bundle of muscle fibers is called a fascicle, which is wrapped in perimysium
The epimysium surrounds the whole muscle
fiber- endomysium –> fascicle-perimysium –> muscle- epimysium

Question 12

Sarcoplasm

Answer 12

cytoplasm of muscle cell

Question 13

Myofiber

Answer 13

Muscle cell

Question 14

Myofibril

Answer 14

Cytoskeletal elements in sarcoplasm, contains sarcomeres

Question 15

Sarcomere

Answer 15

Region of myofibril between 2 successive Z discs; functional unit of skeletal muscle
“muscle segment”

Question 16

A bands

Answer 16

Dark bands on myofibrils

Myosin filaments

Question 17

I bands

Answer 17

Light bands on myofibrils

Actin only

Question 18

Sarcoplasmic Reticulum

Answer 18

Elaborate smooth endoplasmic reticulum; interconnecting tubules surround each myofibril
Regulates intracellular levels of ionic calcium

Question 19

T Tubule

Answer 19

Elongated tube, continuation of sarcolemma extending deep into cell interior
Conduct impulses (signal for every myofibril to contract at same time)

Question 20

Motor Unit

Answer 20

One motor neuron and all the muscle fibers it innervates
Many motor neurons per muscle
The fewer # of fibers per neuron, finer the movement

Question 21

Blood and Nerve Supply of skeletal muscles

Answer 21

One nerve and its branches (voluntary control)
An artery and its branches
One or more veins and their branches

Question 22

Origin

Answer 22

Attachment of muscle to immovable bone

Question 23

Insertion

Answer 23

Attachment to moveable bone

Question 24

Skeletal muscle regions: Anterior View (10)

Answer 24

Facial
Neck
Shoulder
Arm
Forearm
Thorax
Abdomen
Pelvis/Thigh
Thigh
Leg

Question 25

Skeletal muscle regions: posterior view (7)

Answer 25

``` Neck Shoulder Arm Forearm Hip Thigh Leg ```

Question 26

H zone

Answer 26

where only thick filaments are present

Question 27

striated appearance of skeletal muscles

Answer 27

Repeated overlapping of I and A bands

Question 28

H zone

Answer 28

where only thick (myosin) filaments are present

Question 29

M Line

Answer 29

Proteins of M Line connects central portion of each thick (myosin) filament to its neighbors Dark staining proteins, help stabilize positions of thick filaments

Question 30

Myosin

Answer 30

thick contractile protein each molecule resembles 2 golf clubs twisted together myosin heads (cross bridges) extend toward thin filaments

Question 31

Actin

Answer 31

Thin filaments | The myosin-binding site on each actin molecule is covered by tropomyosin in relaxed muscle

Question 32

Regulatory proteins

Answer 32

turn contraction on/off | troponin and tropomyosin

Question 33

Structural proteins

Answer 33

provide proper alignment, elasticity, and extensibility | titin, myomesin, nebuilin, dystrophin

Question 34

Prime Movers/ Agonist

Answer 34

muscle responsible for most of the movement | ex// biceps brachii, flexion of forearm

Question 35

Antagonists

Answer 35

Extensor/Flexor pair oppose/reverse particular movement ex// triceps brachii/biceps brachii

Question 36

Synergists/Fixators

Answer 36

Help agonists Add extra force to movement or reduce undesirable/unnecessary movement ex// extensor carpi muscles are synergists for flexor digitorum when you clench fist