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Chapter 9
A&P I
Question | Answer |
---|---|
What is a function of muscles? | produce movement, maintain posture, stabilize joints, generate heat |
What is the name of the outermost layer of connective tissue surrounding a skeletal muscle? | epimysium |
Which statement describes a sarcomere? | A segment of a muscle fiber |
The amount of oxygen that liver cells require to support the conversion of lactic acid to glucose or glycogen is called the _____________________. | oxygen debt |
A ___________________ is the functional connection between a neuron and a skeletal muscle fiber. | synapse |
What enzyme degrades acetylcholine, keeping it from accumulating in the synapse? | acetylcholinesterase |
What is a motor unit? | a single motor neuron and all the muscle fibers it innervates |
What is a threshold stimulus? | stimulus strength at which the first observable muscle contraction occurs |
What is a myogram? | a chart of the timing and strength of a muscle's contraction |
The term _______________ refers to an increase in the number of motor units activated as a result of more intense stimulation. | recruitment |
Muscle cells that are short in length and have centrally located nuclei are ______________ muscle cells. | smooth |
What type of muscle cells lack transverse tubules, have a single nucleus, and are under involuntary control? | smooth muscle |
What structures connect cardiac muscle cells together? | intercalated discs |
Bones and muscles function together as mechanical devices called _______________. | levers |
What term describes the more movable end of a muscle? | insertion |
What is the linea alba? | Hyperkeratotic line of buccal mucosa along plane of occlusion |
What type of muscle fiber is large in diameter and contains abundant glycogen and relatively few mitochondria? | fast twitch fibers |
What is the main component of thin filaments? | Helix of actin |
Certain natural plant poisons and animal venoms that contain substances that inhibit the function of acetylcholinesterase. If a person is poisoned by one of these substances, which of the following will be the cause of their symptoms? | Muscles will be in a constant state of contraction because acetylcholine won't be broken down and cleared from the neuromuscular junction. |
After finishing a sprint, Tawanda experiences painful cramps in her calf muscles. A deficit in _____________________ would explain her cramping. | ATP |
What has happened in someone with myasthenia gravis that causes them to have muscle weakness? | Decreased number of acetylcholine receptors |
What type of muscle fibers will be stimulated during activities such as distance swimming and distance running? | slow fatigue-resistant fibers |
Doing a "plank" is often part of a yoga or Pilates workout. It is done by holding the body straight in a prone position, engaging the abdominal muscles and supporting oneself on arms and toes. It is much like the "up" position of a push-up, but is held for 30 to 60 seconds. What type of contraction would be occurring in the abdominal muscles? | isometric contraction |
Arrange the steps of muscle fiber contraction in the correct order | 1. The muscle impulse reaches the sarcoplasmic reticulum and calcium is released. 2. Thin filaments are pulled over the thick filaments. 3. Calcium floods the sarcoplasm and binds to troponin molecules leaving active sites. 4. The impulse arrives at the synapse and travels through the transverse tubules. 5. The muscle fiber shortens and contracts. 6. Myosin heads bind to exposed active sites on actin, forming cross-bridges. |
Botulism results from ingestion of a toxin produced by a type of bacterium. Along with other symptoms, it causes a type of paralysis in which the muscles cannot contract. Why does this paralysis occur? | The toxin prevents release of acetylcholine. |
Why are athletes typically able to exercise longer before developing muscle fatigue than non-athletes? | Due to training, athletes have a better blood supply and more mitochondria in their muscles than do non-athletes. |
What is the relationship between ATP and creatine phosphate? | Creatine phosphate supplies energy to produce ATP from ADP and phosphate. |
Why does oxygen debt develop? | The respiratory and circulatory systems are unable to supply enough oxygen for skeletal muscles to work strenuously for a minute or two. |
During strenuous exercise, when muscles are not being supplied with enough oxygen, a shift in metabolism results in the breakdown of pyruvic acid to lactic acid. What is this change in metabolism called? | lactic acid threshold |
