Exam 5 Pt.1

Which of the following protein make up the thin myofilaments?

Actin
Tropomyosin

The enzyme found in myosin is ____

ATPase

Muscle cells contain ___ which contain ____

Myofibrils; Myofilaments

Covers the binding sites on actin

Tropomyosin

Are arranged as sarcomeres ___

Myofilaments

Calcium is released _____

As the action potential passes through the T tubules

The endplate potential triggers an action potential in the motor neuron

False

Which of the following motor units would allow for greater (fine) muscular control?

A motor unit made up of a motor neuron and fiver muscle fibers

All the muscle cells in a motor unit are activated at the same time

True

Calcium is released from the ____ and binds to ___

Sarcoplasmic Reticulum; Troponin

A muscle is able to maintain tension with minimal fatigue because

Motor units can be activated at different times

What types of channels are responsible for creating the endplate potential at the neuromuscular junction?

Ligand Gated sodium channels

In the sliding filament process, the power stroke is immediately followed by ____

Detachment

In the presence of calcium, troponin removes tropomyosin away from the binding sites on actin.

True

In the sliding filament process, crossbridge formation occurs after ____

Activation of Myosin

This reaction is required to trigger the power stroke.

Release of ADP and Pi from myosin

Each crossbridge cycle requires 3 ATP molecules

False

Myosin can perform __ crossbridge cycles per second

10

During muscle contraction the width of the sarcomeres

Narrow

During the sliding filament process, thick filaments slide across thin filaments

False

Myosin is activated when ___

ATP us converted into ADP and Pi

A crossbridge is formed between _____

Actin and Myosin

During muscle contraction, which if the following proteins binds ATP

Myosin

Myosin releases actin when it binds to calcium

False

The head of myosin moves into cocked high energy position ___

When its activated

Calcium binds to ___

Troponin

During concentric contractions, the length of the muscle fibers

Decrease

The biceps brachii muscle is required to slowly lower your forearm to the desk. In this situation, the biceps brachii muscle is undergoing ____

Eccentric Contraction

When the biceps brachii muscle is used to bend the elbow, it is contracting

concentrically

Eccentric contractions are examples of isotonic contractions

True

Muscle contraction without changing the length is called

Isometric Contraction

Pushing against a stationary wall is an example of

Isometric Contraction

Which of the following forms of muscle fatigue involves depletion of intracellular potassium

Conduction Failure

Type 2B fibers make ATP by using both oxidative and glycolytic pathways

False

Type 2B fibers fatigue more quickly than type 1 fibers

True

Which of the following would be dominant fiber type in the ilocostalis muscle which helps to maintain your posture

Type 1

Type 2A fibers are also called

Fast glycolytic oxidative fibers

Type IIB muscle fibers primarily use ___ to make ATP; As a result these fibers will ___

Glycolysis, Fatigue Quickly

Type 2A fibers are ___ than type I fibers

Faster

Training can convert type 2B fibers to type 1 fibers

False

The difference between fast and slow twitch fibers is based on the ___

Speed of the ATPase

Most of the fibers in the quadriceps femoris muscle of a world-class 100 m sprinter will be

Type IIB fast glycolytic fibers

Glycolytic fibers fatigue more quickly than oxidative fibers

True

The function of ATPase enzyme is to

Convert ATP to ADP and Pi