Histology Muscle

Front 1

what do you call the fibrous covering of muscle tissue at the fascicular level

Back 1

perimysium

Front 2

what color are slow fibers

what is their Type

Back 2

red = slow oxidative, fatigue resistant

Type I

Front 3

what type are intermediate muscle fibers

what color are they

Back 3

Type IIa

pink

Front 4

what type are fast glycolytic fibers

what color are they

Back 4

type IIb

white

Front 5

what do you call the distance between the z lines

Back 5

a sarcomere

Front 6

in skeletal muscle fibers, where does the triad of sarcoplasmic reticulum and T tubule attach

Back 6

between the A and I bands

Front 7

muscle fibers are held in alignment by
'intermediate filaments'
composed of these 2 proteins

Back 7

desmin

vimentin

Front 8

what is the ratio of actin to myosin filaments

Back 8

6 to 1

Front 9

diameter of a thick muscle filament

Back 9

12 to 13 nm

Front 10

length of a thick filament

Back 10

1.5 um

Front 11

mysosin fibers are composed of two identical heavy chains and 2 pairs of light chains

the heavy chains are enzymatically cleaved to form 2 fragments, light and heavy ______________

Back 11

meromyosin

Front 12

the rod like part of myosin is composed of what kind of meromyosin

Back 12

light

Front 13

the swiveling head of mysosin is composed of what kind of meromyosin

Back 13

heavy

Front 14

the three subunits of troponin

which one binds Ca++?

Back 14

TnT, TnL and TnC

TnC binds the Ca++

TnT binds the tropomyosin

TnL prevents the interaction between actin and myosin

Front 15

what type of actin do you find in the thin myofilaments

Back 15

type F, formed by the polymerization of G (globular) actin monomers

Front 16

how wide is a thin myofilament

Back 16

5nm in diameter

Front 17

how long is a thin myofilament

Back 17

1.0 um in length

Front 18

where do you find the tropomyosin molecule

Back 18

in the groove of the actin double helix

Front 19

in contraction, of the I, A and H bands, which one does not appear to change in length

Back 19

the A band

Front 20

what do you call that modified muscle cell that functions as a stretch receptor

Back 20

muscle spindle

or

neuromuscular spindle

Front 21

what do you call those modified muscle fibers in spindle cells?

Back 21

intrafusal fibers

2 types: bag and chain

Front 22

in cardiac muscle tissue where do you find the T tubules

Back 22

at the Z line

Front 23

does cardiac muscle exhibit triads

Back 23

cardiac muscle has diads

one T tubule and one profile of Sarcoplasmic reticulum

Front 24

what are those two proteins found in cardiac atrium cell granules

Back 24

Cardiodilatin, a vasodilator


Cardionatrin, a potent natriuretic (Na+ out) and diuretic hormone


these are homeostatic responses to high BP

Front 25

on what side of the cardiac muscle cells do you find gap junctions

Back 25

on the sides

where macula adherens contribute to their stability

Front 26

in cardiac muscle cells what are the two components of an intercalated disc

Back 26

the transverse (across) component- perpendicular to the longitudinal axis of the muscle cell; its major component is fascia adherens

the lateral (beside) component of the intercalated disc is perpendicular to the transverse component and parallel with the axis of the muscle fiber, it contains macula adherens and gap junctions

Front 27

what component of the intercalated disc do you find gap junctions

Back 27

only in the lateral component

(its probably a quieter place to communicate)

Front 28

in which part of the intercalated disc does one find desmosomes

Back 28

only in the transverse part, with the fascia adherens

Front 29

do you find z discs at intercalated discs?

Back 29

no, the transverse portion of the intercalated disc substitutes for them, actin molecules attach to it

Front 30

purkinje fibers are modified muscle fibers that transmit action potentials through which 3 structures

Back 30

gap junctions

desmosomes

fascia adherentes

Front 31

2 things you find in Purkinje fibers

Back 31

Glycogen

Mitochondria

Front 32

can smooth muscle cells regenerate

Back 32

yup

Front 33

what kind of connective tissue fiber network surrounds smooth muscle cells

Back 33

reticular

Front 34

how does the nucleus of a contracted smooth muscle cell appear

Back 34

accordion pleated

deeply indented

'tortuous'

Front 35

in smooth muscle the dense bodies are analogous to what structures in skeletal muscles

Back 35

dense bodies are analogous to z discs, anchoring myofilaments

Front 36

do smooth muscle cells have gap junctions?

Back 36

oh Yes.

Front 37

contraction of smooth muscle can be initiated by what 3 things

Back 37

neural signal

stretching

hormonal signal

Front 38

in nonvascular smooth muscle the intermediate filaments are ___________

in vascular smooth muscle the intermediate filaments are made of_____________

Back 38

nonvascular = desmin


vascular = vimentin

Front 39

vascular smooth muscle is usually initiated by a __________ signal

Back 39

neural, with very little spread of conduction between cells

Front 40

visceral smooth muscle contraction is usually initiated ___________

Back 40

myogenically, by stretch, with the signal spreading via gap junctions

Front 41

other than the uterus, which responds to oxytocin, most smooth muscle in the body responds only to ___________

Back 41

epinephrine

Front 42

what tissue do myoepithelial cells originate from

Back 42

ectoderm

(most smooth muscle cells arise from endoderm)

Front 43

in smooth muscle what does the Ca++ bind to during contraction

Back 43

calmodulin

the Ca++/calumodulin complex then binds to Myosin light chain kinase (MLCK) which then phosphorylates the regulatory light chain of myosin