Muscle fibers generally have only one motor end plate, but a single motor neuron can innervate many different muscle fibers in a group. How does this arrangement affect muscle contraction? | A signal from one motor neuron can potentially stimulate multiple fibers in a group to contract, generating more force. |
Which statement describes the mechanism of muscle contraction? | Actin filaments slide along myosin filaments. |
Which of these events occurs first in muscle fiber contraction? | Acetylcholine is released from the axon of the motor neuron. |
What occurs at a neuromuscular junction? | motor neuron transmits signal to muscle fiber to elicit a contraction by releasing a neurotransmitter that attaches to receptors on the sarcolemma which becomes more permeable to sodium (Na+) with the rushing of sodium into the cell generates action potential that travels along the sarcolemma. |
What is the cause of rigor mortis that occurs in skeletal muscles a few hours after death? | A decrease in ATP and increased membrane permeability to calcium |
What binds to the exposed cross-bridges on actin? | myosin |
What is the function of creatine phosphate? | directly regenerates ATP from ADP within a muscle cell |
What is the function of acetylecholinesterase? | breakdown of acetylcholine |
What is the location of the vesicles containing neurotransmitter molecules? | At distal end of motor axon |
What is the functional unit of muscle contraction? | sarcomere |
A tendon is ________________, whereas an aponeurosis is __________________. | cordlike and connects muscles to bones; a broad, fibrous sheet of connective tissue that connects muscles to muscles |
What is a function of transverse tubules? | Is to quickly transport a muscle impulse from the sarcolemma throughout the entire muscle fiber. |
What causes the striated appearance of skeletal muscle fibers? | Organization of components of the sarcomeres |
What change occurs with aging? | almost half of muscle mass has atrophied (wasted away) |
How does exercise lead to formation of new muscle? | By stimulating skeletal muscle cells to release IL-6, which stimulates satellite cells to divide, producing more muscle cells. Pg 348 |
Which of these is an involuntary type of muscle? Irregular Skeletal Regular Cardiac | Cardiac |
Muscle cells are also known as muscle fibers. In a skeletal muscle, muscle fibers are found as bundles called _________, each enclosed in a connective tissue sheath, called the __________. | Field 1: fascicle or fascicles Field 2: perimysium |
Due to their shape, muscle cells are also called muscle ________ | fibers |
The process of a neuron, its axon, conducts electrical impulses called _______ ________ towards the end of the axon that innervates a target cell. | Field 1: action Field 2: potentials or potential |
What are the three types of muscles found in the human body? cardiac uniform smooth skeletal intestinal | cardiac smooth skeletal |
In excitation-contraction coupling, the protein called _______ moves to expose binding sites on the actin filaments that can form cross-bridges. | Field 1: tropomyosin |
A bundle of skeletal muscle fibers enclosed by a perimysium forms a(n) _________ within a muscle. | fascicle |
Which statements correctly describe changes in a skeletal muscle cell during muscle contraction? Sarcomeres overlap during contraction. Sarcomeres shorten during contraction. Myofilaments overlap during contraction. Muscles shorten during contraction. Myofilaments shorten during contraction. | Sarcomeres shorten during contraction. Myofilaments overlap during contraction. Muscles shorten during contraction. |
A skeletal muscle fiber is ______. a long, cylindrical structure made of several individual muscle cells a single muscle cell a cord of connective tissue that connects a fascicle to a tendon a bundle of muscle cells | a single muscle cell |
In a muscle contraction, the force that shortens the sarcomeres comes from the myosin cross-bridges pulling on the ________ filaments. | Field 1: thin or actin |
What is the name of the process on a neuron that carries electrical impulses toward the cell to be stimulated? T tubule axon dendrite filament | axon |
During which phase are calcium ions actively transported into the sarcoplasmic reticulum? relaxation excitation-contraction coupling contraction | relaxation |
During excitation of a muscle fiber, which one of the following events comes immediately after the release of acetylcholine from the motor neuron? sodium enters the muscle cell action potential arrives at the synaptic knob of the motor neuron acetylcholine binds to its receptors acetylcholine diffuses across the synaptic cleft | acetylcholine diffuses across the synaptic cleft |
