Skeletal muscles Histology

Question 1

Sites of skeletal muscles ?

Answer 1

All muscles attached to the skeleton
Tongue muscles
Eye muscles
Pharynx and larynx

Question 2

What’s the name of cell membrane of muscle fibres

Answer 2

Sarcolemma

Question 3

What’s the name of cytoplasm in muscle fibres

Answer 3

Sarcoplasm

Question 4

Characters of muscle fibres

Answer 4

Voluntary
Striated
Don’t branch

Question 5

What’s the name of the connective-tissue surrounding the whole muscle

Answer 5

Epimysium (EP)

Question 6

Skeletal muscle bundles called

Answer 6

Fascicles

Question 7

Skeletal muscles bundles (Fascicles) are separated by dense connective tissue called

Answer 7

Perimysium (P)

Question 8

Each muscle fiber enclosed by loose connective tissue called

Answer 8

Endomysium (En)

Question 9

When you look at a skeletal muscle with a light microscope what are the things that you comment on ?

Answer 9

Number of cells
Branching
Length
Diameter
Nucleus
Cytoplasm

Question 10

When you look to a skeletal muscle with a light microscope what do you see ?

Answer 10

‏ Single elongated cell
No branching
Lengt 1-40 mm
Diameter 10-100 um

Question 11

Nucleus of skeletal muscles ?

Answer 11

Multinucleated
Flattened
Peripheral

Question 12

Sarcoplasm (Cytoplasm of skeletal muscles) characters?

Answer 12

Acidophilic
Regular striation (myofibrils)

Question 13

When you look at a skeletal muscle with an electron microscope what are the things that you comment on ?

Answer 13

Cytoplasmic content 
Myofibrils 
Sarcomeres 
Thin and thick filaments 
Conducting system

Question 14

Cytoplasmic content of skeletal muscles ?

Answer 14

Sarcoplasmic reticulum 
Numerous mitochondria
Myoglobin
Beta glycogen granules 
Myofibrils

Question 15

Myofibrils of skeletal muscles characters ?

Answer 15

Longitudinal contractile elements

Question 16

Myofibrils bands ?

Answer 16

Light band (I-band) : thin filaments only
Dark band (A-band) : thin and thick filaments

Question 17

H-zone of myofibrils ?

Answer 17

Light area in the center of A-band

Question 18

Z-line of myofibrils ?

Answer 18

Dark line in the center of I-band

Question 19

What does z-line consist of ?

Answer 19

Alpha-actinin protein which ties adjecent sarcomeres

Question 20

Myofibrils consist of successive …………….

Answer 20

Sarcomeres

Question 21

The beginning and the end of the sarcomeres ?

Answer 21

From Z-line to Z-line

Question 22

A Sarcomere consists of ?

Answer 22

A-band (center) (thin and thick filaments)

1/2 I-band (each side) (think filaments)

Question 23

Protein content of thin filaments ?

Answer 23

Actin
Tropomyosin
Troponin complex

Question 24

Thick filaments protein content ?

Answer 24

Myosin

Question 25

F-actin molecule component ?

Answer 25

Formed of 2 strands of G Actin molecules twisted in a double helix

Question 26

G-actin molecules has ?

Answer 26

Binding site for myosin

Question 27

Tropomyosin components and site ?

Answer 27

Long thin molecule formed of 2 polypeptide chains Site : between actin strands

Question 28

Troponin complex parts ?

Answer 28

TnT TnC TnI

Question 29

Troponin parts function :

Answer 29

T : bind to tropomyosin C : binds to calcium ion I : inhibits Actin-myosin interaction

Question 30

Each tropomyosin spans ................

Answer 30

7 G-actin | 1 troponin complex

Question 31

Myosin filaments parts ?

Answer 31

Head | Tail

Question 32

Head of myosin ?

Answer 32

Formed of two identical heavy chains Has ATP-binding site Has actin binding site

Question 33

Tail of myosin ?

Answer 33

Formed of 2 light chains | Bounded to the heavy chains

Question 34

Skeletal muscles conducting system triad :

Answer 34

1 T-tubule | 2 sarcoplasmic tubules

Question 35

T-tubule site :

Answer 35

At A-I junction

Question 36

Classifications of muscle fibres according to concentration of myoglobin in relation to fiber diameter

Answer 36

``` Type I (red, slow) fibers Type II (white, rapid) fibers Intermediate fibers ```

Question 37

In the histochemical staining of mitochondria, the muscle fibres looks

Answer 37

Type I : dark | Type II : light

Question 38

In the histochemical staining of myosin ATPase activity is the muscles fibres looks :

Answer 38

Type I : pale | Type II : dark

Question 39

What are the changes that occur in the myoneural junction :

Answer 39

The nerve replaces myelin with Shawn cells The axoplasm contains numerous Mitochondria Synaptic vesicles The sarcolemma (muscle cell membrane) forms numerous junctional folds has ACh receptors.

Question 40

Synaptic cleft ?

Answer 40

Space between the axon and muscle