Muscle Tissue

Question 1

What’s the overall function of muscle tissue?

Answer 1

Movement

Question 2

What makes movement possible in muscle tissues?

Answer 2

Contractility

Question 3

How is movement generated in muscle tissues?

Answer 3

Movement is generated by the interaction between actin and myosin proteins

Question 4

There are three specialized contractile cells. What are they?

Answer 4

1. Myoepithelial cells
2. Pericytes
3. Myofibroblasts

Question 5

____________________ are specialized contractile cells with secretory functions

Answer 5

Myoepithelial cells

Question 6

__________________ are smooth-muscle-like cells that surround blood vessels

Answer 6

Pericytes

Question 7

__________________ are cells that secrete collagen and have a true contractile role

Answer 7

Myofibroblasts

Question 8

A _____________ is a collection of multicellular contractile units

Answer 8

Muscle

Question 9

Muscle tissue is composed of cells differentiated for __________________ with microfilaments and associated proteins that generate the force necessary for such a function

Answer 9

Contractility

Question 10

Nearly all cells of muscle tissue are of __________________ origin

Answer 10

Mesodermal/mesenchymal

Question 11

Muscle cells differentiate from mesenchymal stem cells by increasing cell ________________ and _____________ protein synthesis

Answer 11

Length

Myofibrillar

Question 12

How many types of muscle tissues are there?

Answer 12

Three: cardiac, skeletal, smooth

Question 13

_______________ muscle tissue has cross-striations and is composed of elongated, branched individual cells

Answer 13

Cardiac

Question 14

At sites of end-to-end contact of cardiac muscle cells, there are _______________________

Answer 14

Intercalated discs

Question 15

Contraction of cardiac muscle is _______________, vigorous, and _______________

Answer 15

Involuntary

Rhythmic

Question 16

___________________ tissue consists of collections of __________________ cells that do not show straitions

Answer 16

Smooth muscle cells

Fusiform

Question 17

In what type of muscle tissue are contraction processes slow and not subject to voluntary control?

Answer 17

Smooth muscle tissue

Question 18

____________________ muscle tissue is composed of bundles of very long, cylindrical, __________________ cells that show ________________

Answer 18

Multinucleated

Cross-striations

Question 19

The contraction of skeletal muscle cells is quick, forceful, and usually under _________________ control

Answer 19

Voluntary

Question 20

The interaction between thin _______________ filaments and thick ___________ filaments results in skeletal muscle contraction

Answer 20

Actin

Myosin

Question 21

What is the fine transparent tubular sheath which envelops the fibers of skeletal muscles called?

Answer 21

Sarcolemna

Question 22

Mature cardiac muscle cells exhibit a cross-striated banding pattern comparable to that of skeletal muscle.Unlike multinucleated skeletal muscle, however, each cardiac muscle cell possesses _____________ centrally located pale-staining nuclei

Answer 22

Only one or two

Question 23

Surrounding muscle cells is a delicate sheat of _____________________ containing a rich capillary network

Answer 23

Endomysium

Question 24

What’s the difference between the sacrolemna and endomysium?

Answer 24

The sarcolemma is the cell (plasma) membrane of the muscle fiber itself. The endomysium is a thin sleeve of fibrous connective tissue over the muscle fiber

Question 25

What is a unique and distinguishing characteristic of cardiac muscle?

Answer 25

The presence of dark-staining transverse lines that cross the chains of cardiac cells are irregular intervals

Question 26

What type of muscle tissue is shown? What does "I" point to? "N"? "D"?

Answer 26

Cardiac muscle fibers I = intercalcated disc N = nuclei D = desmosome (in EM)

Question 27

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ is the interface between adjacent cardiac muscle cells where many junctional complexes are present

Answer 27

Intercalated discus

Question 28

Transverse regions of intercalated discus have many _______________ and \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_, which resemble the zonula adherentes between epithelial cells

Answer 28

Desmosomes Fascia adherentes

Question 29

What's the purpose of desmosomes and fascia adherentes in cardiac muscle cells?