Place the following steps of excitation-contraction coupling in order. calcium binds to troponin Binding sites on actin filaments are exposed Tropopin changes shape and alters the position of tropomyosin calcium is released from the sarcoplasmic reticulum Myosin heads bind to actin | calcium is released from the sarcoplasmic reticulum calcium binds to troponin Tropopin changes shape and alters the position of tropomyosin Binding sites on actin filaments are exposed Myosin heads bind to actin |
Myofilaments shorten during contraction. T/F | F |
What generates the force that shortens the sarcomeres to bring about muscle contraction? ATP binding to myosin heads cross-bridges dissociating from actin filaments troponin pulling on the tropomyosin myosin cross-bridges pulling on the actin filaments | myosin cross-bridges pulling on the actin filaments |
What is the role of creatine phosphate during skeletal muscle contraction? It is used to quickly regenerate ATP from ADP. It is used to pump calcium ions into the sarcoplasm in order to sustain contraction for a longer time. It is used to release myosin heads when ATP is low. | It is used to quickly regenerate ATP from ADP. |
During muscle relaxation, calcium levels in the sarcoplasm fall because ______. calcium is actively transported into the extracellular space calcium diffuses into the sarcoplasmic reticulum calcium is actively transported into the sarcoplasmic reticulum calcium diffuses into the extracellular space | calcium is actively transported into the sarcoplasmic reticulum |
List in order the events leading to excitation of a muscle fiber. Acetylcholine binds to its receptors on the muscle fiber sarcolemma Acetylcholine is released The permeability to sodium ion increases Nerve impulse arrives at a distal end of the axon Acetylcholine diffuses across the synaptic cleft | Nerve impulse arrives at a distal end of the axon Acetylcholine is released Acetylcholine diffuses across the synaptic cleft Acetylcholine binds to its receptors on the muscle fiber sarcolemma The permeability to sodium ion increases |
During excitation-contraction coupling, calcium binds to ______. Multiple choice question. myosin troponin actin tropomyosin | troponin |
What is the first source of energy that is used to convert ADP to ATP after a contraction in a skeletal muscle cell begins? creatine phosphate aerobic respiration glycolysis | creatine phosphate |
Glycolysis is used to produce ATP for muscle contraction and is best described as ______. aerobic breakdown of glucose to produce ATP conversion of ADP to ATP using energy from creatine phosphate anaerobic breakdown of glucose to produce ATP | anaerobic breakdown of glucose to produce ATP |
During which phase are calcium ions actively transported into the sarcoplasmic reticulum? excitation-contraction coupling relaxation contraction | relaxation |
The product of glycolysis, pyruvic acid, is converted to ______ when oxygen is not available. water carbon dioxide lactic acid | lactic acid |
During muscle contraction, the sarcomeres shorten because ______. thick and thin filament slide past one another, decreasing their overlap myosin filaments shorten and in the process pull the actin filaments towards the center of a sarcomere thick and thin filament slide past one another, increasing their overlap | thick and thin filament slide past one another, increasing their overlap |
The process of glycolysis is ______. anaerobic aerobic | anaerobic |
Place in order the steps leading to the relaxation of the muscle. Troponin returns to its relaxed configuration, causing tropomyosin to cover the myosin binding sites on actin acetylcholine releases into the synaptic cleft stops and ACh already in the synaptic cleft is broken down. the nerve signal ceases Calcium is actively transported into the sarcoplasmic reticulum and Ca+2 diffuses away from troponin | the nerve signal ceases acetylcholine releases into the synaptic cleft stops and ACh already in the synaptic cleft is broken down. Calcium is actively transported into the sarcoplasmic reticulum and Ca+2 diffuses away from troponin Troponin returns to its relaxed configuration, causing tropomyosin to cover the myosin binding sites on actin |
Muscle fatigue is a condition described by ______ and is usually caused by prolonged use of a muscle. continuous, sustained contraction the loss of a muscle's ability to contract a tear in the muscle | the loss of a muscle's ability to contract |
When is lactic acid produced? Multiple choice question. during aerobic metabolism during anaerobic metabolism during the citric acid cycle | during anaerobic metabolism |
