test 2 Alain Muscular System lab

What muscles have striations? a.Cardiac and Smooth muscle b.Cardiac and Skeletal muscle c.Skeletal and Smooth muscle d.Cardiac, Skeletal, and Smooth muscle

b.Cardiac and Skeletal muscle

skeletal muscle

nucleus amount: many striations: yes intercalated disks: no

smooth muscle

nucleus amount: one striations: no intercalated disks: no

cardiac muscle

nucleus amount: one, sometimes two striations: yes intercalated disks: yes

The functional unit of the Myofibril, divided into I, A and H bands is known as-functional unit of muscle contraction

Sarcomere

What is the role of acetylcholine in a skeletal muscle contraction?

Acetylcholine binds to receptors in the motor end plate, initiating a change in ion permeability that results in the end-plate potential

Which of the following is NOT a characteristic smooth muscle cells?

Contain striations

Solution that causes the most muscle contraction

0.2% ATP + KCl+ MgCl2

§Three solutions were used during this experiment: A.KCl + MgCl2 à only ions B.0.2% ATP + Distilled water (DI water) à ATP & no ions C.0.2% ATP + KCl + MgCl2 à ATP & ions §Classify them based on contractility: 1.Prominent contraction: C 2.Slight contraction: B 3.No contraction: A

1.0.2% ATP + KCl + MgCl2. This solution contains ATP and salts (ions) so you will have the most contraction here 2.0.2% ATP + Distilled water. This solution does not contain ions, but it contains ATP so that causes a slight contraction when the ATP is hydrolyzed. Can also argue that the movement you see is the muscle relaxing 3.KCl + MgCl2. This solution contains salts (ions) but it does not contain ATP and without ATP the muscle cannot contract.

Sliding Filament Theory - Protocol 1.Which ion stimulates contraction? •Calcium (Ca) ● 2.Where does this ion bind to? •Troponin ● 3.Where is it released from? •Sarcoplasmic Reticulum ● 4.Which filament moves, and which does not move? •Actin (thin) filaments move. •Myosin (thick) filaments do not move

1.Calcium (Ca) 2.Troponin 3.Sarcoplasmic Reticulum 4.Myosin (thick) filaments do not move, Actin (thin) filaments move. Myosin is stationary and pulls on Actin which then moves towards it. •Note: Myosin and Actin do not change in size, what lengthens (during relaxation) or shortens (during contraction) is the sarcomere.

A nervous impulse arrives at the neuromuscular junction, which causes a release of a chemical called Acetylcholine. The presence of Acetylcholine causes the depolarization of the motor end plate which travels throughout the muscle by the transverse tubules, causing Calcium (Ca+) to be released from the sarcoplasmic reticulum.

1st step of sliding filament theory

In the presence of high concentrations of Ca+, the Ca+ binds to Troponin, changing its shape and so moving Tropomyosin from the active site of the Actin. The Myosin filaments can now attach to the Actin, forming a cross-bridge

2nd step of sliding filament theory

The breakdown of ATP releases energy which enables the Myosin to pull the Actin filaments inwards and so shortening the muscle. This occurs along the entire length of every myofibril in the muscle cell.

3rd step of sliding filament theory

The Myosin detaches from the Actin and the cross-bridge is broken when an ATP molecule binds to the Myosin head. When the ATP is then broken down the Myosin head can again attach to an Actin binding site further along the Actin filament and repeat the 'power stroke'. This repeated pulling of the Actin over the myosin is often known as the ratchet mechanism.

4th step of sliding filament theory

This process of muscular contraction can last for as long as there is adequate ATP and Ca+ stores. Once the impulse stops the Ca+ is pumped back to the Sarcoplasmic Reticulum and the Actin returns to its resting position causing the muscle to lengthen and relax.

5th step of sliding filament theory

Spastic paralysis is a condition where your muscles are always contracting (never relaxed). What you think cause this

A drug that block calcium pump

flaccid paralysis is a condition where the muscles aren't able to contract (always relaxed). Which of the following can be a cause of this?

A poison that blocks receptors & Calcium being stuck in the Sarcoplasmic Reticulum

3rd step of neuromuscular junction

ACh binds to into channels in the motor end plate

Written response. What enzyme rapidly degrades Acetylcholine In the synaptic cleft thus making the physiological effects of ACh binding to ACH receptors brief? Note: you must write the full nome not the simplification in order to get full credit.

Acetylcholinesterase

A thin, contractile protein filament, containing 'active' or 'binding' sites is a

Actin

In the Sliding Filament Theorywhen the impulse stops, are transported back to the Sarcoplasmic Reticulum and Actin returns to its resting causes the to lengthen trebux)How are the ions transported back to the Sarcoptascalc ?

Active transport calcium pump

After death, the membrane becomes leaky causing Jons to out from the SR, making the binding of myosin to actin possible cross-bridge is formed)After breathing stops, ATP synthesis stops with it. What state will your muscles be in if the cross-bridges are intact but there is no ATP to break them up?

Calcium , muscle always contracted

Which of the following is NOT a characteristic of Skeletal muscle cells?

