GMS 6474 Exam TEST Questions and
Answers (A+ Solution guide)
Muscles can either be ____ or ____? - Answers -✔✔ 1. Voluntary
2. Involuntary
What is one question to ask when comparing voluntary to involuntary muscles? -
Answers -✔✔ How is the underlying tissue metabolized?
Cardiac functional syncytial vs smooth muscle functional syncytial? - Answers -✔✔
Cardiac - pacemaker cells cause contractions
Smooth - vasodilation/vasoconstriction
True/False: Smooth muscle has striations? - Answers -✔✔ FALSE!
what two factors determine the force production at the sarcomere level? - Answers -✔✔
If they are arranged in parallel or series!
True/False: skeletal muscle cells contain many nuclei and very long - Answers -✔✔
TRUE!
Myofibrils are responsible for what 3 things? - Answers -✔✔ 1. tension generation
2. force production
3. shortening of muscle
What is a sarcomere? - Answers -✔✔ Basic unit of muscle that extends from Z-disc to
Z-disc
Sliding filament theory? - Answers -✔✔ The thick/thin filaments do not change but the
overlap does!
H zone? - Answers -✔✔ H for "heal" aka "light" only tails of myosin molecules
*** THIS COULD DISAPPEAR DUE BC OF CONTRACTIONS**
A-band? - Answers -✔✔ both thick and thin
I band? - Answers -✔✔ only thin - extends both sides of the z-disc
***THIS WILL SHORTEN IF THE MUSCLE CONTRACTS***
What is a triad? - Answers -✔✔ SR, T Tubule, SR
,Why is T-Tubule important? - Answers -✔✔ muscle cells are really long so there needs
to be something that connects the outside with the inside
**allows for better communication system**
** action potentials would not reach the myofibrils if it werent for the T-tubules***
True/False: SR keeps Ca levels low? - Answers -✔✔ TRUE!
Lecture 3 - Answers -✔✔
What are the 3 parts of the thick filament? - Answers -✔✔ 1. tail
2. hinge aka neck
3. head
Which part is responsible for the ATP activity? Aka the binding and splitting of ATP? -
Answers -✔✔ Head
Specifically? - Answers -✔✔ Myosin heavy chains
The myosin light chains are responsible for what? - Answers -✔✔ Modulating the ATP
activity in cardiac/skeletal muscle
When inidividual myosin molecules are placed in a ionic and salt solution, what
happens? - Answers -✔✔ The myosin heads will join together and tails will dimerize to
form one thick cross bridge filament
another reminder....what part of the myosin is responsible for the ATP activity? -
Answers -✔✔ The myosin heavy chains on the myosin heads
what protein is responsible for in participating in the bipolar arrangement and packing
into sarcomere? - Answers -✔✔ Myomicin C protein
Which protein holds the myosin heads together, instead of leaving them in space? -
Answers -✔✔ titin
(attaches myosin to z disc)
thin filament is what? - Answers -✔✔ actin
heavy chains of myosin are going to act upon what? - Answers -✔✔ THE ACTIN!
G actin vs F actin? - Answers -✔✔ Glomerular vs filamentous
What protein strand hides the active site on the actin? - Answers -✔✔ Tropomyosin
,Which part of troponin is acted upon Ca? - Answers -✔✔ C
which two proteins anchor the thin filament to the Z-disc? - Answers -✔✔ 1. alpha-
actinin
2. capZ
Z disc is made up of which two proteins - Answers -✔✔ alpha actinin and CapZ
Which component attaches the sarcolemma to the outside filaments/collagen? -
Answers -✔✔ Dystrophin Associated Complex
_________ links the DAC with the extracellular matrix? - Answers -✔✔ Laminin-2
(attaches to alpha/beta dystroglycans)
a,b,g,d sarcoglycans are inside of the sarcolemma and are held together by what? -
Answers -✔✔ sarcospan
Dystrophin anchors actin on what terminus? - Answers -✔✔ N'
C' terminus anchors what? - Answers -✔✔ nNOS to border of sarcolemma
Desmin is imp for what? - Answers -✔✔ connects outside to inside
Lecture 4 - Answers -✔✔
Motor neurons that innervate the same muscle fiber will have the same ___ and ____? -
Answers -✔✔ metabolic, contractile phenotypes
True/False: The muscle side of the neuromuscular junction is highly folded - Answers -
✔✔ TRUE!