Muscle contractions generate ______, which is important for the overall functioning of the body. Multiple choice question. heat water pyruvate lactic acid | heat |
If a muscle fiber is subjected to stronger and stronger electrical impulses, it will initially be unresponsive until a strong enough impulse is applied which causes it to contract. The level of electrical stimulation needed to stimulate contraction is called the ______. Multiple choice question. threshold stimulus tetanus stimulus contraction stimulus twitch stimulus | threshold stimulus |
Glycolysis is used to produce ATP for muscle contraction and is best described as ______. Multiple choice question. aerobic breakdown of glucose to produce ATP anaerobic breakdown of glucose to produce ATP conversion of ADP to ATP using energy from creatine phosphate | anaerobic breakdown of glucose to produce ATP |
When a single muscle fiber contracts when stimulated by a single impulse, the contractile response is called a(n) _________ | Field 1: twitch |
Why does summation result in an increased force of contraction? Multiple choice question. Individual twitches combine due to the high frequency of stimulation. Action potentials are conducted faster. More motor units become stimulated. | Individual twitches combine due to the high frequency of stimulation. |
Prolonged or intense exercise can lead to a condition called muscle ________ , defined as the loss of a muscle's ability to contract. | fatigue |
Muscles generate heat when they contract. T/F | T |
A motor unit is comprised of a ______ and the ______ that it controls. Multiple choice question. the axon of a motor neuron; a single muscle fiber muscle fiber; motor neuron motor neuron; muscle fibers | motor neuron; muscle fibers |
For a typical muscle fiber in its optimal state, how many action potentials generated by a motor neuron must arrive at the neuromuscular junction to reach the threshold stimulus? Typically, a single action potential is enough to bring the muscle fiber to the threshold. Typically, 3-5 action potentials per second are needed to bring the muscle fiber to the threshold. Depending on the muscle fiber, up to 50 action potentials per second might be needed to bring the muscle fiber to the threshold. | Typically, a single action potential is enough to bring the muscle fiber to the threshold. |
Which type of motor unit produces more force when recruited? small motor units (fewer muscle fibers) large motor unites (more muscle fibers) | large motor unites (more muscle fibers) |
What is a muscle twitch? Multiple choice question. A single contraction of muscle fiber in response to a single stimulation. The period of time in which the pulling force of a muscle is declining. A sustained contraction of a muscle fiber due to prolonged stimulation. The period of time in which the pulling force of a muscle is increasing. | A single contraction of muscle fiber in response to a single stimulation. |
During a(n) ________ muscle contraction, the muscle either lengthens or shortens, while the tension stays constant. | isotonic |
When the frequency of stimulation of a muscle fiber increases, eventually the individual twitches combine by the process of ________ which results in a sustained contraction. | summation |
The cells of ________ muscle are tapered, lack striations, and have a sarcoplasmic reticulum that is not very extensive. | smooth |
A motor neuron and the muscle fibers that it controls constitute a motor ___________ | unit |
Which type of motor unit is more easily stimulated and, thus, is recruited first? small motor units (fewer muscle fibers) large motor units (more muscle fibers) | small motor units (fewer muscle fibers) |
Compared to skeletal muscle, smooth muscle is ______ to contract and ______ to relax. Multiple choice question. slower; faster faster; slower slower; slower faster; faster | slower; slower |
What type of contraction is observed when a muscle shortens? Multiple choice question. isometric slow-twitch isotonic fast-twitch | isotonic |
Which of the following is a characteristic of slow-twitch (type I) fibers? red in color adapted for glycolysis susceptible to fatigue poor blood supply | red in color |
What type of muscle cells lack striations? Multiple choice question. smooth muscle skeletal muscle cardiac muscle | smooth muscle |
Indicate three characteristics of cardiac muscle. Multiple select question. Cardiac muscle cells have large transverse tubules. Cardiac muscle cells lack sarcoplasmic reticulum. Cardiac muscle cells have abundant mitochondria. Each cardiac muscle cell has a single nucleus. Cardiac muscle lacks striations. | Cardiac muscle cells have large transverse tubules. Cardiac muscle cells have abundant mitochondria. Each cardiac muscle cell has a single nucleus. |
