Wiley Ch 10 - Muscular Tissue (complete)
For crossbridges to occur, what events must happen? Select all that apply. a) ATPase breaks down ATP. b) calcium ions be present in the sarcoplasm. c) myosin binding sites be exposed. d) high amounts of sodium be present in the synaptic cleft e) Acetylcholine be present in the synaptic cleft
- ATPase breaks down ATP. - calcium ions be present in the sarcoplasm. - myosin binding sites be exposed.
In skeletal muscles, the combined amounts of creatine phosphate and ATP provide enough energy for the muscle to contract maximally for approximately a) 15 seconds. b) 15 minutes. c) 1.5 minutes. d) 5 seconds. e) one minute.
15 seconds
Which age group would be most susceptible to an increase in slow oxidative muscle fibers? a) pre-teens (9-12 years old) b) teenagers (13-19 years old) c) 20-29 years old d) 30+ years
30+ years
Discuss the steps involved in contraction of smooth muscle and explain why smooth muscle has a slower contraction cycle.
: Upon neural stimulation of the muscle, Ca2+ stored in the caveolae start to flow into the cell. Calmodulin, the regulatory protein in smooth muscles, will bind with the Ca++ which will activate the enzyme myosin light chain kinase (MLCK). This enzyme will use ATP to add a phosphate to the myosin head so that it can bind to actin so that the contraction can occur. The sliding of the actin and myosin is similar to the skeletal muscle. The slowness of the process is due to slow influx of Ca++ from caveolae into the cells (smooth muscles have a poor SR system, therefore, there is very little intercellular Ca++ storage). Also, the enzyme MLCK works very slowly which in turn causes the muscle to contract slowly.
How does a nerve impulse elicit a muscle action potential?
A nerve impulse reaches the synaptic end bulb and causes the release of acetylcholine, which diffuses across the synaptic cleft and binds to and activates acetylcholine receptors on the motor end plate. Binding of acetylcholine opens an ion channel in the acetylcholine receptors allowing Na+ to flow into the cell, which generates an action potential in the muscle cell.
What are the three ways that ATP can be produced in muscle fibers?
ATP can be produced from creatine phosphate, by anaerobic cellular respiration, and by aerobic cellular respiration.
What energizes the myosin head? a) acetylcholine b) calcium ions c) Phosphate release d) ATP hydrolysis reaction e) ADP synthesis
ATP hydrolysis reaction
List the four steps of the contraction cycle in order of occurrence. What is needed for these steps to continuously repeat?
ATP hydrolysis, attachment of myosin to actin forming crossbridges, the power stroke, then detachment of myosin from actin. The cycle will continue as long as ATP and calcium ions are available.
Describe the factors that lead to muscle fatigue
Although the precise mechanisms that cause muscle fatigue are still not clear, several factors are thought to contribute. One is inadequate release of calcium ions from the SR, resulting in a decline of Ca2+ concentration in the sarcoplasm. Depletion of creatine phosphate also is associated with fatigue, but surprisingly, the ATP levels in fatigued muscle often are not much lower than those in resting muscle. Other factors that contribute to muscle fatigue include insufficient oxygen, depletion of glycogen and other nutrients, buildup of lactic acid and ADP, and failure of action potentials in the motor neuron to release enough acetylcholine.
___________: Resists fatigue ___________: Uses aerobic and anaerobic ___________: Lowest myoglobin content Choices: Fast Glycolytic Fast Oxidative Glycolytic Slow oxidative
Answer 1: Slow oxidative Answer 2: Fast Oxidative Glycolytic Answer 3: Fast Glycolytic
Stage 4
At which stage of the contraction cycle (see diagram) do the myosin heads bind ATP, causing the crossbridges to detach from the actin filament?
Compare and contrast the structural characteristics of the three different types of muscular tissue.
Both cardiac and skeletal muscle tissues are striated and smooth muscle is not, hence its name. Skeletal muscle cells have more than one nucleus, are large and run parallel to each other. Cardiac muscle cells usually have only one, sometimes two, centrally located nuclei and are branched. They also are connected to each other via gap junctions. Smooth muscle cells are small but form thick layers of hollow organs. Like cardiac muscle cells, some smooth muscle cells communicate via gap junctions. Skeletal muscle is voluntarily controlled while both cardiac and smooth muscle tissue are involuntary and autorhythmic.
