EXAM2_HE12_13_Muscle

Question 1

Sarcolemma, Sarcoplasm, Sarcoplasmic reticulum

Answer 1

1. Sarcolemma- Plasma membrane
2. Sarcoplasm- Cytoplasm
3. Sarcoplasmic reticulum- Smooth ER

Question 2

Where is Smooth, Skeletal, Cardiac muscle derived from ?

Answer 2

1. Smooth-myoblasts from Visceral Lateral plate mesoderm
2. Skeletal-myoblasts from Paraxial Mesoderm
3. Cardiac- myoblasts from Visceral Lateral Plate mesoderm

Question 3

Thin filament- Thick filament

Answer 3

thin- Skeletal/cardiac actin- tropomyosin-troponin
smooth muscle (actin and tropomyosin only)
thick- myosin II

Question 4

Rhabdomyolysis- What indicates muscle damage? 3 Causes of damage?

Answer 4

Skeletal/Cardiac muscle damage releases TROPONIN and MYOGLOBIN into blood

• excess Mb in blood after skeletal muscle injury leads to fatal kidney damage
• trauma (car crash, electrocution)
• Exertional (crossfit)
• Nonexteritional (drugs, infections)

Question 5

Organization of Muscle fibers? 5 orders of muscle and collagen coverings respectively.
What connects muscle to bone?

Answer 5

1. Myofilaments (actin/myosin)
2. Myofibrils (long rows of myofilaments)
3. Muscle Fibers (myocyte)- endomysium;type III
4. Fascicles (bundle of muscle fibers)-Perimysium typeI
5. Muscle- Epimysium Type I
   TENDONS- Muscle to bone

Question 6

Describe 4 characteristics of Skeletal muscle

Answer 6

1. long, cylindrical cells
2. parallel arrangement
3. multiple nuclei- peripherally located
4. Striated- myofilament arrangement

Question 7

Type I muscle fibers- speed, strength, composition?

Answer 7

Slow
Fatigue resistant- Aerobic
-more Mb, mitochondria, LESS glycogen infusions
-Weaker-smaller diameter
-better O2 diffusion, but less force

Question 8

Type II Muscle fibers

Answer 8

Fast
Fatigue quickly- anaerobic
-more glycogen inclusions
-LESS Mb, Mitochondria
STRONGER- larger diameter-greater force

Question 9

Describe Aband, I band, Zline regions

Answer 9

A band- Actin + Myosin
I band-   Actin only
H band- Myosin only
M line- cytoskeleton?
Z line-

Question 10

You have myofilaments that are arranged and structured in an organized fashion what type of muscle is it?
You have criss cross myofilaments what is it?

Answer 10

Skeletal and cardiac- organized

Smooth-criss crossed

Question 11

In muscles, what layer is the blood supply in?

Answer 11

surrounding CT of each individual cell

Question 12

if you suspect heart attack what protein do you check for in blood? if you suspect skeletal muscle breakdown?

Answer 12

troponin

rhabdomyolysis- Mb

Question 13

Endomysium surrounds what? what made of?

Answer 13

surrounds cells- Type 3

Question 14

Perimysium

Answer 14

surrounds fascicles; type 1

Question 15

Epimysium

Answer 15

surrounds muscle- type 1

Question 16

why are nuclei of skeletal muscle on the periphery of the cell?

Answer 16

the contractile fibrils are located through the middle and the nuclei are pushed out to the outside of the cells

Question 17

dark band
Light band
What is inside the I band?

Answer 17

Dark- A band
Light - I band
Mline inside the A band
the Zline inside I band

Question 18

Where are thick and thin filaments anchored?

Answer 18

Thin filaments anchored to Z line

Thick anchored to Mline

Question 19

What proteins associated with the thin filament?

