Muscle

Question 1

Muscle surrounded by dense connective tissue.

Answer 1

Epimysium

Question 2

What are muscle fiber bundles (fascicles) surrounded by?

Answer 2

Perimysium

Question 3

Muscle fiber bundles consist of what?

Answer 3

Multinucleated muscle fibers that are 10-100um wide and up to 30 cm long.

Question 4

What is endomysium made up of?

Answer 4

Basal lamina and reticular.

Question 5

Where the shit do nuclei lie in muscle fibers?

Answer 5

Just beneath the sarcolemma.

Question 6

Satellite cells found where?

Answer 6

Between sarcolemma and basal lamina.

Question 7

When do cells proliferate from satellite cells?

Answer 7

After trauma.

Question 8

List the order of muscle divisions from largest to smallest.

Answer 8

Muscle-> Fascicle-> Fiber->Myofibril->Myofilaments

Question 9

What is the function unit of contraction!

Answer 9

Sarcomere

Question 10

If I fold in a piece of the sarcolemma (plasma membrane) what do I call that?

Answer 10

T-tubule

Question 11

What is the specialized endoplasmic reticulum called in muscle cells?

Answer 11

Sarcoplasmic reticulum

Question 12

A T-tubule sandwiched between two portions of sarcoplasmic reticulum is called what?

Answer 12

A triad.

Question 13

Where are triads found?

Answer 13

A and I band junctions.

Question 14

What innervates muscle cells?

Answer 14

Motor end plate at the myoneural junction.

Question 15

True or false? Axons going to muscle cells lose their myelin but are still covered by Schwann Cells?

Answer 15

True.

Question 16

What name did people rename Schwann Cells that reach the motor end plate?

Answer 16

Teloglia

Question 17

Acetylcholine crosses what to get from axon terminals to muscle receptors?

Answer 17

Synaptic cleft

Question 18

What is the place acetylcholine receptors are located called?

Answer 18

Junctional folds (subneural clefts) of the sarcolemma

Question 19

How many muscle fibers can a single nerve innervate? And what is this unit called?

Answer 19

One or more. Whatever an axon innervates is referred to as the motor unit

Question 20

Where does Botulism bind to block Acetylcholine (Ach)?

Answer 20

Presynaptic membrane of axon. (Remember it like how botters are goddamn lazy so they don’t bother to go across synaptic cleft)

Question 21

Where does Curare block Ach?

Answer 21

Ach receptor across synaptic cleft. (Remember how “Cur” like a villain will take your shit (receptors).

Question 22

How does Myasthenia Gravis block Ach?

Answer 22

It’s an autoantibody so it attacks the Ach receptor itself. (Remember it as “My” (from Myasthenia) stupid body is attacking itself.)

Question 23

How is action potential brought into the cell?

Answer 23

Via the transverse T tubule system and continuous with the sarcolemma.

Question 24

If I depolarize the cell what will I release and from where?

Answer 24

Ca++ and from the terminal cisternae of the sarcoplasmic reticulum.

Question 25

Describe Red Fiber muscles to me.

Answer 25

Known as type 1 slow twitch, they have high myoglobin, lots of mitochondria, and fatigue resistant.

Question 26

Now do White Fibers.

Answer 26

Type 2, fast twitch, low myoglobin, more stored glycogen, more atpase activity.

Question 27

If I decide to play Frankenstein and start switchin nerves that innervate red and white fibers what will happen?

Answer 27

I can change a red fiber to a white fiber or vice versa.

Question 28

Where do muscle spindles run?

Answer 28

Parallel with the main muscle fibers.

Question 29

And what do the muscle spindles do while we're at it?

Answer 29

They sense changes in muscles length.

Question 30

Intrafusal muscle fibers are skeletal muscle fibers that serve as specialized sensory organs (proprioceptors) inside muscle spindles that detect the amount and rate of change in length of a muscle. They constitute the muscle spindle and are innervated by two axons, one sensory and one motor.

Answer 30

I wasn't asking anything, it was just something from the notes annoying me.

Question 31

If a sensory nerve is stretched what will happen to the nerve discharge rate?

Answer 31

That shit'll go up.

Question 32

Actually, back to intrafusal fibers for a second what are the two types them?

Answer 32

Nuclear bag and nuclear chain.

Question 33

What are the three types of afferent nerve fibers that spindle muscles will recieve?

Answer 33

Annulospiral (spiral), flower spray (cluster), and y-efferents (fusimotor).

Question 34

What's Rigor Mortis and how does it happen?

Answer 34

Ca++ helps myosin and actin attach. And ATP pumps the Ca++ out. But here's the problem once a person dies they run out of ATP to pump the Ca++ out and cell become even more permeable to the Ca. So the muscles stay stuck together.

Question 35

What happens in muscle atrophy?

Answer 35

Muscle fiber size is reduced, the number of fibers itself doesn't change.

Question 36

Can I see myofilaments in a light microscope?

Answer 36

No. Go get an electron microscope.

Question 37

List the four main proteins of myofilaments.

Answer 37

Actin, tropomyosin, troponin, and myosin.

Question 38

What's titin do?