Which ion is required for exocytosis of ACh? Cl-1 K+1 H+1 Na+1 Ca+2
Ca+2
H zone
Choose the region that will narrow or disappear during muscle contraction?
myosin
During the contraction cycle, ATP attaches to
Muscular tissue has several important properties, such as electrical excitability. Another property of muscular tissue is that it is able to stretch, and return to its original size and shape. Which property of muscular tissue is this? Conductivity Elasticity Extensibility Plasticity None of these is correct
Elasticity
Stretching is most effective at reducing injury and promoting greater flexibility if it is done over the course of many weeks, and always when the muscle is cold (before beginning to exercise). False True
False
The ability of muscular tissue to contract forcefully when stimulated by an action potential is called extensibility. T/F?
False
True
Fascia is a sheet or band of irregular connective tissue. T/F
What is the major difference between the two types of smooth muscle tissue?
In single-unit smooth muscle tissue, action potentials are initiated in response to neurotransmitters, hormones, or an autorhythmic signal. The action potential spreads throughout the tissue by moving through gap junctions that connect all the muscle cells together within the tissue. It is found in the skin and in tubular arrangements that form part of the walls of small arteries and veins and of hollow organs such as the stomach, intestines, uterus, and urinary bladder. In multiunit smooth muscle tissue, muscle cells have few gap junctions with neighboring cells and thus must be excited by their own motor neuron terminal. It is found in the walls of large arteries, in airways to the lungs, in the arrector pili muscles that attach to hair follicles, in the muscles of the iris that adjust pupil diameter, and in the ciliary body that adjusts focus of the lens in the eye
muscle fiber
In the drawing, the circle is indicating a:
During muscle contractions , thin filaments are pulled towards the a) Z disc. b) H zone. c) M line. d) A band. e) I band.
M line
In embryonic muscle development, what happens to the somites?
Somite cells differentiate into myotome, dermatome, and sclerotome.
electrical excitability, contractility, extensibility and elasticity.
The properties of muscle tissue include:
fascia
The sheet or broad band of fibrous connective tissue that supports and surrounds muscles and other organs of the body is called
Glycolysis is part of anaerobic cellular respiration. T/F?
True
Nearly all muscles of the body develop from an early embryonic layer of cells called the mesoderm. True False
True
Oxygen for aerobic cellular respiration in skeletal muscle is supplied by hemoglobin and myoglobin. T/F
True
Warm up exercise before stretching or strenuous muscle activity prevents injury because tissues stretch best when gentle force is applied at elevated temperatures. True False
True
fused (complete) tentanus
When a person is hooked up to a machine that will record myograms, a record of their muscle activity can be produced (depending on the frequency and strength of the stimuli that generate an action potential in their muscle tissue). If the person receives a series of multiple stimuli in a short period of time, the wave of muscle activity that will be recorded will show a sustained contraction with no period of relaxation in between the periods when they receive the stimuli. The myograms has recorded:
acetylcholine
Which of the following is directly responsible for transmitting an action potential from a motor neuron to a skeletal muscle fiber?
F
Which of the structures in the figure is the contractile organelle that contains the thick and thin filaments?
Z disc
Which structure occurs at the border between two adjacent sarcomeres? Consult the image for assistance.