Contain no nucleus

Which of the following is NOT a characteristic of cardiac muscle cells?

Contain no striations

Select all that apply. Tetanus is caused by a bacteria which contains toxins that prevent the release of inhibitory neurotransmittersWithou Inhibitory neurotransmitters the muscles cannot relax so they are a state of constant contraction, Which of the following are inhibitory neurotransmitter

GABA and glycine

Myasthenia Gravis is an autoimmune disorder that causes muscle weakness in skeletal muscle by blocking Acetylcholine (ACh) receptors in the post-synaptic cell. Which of the following is NOT an effect of this?

Muscle cannot relax so they are always contracted

A cylindrical organelle running the length of the muscle fiber, containing Actin and Myosin filaments is known as-organelle packed with myofilaments

Myofibril

What is the name of the cylindrical organelle that runs the length of the muscle fiber and contains actin and myosin filaments

Myofibril

What is the correct level of muscular connective tissue organization (from smallest to largest)?

Myofibril Muscle fiber < Fascicle < Muscle

A thick, contractile protein filament, with protusions known as Myosin Heads iscalled a

Myosin

According to the sliding filament theory, when the ATP molecule bound to the Myosin head is hydrolyzed what happens?

Myosin head bind actin

When you are working out for a long period of time sometimes you will feel a stinging sensation in your muscle tissue. This is because there is a lack of ———used to produce ATP via aerobic respiration, so your body does ———-to produce ATP. The accumulation of lactic acid lowers the blood's pH which causes that burning/stinging sensation.

Oxygen and lactic acid fermentation

The binding of Acetylcholine (neurotransmitter) from the pre-synaptic cell to the ACh receptors gated channels of the post-sysaptic muscle allow the influx of what ion from the synaptic cleft into postsynaptic muscle

Sodium

According to the protocolwhich solution is able to yleld the highest degree of contractility in glycerinated muscle?

Solution containing salt containing ATP

An actin-binding protein which regulates muscle contraction is called

Tropomyosin

What is the actin binding protein that regulates muscle contractions by covering the active site on actin

Tropomyosin

A complex of three proteins, attached to Tropomyosin is the

Troponin

True/False. When we cannot generate ATP via aerobic means we resort to using anaerobic processesLactic acid fermentation the process that pyruvate into lactic acid and generates ATP for the body to use

True

True/False. You are very likely to experience muscle fatigue during a workout because when undergoing strenuous activity you are more oxygen and when those levels are depleted so is the energy you have available to generate force.

True

The sarcomere the functional unit of the myofibril. Which of the following is NOT a part of the sarcomere?

X band

Fascicle

a bundle of muscle fibers

An invagination of the sarcolemma is also called _____. a.Transverse tubule b.Motor end plate c.Fascicle d.Triad

a.Transverse tubule

Which filament moves, and which does not?

actin move myosin no move

1st step of neuromuscular junction

an action potential arrives at the axon terminal

Which ion stimulates contraction?

calcium

Epimysium

connective tissue wrapping around a muscle

Endomysium

connective tissue wrapping around a muscle fiber

Perimysium

connective tissue wrapping around fascicle

thin filament

consists of actin, troponin, and tropomyosin

thick filament

consists of myosin

The influx of sodium causes

depolarization

5th step of neuromuscular junction

entry of Na+ depolarizes the sarcolemma locally, producing an end plate potential

T/F. In the sliding filament theory, the only time ATP is used is to attach the myosin head to the actin filament. a.True b.False

false

What causes the migration of synaptic vesicles and causes them to exocytose ACh?

influx of calcium

What generates the action potential in the POST synaptic membrane?

influx of sodium

Predict the effect on muscle contraction of each of the following situations, and then explain the basis for each prediction: a drug that blocks calcium pumps on the terminal cisternae

inhibition of muscle contraction

Predict the effect on muscle contraction of each of the following situations, and then explain the basis for each prediction: a poison that blocks ACh receptors

inhibition of muscle contraction

transverse tubules

invagination of the sarcolemma

4th step of neuromuscular junction

ion channels open and Na+ enter the muscle fiber

Where is calcium released from?

sarcoplasmic reticulum

sarcoplasmic reticulum

stores calcium

2nd step of neuromuscular junction

synaptic vesicles release ACh into the synaptic cleft

motor end plate

the region of sarcolemma across from the axon terminal at the neuromuscular junction

triad

transverse tubule and its flanking terminal cisternae

Where does the calcium ion bind to?

troponin

§The Sarcomere is the functional unit of the myofibril. §Z Disc: limits of the sarcomere § §M Line: middle of the sarcomere § §H Band: contains thick filaments only § §I Band: contains thin filaments only § §A Band: contains both thick and thin filaments

•Myosin: thick filaments •Actin: thin filaments •Z Disc: limits of the sarcomere, here think filaments attach to each other •M Line: central point of the sarcomere, here thick filaments attach to each other •H Band: area of only thick filaments •I Band: area of only thin filaments •A Band: area of both thin and thick filaments