A motor unit is comprised of a ______ and the ______ that it controls. Multiple choice question. the axon of a motor neuron; a single muscle fiber motor neuron; muscle fibers muscle fiber; motor neuron | motor neuron; muscle fibers |
A fulcrum, a force, and an object moved against resistance make up a ______. Multiple choice question. cross-bridge syncytium prime mover lever | lever |
Smooth muscle can maintain a forceful contraction longer than skeletal muscle. True false question. True False | True |
The end of a muscle that is fixed (relatively immovable) is called its ______. Multiple choice question. insertion fulcrum origin | origin |
What is an isotonic contraction? Multiple choice question. Muscle contracts, but the bones it is attached to don't move. A muscle changes in length, but its tension stays constant. A muscle tenses, but does not change length. | A muscle changes in length, but its tension stays constant. |
A muscle that functions to cause action is referred to as the ______. Multiple choice question. agonist antagonist | agonist |
Choose all characteristics of slow-twitch fibers. Multiple select question. They are well supplied with capillaries and mitochondria. They contract very slowly. They contain large amounts of myoglobin. They are also called red fibers. They are also called white fibers. | They are well supplied with capillaries and mitochondria. They contain large amounts of myoglobin. They are also called red fibers. |
Multiple Choice Question Consider the naming of the temporalis muscle. What does the name tell you about the muscle? Multiple choice question. It provides information about the size of the muscle. It provides information about the overall shape of the muscle. It provides information about the locations of the origins and/or insertions for the muscle. It provides information about the number of heads (origins). | It provides information about the locations of the origins and/or insertions for the muscle. |
Muscle tissue that has a well-developed sarcoplasmic reticulum, many mitochondria, and branching cells with one nucleus is classified as ______ muscle. Multiple choice question. smooth cardiac skeletal | cardiac |
When a part of the body moves, the muscles and bones responsible for the movement act as a mechanical device known as a(n) ________ | Field 1: lever or levers |
Match each letter with the correct facial muscle. The muscle on the top portion of the human head anatomy is labeled as A. The muscle in the forehead is labeled as B. The muscle on the back portion of the head is labeled as C. The portion of muscle above the ear is labeled as D. | A -> epicranial aponeurosis B -> frontails C -> occipitalis D -> temporalls |
The point of attachment for a muscle that remains relatively stationary is its ________ | Field 1: origin or muscle origin |
The muscles of mastication include the medial and lateral pterygoid, _________ and _________ | Field 1: masseter or masseter muscle Field 2: temporalis or temporalis muscle |
When describing the roles of muscles in an action, what is the role of the agonist? Multiple choice question. to oppose an action to cause an action to assist in causing an action | to cause an action |
On this diagram depicting muscles in the back, match each letter with the name of the muscle. The area of the shoulder joint in the backside of the human body is labeled as A. The area of the shoulder below the neck is labeled as B. The area on the left side of the spinal cord is labeled as C. The area on the right side of the spinal cord is labeled as D. | A-> deltoid B-> trapezius C-> latissimus dorsi D-> rhomboid major |
Consider the naming of the triceps brachii muscle. What does the name tell you about the muscle? Multiple choice question. It provides information about the overall shape of the muscle. It provides information about the locations of the origins and/or insertions for the muscle. It provides information about the number of heads (origins). It provides information about the size of the muscle. | It provides information about the number of heads (origins). |
Which of the following are muscles that move the pectoral girdle? Multiple select question. Trapezius Rhomboid major Serratus anterior Deltoid Latissimus dorsi Levator scapulae Pectoralis major | Trapezius Rhomboid major Serratus anterior Levator scapulae |
Which type of muscle have striated cells that form interconnected, branching, three-dimensional networks? Multiple choice question. visceral smooth muscle multiunit smooth muscle cardiac muscle skeletal muscle | cardiac muscle |