For the muscle to contract and relax, what must be present (choose all that apply)? a) ATP b) calcium ions c) ACh d) sodium ions
a b c
Myofibrils contain what type of proteins? Select all that apply. a) contractile proteins. b) regulatory proteins. c) structural proteins. d) tensile proteins
a b c
Which regions of the sarcomere contain thick filaments? Select all that apply. a) zone of overlap b) A band c) H zone d) I band
a b c
What proteins are found in thin filaments of skeletal muscle fibers? Select all that apply a) troponin b) tropomyosin c) myosin d) titin e) actin f) nebulin g) dystrophin
a b c e f
Writer's cramp can occur in Anatomy and Physiology lecture class. What factor would most likely contribute to the muscles not being able to relax? a) oxygen being delivered by myoglobin and hemoglobin b) a deficit of ATP keeping myosin from detaching c) calcium being pumped into the sarcoplasmic reticulum d) ACh being degraded by AChE
a deficit of ATP keeping myosin from detaching
At the neuromuscular junction, _______must enter the synaptic end bulb to stimulate the release of ____________, which binds to ligand gates so ________can enter the muscle fiber. a) calcium ions; ACh, sodium ions b) sodium ions, calcium ions, ACh c) ACh, calcium ions, sodium ions d) sodium ions, ACh, calcium ions e) calcium ions, sodium ions, ACh
a) calcium ions; ACh, sodium ions
What is the result of acetylcholine attaching to the ligand gates of the motor end plate? a) the sarcolemma increases permeability to sodium b) the positive charge of the sarcolemma decreases c) calcium ions will be actively transported into the SR d) calcium voltage gates on the neurolemma are inactive
a) the sarcolemma increases permeability to sodium
Which of the following would not be a contributing factor to muscle fatigue? a. release of excessive amounts of acetylcholine at the neuromuscular junction b. a feeling that you want to quit, that the activity is too difficult (central fatigue) c. depletion of adequate supplies of oxygen and ATP d. a buildup of lactic acid e. all of these contribute to muscle fatigue
a. release of excessive amounts of acetylcholine at the neuromuscular junction
The opening of ligand gates on the sarcolemma is directly caused by a) acetylcholine attachment. b) calcium influx into the motor neuron . c) sodium influx into the muscle fiber. d) acetylcholinesterase activity e) all choices are correct
all choices
After prolonged strenuous exercise has stopped, heavy breathing will often continue for several minutes in order to provide the oxygen needed to a) convert the lactic acid produced during exercise back into glycogen. b) resynthesize creatine phosphate. c) replace oxygen displaced from muscle myoglobin. d) all of these choices are correct
all of the choices
Which ATP production would be sufficient to run in place for one minute? a) creatine phosphate b) anaerobic cellular respiration c) aerobic cellular respiration
anaerobic cellular respiration
Which correctly lists the sequence of structures that action potentials must move through to excite skeletal muscle contraction? a) sarcolemma, axon of neuron, T tubules b) T tubules, sarcolemma, myofilament c) muscle fiber, axon of neuron, myofibrils d) axon of neuron, sarcolemma, T tubules e) myofibrils, myofilaments, mitochondria
axon of neuron, sarcolemma, T tubules
Which region of a sarcomere contain thin filaments? a) I band b) A band c) H zone d) Both I band and A band
both I and A
Which list of organs contains smooth muscle tissue? blood vessels, stomach, esophagus bladder, uterus, small intestine biceps brachii, triceps brachii (muscles of the arm) heart both blood vessels, stomach, esophagus and bladder, uterus, small intestine
both blood vessels, stomach, esophagus and bladder, uterus, small intestine
Autonomic motor neurons regulate: skeletal muscle only smooth muscle only cardiac muscle only both smooth and cardiac muscle both cardiac and skeletal muscle
both smooth and cardiac muscle
In a neuromuscular junction, the effect of acetylcholine (ACh) binding to receptors on the motor end plate lasts only briefly due to a) rapid uptake of the ACh into the myofiber. b) endocytosis of the ACh receptor into the myofiber. c) rapid destruction of ACh in the synaptic cleft by acetylcholinesterase. d) rapid destruction of ACh in the synaptic cleft by monoamine oxidase. e) diffusion of the ACh out of the synaptic cleft.
c) rapid destruction of ACh in the synaptic cleft by acetylcholinesterase.