Answer 29

To bind cardiac cells firmly together and to prevent their ripping under constant contractile activity

Question 30

Longitudinal portions of each intercalated disc have multiple \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_, which provide ionic continuity between adjacent cells and act as electrical synapses, of sorts

Answer 30

Gap junctions

Question 31

Gap junctions in cardiac muscle cells allow for such cells to act as a ______________________ with contraction signals passing in waves from cell to cell

Answer 31

Multinucleated syncytium

Question 32

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ consists of muscle fibers, long, cylindrical multinucleated cells

Answer 32

Skeletal muscle

Question 33

Why are skeletal muscle cells multinucleated?

Answer 33

Because they result from fusion of embryonic mesenchymal cells (myoblasts)

Question 34

The nuclei of skeletal muscle cells are ______________ in shape and found at the ______________ of the cell

Answer 34

Oval Periphery

Question 35

What's the cytoplasm of muscle cells called?

Answer 35

Sarcoplasm

Question 36

What's the smooth ER of muscle cells called?

Answer 36

Sarcoplasmic reticulum

Question 37

What's the plasma membrane of muscle cells called?

Answer 37

Sacrolemma

Question 38

Skeletal muscle cells develop from mesenchymal cells called _________________ that align and fuse together, making long, multinucleate tubes called \_\_\_\_\_\_\_\_\_\_\_\_\_\_, which then synthesize proteins to create myofilaments and continue differentiation into functional microfilaments

Answer 38

Myoblasts Myotubes

Question 39

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ is the external sheath of dense connective tissue that surroundings the entire muscle

Answer 39

Epimysium

Question 40

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ is the thin septa of connective tissue that extends inward from the epimysium, surrounds the __________________ or fiber bindles within a muscle, and contains a rich capillary network

Answer 40

Endomysium Fascicles

Question 41

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ is the connective tissue that surrounds each fascicle

Answer 41

Perimysium

Question 42

What's the purpose of the connective tissues surrounding muscle and its fibers and cells?

Answer 42

To transmit the mechanical forces generated by contracting muscle cells and fiber

Question 43

Most muscles taper off at their \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Answer 43

Extremities

Question 44

At the ________________ junction, the connective tissue components of the epimysium associate with tendons

Answer 44

Myotendinous junction

Question 45

At the myotendinous junction, collage fibers of the ______________ insert themselves among the muscle fibers and associate with the \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Answer 45

Tendon Sarcolemma

Question 46

Myotendinous junctions join muscles to the __________________ of bones

Answer 46

Periosteum

Question 47

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ muscle fibers are elongated, tapered, and non-striated cells

Answer 47

Smooth

Question 48

Each smooth muscle cell is enclosed by a thin _________________ and a fine network of \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_, which serve to combine the forces generated by each smooth muscle fiber into a concerted action (e.g., peristalsis in the intestine)

Answer 48

Basal lamina Reticular fibers

Question 49

Where would you find the nucleus of a smooth muscle cell?

Answer 49

At the center of the cell's broadest part

Question 50

Muscle cells are pseudo-\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_, where the narrow part of one cell lies adjacent to the broad part of another cell (i.e., like pringles)

Answer 50

Staggered

Question 51

The borders of smooth muscle cells become __________________ when they contract and the nucleus becomes \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Answer 51

Scalloped Distored

Question 52

In skeletal muslce, there are alternating light and dark bands. What are the darker bands called?

Answer 52

A bands for anisotropic

Question 53

What are the lighter bands called?

Answer 53

I bands for isotropic

Question 54

What's a way to remember that the darker bands are A bands, the lighter bands are I bands?

