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Pathophysiology > Chapter 12 > Flashcards

Chapter 12 Flashcards

1
Q

skeletal muscle fiber characteristics

A

large, multinucleate cells that appear striped or striated under the microscope.

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2
Q

Cardiac muscle fiber characteristics

A

also striated but they are smaller, branched, and uninucleate. Cell sare joined in series by junctions called intercalated discs, which help transmit rapid signaling.

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3
Q

satellite cells

A

multi potent cells that eventually differentiate into muscle cells.

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4
Q

skeletal muscle breakdown

A

made of several muscle fascicles which are bundles of muscle fibers.

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5
Q

Muscle Cell ::___

A

muscle fiber

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6
Q

cell membrane ::__

A

Sarcolemma

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7
Q

Cytoplasm ::__

A

Sarcoplasm

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8
Q

Endoplasmic reticulum ::__

A

Sarcoplasmic reticulum

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9
Q

T Tubules

A

extensions of the cell membrane (sarcolemma)that associate with the ends (terminal cisternae) of thesarcoplasmic reticulum. brings actionpotentials into interiorof muscle fiber.

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10
Q

Sarcoplasmic reticulum

A

stores Ca2+

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11
Q

Thick filaments

A

~ 250 myosin molecules join to create a thick filament

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12
Q

Thin filaments

A

Actin is a protein that makes up thin filaments.

Multiple single actin molecules (G-actin) line up to form F-actin filaments; in skeletal muscle, 2 F-actin polymers twist together to create thin filaments

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13
Q

Myofibril structure

A
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14
Q

I band

A

Z disc is in the middle

contains actin only

from one myosin/actin overlap to another, with actin the only thing in the middle

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15
Q

A band

A

from I band to I band

edges contain actin and myosin overlap

H zone in the middle

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16
Q

H zone

A

Myosin only

in the middle of the sarcomere

edges are where myosin/actin overlaps are

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17
Q

M Line

A

Smack dab in the middle of the sarcomere

Myosin linked with accessory proteins

In the middle of the H band

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18
Q

Z disc

A

the Z shaped line that occurs when titin:Actin: titin connects with Actin:Actin

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19
Q

Titin

A

a giant accessory protein that spans the distance from one Z disc to the neighboring M line

Provides elasticity and helps align myosin

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20
Q

Nebulin

A

a giant accessory protein that lies along the thin filament and attaches to a z disc.

Does not extend to the M line.

It helps align actin

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21
Q

muscle tension

A

•force created by muscle contraction

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22
Q

Load

A

weight or force opposing contraction

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23
Q

Contraction

A

•creation of tension in muscle

(requires ATP)

24
Q

Relaxation

A

•release of tension caused by a contraction

25
strucutre of sarcomere during contraction
sarcomere shortens during contraction, as actin and myosin slide past one another the H zone and I band both shorten The A band remains the same size
26
During relaxed state ...
Myosin head is cocked Tropomyosin partially blocks binding site on actin Myosin is weakly bound to actin
27
In rigor state...
Myosin is bound to G protien on actin. No ATP or ADP is bound to myosin This is very brief! Ends when ATP binds to myosin, which releases myosin from G protein
28
myosin head re-cocking
Myosin hydrolyzes ATP --\> ADP. The energy released rotates the myosin head back to a cocked position, where it weakly binds/associates with the actin G protein.
29
Power stroke
myosin:ADP is weakly associated with actin G protien. Ca signal comes in, and Ca binds to Troponin--\> this makes tropomyosin shift, exposing the binding site on Actin Myosin binds strongly to actin, and actin shifts. This is the power stroke. Myosin releases ADP at the end of the stroke.
30
Motor end plate
a region of muscle membrane that contains high concentrations of ACh receptors.
31
The neuromuscular junction
consists of axon terminals, motor end plates on the muscle membrane, and Schwann cell sheaths.
32
To end a muscle contraction, Ca2+ needs to be removed from the sarcoplasm...
1. Ca-ATPase pumps Ca back into the sarcoplasmic reticulum 2. overallt decreas of Ca concentration causes Ca to unbind from troponin 3.
33
Excitation- Contraction coupling
End plate potential--\> twitch--\> latent period
34
End plate potential
caused by depolarization at the muscle
35
Muscle twitch
A single contraction- relaxation cycle
36
latent period
•the short delay between the muscle action potential and beginning of muscle tension development –this represents the time required for calcium release and binding to troponin
37
slow twitch fiber
•Rely primarily on oxidative phosphorylation Darker in color, fatigue less easily. Marathon runners have more slow twitch
38
fast twitch fiber
–Develop tension faster Split ATP more rapidly Rely primarily on anaerobic glycolysis •Use oxidative and glycolytic metabolism Lighter in color- fatigue more easily. Sprinters have more fast twitch fibers.
39
Length- tension relationship
There is an ideal resting tension of the actin and myosin filaments. Anything greater or lesser than the optimal length is going to decrease the ability of the fiber to contract to its fullest potential.
40
Summation
Stimuli closer together do not allow muscle to relax fully
41
unfused tetanus
many small rapid contractions are happening and summating to the point where they are at their maximum tension. There are small wave breaks.
42
complete tetanus
Muscle reaches steady tension. If muscle fatigues, tension decreases rapidly.
43
motor unit
one motor neuron and all the muscle fibers it innervates. A muscle may have many motor units of different types
44
contraction force
•Recruitment of additional motor units by the nervous system increases contraction force •Asynchronous recruitment of motor units helps avoid fatigue –Different motor units take turns maintaining tension
45
isotonic contraction
concentric action creates a shortening eccentric action creates a lengthening isotonic contraction creates a force to move a load
46
isometric contraction
the muscle isnt changing in size. creates a force, without moving a load
47
bones form \_\_\_
levers
48
joints form \_\_\_
Fulcrums
49
relaxed phasic smooth muscle contraction graph
Example: esophagus
50
Cyclicly contracting phasic smooth muscle
like the intestines
51
Tonic smooth muscle that is usually contracted
ex: a sphincter that relaxes to allow material to pass
52
tonic smooth muscle with varied contraction
ex: vascular smooth muscle
53
Single unit smooth muscle cells
connected by gap junctions- allows muscles to act as one functional unit. ex: Contracting uterus
54
multi-unit smooth muscle cells
are not electrically linked. each cell has to be stimulated independently. ex: eyeball
55
smooth muscle properties
acts slower uses less energy one nucleus not arranged in sarcomeres controlled by ANS More actin, less myosin no Troponin No t-tubules--\> caveolae Ca2+ from the extracellular fluid initiates a cascade ending with phophorylation of myosin light chain and activation of myosin ATPase

Pathophysiology (8 decks)

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