Why will and individual who lifts weights build larger muscles? a) skeletal muscles are hyperplasic and respond to stress b) skeletal muscle myofibrils and cells increase in number c) skeletal muscles increase number of myofibrils but not number of cells d) skeletal muscles signal satellite cells to increase number of cells
c) skeletal muscles increase number of myofibrils but not number of cells
Smooth muscle tone is maintained by the prolonged presence of [_____] in the muscle cell's cytosol? a) ATP b) calcium ions c) sodium ions d) acetylcholine e) oxygen
calcium ions
Contraction of myofibrils within a muscle fiber begins when a) sodium enters the muscle fiber b) acetylcholine binds to ligand gates c) calcium is released from the sarcoplasmic reticulum d) an action potential travels t-tubules e) calcium is moved into the sarcoplasmic reticulum
calcium is released from the sarcoplasmic reticulum
Which type of muscle tissue contracts when excited by their own autorhythmic muscle fibers? a) cardiac muscle b) slow twitch oxidative skeletal muscle c) multi-unit smooth muscle d) fast twitch glycolytic skeletal muscle
cardiac muscle
When an athlete performs a pull up (raising their chin to a bar while their body hangs), the process of pulling the body up so the chin can touch the bar is a) Concentric b) Eccentric c) Isometric
concentric
The zone of overlap increases during the a) latent period b) contraction period c) relaxation period d) absolute refractory period e) relative refractory period
contraction period
The relaxation phase of a muscle contraction is often prolonged in a fatigued muscle, raising the likelihood of fused summation of action potentials causing painful disturbances to a skeletal muscle. What disturbance is being described? a) fasciculation b) tremor c) fibrillation d) cramp
cramp
Which protein is used to reinforce the sarcolemma and help transmit the tension generated by the sarcomeres to the tendons? a) troponin b) tropomyosin c) myosin d) actin e) dystrophin
dystrophin
When an athlete performs a pull up (raising their chin to a bar while their body hangs), the process of lowering the body down is a) Concentric b) Eccentric c) Isometric
eccentric
Muscle tissue has several important properties, such as electrical excitability. Another property of muscle tissue is that it is able to contract or extend, yet return to its original size and shape. Which property of muscle tissue is this?
elasticity
The outermost layer of connective tissue surrounding a skeletal muscle is the a) tendon b) ligament c) endomysium d) epimysium e) perimysium
epimysium
Which property of muscle gives it the ability to stretch without damage? a) electrical excitability b) contractility c) extensibility d) elasticity
extensibility
What type of skeletal muscle fiber would an Olympic quality weight lifter specifically be developing during training, to enhance his or her weight lifting power? slow oxidative fibers fast oxidative-glycolytic fibers fast glycolytic fibers all of these choices none of these choices
fast glycolytic fibers
World class shot-putters will have a higher percentage of ______in their arm muscles. a) slow oxidative fibers b) fast oxidative fibers c) fast glycolytic fibers
fast glycolytic fibers
Leg muscles are predominantly composed of which type of muscle fiber? a) slow oxidative b) fast glycolytic c) fast oxidative-glycolytic d) slow glycolytic e) fast oxidative
fast oxidative- glycolytic
Which of the regions of a sarcomere contain titin? a) the A band only b) the H zone only c) the zone of overlap only d) from M line to Z disc e) the I band only
from m line to z disc
After the fusion of myoblasts, the muscle fiber loses its ability to a) grow b) lengthen c) contract d) go through mitosis
go through mitosis
Strength training would result in a) atrophy of fast oxidative-glycolytic fibers b) hypertrophy of fast oxidative-glycolytic fibers c) hyperplasia of fast oxidative-glycolytic fibers d) conversion of slow oxidative fibers to fast oxidative-glycolytic fibers
hypertrophy of fast oxidative-glycolytic fibers
Motor unit recruitment occurs when there is a(n) [increase] in the number of active motor units within a skeletal muscle. a) increase b) decrease c) no change
increase
As one ages, the presence of slow oxidative fibers ___. decreases increases stays the same slightly decreases
increases
This structure is unique to cardiac muscle cells, and allows individual cells to be firmly attached to each other (to provide mechanical strength during contraction), and also allow the action potential to spread rapidly through the cardiac muscle tissue, so that contractions are smooth and coordinated. Z discs intercalated discs desmosomes gap junctions sarcomeres