Answer 54

d**A**rker = A bands l**i**ghter = I bands

Question 55

Each band of a muscle fiver is bisected by a dark transverse line called the ___________ line

Answer 55

Z line

Question 56

The functional unit of the muscle fiber is the ______________ and extends from ____ line to ____ line

Answer 56

Sarcomere Z line to Z line

Question 57

Each muscle fiber contains several parallel bundles of \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Answer 57

Myofibrils

Question 58

Myofibrils are long series of ________________ with thick and thin filaments separated by \_\_\_\_\_\_\_\_\_\_\_\_

Answer 58

Sarcomeres Z discs

Question 59

What causes the A and I banding pattern in sarcomeres?

Answer 59

The regular arrangement of two types of myofilaments, thick and thin

Question 60

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ make up myofibrils

Answer 60

Myofilaments

Question 61

There are two types of myofilaments: thin filaments, which are composed of \_\_\_\_\_\_\_\_\_\_\_\_\_, and thick filaments, which are composed of \_\_\_\_\_\_\_\_\_\_\_\_

Answer 61

Actin Myosin

Question 62

Thick filaments are composed primarily of \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Answer 62

Myosin

Question 63

\_\_\_\_\_ bands are mainly thick filaments but also have overlapping portions of thin filaments. These are the darker bands

Answer 63

A bands

Question 64

The ______ is where there are no *thin* filaments present

Answer 64

H zone

Question 65

The ________ is in the middle of the H zone and is a region of connection between adjacent thick filaments

Answer 65

M line

Question 66

What is the major protein of the M line?

Answer 66

Myomesin

Question 67

What binds to myosin and holds thick filaments in place?

Answer 67

Myomesin

Question 68

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ has a molecular mass of around 500 kDa and can be dissociated into two identical heavy chains and two light chains. The heavy chains are thin, rod-like molecules, which twist together to form _______________ tails

Answer 68

Myosin Myosin

Question 69

Thin filaments are composed of \_\_\_\_\_\_\_\_\_\_\_\_\_, the long filamentous polymers of its globular monomer

Answer 69

F-actin

Question 70

What shape does F-actin have?

Answer 70

Double helix shape

Question 71

Polymerization of F-actin produces a filament with \_\_\_\_\_\_\_\_\_\_\_\_\_\_

Answer 71

Polarity

Question 72

F-actin is associated with ________________ and \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Answer 72

Tropomyosin Troponin

Question 73

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ is a long and thin protein composed of two polypeptide chains that assemble into longer polymers within the groove between two twisted actin strands

Answer 73

Tropomyosin

Question 74

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ is a protein complex of three subunits that attaches to tropomyosin at regular intervals

Answer 74

Troponin

Question 75

In muscle cells, the sarcoplasmic reticulum is specialized for _____________ sequestration

Answer 75

Caclium ion

Question 76

Where does the depolarization of the sarcoplasmic reticulum occur?

Answer 76

The myoneuronal junction on the surface of the muscle cell

Question 77

To provide for uniform contraction, skeletal muscle fivers have a system of \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Answer 77

Transverse (T) tubules

Question 78

What a transverse (T) tubules?

Answer 78

Fingerlike invaginations of the sarcolemma that form a complex network of tubules that encircle every myofibril near the A and I band boundaries of each sarcomere

Question 79

Which of the muscle tissue types have the greatest regeneration potential and why?

Answer 79

Smooth muscle tissue because it's composed of simpler, mononucleated cells that are capable of more active regenerative response. After injury, viable cells undergo mitosis and replace damaged tissue, and pericytes can help repair vascular smooth muscle

Question 80

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ are cells that can help repair vascular smooth muscle

Answer 80

Pericytes

Question 81

Of the three muscle tissue types, whcih is the least capable of regeneration? Why?

Answer 81

Cardiac muscle tissue because it lacks satellite cells so there is no regenerative capacity beyond early childhood

Question 82

Why do skeletal muscle tissues have limited regeneration?

Answer 82

Because their nuclei do not undergo mitosis as they develop from fusion of early muscle cells

Question 83

In skeletal muscle, there is a small population of \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_, an inactive researve of myoblasts remaining after muscle differentiation, that can be activated after injury or other stimuli

Answer 83

Mesenchymal satellite cells