Muscle development

Question 1

Muscle development derived from?

Answer 1

paraxial mesoderm

Question 2

Head muscles are formed by?

Answer 2

7 somitomeres

Question 3

axial skeleton/abdomen body/limbs are composed of?

Answer 3

somites

Question 4

Which molecule determines whether their is muscle differentiation or not?

Answer 4

BMP4

Question 5

BMP4 molecule gives rise to which molecules?

Answer 5

MyoD and MyF5

Question 6

What are the key structures of embryo development in charge of creating muscles?

Answer 6

dorsomedial muscle cells and ventrolateral muscle cells

Question 7

What are some muscle development conditions?

Answer 7

poland sequence
muscle dystrophies(x-linked recessive) (dystrophin gene mutation)

Question 8

What are the 3 types of muscle tissue?

Answer 8

1. smooth
2. cardiac
   3.skeletal

Question 9

What is the histological hallmark of cardiac muscle cells?

Answer 9

having intercalated discs

Question 10

How many muscles are in the human body approx.?

Answer 10

640

Question 11

Which is the smallest muscle in the human body?

Answer 11

stapedius

Question 12

Which is the longest muscle in the human body?

Answer 12

sartorius

Question 13

What is the sarcomere reffered to?

Answer 13

functional unit of the skeletal muscle

Question 14

Myofibrils are the ones that…..?

Answer 14

produce the contraction

Question 15

Which is the thin filament?

Answer 15

actin

Question 16

Which is the thick filament?

Answer 16

myosin

Question 17

What are the 2 proteins that maintains the skeletal arquitecture?

Answer 17

titin and nebulin

Question 18

Which elastic protein holds myosin in place?

Answer 18

titin

Question 19

Which elastic protein aligns actin?

Answer 19

nebulin

Question 20

Thin filament(actin) is formed by the juncture of 3 molecules?

Answer 20

1.troponin
2.tropomyosin
3.G-actin

Question 21

Troponin has 3 subunits?

Answer 21

T=has affinity to tropomyosin
I=has affinity to actin
C=has affinity to Ca+

Question 22

Action potential travels along which type of neuron?

Answer 22

efferent neurons because are the ones that get to the effector site to produce a action

Question 23

End Plate potential?

Answer 23

when ach released from NMJ enters muscle fiber and allows NA+,K+,Ca+ ions to enter causing fiber to produce ion modulated action potential

Question 24

Dystrophin

Answer 24

-located on the plasma membrane of the muscle fibers
-glycoprotein
-provides mechanical reinforcement to sarcolemma
-if not present, will be digested by proteases
-loss of dystrophin can cause degeneration of muscle fibers thus causing muscle weakness
-Causes Muscle dystrophies(x-linked recessesive)

Question 25

What are the dystrophinopathies called?

Answer 25

Becker and Duchenne

Question 26

What is dystrophinopathies?

Answer 26

-mutation in dystrophinin gene
-leads to muscle dystrophies
-main symptom is WEAKNESS(due to degeneration of the muscle fibers)

Question 27

Tubacurarine

Answer 27

blocks ACh release thus can not generate action potential

Question 28

Toxin

Answer 28

reduces ACh release thus becomes too weak to generate an action potential

Question 29

Which is the molecule that act as a Ca+ buffer in the sarcoplasmic reticulum? (molecule that holds excess Ca+)

Answer 29

calsequestrin

Question 30

Ca+ will bind to _____________ and ___________ thus __________ binding sites

Answer 30

tropomyosin and troponin
unblocking

Question 31

Each cross-bridge cycle(contraction) “walks” myosin head, how many nanometers?

Answer 31

10 nanometers along the actin filament

Question 32

Muscles ALWAYS _____________________?

Answer 32

PULL

Question 33

Heavier the weight= __________ muscle fiber shortens, _________ duration of contraction, ___________ speed of contraction

Answer 33

less shortens
less duration
slower speed

Question 34

Lighter the weight= __________ muscle fiber shortens, _________ duration of contraction, ___________ speed of contraction

Answer 34

more shortens
more duration
faster speed

Question 35

Isotonic

Answer 35

-movement
-muscle contracts and shortens(thus allowing movement)

Question 36

Isometric

Answer 36

-NO movement
-muscle contracts BUT does nor shorten (thus not allowing movement)

Question 37

Toxin of tetanus?

Answer 37

tetanospasmin

Question 38

Fast reacting muscles, have …….

Answer 38

more neuronal tissue than muscle tissue

Question 39

Slow reacting muscles, have…….

Answer 39

more muscle tissue than neuronal tissue

Question 40

tetanization

Answer 40

continous contraction that cannot return to resting state