intercalated discs
Which microscopic structure is found only in the cardiac muscle tissue? a) myosin b) tropomyosin c) sarcomeres d) intercalated discs e) striations
intercalated discs
When an athlete is preparing to perform a pull up, they hang from the bar. At this point, they are performing what type of contractions? a) Concentric b) Eccentric c) Isometric
isometric
When oxygen is plentiful inside a skeletal muscle cell, what happens to the pyruvic acid that is formed during glycolysis? it is converted into glycogen it diffuses out of the cell and into the bloodstream it diffuses into mitochondria to be broken down to generate ATP it is used to convert creatine into creatine phosphate it is converted into lactic acid
it diffuses into mitochondria to be broken down to generate ATP
Which term describes a somatic motor neuron and all the skeletal muscle fibers it stimulates? a) synapse b) motor unit c) neuromuscular junction d) motor end plate
motor unit
Which function do all three muscles perform? a) moving and storing material throughout the body b) generating heat through contractions c) stabilizing the movement of joints d) promoting movement of body structures
moving and storing material throughout the body
Which of the following is not a function of skeletal muscle tissue? moving your eyes from left to right as you read this question holding your head up moving food through the small intestine shivering to generate body heat when you've become chilled stabilizing joints and helping to maintain body positions
moving food through the small intestine
A small amount of muscle tension and muscle definition (the appearance of muscle beneath the skin) is present even in a relaxed muscle. A person who is physically fit due to regular exercise, will have more of this characteristic of muscle tissue than someone who is not fit. What is this characteristic? muscle recruitment muscle refraction muscle tone muscle relaxation muscle contraction
muscle tone
Which disorder occurs when little to no proteins are produced to support the sarcolemma? a) muscular hypertrophy b) muscular atrophy c) fibromyalgia d) myasthenia gravis e) muscular dystrophy
muscular dystrophy
The contractile organelles of a skeletal muscle fiber are _________, which are composed of repeating units called ________. Answer 1 choices: myocytes sarcomeres myofibrils fascicles Answer 2 choices: fascicles myofibrils sarcomeres myocytes
myofibrilis sarcomeres
Which of the following molecules found in skeletal muscle cells binds oxygen that can later be used during aerobic metabolism to help generate ATP? glycogen creatine phosphate creatine myoglobin titin
myoglobin
Muscle damage can be indicated by... a) myoglobin found in blood. b) few mitochondria located in muscle fibers. c) low concentration of creatine kinase in the sarcoplasm. d) slow myosin ATPase. e) high amount of glycogen in the sarcoplasm
myoglobin found in blood
Which functions as a motor protein in all three types of muscle tissue? a) actin b) myosin c) troponin d) titin e) tropomyosin
myosin
Cross bridges are formed during muscle contraction when _____ binds to _____. a) myosin; troponin b) actin; troponin c) myosin; actin d) actin; myosin e) actin; tropomyosin
myosin actin
The site where a somatic motor neuron releases acetylcholine to stimulate a skeletal muscle fiber is called the myofibril sarcolemma motor end plate neuromuscular junction synaptic end bulbs
neuromuscular junction
Skeletal muscle is covered, surrounded and protected by various layers of connective tissue. Which layer of connective tissue would surround a bundle of muscle fibers (muscle cells)? endomysium perimysium epimysium fascia hypodermis
perimysium
Which type of muscle tissue is capable of undergoing the stress-relaxation response when stretched? a) cardiac muscle fibers b) fast glycolytic fibers c) fast oxidative-glycolytic fibers d) multiunit smooth muscle fibers e) single-unit smooth muscle fibers
single-unit smooth muscle fibers
Place the muscle tissue type in order from least to most ability to regenerate. a) smooth, skeletal, cardiac b) skeletal, cardiac, smooth c) cardiac, smooth, skeletal d) skeletal, smooth, cardiac e) cardiac, skeletal, smooth
skeletal cardiac smooth
If you are an endurance athlete, you especially rely on which type of skeletal muscle fiber to perform your sport? slow oxidative fibers fast oxidative-glycolytic fibers fast glycolytic fibers all of these choices are correct none of these choices is correct
