Ligands, channels, receptors, etc.
Muscle Anatomy
Muscle Contraction
More muscle anatomy & physiology
Wild card
100

Concerning concentration differences across the plasma membrane (at rest), there is

A) more K+ and Na+ outside the cell than inside

B) more K+ and Na+ inside the cell than outside

C) more K+ outside the cell than inside and more Na+ inside the cell than outside

D) more K+ inside the cell than outside and more Na+ outside the cell than inside.

D) more K+ inside the cell than outside and more Na+ outside the cell than inside.

100

Muscles may be named according to:  

         a) points of attachment.   

        b)   direction of fibers

        c) function 

        d) all are true

   

        d) all are true

100

Which of these events occurs during the lag (latent) phase of muscle contraction? 

a) cross-bridge movement

b) active transport of Ca2+ into the sarcoplasmic reticulum 

c) Ca2+ binding to troponin

d) sarcomere shortening

e) breakdown of ATP to ADP 

c) Ca2+ binding to troponin

100

Which of the following ends the stimulation of a muscle fiber?

a.Calcium

b.AChE

c.Sodium

d.ACh

b. AChE

100

Connective tissue that binds fascicles together is the 

a) epimysium

b) perimysium

c) endomysium

d) sarcolemma

b) perimysium

200

What binds to Na+ channel receptors on the sarcolemma? 

a) Na+

b) K+ 

c) Acetylcholine

d) Ca2+

c) Acetylcholine

200

Which of the following contains both thick and thin filaments?

a.I band

b.H zone

c.Z line

d.A band

d. A band

200

To which of the following does ATP bind?

a.Actin molecules

b.Myosin heads

c.Troponin

d.Tropomyosin

b.Myosin heads

200

The type of lever arrangement in which the force of muscle (pull) is exerted between the fulcrum and force of weight (load) to be moved is a:

a) Class I lever

b) Class II lever

c) Class III lever

d) Class IV lever

c) Class III lever

200

The most movable attachment of a muscle is its 

a) insertion

b) origin

c) belly

d) fulcrum

a) insertion

300

Ligands can: 

a) speed up or slow down cell activity

b) make cells divide

c) open or close channels in cell membrane

d) all of the above

d) all of the above

300

Each myofibril 

a) is made up of many muscle fibers

b) contains sarcoplasmic reticulum

c) is made up of many sarcomeres

d) contains T tubules

e) is the same thing as a muscle fiber

c) is made up of many sarcomeres

300

Given these events:

1) Calcium ions combine with tropomyosin
2) Calcium ions combine with troponin
3) Tropomyosin pulls away from actin
4) Troponin pulls away from actin

5) Tropomyosin pulls away from myosin
6) Troponin pulls away from myosin
7) Myosin binds to actin

Choose the arrangement that lists the correct events in the order they occur in muscle contraction.

A) 1, 4, 7

B) 2, 5, 6

C) 2, 3, 7

D) 1, 3, 7

C) 2, 3, 7

300

As a muscle increases in length (up to its optimal length), would the active tension increase or decrease? 

a) increase

b) decrease

a) increase

300

How much energy does creatine phosphate produce? 

a) short bursts of energy

b) long-term energy


a) short bursts of energy

Why? 

400

Fill in the blank: 

Protein ligands can bind to ___________ receptors and activate a ___________________.

Protein ligands can bind to membrane-bound receptors and activate a second messenger system.

400

Muscles that have fascicles that join at one common tendon from a wide area and are triangular in shape are: 

a) parallel

b) circular

c) convergent

d) pennate

c) convergent

(Define and describe the other types of fiber patterns)

400

A weight lifter attempts to lift a weight from the floor, but the weight is so heavy that he is unable to move it. The type of muscle contraction the weight lifter is using is mostly: 

a) isometric

b) isotonic

c) eccentric

d) concentric

a) isometric

400

Match the terms to the correct description.

1) Treppe

2) Incomplete Tetanus

3) Complete Tetanus


a) When the action potential frequency is high enough that no relaxation of the muscle fibers occurs

b) the graduated series of increasingly vigorous contractions that results when a corresponding series of identical stimuli is applied to a rested muscle.

c) When the action potential frequency is low enough to allow partial relaxes of the muscle fibers

1) Treppe: B) the graduated series of increasingly vigorous contractions that results when a corresponding series of identical stimuli is applied to a rested muscle.

2) Incomplete Tetanus: C:When the action potential frequency is low enough to allow partial relaxes of the muscle fibers

3) Complete Tetanus: A) When the action potential frequency is high enough that no relaxation of the muscle fibers occurs

400

Muscles that contract at the same time as the prime mover are called:

A.  synergists.

B.  fixators.

C. antagonists.

D. both A and B.

D. both A and B.

(It might help to define all these terms here)

500

Describe the process of the the Na+/K+ pump. Why is it important? 

The Na+/K+ pump actively pumps out 3 Na+ out of the cell and 2 K+ into the cell. 

This ultimately leads to the outside of the cell being more positive and the inside of the cell being less positive, bringing the cell back to resting membrane potential. 

500

What is the rectus abdominis muscle named for?  

fiber pattern/orientation of fascicles and location

500

Describe the process of muscle contraction, starting with acetylcholine and ending with the formation of a cross-bridge. (8 steps)

A motor neuron releases ACh into the synaptic cleft of the neuromuscular junction.
 
2.  ACh binds to the ligand/chemically – gated Na+ channels of the sarcolemma
causing them to open.  
 
3. Na+ (previously pumped out by the Na+ K+ pump) will rush into the cell from the
extracellular fluid.  This influx of Na+ is called a “local” or “graded” potential.
 
4.  If the local potential is strong enough (if enough Na+ gets in), this will trigger the
opening of the voltage – gated Na+ channels of the sarcolemma.  Once the voltage –
gated channels start to open...they will all open in a self –propagating, unstoppable
wave all over the sarcolemma and down the T – tubules.  This is called an Action
Potential.  
 
5. The voltage wave passing down the T – tubules will trigger the opening of the
voltage – gated Ca++ channels found on the sarcoplasmic reticulum (SR).
 
6. Ca++ that was stored in the SR will rush out into the sarcoplasm.
 
7. The Ca++ will bind to troponin proteins and the troponins will “change position”/
“pivot”/ “roll over”/ “fall down” pulling the tropomyosin proteins off of the active
sites on the actin filaments.  
 
8. Once the active sites are exposed the myosin heads will attach to and “pull” or
“ratchet” the actin filaments toward the center of the sarcomere.  [this would be
that “sliding filament” idea]
 
 
 
 

500

First, define: What is a motor unit? 

Match the type of movements with the size of motor units and amount of muscle fibers. 

1) Small motor units

2) Large motor units


A) Delicate tasks requiring fine motor skills

B) More coarse tasks

C) Running or jumping

D) Blinking


A motor unit is made up of a motor neuron and the skeletal muscle fibers innervated by that motor neuron's axonal terminals.

Small motor units: more precise tasks, e.g. blinking

Large motor units: more coarse tasks, e.g. running or jumping

500

Which of these conditions would you expect to find within the leg muscle fibers of world-class marathon runner? 

A) myoglobin-poor

B) contract very quickly

C) primarily anaerobic

D) numerous mitochondria

Part 2: What type of muscle fibers, Type I, IIa, or IIb, would this marathon runner have?

D) numerous mitochondria

Type I (slow twitch)