Exam 3 Flashcards
What are the three types of muscle tissue?
Cardiac, smooth, and skeletal
What are the four properties of muscle tissue?
excitability (capable of changing its membrane potential like neurons), contractility, elasticity (recoil), and extensibility (elongate).
What kind of a cell creates muscle fiber?
myoblast
what kind of cell is responsible for repairing a muscle cell when it is damaged?
myosatellite (muscle stem cell)
How are muscle cells formed during embryonic development?
myoblasts merge and fuse together until a single muscle cell is multinucleated
Describe the nesting doll approach within a muscle:
Bundles of myofilaments make up microfibrils. Bundles of microfibrils make up myofibrils. Bundles of myofibrils make up a muscle cell. Bundles of muscle cells make up a fascicle. Bundles of fascicles make up a muscle.
Connective tissue above the muscle (the top most layer) that separates muscles from other muscles:
Epimysium
A long continuous sheet that separates fascicles from each other:
Perimysium
Long continuous sheet surrounding individual muscle fibers/cells:
Endomysium
The membrane layer directly under the endomysium:
Sarcolemma
These group together to form a muscle fiber:
myofibrils.
What wraps around each individual myofibril and acts as the endoplasmic reticulum within a muscle?
Sarcoplasmic reticulum
Extensions of the sarcolemma (cell membrane) in a muscle cell that wrap around each individual microfibril:
Transverse tubules
Membranes consist of a _____ _____.
Phospholipid bilayer
Sarcoplasmic reticulum that forms a tube like structure on both sides of transverse tubules/ terminal cisternae:
Lateral sacs
Formed by one T tubule and two terminal cisternae:
Triad
What bundles together to make up microfibrils and is responsible for muscle contraction?
Myofilaments
List the two types of myofilaments
Actin and myosin
Which myofilament is thick and which one is thin?
Actin myofilament is thin and myosin myofilament is thick
Z line to Z line is one _____.
Sarcomere
Two strands of _____ _____ molecules form actin myofilaments, while two strands of _____ spiral around those molecules lengthwise. Widthwise, the _____ _____ wraps around the other two components.
G-actin protein, tropomyosin, troponin complex.
_____ and _____ directly connect to the Z line.
Actin and Titin
The ends of myosin myofilaments are made of _____ which is an _____ protein.
Titin, elastin
Is the inside of a cell more negative or positive than the outside of a cell? Why?
negative, because of the amino acids and proteins.
The membrane potential (mV) is _____ in voltage across a cell membrane.
different
There is always more ___ inside the cell compared to how much there is outside.
Potassium
There will always be less ___, ___, and ___, inside the cell compared to outside.
Sodium, chloride, and calcium
A _____ is a type of carrier that carries two (usually) substances in the same direction across a membrane. Ex. Na+/GLU secondary active transporter
Symporter
A _____ is a type of carrier that carries two substances in opposite directions across a membrane. Ex Na+/K+ ATPase pump
Antiporter
_____ solutions are solutions with higher amounts (concentrations) of solutes compared to the other solution.
Hypertonic
_____ solutions are a solution with lower concentrations of solutes compared to the other solution.
Hypotonic
Sodium has a net diffusion (into/out of) cells. What does this do to the charge of the cell?
into; becomes more positive
What is the resting membrane potential?
-90 mV
What is responsible for maintaining the concentration gradient?
Ion pumps
Pumps require _____ when moving molecules across a concentration gradient
ATP
What needs to happen for exocytosis to occur and neurotransmitters to be released?
Calcium must attach to a vesicle; its a calcium dependent process
Directly under the motor neuron exists the _____ _____ _____.
Motor end plate
_____ gated channels exist everywhere except the motor end plate, while _____ gated channels exist within the motor end plate only.
Voltage, chemical
Voltage gated channels must reach a threshold of ___ mV to open (from -90 mV)
-65 mV …or -64, -63, etc.
What are the three types of voltage gated channels?
potassium (K), calcium, and Sodium (Na)
What exists between the voltage gated channels?
