Chapter 11 study questions

Electrolyte loss, fuel depletion, and central fatigue.

List three situations that lead to fatigue and long duration exercise

Contractility

Muscle cells are unique in their ability to shorten substantially when stimulated. This enables them to pull one bones and other organs to create movement. What universal characteristic of muscle is this?

Varicosities

Name the autonomic nerve or regions of that innervates smooth muscle.

T tubules

Name the membranous cellular structures that are important in conducting impulses through the sarcoplasm and and stimulating the release of calcium

Calmodulin

Name the regulatory protein and smooth muscle that binds calcium in activates the myosin light chain kinase

Troponin

Each tropomyosin molecule has a small calcium binding protein called what bound to it?

1,000

One motor neuron make control up to how many muscle fibers?

Myogram

This is a record of the timing and strength of the muscles contraction.

Acetylcholinesterase

What enzyme breaks down acetylcholine?

Aerobic respiration

Does aerobic respiration or anaerobic fermentation produces the most ATP?

Repolarization

During an action potential, the loss of potassium ions from the cell results in what of the membrane?

Temporel summation

Incomplete tetanus results from what?

Contraction

The step in which the muscle fiber develops tension and may shorten is called what? The mechanism of this is called the sliding filament theory.

Perimysium

This is the connective tissue covering bundles of muscle fibers

Acetylcholine

This is the neurotransmitter secreted at the neuromuscular junction

Elastic elements provide the recoil that helps return the sarcomere to its resting length.

What is the importance of the elastic elements to muscle function?

Excitation

What is the process called in which action potentials in the nerve fiber lead to action potentials in the muscle fiber?

Calcium must bind to troponin first

What must occur before tropomyosin can move away from the myosin binding sites on actin?

End plate potential

What potential causes the opening of ion channels, which results in the initial movement of sodium and potassium across the plasma membrane at the neuromuscular junction? If continued, this in turn can trigger an action potential at the neighboring sarcolemma

Elasticity

When a muscle cell is stretched and then released, it recoils to a shorter length. If it were not for this elastic recoil, resting muscles would be to slack. What universal characteristic is this called?

Sodium

When acetylcholine fines to its receptors on the motor and plate, and ion channel opens and what kind of ions diffuse quickly into the muscle cell?

Sarcoplasmic reticulum (SR)

Where is calcium stored that is needed for contraction?

Found in the heart where it's function is to pump blood

Where is cardiac muscle found?

H band

Within a sacrament, the region within the A band that lacks thin filaments is called the what? This is the region where there is only thick filaments.

Over-contracted r overstretched

Ta week contraction will result when the sacromeres are what?

Involuntary

The action of muscles that are not under conscious control are considered what?

Depolarization

The change in membrane potential with the entry of sodium ions is called what?

Contraction

The cocking of the myosin head, hydrolysis of ATP in the power stroke occurr during what phase of skeletal muscle contraction?

ATP

The cross bridge created by the binding of the myosin and actin is broken with the binding of what?

A band (anisotropic)

The darker striation of a muscle is called what?

Glucose

The glycogen lactic acid system utilizes what molecule as fuel to generate ATP? Can generate a net gain of two ATP for everyone of these molecules consumed. Can produce enough ATP for 30 to 40 seconds of maximum activity

Endomysium

The innermost layer of connective tissue that surrounds each muscle fiber is called?

I bands (isotropic)

The lighter striation of a muscle is called what? They are bisected by a Z desk, to which Acton and elastic filaments are anchored

Threshold

The minimum voltage necessary to generate an action potential

Longer

The myogram is asymmetrical, indicating that the relaxation phase is what compared to the contraction phase?

Synaptic knob

The nerve fiber ends in a Boba swelling at each synapse, what is the structure called?

Several points

The nerve fiber stimulates the muscle fiber at how many points within the neuromuscular junction?

Muscle tone

The partial contraction of resting muscles is defined as what?

Sarcomere

The portion of the myofibril from on Z disk to the next is called what?

Fatigue

The progressive weakness and loss of contractility that results from prolonged use of the muscle is known as what?

Action potential

The quick up-and-down voltage shipped from negative to positive, created by the movement of sodium and potassium across the cell membrane is called what?

Latent period

The time between stimulus and the twitch. A delay

Isometric contraction

The type of contraction that maintains joint stability and posture is called a what?

Smooth muscle

These are characteristics of what type of muscle... No T tubules, uninucleated, and has little SR

Cardiac muscle

These are characteristics of what type of muscle... Uses aerobic respiration almost exclusively, it is rich in myoglobin, and it has large stores of glycogen.

Smooth muscles

These are the characteristics of what type of muscle... Little SR, no T tubules, and Uni nucleated

Myosin

These are the thick filaments of the myofibril and are composed of the protein what?

Intercalated discs

These are the thickened notched ends of cardiac muscle cells which contain gap junctions.

T tubules

These carry the action potential through the sarcoplasm.

Cardiac cells

These characteristics are of what type of cells... They contract with regular rhythm, they are resistant to fatigue, and they contract nearly in unison.

Fast glycolytic

These type of fibers are adapted for a quick response.

Cardiac muscles

These type of muscles are considered auto rhythmic and contract independently

Anaerobic fermentation

This enables a cell to produce ATP without the need for oxygen, but the ATP yield is very limited and the process generates lactic acid, which may contribute to muscle fatigue

Acetylcholinesterase

This enzyme breaks down ACh, ending muscle stimulation.

