Muscular System

Question 1

Functions

Answer 1

1. Movement of Body 2. Maintenance of Posture 3. Respiration 4. Production of Body Heat 5. Communication 6. Constriction of organs and vessels 7. Contraction of the Heart

Question 2

Contractility

Answer 2

Ability of muscle to shorten forcefully

Question 3

Excitability

Answer 3

Capacity of muscle to respond to stimulus

Question 4

Extensibility

Answer 4

Muscle can stretch beyond its normal resting length and still be able to contract

Question 5

Elasticity

Answer 5

Ability of muscle to recoil to its original resting length after its been stretched

Question 6

Skeletal Muscle

Answer 6

-responsible for locomotion, facial expressions, posture, respiratory functions, etc -has striations -voluntary and involuntary (RELFEXES)

Question 7

Smooth Muscle

Answer 7

-Found in the walls of hollow organs and tubes, blood vessels, eyes, glands, and skin -no striations -involuntary

Question 8

Cardiac Muscle

Answer 8

-heart -has striations -involuntary- automatic nervous and endocrine systems

Question 9

Skeletal muscle fibers

Answer 9

muscle cell

Question 10

Fasciculi

Answer 10

bundles of muscle

Question 11

Perimyseum

Answer 11

heavy connective tissue layer surrounding fasciculi

Question 12

Epimysium

Answer 12

layer of connective tissue surrounding the entire muscle- composed of dense collagenous connective tissue

Question 13

Fascia

Answer 13

connective tissue sheets within the body

Question 14

Muscular fascia

Answer 14

separates and compartmentalizes individual muscles or groups of muscles

Question 15

Motor neurons

Answer 15

specialized nerve cells that stimulate muscles to contract

Question 16

Answer 16

Muscle Structure

Question 17

Striations

Answer 17

Alternating light and dark bands give a striped appearance

Question 18

Myoblasts

Answer 18

less mature, multinucleated cells that develope into muscle fibers

Question 19

Hypertrophy

Answer 19

Enlargment of muscles due to an increase in SIZE of muscle fibers

Question 20

Sarcolemma

Answer 20

plasma membrane of a muscle fiber

Question 21

External Lamina

Answer 21

deeper, thin layer of delicate connective tissue layer located on outside of sarcolemma

• consists of reticular (collagen) fibers

Question 22

Endomysium

Answer 22

the other layer of the sarcolemma- much thicker

Question 23

Transverse Tubules (T Tubules)

Answer 23

tubelike invaginations of the sarcolemma

extend inward, connecting extracellular environment with interior of the muscle fibers

Question 24

Sarcoplasmic Reticulum

Answer 24

highly organized smooth endoplasmic reticulum

Question 25

Sarcoplasm

Answer 25

cytoplasm- cell packed with organelles including mitochondria and energy storing glycogen granules

Question 26

Myofibrils

Answer 26

bundles of protein filaments in the sarcoplasm

Question 27

Myofilaments

Answer 27

protein filaments in the myofibril Actin- thin Myosin- thick

Question 28

Sarcomeres

Answer 28

actin and myosin myofiliments for highly ordered units joined end to end to form myofibrils

Question 29

Answer 29

Parts of a muscle

Question 30

Z Disk

Answer 30

filamentous network of protein forming a dislike structure for the attachment of actin myofilaments

Question 31

Isotropic Band (I Band)

Answer 31

includes a Z Disk- extends from each side of z disk to ends of myosin filaments

Question 32

Anisotropic Band (A Band)

Answer 32

extends the length of the myosin myofilaments within a sacromere

Question 33

H zone

Answer 33

* in the center of each A band- actin and myosin myofilaments dont overlap * only myosin myofilaments are present

Question 34

M line

Answer 34

middle of H zone- delicate filaments attach to the center of myosin myofilaments

Question 35

Titin

Answer 35

largest know protein- holds actin and myosin in place-- muscles ability to stretch and recoil

Question 36

Sliding Filament Model

Answer 36

shortening of sarcomeres that is responsible for contraction of skeletal muscles

Question 37

Action Potentials

Answer 37

electrical signals that travel from the brain or spinal cord along the axons to muscle fibers and causes them to contract

Question 38

Ion channels- 2 major types

Answer 38

nongated (leak) and gated

Question 39

Ligan-gated ion channels

Answer 39

open when a ligand (**neurotransmitter**), a chemical signal, binds to a receptor that is part of the ion channel

Question 40

Polarized

Answer 40

the inside of most plasma membranes is negatively charged compared with the outside

Question 41

Resting membrane potential

Answer 41

the charge difference across the plasma membrane of an unstimulated cell

Question 42

Action Potential- resting membrane potential

Answer 42

charge difference across the plasma membrane of cells