Na & K leaky channels as well as Sodium Potassium ATPase pumps.
What type of voltage gated channel has two doors? Which one has only one door?
Sodium has two doors and potassium has one door.
Which voltage gated channel responds the quickest to the change in membrane potential? (they both sense it)
Na voltage gated channel opens and closes as K voltage gated channel begins to open.
Sodium ___, Potassium ___.
in, out
More sarcomeres = more _____.
force
Motor neuron synapses with muscle cells in what area of the cell?
The middle length.
True or false: Motor units mix and match
false
List the three types of muscle fibers (motor units), their name, and their type:
Type I = slow / slow oxidative, Type IIa = intermediate/ fast aerobic, Type IIb = fast/ fast anaerobic
Compare slow muscle fibers to fast muscle fibers:
Slow muscle (red) fibers are 1/2 the diameter, contain a lot of capillaries and mitochondira, and are good for endurance. Fast muscle (white) fibers have a lot of glycogen stores. They are both genetically determined.
Which motor unit is not genetically determined? What is it determined by?
Intermediate/ fast aerobic; environmental conditions (fast can take on characteristics of intermediate due to training).
List the four muscle fiber organizations:
Parallel muscles, circular muscles, convergent muscles, and pennate muscles.
Name the muscle fiber organization: High endurance, most common type, “body” increases.
Parallel muscles
Name the muscle fiber organization: Sphincters (round); used to control the movement of material.
Circular muscles
Name the muscle fiber organization: associated with tendons, variable direction of limb movement
Convergent muscles
Name the muscle fiber organization: Feather design, good for power and the strongest of all the groups
Pennate
How do ions cross a membrane?
Facilitated diffusion and concentration gradient
What happens to a protein when a chemical binds to it?
It changes shape
Where do ions have to go once they cross a membrane? how do they get there?
They have to go back to where they came from by pumps.
What does the terminal cisternae of the sarcoplasmic reticulum store?
Calcium ions
What happens to allow muscles to contract?
Ca2+ binds to troponin, troponin then changes shape, tropomyosin moves and uncovers the myosin binding site on actin filament, the myosin head attaches and pulls actin filaments towards the center which causes the muscle to contract.
Where is acetylcholmesterase found?
The motor end plate only (where acetylcholine is found)
Myosin heads have a high affinity. What happens to lower their affinity (desire for binding)?
When ATP attaches to myosin head.
Name the three actions of skeletal muscles:
Agonist, antagonist, and synergist.
What does the agonist do?
Produces specific movement when it contracts; its the prime mover
What does the antagonist do?
It opposes movement
What does the synergist do?
It’s the helper; creates smooth movement
Myosin heads have a high affinity. What is on the myosin head that causes this?
ADP and phosphate
What happens when the the affinity is lowered on a myosin head?
The head detaches from the actin filament, the myosin ATPase breaks ATP into ADP and phosphate, and the myosin head goes back into the starting position.
Acetylcholinesterase forms a _____ binding with acetylcholine, which breaks acetylcholine into its monomers so that it can’t attach to chemical gated _____ channels.
ligen, sodium
List the two types of skeletal muscle tension:
Isotonic and isometric contraction
During _____ muscle tension, skeletal muscle changes in length and results in motion. During _____ muscle tension, skeletal muscle develops tension but is prevented from changing in length.
isotonic, isometric
what happens when muscle tension is greater than the resistance (load)?
Concentric contraction occurs; muscle shortens (pulls closer to body)
What happens when resistance (load) is greater than muscle tension?
eccentric contraction occurs; muscle lengthens (moves away from body)
What is an example of isometric contraction?
Carrying something heavy in front of you
True or false:
All myosin heads do a power stroke at the same time
False
True or false:
Every sarcomere is involved in a contraction.
True
How do muscle fibers shorten?
As sarcomeres shorten, muscles pull together to produce tension.
What two things are involved in the contraction cycle?