Ach diffuses across synaptic cleft and binds to ______ receptors? - Answers -✔✔
nicotinic
what happens when Ach binds to these ligand-gated receptors? - Answers -✔✔ Na+
and K+ permeability increases!
----> End plate potential occurs
true/false: the end-plate potential is stationary so it will only stay w/i the NM junction? -
Answers -✔✔ TRUE!
, what happens when end-late potential occurs? - Answers -✔✔ fires AP on either side
and voltage gated channels open to propagate a moving AP
which one is bigger, EP or AP? - Answers -✔✔ Action potential! (end plate is too small)
Action potential is blocked by ____ and not influenced by ______ - Answers -✔✔ 1.
tetrodotoxin
2. curare
is this the same for EP? - Answers -✔✔ NO! it is opposite!!!
in an EPP, is there a falling phase? - Answers -✔✔ Yes but not because of increase in
K permeability but bc there will be no Ach due to the Ach-ase
Once the AP moves along the sarcolemma and hits the T-Tubule and then reaches the
Triad, what happens? - Answers -✔✔ A voltage sensitive Dihydropyridine receptors
(DHPR) is activated and then opens the ryanodine receptor (RyR).
What releases the Ca into the SR? - Answers -✔✔ RyR!!!!
What type of channel is DHPR? - Answers -✔✔ L-type!
an anesthesia, halothane, does what? - Answers -✔✔ leaks across muscles and directly
binds to RyR and releases Ca uncontrollably. This was the leading cause of death in the
ER bc of malignant hypothermia causing sustained contractures increasing temperature
True/false: Troponin C has two Ca binding sites but can also bind mg at rest? - Answers
-✔✔ TRUE!
What comes off first? Pi or ADP? - Answers -✔✔ In the cross bridge cycling, Pi is
released first and then ADP comes off.
rigor state means what? - Answers -✔✔ Myosin is attached to actin and will not remove
no matter what!!! firmly attached
how does the myosin release then? - Answers -✔✔ ATP! ATP comes and attaches and
then myosin is released
the myosin heavy chains then does what? - Answers -✔✔ Converts the ATP to ADP
and Pi to ACTIVATE MYOSIN AGAIN TO REATTACH TO THE ACTIN!
as a reminder, what causes the power stroke? - Answers -✔✔ The removal of Pi!! the z-
disc comes towards center of sarcomere
Answers (A+ Solution guide)
Muscles can either be ____ or ____? - Answers -✔✔ 1. Voluntary
2. Involuntary
What is one question to ask when comparing voluntary to involuntary muscles? -
Answers -✔✔ How is the underlying tissue metabolized?
Cardiac functional syncytial vs smooth muscle functional syncytial? - Answers -✔✔
Cardiac - pacemaker cells cause contractions
Smooth - vasodilation/vasoconstriction
True/False: Smooth muscle has striations? - Answers -✔✔ FALSE!
what two factors determine the force production at the sarcomere level? - Answers -✔✔
If they are arranged in parallel or series!
True/False: skeletal muscle cells contain many nuclei and very long - Answers -✔✔
TRUE!
Myofibrils are responsible for what 3 things? - Answers -✔✔ 1. tension generation
2. force production
3. shortening of muscle
What is a sarcomere? - Answers -✔✔ Basic unit of muscle that extends from Z-disc to
Z-disc
Sliding filament theory? - Answers -✔✔ The thick/thin filaments do not change but the
overlap does!
H zone? - Answers -✔✔ H for "heal" aka "light" only tails of myosin molecules
*** THIS COULD DISAPPEAR DUE BC OF CONTRACTIONS**
A-band? - Answers -✔✔ both thick and thin
I band? - Answers -✔✔ only thin - extends both sides of the z-disc
***THIS WILL SHORTEN IF THE MUSCLE CONTRACTS***
What is a triad? - Answers -✔✔ SR, T Tubule, SR
,Why is T-Tubule important? - Answers -✔✔ muscle cells are really long so there needs
to be something that connects the outside with the inside
**allows for better communication system**
** action potentials would not reach the myofibrils if it werent for the T-tubules***
True/False: SR keeps Ca levels low? - Answers -✔✔ TRUE!