Which muscle of the anterior surface of the arm is indicated by the arrow? | deltoid |
Match each facial muscle with the arrow that points to it. The area of the cheek near the ear in the human head anatomy is labeled as A. The area surrounding the eye is labeled as B. The area below the mouth is labeled as C. The area of the neck is labeled as D. The area of the side neck below the ear is labeled as E. | A-> masseter B-> orbicularis oculi C-> orbicularis oris D-> platysma E-> sternoclidomastoid |
What four pairs of muscles are considered muscles of mastication? | temporalis medial pterygoid masseter lateral pterygoid |
Match muscles responsible for forearm movements (at the elbow joint) to their actions. flexion extension rotation | flexion - biceps brachii & brachioradialis extension - triceps brachii rotation - supinator & pronator quadratus |
The trapezius, the rhomboid major and minor, and the levator scapulae are all muscles that move the _______ girdle. | pectoral |
Use this diagram of the anterior shoulder and arm to match the letters to the muscles they indicate. The muscular portion of the chest is labeled as A. The muscular portion near the underarm is labeled as B. The muscular portions at the upper and middle arm are labeled D and C. | A - subscapularis B - coracobrachialis C - biceps brachii D - deltoid |
Muscles found on the ______ surface of the humerus cause flexion of the forearm at the elbow. Multiple choice question. anterior posterior | anterior |
Where are the extensors of the hand located? Multiple choice question. posterior side of the forearm anterior side of the forearm posterior side of the arm anterior side of the arm | Where are the extensors of the hand located? Multiple choice question. posterior side of the forearm anterior side of the forearm posterior side of the arm anterior side of the arm |
What is the function of the linea alba? Multiple choice question. to support the lower back to provide attachment for abdominal muscles correct to support the organs within the pelvic cavity to anchor the scapula to the vertebral column | to provide attachment for abdominal muscles |
The flexors of the hand are located on the ______ side of the forearm. Multiple choice question. anterior posterior | anterior |
The ______ is part of the perineum and is located within the pubic arch. Multiple choice question. pelvic floor urogenital diaphragm pelvic diaphragm | urogenital diaphragm |
Muscles with attachment points at the (1) pelvic girdle and (2) the femur will cause what type of movement? Multiple choice question. movement of the leg movement of the foot movement of the thigh | movement of the thigh |
Some abdominal muscles are attached to a band of connective tissue that extends from the xiphoid process of the sternum to the pubic symphysis called the | linea alba |
Matching Question Place the muscles into the appropriate category based on the action on the knee. | flex the knee - biceps femoris, semitendinosus & semimembranosus extend the knee - vastus lateralis, vastus medialis & rectus femoris |
To move the foot upwards towards the shin is known as ________. To turn the sole of the foot medially is known as _________ . | Field 1: dorsiflexion or dorsiflex Field 2: inversion or invert |
Muscles tend to atrophy with age. T/F | T |
The ________ diaphragm is the deep layer of muscle at the pelvic outlet, serving to support the pelvic viscera. | Field 1: pelvic or urogenital |
Muscles that move the thigh are attached to the ________ girdle and the ________ | Field 1: pelvic Field 2: femur |
Muscles of the ______ muscle group flex the knee and those of the ______ muscle group extend the knee. Multiple choice question. hamstrings; quadriceps femoris quadriceps femoris; hamstrings | hamstrings; quadriceps femoris |
The muscles that move the foot attach the femur, _______, and fibula to bones in the foot, generating four types of movement: dorsiflexion, plantar ________, inversion, and eversion. | Field 1: tibia Field 2: flexion |
Which three characteristics are signs of aging in the muscular system? Multiple select question. atrophy cramping weak contractions slow reflexes hypertrophy | atrophy weak contractions slow reflexes |
Match the action of the foot with the description. | dorsiflexion- move the foot upwards plantar flexion- move the foot downward inversion- turn the sole of the foot medially eversion- turn the sole of the foot laterally |
To move the foot upwards towards the shin is known as ________, to turn the sole of the foot medially is known as _______ | To move the foot upwards towards the shin is known as dorsiflexion, to turn the sole of the foot medially is known as inversion. |