w8 histology of muscle

Question 1

spindle-shaped central nucleus, no striations which muscle tissue, single cells, single central nucleus

Answer 1

smooth muscle

Question 2

linear branched, single central nucleus, intercalated discs

Answer 2

cardiac muscle

Question 3

elongated, striated many peripheral nuclei

Answer 3

skeletal muscle

Question 4

largest striated peripheral nuclei

Answer 4

skeletal

Question 5

branched intercalated discs, striated central nuclei (larger cytoplasm to nuclear ratio)
cylindrical cells arranged end to end, fatty acids as a major fuel

Answer 5

cardiac

Question 6

smallest fusiform, not striated, central nuclei (small cytoplasm to nuclear ratio)

Answer 6

smooth

Question 7

surrounds single muscle fiber (cells)
runs parallel to muscle fibers
contains small blood vessels, fine neuron branches

Answer 7

endomysium

Question 8

-surrounds the facicles (bundles) of muscle fibers
-larger blood vessels and nerves travel here

Answer 8

perimysium

Question 9

-covers entire skeletal muscle
-major vascular and nerve supply penetrates here

Answer 9

epimysium

Question 10

structural and functional unit of muscle fiber is what

Answer 10

myofibril

Question 11

myofibrils are composed of bundles of what

Answer 11

myofilaments

Question 12

what gives the straited appearance

Answer 12

myofilaments

Question 13

which is thick and thin myofilaments

Answer 13

myosin - thick
actin - thin

Question 14

sarcomere is between what lines

Answer 14

Z lines

Question 15

A band includes what myofilaments

Answer 15

actin and myosin

Question 16

I band includes what myofilaments

Answer 16

actin only

Question 17

what is the most clincally important accessory protein and what does it do

Answer 17

dystrophin
links actin in outermost myofilaments to transmembrane proteins and eventually to fibrous endomysium surrounding the entire muscle cell

Question 18

which bands shorten and do not

Answer 18

A band does not shorten
H band shorterns
I band has the distance between A bands of successive sacromeres shorten

Question 19

H band includes what myofilament

Answer 19

only myosin

Question 20

what are invaginations of plasma membrane

invaginations of the sarcolemma penetrating into the myocyte interior, forming a highly branched and interconnected network that makes junctions with the sarcoplasmic reticulum.

Answer 20

T tubules

Question 21

what role does SR (smooth ER of muscle) play in muscle

Answer 21

calcium storage, release, re-uptake

Question 22

what are dilated portions of SR

Answer 22

terminal cisterna

Question 23

what is the contact between a T-tubule and 2 terminal cisternae

Answer 23

triad

Question 24

what is rigor mortis

Answer 24

permanent contraction due to depletion fo ATP postmortem
muscle cells unable to prevent calcium entry therefore myosin binds to actin

Question 25

what is the stretch receptor

Answer 25

muscle spindle

Question 26

multinucleated syncytium is formed by fusion of what

Answer 26

myoblast

Question 27

syncytium

Answer 27

A large cell-like structure formed by the joining together of two or more cell

Question 28

satellite cell function and location

Answer 28

Satellite cells are myogenic stem cells responsible for muscle regeneration throughout the lifespan (skeletal muscle repair) between the sarcolemma and basal lamina of their associated muscle fiber

Question 29

how is the mitochondria number in cardiac muscle and where are the glycogen storage

Answer 29

numerous large mitochondria glycogen stores adjacent to each myofibril

Question 30

how do cardaic T tubulers compare w skeletal muscle

Answer 30

larger, and located at the level of the Z line

Question 31

in cardiac muscle, portion of the sarcoplasmic reticulum adjacent to T tubule is organized as a what

Answer 31

diad

Question 32

intercalated disc contains what kind of junctions

Answer 32

gap junctions, fascia adherens, desmosomes

Question 33

in transverse regions between cardiac muscle cells, what do fascia adherens and desmosomes do

Answer 33

bind cells together, prevents separation during contraction cycles

Question 34

what type natriuretic factor is elevated in congestive heart failure

Answer 34

B type

Question 35

what systems innervate/stimulate cardiac muscle

Answer 35

sympathetic and parasympathic (modify rate of contraction but do not initiate it)

Question 36

can cardiac tissue regenerate in adult humans?

Answer 36

no

Question 37

what muscle has the greatest capacity to regenerate

Answer 37

smooth muscle, capable of dividing

Question 38

close to endothelial cells of blood capillaries and small venules (source of new smooth muscle cells repair damage)

Answer 38

pericytes

Question 39

what do dense bodies do and what do they attach to

Answer 39

serve as anchors from which the thin filaments can exert force (analogous to Z lines) attach to actin and intermediate filaments

Question 40

are there T tubules in smooth muscle contraction

Answer 40

no

Question 41

contraction speed and energy use compared to skeletal muscle

Answer 41

smooth muscle contracts more slowly and uses less energy than skeletal muscle (lower myosin ATPase activity results in slower contraction) (slower rate of Ca2+ removal results in slower relaxation)

Question 42

what nerve endings release acetylcholine or norepinephrine

Answer 42

autonomic nerve endings

Question 43

what may depolarize spontaneously or in response to chemicals binding to receptors linked to G-proteins

Answer 43

hormones and local factors

Question 44

lack of oxygen, histamine, excess CO2, low pH may signal what

Answer 44

signal contraction by affecting Ca2+ entry into the sarcoplasm

Question 45

smooth muscle innervation done by what axon terminals

Answer 45

autonomic

Question 46

smooth muscle what kind of junctions connect adjacent cells

Answer 46

gap junctions

Question 47

smooth muscle cells can synthesize what

Answer 47

collagen, elastin, proteoglycans, (influences extracellular matrix)