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21 fall: histology > lecture 2 muscles > Flashcards

lecture 2 muscles Flashcards

1
Q

3 types of muscle

A

skeletal
smooth
cardiac

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2
Q

make up of muscles

A

contractile proteins
actin
myosin
proteins specialized in force delivery
ATP production

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3
Q

for muscle to work you need

A

communications: nerves
energy
structural support
contractile proteins

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4
Q

whole muscle is surrounded by ___

A

epimysium

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5
Q

Fasicle is surrounded by ___

A

perimysium

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6
Q

muscle fiber is surrounded by ___

A

endomysium

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7
Q

make up of a muscle from outside to inside

A

epimysium
-muscle (serveral fascicles)
perimysium
-fascicle (several muscle fibers)
endomysium
-muscle fiber
sarcolemma (plasma membrane of muscle fiber
myofibril- chain of sarcomeres
myofilaments

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8
Q

the plasma membrane of the muscle cell/fiber

A

sarcolemma

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9
Q

red blood cell are how big? Can you see them with a light microscope?

A

7 micrometers
yes

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10
Q

can you see myofibrils with a light microscope?

A

no

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11
Q

skeletal muscle has __ nucleus

A

many

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12
Q

nucleus of skeletal muscle are at the ___ of the cell

A

outside

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13
Q

what cells in skeletal muscle can divide and repair and regenerate?

A

satellite cells

live on the outside, moves inside when muscle is injured, fixes things then goes back out

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14
Q

satellite cells lie under the ___ but outside the ___

A

basal lamina (endomysium)

outside the sarcolemma (plasma membrane)

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15
Q

why can’t muscle cells fix themselves?

A

mature muscle cells are post mitotic, unable to divide

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16
Q

deep fascia (dense CT) that envelopes entire muscle and becomes less flexible with aging

A

epimysium

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17
Q

another name for endomysium

A

basal lamina

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18
Q

muscle cells form a ___ syncytium, sheathed by ___ layers of connective tissue. The CT serves as a pathway for ___ and ___ to reach individual muscle cells

A

multinucleated
three
vessels
nerves

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19
Q

single motor neuron and all the muscle fibers it innervates

A

motor unit

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20
Q

small motor units results in ___

A

fine control

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21
Q

large motor units occur in ___

A

large, powerful muscles that do not need fine control

1 neuron= many muscle fibers

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22
Q

each skeletal muscle contraction is initiated by an ___ from an alpha motor neuron