Fibers shortening and contraction duration
***What three things are involved in contraction duration?
Duration of neural stimulus, number of free calcium ions (which come from the lateral sac) in sarcoplasm, and availability of ATP
List the three phases of a SINGLE muscle contraction (a.k.a. twitch)
Latent period, contraction phase, relaxation phase.
Describe the latent period:
The time before the contraction begins once the stimulus is applied
What causes relaxation of a muscle contraction? (list three ways)
- calcium concentrations diminish into the sarcoplasm by calcium pumps and tension decreases.
- Calcium detaches from troponin
- Sarcomeres remain contracted.
What determines the force of a contraction?
The number of fibers involved, the size (diameter) of the fibers, frequency of stimulation (higher frequency=greater force) and the length of the muscle at the start of contractions.
As mucle length increases, the ability of muscle tension (does/ does not) increase.
does NOT
What is a motor unit?
The motor neuron and muscle fibers it interacts with.
Describe recruitment tension:
Recruit more motor units as others begin to relax until they can take over again.
List the five things that Energy is stored as:
ATP, CP, Glycogen, Lipids, and skeletal muscle
What are the two ways that cells produce ATP?
Aerobic metabolism and Anaerobic metabolism
_____ metabolism takes place in the mitochondria while _____ metabolism takes place in the cytoplasm.
Aerobic, anaerobic
1 glycogen produces ___ pyruvic acids. 2 pyruvates produce ___-___ ATP.
2, 28-30
Simplify glycolysis:
When glucose produces pyruvate acid
Anaerobic metabolism relies on _____ and the use of _____.
Glycolysis, Creatine
Aerobic metabolism relies on _____ _____, use of _____ _____, and use of _____ _____.
fatty acids, amino acids, and pyruvic acid.
Oxygen is only required by the _____. It produces _____ and _____ as byproducts.
ETC, ATP, and H2O.
ATP is the _____ energy molecule. The storage molecule for excess ATP energy in a resting muscle is _____.
Active, CP- Creatine phosphate.
Energy transfer recharges ADP to ATP using the enzyme __________. When CP is all used up, the other mechanisms generate _____.
Creatine phosphokinase (CPK/ CK), ATP
Creatine kinase allows ADP and creatine phosphate to become _____ and _____.
ATP and creatine
creatine kinase allows ATP and creatine to become _____ and _____.
ADP and creatine phosphate
Resting muscle: _____ are catabolized; the ATP produced is used to build energy reserves of _____, _____ and _____. Is oxygen required?
fatty acids, ATP, CP, and glycogen. yes.
Moderate activity: _____ and _____ are catabolized. The ATP produced is used to power _____, Is oxygen required?
glucose and fatty acids, no.
Peak activity: most ATP is produced through _____. Mitochondrial activity provides _____ of ATP consumed. Is oxygen required?
glycolysis, 1/3, no.
Which of the following is not a part of the myofilaments structure?
- troponin
- titin
- actin
- tropomyosin
Titin
How many neuromuscular junctions are present in a single muscle cell?
1
A troponin complex has how many parts?
3
What is the function of sarcoplasmic reticulum?
Storage of ca2+
During the excitation contraction process in skeletal muscle fibers:
Ca2+ floods the cytosol through voltage gated channels
Ions that enter the skeletal muscle cell during the generation of an action potential come from:
Extracellular fluid
How many ATP produced during glycolysis?
4
List the three ways muscular force can be adjusted to match different loads (weight that changes):
Activation larger motor units, changing the frequency of action potentials sent to those fibers, and activating more motor units
How many ATP used during the cori cycle?
6
What makes the myosin head move back to the starting position?
ATP becoming ADP ?
Interactions between actin and myosin myofilaments are responsible for :
Causing the sarcomere to shorten
A resting muscle fiber generates most of its ATP by:
Aerobic metabolism of fatty acids
Action potentials are conducted into a skeletal muscle cell due to:
Transverse tubules
The most important factor in lowering the intercellular concentration of calcium found in the sarcoplasm of skeletal muscle cells is:
Active transport of calcium into the lateral sacs