slow oxidative fibers
Which type of muscle tissue is involuntary (can't be consciously controlled)? skeletal muscle smooth muscle cardiac muscle skeletal muscle and smooth muscle smooth muscle and cardiac muscle
smooth muscle and cardiac muscle
Depending on how specialized a type of muscle tissue is, the muscle fibers or cells of that tissue will have varied abilities to regenerate (healing and production of new cells). What type of muscle tissue has the greatest ability to regenerate? smooth muscle cells have the greatest ability to regenerate skeletal, cardiac and smooth muscle all have similar abilities to regenerate although all muscle cells can undergo some regeneration, only skeletal muscle fibers can do it easily and frequently, especially when we regularly exercise only skeletal and cardiac muscle cells can undergo limited regeneration only cardiac and smooth muscle cells can undergo regeneration
smooth muscle cells have the greatest ability to regenerate
Smooth muscle fibers do not have striations like skeletal and cardiac muscle cells do. This is because: the sarcomeres are smaller than in cardiac muscle cells and skeletal fibers, and aren't visible even when smooth muscle fibers are examined microscopically smooth muscle fibers contain only intermediate filaments, which aren't arranged in sarcomeres smooth muscle fibers contain thin and thick filaments, as well as intermediate filaments, but none of them are arranged in sarcomeres visceral smooth muscle fibers don't have striations, but multiunit smooth muscle cells do, but these cells are more rare, and so we rarely have a chance to view them with a microscope smooth muscle fibers contain only intermediate filaments, which aren't arranged in sarcomeres and visceral smooth muscle fibers don't have striations, but multiunit smooth muscle cells do, but these cells are more rare, and so we rarely have a chance to view them with a microscope
smooth muscle fibers contain thin and thick filaments, as well as intermediate filaments, but none of them are arranged in sarcomeres
Which characteristics describe both skeletal and cardiac muscle? a) striations b) autorhymicity c) cell shape d) autonomic control e) somatic control
striations
Skeletal muscle contraction is triggered to begin when calcium is released from a) myofibrils b) mitochondria c) terminal cisterns of sarcoplasmic reticulum d) T-tubules
terminal cisterns of sarcoplasmic reticulum
Myasthenia Gravis is an autoimmune disorder that targets the ACh receptors at the NMJ and ultimately reduces the number of available receptors. Predict what happens if you treat the patient with a drug that inhibits the activity of acetylcholinesterase? a) The drug will prevent contraction. b) The drug will cause a weak contraction. c) The drug will increase contraction. d) The drug will cause spasm.
the drug will increase contraction
Which statement explains the sarcomere appearance change during a muscle contraction? a) The light A bands remain at a constant length. b) The I bands lengthen. c) The I bands will only consist of thin filament. d) The h zone shortens as actin filaments slide towards the m-line.
the light A bands remain at a constant length
The contractile organelle of skeletal muscle fibers is the myofibril the endoplasmic reticulum the T tubule the myofilament the sarcomere
the myofibril
Mitochondrial activity in skeletal muscle cells are usually efficient, but can have limited ATP production if a) there is pyruvic acid accumulation. b) there is limited O2 availability c) CO2 is produced as a waste product
there is lmited O2 availability
Why would cardiac muscles have longer refractory periods than skeletal muscles. Choose the best answer? a) to preserve the normal rhythm of the heart and prevent fatigue b) the muscle types contain different contractile proteins c) skeletal muscle is autorhythmic d) skeletal muscles have prolonged calcium influx e) cardiac muscle is not dependent on aerobic respiration to produce ATP
to preserve the normal rhythm of the heart and prevent fatigue
To delay the onset of muscle fatigue, not all the motor units in a muscle will contract at the same time. Some will remain relaxed while others are contracting. If the contraction continues, and greater force is needed, more motor units will be recruited. True False
true
A brief contraction of all muscle fibers in a motor unit in response to a single action potential moving down the somatic motor neuron is known as a) unfused tetanus. b) fused tetanus c) wave summation. d) refractory period. e) twitch contraction
twitch contraction