Complete tetanus

This is a continuous forceful contraction in a muscle with no relaxation between stimuli.

Muscular dystrophy

This is a genetic condition in which an abnormal the form of the dystrophin protein is produced

Myosin

This is a molecule shaped like a golf club, with two chains intertwined to form a shaft like tail and A double globular head projecting from at an angle.

Myoglobin

This is a molecule that stores oxygen in the muscles. It is a red pigmented

Endurance exercise

Fatigue resistance of muscles is improved by what type of exercise which enhances delivery and use of oxygen

Slow twitch fibers

Fibers that are well adapted to aerobic respiration are called what?

Small motor units

Find motor control requires what?

Moves material through the digestive tract, regulates pupil diameter, and constricts or dilates blood vessels to control blood pressure.

Functions of the smooth muscle

Cardiac muscles

Gap junctions allow these muscle cells to contract and a coordinated fashion, what muscle?

Calcium

Gated channels in the sarcoplasmic membrane open to release what into the cytosol which activates the muscle contraction process?

Warm muscle conditions

Indicate a condition that would result in a stronger twitch.

Stimulation frequency, temperature of the muscle, how stretched the muscle was just before it was stimulated, and muscle fatigue.

Indicate the parameters that affect twitch strength.

Triad

Infoldings of the sarcolemma, called transverse tubules, are associated with two terminal cisterna, this forms a unit called what?

Actin and myosin

Internal transportation, cellular movement, and chromosome movement our functions of what?

Anaerobic fermentation and aerobic respiration

Name the two pathways to generate ATP

The blood vessels and in the digestive, respiratory, urinary, and reproductive tracks

Sites for single unit smooth muscle

Striations

Skeletal muscles exhibit alternating light and dark band called what?

Steps in the relaxation phase

1. Nerve signal ceases 2. AChE breaks ACh down 3. Active transport pumps in the sarcoplasmic reticulum begin to pump calcium back into the cisternae 4. Calcium releases from troponin 5. Tropomyosin covers the myosin binding sites

Concentric contraction

A muscle shortens as it maintains tension in what type of contraction?

Neuromuscular junction

A synapse is the point where a nerve fiber meets a target cell. When the target cell is a muscle fiber, this type of synapse is called though what?

T tubules

Action potentials cause the opening of voltage gated sodium ion channels in the what? This leads to the opening of calcium ion channels in the terminal cisterna of the sarcoplasmic reticulum

Large motor units

Actions that require physical strength typically involve what?

Caveolae

And smooth muscle the sarcolemma has pockets that increase the cell surface and the number of calcium channels, what are they

Multiple motor unit summation (MMU)

As a stimulus increases, an increasing number of motor neurons excites an increasing number of motor units, what is this called?

Power stroke

As myosin releases ADP and flexes, this pulls the thin filaments toward that M line. This is called the what?

ACh

At the presynaptic terminal, synaptic knob, of the motor neuron, calcium stimulates exocytosis of the synaptic vesicles to release what into the synapse?

Smooth and cardiac muscles

Autonomic nervous system is important in the control of what to muscle types?

Weaker

Below normal sarcoplasmic pH will cause what type of muscle twitches?

Neurons and myofibers

Both of these have membranes that undergo voltage changes when stimulated.

Relaxation phase

Calcium levels in the sarcoplasm fall, myosin releases thin filaments, and muscle tension declines. What phase does this occur?

Involuntary muscle type

Cardiac and smooth muscle are considered what type of muscle tissues, not usually subject to our conscious control?

Sarcoplasmic reticulum

During relaxation, calcium is actively pumped back into the what?

Creatine phosphate

During short bursts of intense activity, the supply of ATP and muscle is maintained by what?

Contraction phase

During what phase does a muscle generate tension, pulling on its attachments?

Just one

Each muscle fiber is innervated by how many motor neurons

ATP and creatinine phosphate

Energy needed for short bursts of intense activity are provided by what two molecules?

Excitability (responsiveness)

This is a property of all living cells, but muscle and nerve cells have developed this property to the highest degree. When stimulated by chemical signals, stretch, and other stimuli, muscle cells respond with electrical changes across the plasma membrane

Myosin ATPase

This is an enzyme located in the myosin head that Hydrolyzes ATP

Myoglobin

This is the red pigment that stores oxygen needed for muscular activity

The all or none lot of muscle physiology

This law indicates that once the threshold has been reached the fiber will contract

Cardiac pacemaker

This triggers contraction in the heart muscle.

Resistance exercise

This type of exercise is a contraction of muscles against a load that resists movement

Smooth muscle

This type of muscle cells have a fusiform shape and taper to a point at the ends

Iso tonic contraction

This type of muscle contraction in which there is a change in length, but no change in tension

Cardiac muscle

This type of muscle is striated, Uninucleated, and branching.

Smooth muscle

This type of muscle is typically slow to contract and slow to relax.

Smooth muscle

This type of muscle is un- nucleated and non-striated.

Regulatory proteins

Tropomyosin and troponin are what kind of proteins? They act like a switched to determine when the fiber can contract and when It cannot.

Fatty acids and glucose

What does a aerobic metabolism utilize as fuel to generate ATP?

Muscle contraction

What does the sliding filament theory describe?

The duration of exercise

What does the source of ATP depend on

It causes trouble my sent to move away from the active site on actin

What happens as a result of calcium binding to troponin?

Motor unit

muscle fibers innervated by a single motor nerve fiber.