Answer 38

Connects mysoin to Z disk and keeps myosin filaments in sarcomere. (Remember that myosin is the thick filament and titin is the only "Titan" that can hold it in place)

Question 39

Nebulin does what?

Answer 39

Inelastic protein attached to z disk, runs parallel to actin. (Remember it as it's like a nebulla in space. It doesn't really do anything.)

Question 40

Myomesin is what?

Answer 40

Myosin binding protein, holds myosin filaments in register at M-line.

Question 41

C protein?

Answer 41

Myosin binding protein - functions similar to myomesin

Question 42

a- actinin?

Answer 42

Bundles actin filaments into parallel arrays and anchors them to the z disk.

Question 43

Desmin: Intermediate filament that helps bind myofibrils to each other. Also encircles Z-disk and is linked to each other by plectin protein.

Answer 43

I fucked up and put definition in first box so there ya go.

Question 44

Dystrophin?

Answer 44

Actin binding protein- absent in Duchenne muscular dystrophy patients.

Question 45

Difference between F-actin and G-actin?

Answer 45

F-actin is made out of globular actin.

Question 46

What regulates polymerization of actin?

Answer 46

thymosin B4

Question 47

How large is tropomyosin? And where is it?

Answer 47

35K m.w. Lies in the grooves of the actin helix.

Question 48

What three molecules of troponin does tropomyosin bind?

Answer 48

Tn-T, Tn-I, and Tn-C

Question 49

What does each do?

Answer 49

Tn-T: binds the Tn complex to tropomyosin Tn-I: inhibits the binding of actin to myosin Tn-C: Ca binds here and stops Tn-I from inhibiting the binding.

Question 50

aB-crystallin protects what?

Answer 50

Desmin from stress induced damage

Question 51

How many myosin molecules do thick myofilaments consist of?

Answer 51

300-400

Question 52

How many chains is each myosin molecule made up into?

Answer 52

2 heavy chains and 2 light chains.

Question 53

During proteolytic digestion the heavy chain cleaves and produces what?

Answer 53

Globular head termed heavy meromyosin and rodlike a-helical tail called light meromyosin.

Question 54

How many light chains does each mysoin head bind?

Answer 54

2

Question 55

In striated muscle what does myosin form?

Answer 55

bipolar filaments

Question 56

Where is the actin and ATP binding region located?

Answer 56

Heavy meromyosin on the head

Question 57

Where is the nucleus located in cardiac cells?

Answer 57

More centrally than in skeletal muscle.

Question 58

How many nuclei are there per cardiac cell?

Answer 58

1

Question 59

What joins the cardiac cells into a cardiac muscle fiber?

Answer 59

Intercalcated dics.

Question 60

What does the intercalcated disc transverse portion contain?

Answer 60

Fasciae adherens (which is an actin filament anchor site) and macula adherens (desmosomes)

Question 61

The lateral portion of intercalcated discs have?

Answer 61

Gap junctions

Question 62

Cardiac muscle has more of what than skeletal muscle?

Answer 62

Mitochondria and extrafibrillar sarcoplasm

Question 63

How are the T-tubules different between cardiac and skeletal?

Answer 63

They are larger in cardiac muscle and located at the Z-disk.

Question 64

Cardiac v. Skeletal triads?

Answer 64

Triads less common in cardiac, diad arrangement where it's at.

Question 65

What is smooth muscle under the control of?

Answer 65

Sympathetic or parasympathetic nervous system.

Question 66

What shape are smooth muscle cells?

Answer 66

Spindle shaped.

Question 67

How many nuclei for SM?

Answer 67

1 located in the center with 1 or more nucleoli.

Question 68

What do the gap junctions do for smooth muscle cells?

Answer 68

They facilitate electrical conduction.

Question 69

Where are myoepithelial cells of ectodermal origin (single smooth muscle cells) found?

Answer 69

Sweat, salivary, lacrimal, and mammary glands.

Question 70

Mesodermal origin SM cells found?

Answer 70

Respiratory, circulatory, digestive, and reproductive tracts.

Question 71

Ectodermal origin of SM?

Answer 71

Iris and ciliary body of the eye,

Question 72

Does smooth muscle contain sarcomeres?

Answer 72

No.

Question 73

Function equivalent of Z disk in smooth muscle?

Answer 73

Membrane associated and cytoplasmic dense bodies containing a-actinin

Question 74

Smooth muscle cytoplasm contains actin and tropomyosin but is missing what?

Answer 74

troponin

Question 75

SMooth muscle myosin has how many heavy and light chains?

Answer 75

2 heavy 4 light

Question 76

When is SM completely soluble?

Answer 76

When SM myosin is dephosphorylated.

Question 77

In SM what does Ca complex with?

Answer 77

Calmodulin

Question 78

What does the Ca-calmodulin complex activate?

Answer 78

Myosin light chain kinase which phosphorylates myosin

Question 79

What is the effect of cAMP on SM?

Answer 79

It can activate myosin light chain kinase thereby also allowing myosin to interact with actin.

Question 80

Estrogen effect on cAMP?

Answer 80

Increase

Question 81

Progesterone effect on cAMP?

Answer 81

Decrease