Answer 19

Thin- Tropomyosin, G-actin, troponin, F-actin

Thick- myosin II

Question 20

DYSTROPHIN

Answer 20

accessory protein- Anchors sarcomeres to the sarcolemma and ECM around the myocyte with CT (fibroblasts)

Question 21

Muscular dystrophies

Answer 21

genetic disorders lacking dystrophin (only in males) tears sarcolemma and cell will die. Skeletal and cardiac muscle degeneration- bad cells replaced with CT (FIBROSIS)

Question 22

motor unit

Answer 22

Lower motor neuron (LMN) + muscle fibers it innervates

Question 23

NM synapse- 4 steps of muscle contraction

Answer 23

1. synaptic vesicle w/ ACh released into synaptic cleft
2. ACh binds receptors in Junctional folds of sarcolemma
3. muscle contracts
4. AChE on sarcolemma degrades ACh in synaptic cleft so muscle can relax

Question 24

External Lamina- Structure- Function

Answer 24

like basal lamina

holds everything together has ecm and allows fluid flow. type 3 collagen

Question 25

Botulism
Black Widow
Myasthenia gravis

Answer 25

BOT- inhibits ACh release- paralysis
BW- causes release of ACh- spasms
MG- autoimmune- antibodies bind to AChRs- muscle weakness or death
Can’t keep eye open

Question 26

T Tubule

Answer 26

• invagination of sarcolemma

- carries AP to SR

Question 27

SR- function- 2 parts

What is Triad?

Answer 27

Ca bound to calsequestrin
-AP signals Ca release
2 parts: 
Terminal cisterna
Tubules
Triad: 2 terminal cisternae + 1 T tubule

Question 28

Muscle spindle

Golgi tendon organ

Answer 28

monitors length change

monitors tension change

Question 29

What two ways does CNS sense what skeletal muscle is doing? Why relevant to OMT?

Answer 29

1. muscle spindle (within muscle)- length change
2. golgi tendon organ- tension change
   also tendon sensory nerves
   - Targets of counterstrain

Question 30

Hyperplasia

Answer 30

satellite cells differentiate into myoblasts; requires intact external lamina
Muscle fiber death results in fibrosis

Question 31

cardiomyocytes- structure, location

Answer 31

cardiac muscle fibers-

located in myocardium of heart & proximal portion of pulmonary veins

Question 32

Cardiac muscle structure/ function

Answer 32

• Sarcomeres/striated
  -autorhythmic/gap junctions/ANS regulates rate-
• SINGLE NUCLEUS (Centrally located)
  -branched (pull in multiple directions)
  -INTERCALATED DISCS- Sites of attachments of end connections
  -DESMOSOMES -
  FASCIA ADHERENS- Actin

Question 33

Intercallated disc

Answer 33

very irregular- not straight as seen at LM

Question 34

Inside Cardiac Cells-
How they contract?
Where calcium?
SR compared to skeletal muscle?

Answer 34

CM gets calcium from outside the cell

• large T tubules used for calcium to pass into the cell.
• SR -sparse (source is extracelluar not intracellular like SM)
• DIAD- 1 terminal cisternae(incomplete) + 1 ttubule.

Question 35

Purkinje fibers

Answer 35

Specialized cardiac cells in subendocardium - rapidly depolarize
-transmit impulse through myocardium

Question 36

Cardiac Stress/injury

Answer 36

• Hypertrophy- increases in size and decreases inside volume

- dilated cardiomyopathy- large heart- large volume inside cavity

Question 37

Smooth muscle- location- structure- shape-

Answer 37

Hollow organs, BV's, dermis, respiratory passages
- arranged in perpendicular  layers
-Non striated
fusiform shape
-derived from one myoblast like cardiac
-single central nucleus

Question 38

Caveolae

Answer 38

SM- endocytotic vesicles (not regulated- no cathrene coat)
slowest way to bring calcium into cell
-Ca is in ECM like cardiac
but sm has no t tubules

Question 39

Smooth Muscle fiber organization- what anchored to- what stabilized by? what shape?

Answer 39

-crisscross pattern of myofilaments
-actin anchored at dense bodies (similar to Z disk)
-stabilized by intermediate filaments
fusiform shape

Question 40

3 ways of SM contraction

Answer 40

1. Electrical (ANS)
2. Mechanical (stretch-food bolus)
3. Chemical (signaling-angiotensin II/ vasoconstriction)

Question 41

Multiunit contraction vs single unit contraction

Answer 41

MU-multiple cells by single ANS neuron

SU-gap junctions allow contraction as single unit

Question 42

SM response to stress/injury

Answer 42

Hyperplasia- regenerates via mitosis

Hypertrophy- addition of proteins

Question 43

2 Non-Muscle contractile cells and examples

what most similar to?

Answer 43

1. myoepithelial cells- glands
2. Myofibroblasts- wound contraction/tooth eruption
   - both have actin/myosin & similar to smooth muscle cells