Muscle Tissue (Histology) Oct30 M2

Question 1

embryonic origin of muscular tissue

Answer 1

mesoderm

Question 2

what muscle type see no myofibrils on cross section

Answer 2

SM

Question 3

what muscle type is multinucleated

Answer 3

skeletal

Question 4

nucleus location in SM, SkM, CM

Answer 4

SM and CM: central

SKM: peripheral

Question 5

different bands and lines of striated muscles

Answer 5

A band: dark. I band: light. pseudoband H: lighter one in A band. M line in middle of H. Z line in middle of I.

Question 6

other names for plasma membrane in muscle

Answer 6

plasmalema or sarcolema

Question 7

SkM and CM: what can be seen around the cells on LM

Answer 7

CT: fibrocytes

Question 8

cardiac muscle special thing around nucleus and why

Answer 8

halo (lighter halo) bc of golgi apparatus

Question 9

name of region where two cardiac muscle cells join

Answer 9

intercalated disk

Question 10

what muscle type has satellite cells

Answer 10

skeletal muscle

Question 11

function of satellite cells

Answer 11

potential to repair muscle. if tearings, it divides and replces the muscle in that area

Question 12

location of satellite cells around the muscle

Answer 12

between the sarcolema and the BM

Question 13

BM present in what muscle types

Answer 13

all

Question 14

name of junction at end of skeletal muscle and with what structure

Answer 14

musculotendinous junction (with CT of tendon)

Question 15

other structure seen around SkM on cross section

Answer 15

reticular fibers (CT with collagen type III)

Question 16

SM cells size compared to cardiac and SkM

Answer 16

much smaller diameter for SM cells

Question 17

what muscle type under voluntary vs involuntary control

Answer 17

voluntary is skeletal

Question 18

hypertrophy vs hyperplasia: for what muscle types these terms are

Answer 18

SM: hyperplasia

SKM and CM: hypertrophy

Question 19

SKM hypertrophy: normal or not + mechanism

Answer 19

Normal: Production of myoglobin and increase in number of myofibrils in cytoplasm

Question 20

Cardiac muscle hypertrophy normal or abnormal

Answer 20

abnormal sometimes

Question 21

why use the term hyperplasia for SM

Answer 21

bc it’s the NUMBER of cells that increases, not their size

Question 22

most abundant tissue in the body

Answer 22

SKM

Question 23

3 tissue layers around SKM

Answer 23

epimysium, perimysium, endomysium

Question 24

epimysium location and def

Answer 24

surrounds all the SKM. thick layer of CT

Question 25

perimysium location and def

Answer 25

surrounds a bundle or fascicle of muscle cells. Think filaments (septa) of CT

Question 26

cells found in perimysium and what they do

Answer 26

fibrocytes. attach to other fibrocytes with gap junctions

Question 27

endomysium location

Answer 27

around cells

Question 28

endomysium content (5)

Answer 28

capillaries, nerve fibers, fibrocytes, reticular fibers, BM

Question 29

branching principle through epi, peri and endo mysium

Answer 29

vessels and nerves branch and become smaller from epi to peri to endo mysium

Question 30

the endomysium is essentially a ____

Answer 30

basement membrane

Question 31

shape of sarcolema at the junctional complexes (musculotend. junction)

Answer 31

finger like projections of the sarcolema

Question 32

what is found in the finger-like projections

Answer 32

actin filaments that insert in dense areas near on inner side of plasmalema called dense bodies

Question 33

what is found on external portion of finger like projections

Answer 33

BM interacts with collagen fibers of the CT

Question 34

how many myofibrils in one cross section of striated muscle

Answer 34

1500

Question 35

number of myosin and actin filaments in one myofibril

Answer 35

thin (actin): 3000 | thick (myosin): 1500

Question 36

shape or configuration obtained when cutting cross section of myofibril

Answer 36

hexagon

Question 37

cross section of striated muscle depends on what

Answer 37

depends on region where we cut

Question 38

4 diff cuts that can give diff cross sections of striated muscle

Answer 38

Through: I band, A band (dark portion), pseudo band H but not the middle, M line

Question 39

sarcomere size and def

Answer 39

2-3 microns. structure from one Z line to the other

Question 40

what is found at the M line (3)

Answer 40

cross bridges of myosin creatine kinase myomesin

Question 41

protein at Z line and function

Answer 41

alpha actinin. anchors actin

Question 42

what cratine kinase does at the M line and why

Answer 42

converts phosphocreatine + ADP to ATP + creatine (and can also do the opposite reaction) Reason: ATP obtained is necessary in contraction of SKM and CM

Question 43

myomesin at M line, function

Answer 43

not known

Question 44

gross components of myosin molecule

Answer 44

2 heavy chains and 4 light chains

Question 45

name of myosin molecule subunits (3)

Answer 45

``` light meromyosin (LMM) heavy meromyosin (HMM) divided into HMM subunit 1 and HMMS-2 ```

Question 46

what LMM corresponds to

Answer 46

two heavy chains halves that are far from light chains

Question 47

what HMMS-1 corresponds to (in terms of heavy and light chains)

Answer 47

region beyond the split of the heavy chains (the two heads)

Question 48

what HMMS-2 corresponds to

Answer 48

two heavy chains halves that are between LMM and split of heavy chains

Question 49

what enzyme cuts myosin into LMM and HMM

Answer 49

chymotrypsin

Question 50

what enzyme cuts HMM into HMMS-1 and HMMS-2

Answer 50

papain

Question 51

head of myosin corresponds to what subunit and what does it contain

Answer 51

HMMS-1. ATPase acivity where ATP cleaved into ADP and phosphate

Question 52

purpose of the phosphate myosin obtains in ATPase activity

Answer 52

is what generates energy for contraction

Question 53

HMMS-1 has binding site for what

Answer 53

actin

Question 54

actin monomers name and charact.

Answer 54

G-actin. Very polarized.

Question 55

actin filaments name and charact.

Answer 55

F-actin. Slightly twisted, contain groove between molecules of actin.

Question 56

molecule found in F-actin groove

Answer 56

tropomyosin. is in the groove along all the length

Question 57

what molecule attaches to tropomyosin

Answer 57

troponin

Question 58

troponin subunits

Answer 58

TnI, TnC, TnT

Question 59

TnI function

Answer 59

inhibits actin myosin interaction

Question 60

TnC function

Answer 60

binds calcium

Question 61

TnT function

Answer 61

anchors to tropomyosin

Question 62

What Ca release allows in striated muscle (mechanism for contraction)

Answer 62

binds troponin (TnC). Config change. Myosin already bound to ATP binds actin. Binding activates ATPase. Phosphate release allows bending of myosin and pulling

Question 63

the sarcoplasmic reticulum is basically the _____

Answer 63

endoplasmic reticulum

Question 64

what changes in size at contraction and what doesn't

Answer 64

sarcomere and pseudoband H decrease. Actin and myosin length unchanged.

Question 65

nebulin function

Answer 65

covers completely F-actin and serves to anchor it to alpha actinin on Z line

Question 66

Titin function

Answer 66

anchors myosin to the Z line