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APK2100 EXAM 2 > Ch. 10 > Flashcards

Ch. 10 Flashcards

1
Q

What does the root word Sarc- mean?

A

Flesh

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2
Q

Define Sarcolemma, sarcoplasma, and sarcoplasmic reticulum

A

Plasma membrane of muscle fibers
cytoplasm of muscle fibers
Smooth ER of muscle fibers

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3
Q

What are the functional characteristics of all muscle cells which basically apply to all muscles but she is going to focus on skeletal?

A

Contractility- ability to shorten and generate forces muscles only pull
Excitability- ability to respond to stimuli by producing electrical signals that come from the somatic motor neurons
Extensibility- ability to stretch without damage
Elasticity- ability to return to its original shape following distension

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4
Q

What are the functions of muscles?

A

Movement
Posture and joint stabilization (examples knee joint, glenohumeral joint—>rotator cuff muscles)
Open/close body passage ways- forming sphincters that are found at body opening (orbicularis oculi, orbicularis oris)
Thermogenesis

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5
Q

How do smooth muscle and skeletal muscle thermoregulate the body?

A

Skeletal muscles: produce heat
–involuntary(when you are so cold you start to shiver, you trying to prevent that is what causes those shivery shakes) and voluntary contraction
–contracting them causes to increase their metabolism and heat is a byproduct.
Smooth muscle: helps prevent heat loss
–goose-bumps: via the arrector pilli muscle—> in terms of furry animals, this muscle sticks their hairs up to prevent heat loss.
–Dartos muscle: when the scrotum is cold, it crinkles the skin of the scrotum making it thicker so too much heat doesnt come out and bringing the testes (which are inside the scrotum) closer to the body to keep them closer to core body temp

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6
Q

What is endomysium?

A

Connective tissue sheath that wraps around the individual muscle fibers and fills up the space in between muscle fibers.

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7
Q

What are fascicles?

A

A bundle of muscle fibers wrapped by endomysium that are collectively wrapped by perimysium. Groups of fasciles create the muscle organ

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8
Q

What is the function of the connective tissues in muscular tissue?

A

provide an elasticity component to muscles
to bind the cells together in an organized manner (sheaths)
—sheaths hold skeletal muscle tightly together in parallel alignment so that they can generate forces as a whole

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9
Q

What are tendons and what are they made out of?

A

Connect muscles to bones
They are continuous with the perimysium, endomysium, and epimysium.
Dense regular connective tissue proper- same as ligaments

(REMEMBER: periosteum is made of dense irregular, and holding the periosteum is are perforating collagen fibers—sharpeys fibers)

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10
Q

What is an aponeurosis?

A

A broad, flat tendon

has all three connective tissue sheaths

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11
Q

What is indirect and direct attachment?

A

Indirect= has a very long cord like tendon or an aponeurosis

Direct: the tendon is so short that it looks like the muscle is attaching directly to the bone.

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12
Q

What is origin and insertion?

A

Origin: does not move
Insertion: muscle

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13
Q

What is the difference between a sprain and a strain?

A

Sprain: damaged the ligaments
STrain: damaged the muscles or tendons
“t for tendon”

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14
Q

Muscles as organs contain what types of tissues?

A

Skeletal, connective, nervous, blood vessels

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15
Q

A muscle cell can be innvervated by an axon how many times?

A

ONLY ONCE; EVERY SINGLE MUSCLE CELL IS INNVERVATED THIS WAY

Each axon making up the nerve may synapse with multiple muscle cells but each muscle cell is innervated ONCE.

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16
Q

What is a motor unit?

A

somatic motor neuron + all of the individual muscle cells that are innvervated by that neuron.

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17
Q

Each muscle is typically innvervated by how many arteries?

A

typically one and it branches out extensively within the CT sheaths.

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18
Q

The capillary networks in the endomysium are arranged in what manner and why?

A

Muscle tissue and muscle cells are elastic and extensible —> they can stretch and recoil with no damage.
Capillaries are not elastic nor extensible so they are arranged in a wavy kinky manner so that when the muscle does stretch, the capillaries straighten out and do not rupture.
When the muscle is relaxed, it returns to its natural shape using its natural elastic recoil ability

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19
Q

What color is the A band?

A

Dark, denser proteins

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20
Q

What color is the i band?

A

Lighter, less dense proteins

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21
Q

What are the contractile organelles of muscle cells?

A

myofibrils, there are bundles of them in on muscle fiber

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22
Q

Why are skeletal muscle cells striated?

A

because the light stripes and dark stripes of the myofibrils line up so what is reflected when looking from the sarcolemma inwards are striations

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23
Q

What are sarcomeres?

A

the smallest functional unit of contraction of a whole skeletal muscle.
in series they create myofibrils.
z-disk/line to z-disk/line

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24
Q

What are z-discs and functions?

A

distinct line running down the i band that represents the end of a sarcomere
anchors the actin of adjacent sarcomeres

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25
Q

What is the m-linE and it’s function?

A

midline of the sarcomere. dense band of protein running down the middle of the A band.
Function: lots of proteins that are holding the myosin filaments together on both sides so essentially fusing them together

26
Q

What is the A band?

A

represents the length of the myosin thick myofilament that is making up the midsection of the sarcomere

27
Q

What is actin?

A

thin myofilament that is found in both the I band and A band

28
Q

What is the I band?

A

light band, does not contain myosin thick myofilament and is shared by adjacent sarcomeres

29
Q

What happens to the H-zone during contraction?

A

Heads of myosin are pulling the actin filaments towards the M-line causing the H-zone to go away or disappear

30
Q

What are myosin thick myofilaments?

A

strands of protein that have bulbous looking heads that look like double headed gold clubs and point towards the z-disc

31
Q

What is the H-zone?