A

action potential

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23
Q

place where nerve interacts with muscle fiber

A

neuromuscular junction

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24
Q

there is ___ point/s of connection between a muscle fiber and its nerve

A

one

neuromuscular junction

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25
motorneuron ends at the \_\_\_, where the signal is transferred from the nerve to the muscle across the \_\_\_
motor end plate synaptic cleft
26
synaptic cleft
invagination on the surface of the muscle cell coated with basal lamina. acetylcholine is released from the motor neuron into the synaptic cleft- binding to ACh receptors, which causes a depolarization in the sarcolemma of the muscle cell
27
there is a __ number of nuclei at the neuromuscular junction
high highly active area of the muscle cell/fiber
28
Muscle Triad
T tubules 2 sarcoplasmic reticulum
29
action potential across a muscle travel across the sarcolemma and down into the \_\_\_. This releases \_\_\_
T tubules Calcium (Ca2+)
30
Where calcium stores live in muscle fiber
sarcoplasmic reticulum release calcium = muscle contracts take back calcium= calcium ATPase Pumps= muscle relaxes
31
skeletal muscles have \_\_: \_\_ T tubules and ___ SR and cardiac muscles have \_\_\_: \_\_ T tubules and ___ SR
Triads 1 and 2 Diads 1 and 1
32
\_\_\_ are sarcoplasmic reticulum proteins which are linked to the depolarization of T-tubules to release calcium
dihydropyride receptor Ryanodine receptor
33
\_\_\_ will bring calcium back into the sarcoplasmic reticulum
calcium ATPase pump
34
a muscle cell/fiber is composed of \_\_\_
myofibrils
35
a myofibril is composed of a repeating contractile unit known as a \_\_\_.
sarcomere
36
the ___ is the basic contractile unit of striated muscle
sarcomere
37
the sarcomere is composed of ___ and \_\_\_.
myofilaments thin filaments: actin thick filaments: myosin
38
what is z disk
border of sarcomere, where thin filament, actin align
39
what is I band
thin actin filaments only -will reduce when muscle contracts
40
What is A band
thick myosin filaments the whole length of thick myosin filaments, has zone of overlap with actin
41
What is H band
part of myosin, thick filament that does not bind with actin center part of sarcomere
42
What is M line
center of sarcomere where myosin filaments line up
43
thin filaments
actin =globular protein called G-actin G actin form chains of F actin, two chains of F actin wrap together and create a double helix. **Tropomyosin** sit in the groove of the two actin strands- extends the length of 7 actin monomers and binds the troponin complex * *Troponin** - 3 subunits - site of anchoring for myosin, thick filaments anchored to the Z-disk
44
\_\_ consist of 2 long proteins that sit in the groove between two actin strands
tropomyosin consists of two nearly identical alpha helicl polypeptides twisted around each other, tropomyosin runs in the groove formed by F-actin strands, Each molecule of tropomyosin extends for the length of 7 actin monomers and binds the troponin complex
45
Troponin
Troponin T: bind troponin to tropmyosin Troponin I: binds to actin, inhibits myosin from binding to actin by covering the binding site Troponin C: binds Ca2+
46
how does Calcium work on actin
calcium binds to TN-C (troponin-C), it triggers a conformation change in troponin allowing for the myosin cross bridges to interact with actin
47
Thick filaments
myosin thick filament is composed of 200-300 myosin molecules anchored to the M line paired **head(** cross bridging) and **tail** (self assembly region) coiled around each other Head has an actin binding site as well as an ATP binding site
48
Head of myosin has a ___ binding site and a ___ binding site
actin ATP
49
light area of sarcomere in electron microscope is the \_\_\_
I band where thin filaments are Z line connects two sarcomeres together
50
\_ bands and __ zone shrink during contaction
I band (thin only) H zone (myosin only)
51
Z line/disk/band
end of sarcomere where actin attaches
52
A band A stands for
A stands for "anisotropic"
53
I in I band stands for
isotropic
54
creatine kinase which helps for ATP is found in the __ band of the sarcomere
H
55
\_\_ keeps thick filaments in line
titin
56
titin
extends from the Z disk to the M line- keep myosin in line, ends are coiled/stretchy will stretch and contract
57
\_\_\_ will keep actin in line
nebulin
58
nebulin
extends from the Z band along the length of actin filament, keep actin inline
59
\_\_\_extends from the sarcolemma between the myofibrils helping maintain the conformation of the fibers during contractions
desmin
60
desmin
extends from plasma membrane of muscle fiber (sarcolemma) keep myofibrils in line
61
Force Delivery
proteins that deliver force from sarcomere to tendon
62
Cardiac muscle
striated intercalated discs central nucleus diads instead of triads purkinje fibers bundle of his
63
intercalated dics
allow contraction to go from cell to cell quickly, found in cardiac muscle in between cells allow transmission of the electrical signal to the next cardiac cell to stimulate contraction.
64
specialized cardiac cells that aid in the terminal conduction of the action potential to depolarize cardiac muscle
purkinje fibers
65
smooth muscle
sheets -covered by epithelium or endothelium based on where it is bundles in eyes two directions- inner circular layer, outer longitudinal layer spindle shape (long stretched out) not striated- thin and thick lined up randomly throughout cell to allow force contraction when empty or stetched central nucleus connected to each other by gap junctions
66
gap junctions in smooth muscles allows \_\_\_
synchronized overall muscle contraction
67
smooth muscles lack ___ and \_\_\_
sarcomeres and troponin
68
Most of the calcium ions initiate the contraction of smooth muscles from \_\_\_
outside the cell, not within
69
contractile proteins
generate tremendous forces that can not be transmitted through a normal cell's plasma membrane or basement membrane. To enable this force transmission, there is a system of proteins which deliver the force from the myofibrils through the sarcolemma and on to the endomysium.
70
what is the largest contractile protein
dystrophin part of the dystrophin complex of proteins (also known as the costamere). Dystrophin is an intracellular protein which connects to the myofibrils and extends to the sarcolemma, where it is attached to about 5 other smaller proteins which span the sarcolemma and pass the force on to the endomysium and then on to the tendons/bone.
71
another name for dystrophin complex of proteins
costamere
72
mutation in dystrophin protein
Duchene’s muscular dystrophy makes the dystrophin protein unable to transmit force effectively and ultimately leads to the muscle degeneration seen in muscular dystrophy.
73
mild form of muscular dystrophy
becker's dystrophy when there is a defect in one of the protein in the dystrophin complex of proteins other than Dystrophin
74
how heart pumps
The atrial contractions, which occur first, push the blood through the bicuspid or tricuspid valves. second: push the blood from the base of the ventricles upwards towards and through the valves to the aorta or pulmonary artery.
75
why does the heart have more mitochondria?
heart muscle must be very resistant to fatigue, so having a ready supply of energy is really imperative to its health.
76
why is smooth muscle disorganized, not have sarcomeres like cardiac and skeletal?
smooth muscle must undergo huge length changes and still generate force
77
smooth muscle lack ___ and \_\_\_
smooth muscle lacks the troponin tropomyosin system to control contraction.

21 fall: histology (36 decks)

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