Module 14: Muscular System

Question 1

What are the functions of the muscular system?

Answer 1

(1) Movement
(2) Maintain posture
(3) Stabilize joints
(4) Production of body heat
(5) Respiration and heart beat
(6) Communication
(7) Contraction of organs and vessels

Question 2

This property of the muscle is delineated as the faculty of the muscle to shorten forcefully or contract.

Answer 2

Contractility

Question 3

This property of the muscle is delineated as the capacity to respond to stimulus.

Answer 3

Excitability

Question 4

This property of the muscle is delineated as the ability to be stretched beyond its normal resting length and still be able to contract.

Answer 4

Extensibility

Question 5

This property of the muscle is delineated as the ability of the muscle to recoil to its original resting length after it has been stretched.

Answer 5

Elasticity

Question 6

This type of muscle is characterized to be attached to the bones, striated, and voluntarily controlled.

Answer 6

Skeletal muscle

Question 7

This type of muscle is characterized to be located in the hear, striated, and involuntarily controlled.

Answer 7

Cardiac Muscle

Question 8

This type of muscle is characterized to be located in the blood vessels along with hollow organs, non-striated and visceral, and involuntarily controlled.

Answer 8

Smooth Muscle

Question 9

The skeletal muscle or striated muscle is associated with what tissue?

Answer 9

Connective Tissue

Question 10

Why is the skeletal muscle also known or called as the striated muscle?

Answer 10

Because transverse bands or striations can predominantly be perceived in the muscle under the microscope.

Question 11

Individual skeletal muscles, such as the biceps brachii are characterized to be complete organs because?

Answer 11

Because it is a result of being comprised of several tissues such as muscle, nerve, and connective tissue.

Question 12

This is defined as the connective tissue sheath that surrounds each skeletal muscle.

Answer 12

Epimysium

Question 13

A skeletal muscle is further subdivided intro groups of muscle cells termed as what?

Answer 13

Fascicles

Question 14

This is defined as the connective tissue covering that surrounds each fascicle.

Answer 14

Perimysium

Question 15

This is defined as a connective tissue covering that surrounds each skeletal muscle (fiber).

Answer 15

Endomysium

Question 16

This is characterized as a single cylindrical cell with several nuclei located at its periphery.

Answer 16

Muscle Fibers

Question 17

Muscle fibers ranges from what length?

Answer 17

From 1cm to 30cm

Question 18

Muscle fibers are characterized to generally to be __________ in diameter.

Answer 18

0.15 mm

Question 18

These are delineated to contain several nuclei that are located at the periphery of the fiber.

Answer 18

Skeletal Muscle Fibers

Question 19

This is composed of many tube-like inward folds called transverse tubules or T tubules.

Answer 19

Sarcolemma

Question 20

The sarcolemma (cell membrane) has many tube-like inward folds, called ______________.

Answer 20

Transverse tubules, or T tubules.

Question 21

These occur at regular intervals along the muscle fiber and extend into the center of the muscle fiber.

Answer 21

T tubules

Question 22

These are characterized as enlarged portions of the smooth endoplasmic reticulum and are described to be associated with T tubules.

Answer 22

Sarcoplasmic reticulum

Question 23

These are characterized to be the enlarged portions of the muscle fiber structure.

Answer 23

Terminal Cisternae

Question 24

How is the muscle triad formed?

Answer 24

This is generated when T tubules connect the sarcolemma to the terminal cisternae.

Question 25

This is characterized to have relatively high concentration of Ca+2 (which plays a major role in muscle contraction).

Answer 25

Sarcoplasmic Reticulum

Question 26

The sarcoplasmic reticulum have a relative high concentration of this and is defined to have a major role in muscle contraction.

Answer 26

Ca+2

Question 27

This is defined as the cytoplasm of a muscle fiber and contains many bundles of protein filaments.

Answer 27

Sarcoplasm

Question 28

These are characterized as bundles of protein filaments of the muscle fiber structure,

Answer 28

Myofibrils

Question 29

The myofibrils are constituted of what:

Answer 29

(1) Myofilaments
(2) Actin
(3) Myosin

Question 30

This is the basic structural and functional unit of a skeletal muscle because it is the smallest portion of a skeletal muscle capable of contracting.

Answer 30

Sarcomere

Question 31

Why is the sarcomere known as the functional unit of a skeletal muscle?

Answer 31

Because it is the smallest portion of a skeletal muscle capable of contracting.

Question 32

These from the sarcomere, form a network of protein fibers that both serve as an anchor for actin myofilaments and separate one sarcomere from the next.

Answer 32

Z disks

Question 33

The sarcomere extends from what?

Answer 33

From one Z disk to the next Z disk

Question 34

These are characterized to consist only actin and they extend towards the center of the sarcomere to ends of the myosin myofilaments.

Answer 34

Light Bands or L bands

Question 35

These are known to extend the length of the myosin myofilaments.

Answer 35

Dark staining bands or A bands

Question 36

What causes contraction?

Answer 36

The actin and myosin myofilaments overlap for some distance on both ends of the A band (dark staining bands); this overlap causes the contraction.

Question 37

Actin myofilaments are made up of three (3) components: namely

Answer 37

(1) Actin
(2) Troponin
(3) Tropomyosin

Question 38

These molecules are characterized to have binding sites for Ca+2.

Answer 38

Troponin Molecules

Question 39

These molecules are characterized to block the myosin myofilament binding sites on the actin myofilaments.

Answer 39

Tropomyosin Filaments

Question 40

These are known as thick myofilaments and these also resemble bundles of tiny golf clubs.

Answer 40

Myosin Myofilaments

Question 41

These have ATP binding sites, ATPase and attachment spots for actin.

Answer 41

Myosin heads

Question 42

This is defined as the electrical charge difference across the cell membrane of an unstimulated cell.

Answer 42

Resting membrane potential

Question 43

Explain the excitability of muscle cells (fibers).

Answer 43

Muscle cell (fibers) have a resting membrane potential, but can also perform action potentials.

Question 44

Why do muscle fibers have a resting membrane potential?

Answer 44

The resting membrane potential is due to the inside of the membrane being negatively charged in comparison to the outside of the membrane being positively charged.

Question 45

Why are there action potentials in muscle fibers?

Answer 45

Action potentials are due to the membrane having gated channels.

Question 46

Why does the resting membrane potential exist?

Answer 46

(1) The concentration of K+ being higher on the inside of the cell membrane and the concentration of the Na+ being higher on the outside.
(2) The presence of many negatively charged molecules, such as proteins, inside the cell that are too large to exit the cell.
(3) The presence of leak protein channels in the membrane that are more permeable to K+ than it is to Na+.

Question 47

What is the tendency of Na+ under the resting membrane potential?

Answer 47

Na+ tends to diffuse into the cell and K+ tends to diffuse out of the cell.

Question 48

How do you maintain the resting membrane potential?

Answer 48

In order to maintain the resting membrane potential, the sodium-potassium pump recreates the Na+ and K+ ion gradient by pumping Na+ out of the cell and K+ into the cell.