Unit 1 Skeletal Muscle Anatomy

Question 1

Skeletal Muscle Cellular Organelles

Answer 1

1. Nuclei
2. Synthetic Machinery
3. Mitochondria

Question 2

What is an important characteristic regarding the nuclei of skeletal muscle?

Answer 2

Multinucleated

Question 3

Location of myonuclei in the muscle?

Answer 3

-Dispersed along the inner surface of the plasmalemma, particularly dense in the motor end-plate region

Question 4

Contents of myonuclei

Answer 4

1. Nuclear DNA
2. RNA (m and t)
3. Ribosomes
4. Codons

Question 5

Components of the Synthetic Machinery

Answer 5

1. Endoplasmic Reticulum
2. Ribosomes

Question 6

Characteristics of the Endoplasmic Reticulum

Answer 6

1. Associated with nucleus
2. transportation and modification of cellular proteins outside of cell

Question 7

Role of Ribosomes

Answer 7

Coordinate protein synthesis

Question 8

Substances associated with mitochondira

Answer 8

1. ATP
2. NADH
3. FADH2

Question 9

Metabolic processes associated with mitochondria

Answer 9

Electron Transport Chain

Question 10

Bioenergetic imperative for mitochondria to operate

Answer 10

Oxygen (Aerobic)

Question 11

Location of mitochondria within the muscle cell

Answer 11

between myofibrils in the z-line region and in relation to nuclei and motor end-plate

Question 12

Unique feature of mitochondria when viewed cross sectionally

Answer 12

oval shaped

Question 13

Key structural features of mitochondria

Answer 13

1. Inner and Outer membrane
2. inner membrane folds called cristae
3. Matrix between cristate

Question 14

What is housed in the inter-cristae matrix

Answer 14

1. Krebs cycle enzyme
2. Mitochondrial DNA (mtDNA)

Question 15

Types of mitochondria

Answer 15

1. Subsarcolemal
2. Intermyofibrillar

Question 16

Primary location of subsarcolemmal mitochondria

Answer 16

Immediately beneath cell membrane (sarcolemma)

Question 17

What is the functional significance of the location of subsarcolemmal mitochondria?

Answer 17

They can easily receive arterial oxygen

Question 18

Key difference between Intermyfibrillar and subsarcolemmal type mitochondria?

Answer 18

Intermyofibrillar may have higher activity per unit mass

Question 19

Key role of intermyofibrillar mitochondria

Answer 19

Maintaining ATP supply for energy transduction during contraction

Question 20

Intermyfibrillar Mitochondria Location

Answer 20

Deep within the cell in the contractile elements

Question 21

Cytoplasmic Components

Answer 21

ANAEROBIC
1. Soluble Proteins, Cytoskeletal Components
2. Glycogen Granules
3. Glycolytic Enzymes

Question 22

Filamentous Components

Answer 22

1. Myofibrils
2. Sarcomeres
3. Myosin Isoforms
4. Actin

Question 23

Function of Myofibrils

Answer 23

Contraction and relaxation

Question 24

Location of myofibrils

Answer 24

Separated by mitochondria and sarcoplasmic and transverse tubular system

Question 25

Primary protein filaments found in myofibrils

Answer 25

1. Actin 2. Myosin

Question 26

How do contractile proteins connect to tendon?

Answer 26

Endomysial connective tissue

Question 27

What are the myotendinous attachment proteins?

Answer 27

1. Vinculin 2. Talin 3. Paxillin 4. Tensin

Question 28

A- Bands

Answer 28

Anisotropic, dark bands

Question 29

What causes the dark banding of the A band?

Answer 29

myosin

Question 30

I bands

Answer 30

Isotropic, light bands

Question 31

What causes the light color of the I band?

Answer 31

actin

Question 32

Describe the contractile proteins in reseting muscle

Answer 32

Actin and myosin overlap

Question 33

H zone

Answer 33

pale area no overlap

Question 34

What causes the dark banding in the M region?

Answer 34

filaments cross connecting myosin

Question 34

M region

Answer 34

Dark region in the middle of the H zone

Question 35

Describe the structure of the myofilament

Answer 35

Each myosin filament surrounded by hexagonal lattice of actin

Question 35

Types of troponin

Answer 35

1. Troponin I (Tnl) 2. Troponin C (TnC) 3. Troponin T (TnT)

Question 35

Tropomyosin

Question 36

Nebulin

Question 37

Myosin Filament Array

Answer 37

1. M lines (M region) Visible

Question 38

Titin

Answer 38

Large protein that connects thick myosin filaments to Z disks

Question 39

Role of titin

Answer 39

Longitudinal stabilizer for myosin

Question 40

Where does titin bind?

Answer 40

1. thick myosin to z disk 2. a-actinin to z disk 3. myomesin in M region

Question 41

What is the role of nebulin in the I band?

Answer 41

supports actin and inserts to z disk

Question 42

Primary components of the Z disk

Answer 42

1. a-actinin 2. desmin 3. vimentin 4. Synemin

Question 43

Intermediate filaments

Answer 43

1. Desmin 2. Vimentin 3. Synemin

Question 44

Role of the intermediate filaments

Answer 44

1. Transverse connections between Z disks 2. Keeps myofibrils in order 3. Attach Z disk to cytoskeleton

Question 45

Membrane Components

Answer 45

1. Sarcoplasmic Reticulum 2. Transverse Tubules

Question 46

Describe the tubular systems

Answer 46

interlacing network within muscle fiber

Question 47

Role of Sarcoplasmic Reticulum

Answer 47

Releases Ca2+ into cytosol around myfibril

Question 48

Role of Ca2+ in muscle

Answer 48

Binds with TnC, causes contraction

Question 49

Which structure is the site of Ca2+ release?

Answer 49

Terminal Cisternae

Question 50

Important Components of the SR membrane

Answer 50

1. Ca2+ release channels (ryanodine receptors) 2. Ca2+ ATPase (SERCA)

Question 51

What are ryanodine receptors

Answer 51

Ca2+ channels