Lecture 3 - Answers -✔✔
What are the 3 parts of the thick filament? - Answers -✔✔ 1. tail
2. hinge aka neck
3. head
Which part is responsible for the ATP activity? Aka the binding and splitting of ATP? -
Answers -✔✔ Head
Specifically? - Answers -✔✔ Myosin heavy chains
The myosin light chains are responsible for what? - Answers -✔✔ Modulating the ATP
activity in cardiac/skeletal muscle
When inidividual myosin molecules are placed in a ionic and salt solution, what
happens? - Answers -✔✔ The myosin heads will join together and tails will dimerize to
form one thick cross bridge filament
another reminder....what part of the myosin is responsible for the ATP activity? -
Answers -✔✔ The myosin heavy chains on the myosin heads
what protein is responsible for in participating in the bipolar arrangement and packing
into sarcomere? - Answers -✔✔ Myomicin C protein
Which protein holds the myosin heads together, instead of leaving them in space? -
Answers -✔✔ titin
(attaches myosin to z disc)
thin filament is what? - Answers -✔✔ actin
heavy chains of myosin are going to act upon what? - Answers -✔✔ THE ACTIN!
G actin vs F actin? - Answers -✔✔ Glomerular vs filamentous
What protein strand hides the active site on the actin? - Answers -✔✔ Tropomyosin
,Which part of troponin is acted upon Ca? - Answers -✔✔ C
which two proteins anchor the thin filament to the Z-disc? - Answers -✔✔ 1. alpha-
actinin
2. capZ
Z disc is made up of which two proteins - Answers -✔✔ alpha actinin and CapZ
Which component attaches the sarcolemma to the outside filaments/collagen? -
Answers -✔✔ Dystrophin Associated Complex
_________ links the DAC with the extracellular matrix? - Answers -✔✔ Laminin-2
(attaches to alpha/beta dystroglycans)
a,b,g,d sarcoglycans are inside of the sarcolemma and are held together by what? -
Answers -✔✔ sarcospan
Dystrophin anchors actin on what terminus? - Answers -✔✔ N'
C' terminus anchors what? - Answers -✔✔ nNOS to border of sarcolemma
Desmin is imp for what? - Answers -✔✔ connects outside to inside
Lecture 4 - Answers -✔✔
Motor neurons that innervate the same muscle fiber will have the same ___ and ____? -
Answers -✔✔ metabolic, contractile phenotypes
True/False: The muscle side of the neuromuscular junction is highly folded - Answers -
✔✔ TRUE!
Ach diffuses across synaptic cleft and binds to ______ receptors? - Answers -✔✔
nicotinic
what happens when Ach binds to these ligand-gated receptors? - Answers -✔✔ Na+
and K+ permeability increases!
----> End plate potential occurs
true/false: the end-plate potential is stationary so it will only stay w/i the NM junction? -
Answers -✔✔ TRUE!
, what happens when end-late potential occurs? - Answers -✔✔ fires AP on either side
and voltage gated channels open to propagate a moving AP
which one is bigger, EP or AP? - Answers -✔✔ Action potential! (end plate is too small)
Action potential is blocked by ____ and not influenced by ______ - Answers -✔✔ 1.
tetrodotoxin
2. curare
is this the same for EP? - Answers -✔✔ NO! it is opposite!!!
in an EPP, is there a falling phase? - Answers -✔✔ Yes but not because of increase in
K permeability but bc there will be no Ach due to the Ach-ase
Once the AP moves along the sarcolemma and hits the T-Tubule and then reaches the
Triad, what happens? - Answers -✔✔ A voltage sensitive Dihydropyridine receptors
(DHPR) is activated and then opens the ryanodine receptor (RyR).
What releases the Ca into the SR? - Answers -✔✔ RyR!!!!
What type of channel is DHPR? - Answers -✔✔ L-type!
an anesthesia, halothane, does what? - Answers -✔✔ leaks across muscles and directly
binds to RyR and releases Ca uncontrollably. This was the leading cause of death in the
ER bc of malignant hypothermia causing sustained contractures increasing temperature
True/false: Troponin C has two Ca binding sites but can also bind mg at rest? - Answers
-✔✔ TRUE!
What comes off first? Pi or ADP? - Answers -✔✔ In the cross bridge cycling, Pi is
released first and then ADP comes off.
rigor state means what? - Answers -✔✔ Myosin is attached to actin and will not remove
no matter what!!! firmly attached
how does the myosin release then? - Answers -✔✔ ATP! ATP comes and attaches and
then myosin is released
the myosin heavy chains then does what? - Answers -✔✔ Converts the ATP to ADP
and Pi to ACTIVATE MYOSIN AGAIN TO REATTACH TO THE ACTIN!
as a reminder, what causes the power stroke? - Answers -✔✔ The removal of Pi!! the z-
disc comes towards center of sarcomere
