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.