A

no heads of myosin there. bare zone

32
Q

What is Titin and functions?

A

structural protein
looks like an acordian or nesting dolls
A large ELASTIC protein
Function: Anchors the myosin thick myofilaments to the z-discs
Function: As the muscle becomes stretched out, titin basically unfolds and allows the sarcomere to stretch out and helps it recoil back into position. gives the tissue as a whole extensible and elastic.

33
Q

What proteins are in the I band?

A

Actin, titin, z-discs

34
Q

What is the 3-D or realistic shape of myofibrils and how many actin filaments encircle on myosin myofilament in a sarcomere?

A

Cylindrical shape and 6 actin to one myosin

35
Q

What are three types (overall categories) of proteins in the myofibrils and what are the proteins in each category?

A

Contractile - myosin/actin
Regulatory - Troponin/Tropomyosin
Structural proteins - titin/ dystrophin

36
Q

What is the shape of actin?

A

double helix, like two strands of pearls intertwined

37
Q

What is the myosin binding site and what happens during contraction?

A

located on actin filament
Where the double head of the myosin is able to chemically bind with an individual actin filament
during contraction: myosin binds to an actin and it cranks/pivots it towards the midline

38
Q

What is the purpose of the regulatory proteins?

A

regulate the process whether or not actin and myosin will bind or not.

39
Q

What is tropomyosin and function?

A

cord like fibrous protein that stretches along the actin filaments.
one tropomyosin for each strand of the double helix of the actin filament
Function: to cover the myosin binding site preventing the myosin head to bind

40
Q

What is troponin and function?

A

Protein complex that is attached to the tropomyosin
Function: bind Ca2+ ions
When Ca2+ is present, it will bind to the troponin and cause a conformational change pulling off the tropomyosin off of the actin freeing the myosin binding site.
–without the conformational change of troponin, calcium ions, tropomyosin being pulled off you do not get muscle contraction. all this must occur for there to contraction!

41
Q

What is dystrophin and function?

A

Structural protein
Located at the ends of the myofibrils where they are coming in contact with the sarcolemma
Function: protein complex that anchors the myofibrils to the sarcolemma so that when they contract, the whole cell contracts.

42
Q

What are T-tubules and function?

A

Transverse tubules
A tubule of the sarcolemma passing its way transversely through the myofibrils
Function: tell the sarcoplasmic reticulum when to release calcium

43
Q

What is the sarcoplasmic reticulum and function?

A

membrane enclosed organelle
mesh-like that surrounds all of the myofibrils
Smooth ER of muscle fibers
houses and stores calcium

44
Q

Where are the terminal cisternae (cistern single) located and what do they look like?

A

Located where the Sarcoplasmic reticulum and t-tubule meet.

This part of the Sarcoplasmic reticulum is much thicker.

45
Q

What is a triad and where do they occur and function?

A

Where the Terminal cisternae from both sides of the T-tubules meet up.
Occur where the A-band ends and the I-band begins (twice in on sarcomere) called the A-I Junction
Function: allows for even distribution of calcium throughout the entire length of the myofibrils

46
Q

Describe the sliding filament mechanism of contraction?

A

When individual heads of myosin are grabbing actin filaments at different time than the myosin head on the other side of the sarcomeres. They take turns
They do not grab at the same time
This allows for a smooth contraction

47
Q

During contraction which band stays the same and which band gets smaller?

A

I band gets smaller because there is never myosin in it and the myosin heads are pulling the z-disc closer towards the m-line.
None of the proteins are shortening, only the actual myofibril will shorten and I band. A band stays the same because it is the length of the myosin filament.

48
Q

Do all muscles need nervous innervation to contract?

A

No, cardiac myocyes do not need to

49
Q

What is the difference between small and large motor units?

A 
Small = less innervation because movement needs less contraction capacity, so does not need a lot of force but requires fine movement
Large= less fine tuning, but needs a lot of force
50
Q

What are the three main components of a neuromuscular junction?

A

axon terminal, junctional folds of the sarcolemma, synaptic cleft

51
Q

What is the terminal bouton and what is inside of it for what purposes?

A

The axon terminal, bulbous shape.

  • Abundance of mitochondria: producing the energy necessary for exocyotsis to occur
  • synaptic vesicles containing neurotransmitter ACh
52
Q

What is the synaptic cleft and what is happening there?

A

-physical space that exists between the axon terminal and the junctional folds of the sarcolemma (motor end plate)
space is filled with extracellular fluid
-What is happening is ACh is being exocyosed and its diffusing down the synaptic cleft until it reaches the sarcolemma of the cell.

53
Q

What is the motor end plate and purpose?

A

Junctional folds of the sarcolemma
contains ACh receptors which are transmembrane proteins
Function: triggers the electrical thing that happens on the surface of the cell which will then go into the cell and tell it do its contractile thing.

54
Q

What is myoglobin content of type1, typeiia, and type 2b/iix?

A

High (red), not as high (pink), low (white)

55
Q

Contraction velocity of typei, typeiia, typeiib/iix

A

slow, fast, fast

56
Q

Metabolic process of typei, typeiia, typeiib/iix

A

aerobic, anaerobic/aerobic, anaerobic

57
Q

Fatigue resistance of typei, typeiia, typeiib/iix

A

High, medium, low

58
Q

Fiber diameter of typei, typeiia, typeiib/iix

A

small, intermediate, large

59
Q

primary functions of typei, typeiia, typeiib/iix

A
  • maintaining posture, endurance activities
  • walking sprinting
  • rapid intense movement for short durations
60
Q

What plays a predominant role in muscle fiber distribution?

A

genes

muscles have all three types,just depends how much of each one.

APK2100 EXAM 2 (4 decks)

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