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chap 9A& P
| Question | Answer |
|---|---|
| Which of the following are types of muscles and are involuntary? | smooth & cardiac muscle |
| 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_____ | fascicle & perimysium |
| Due to their shape, muscle cells are also called muscle______ | fibers |
| The sarcoplasm of a muscle fiber contains many parallel structures made of proteins. These structures are called ______. | myofibrils |
| thin filaments | actin, troponin, tropomyosin |
| thick filaments | myosin |
| The three types of muscle are_____ muscle, _____ muscle, and _____ muscle | skeletal, smooth, cardiac muscle |
| How many myofibrils and sarcomeres are found in a muscle fiber? | Each muscle fiber contains many myofibrils, each made of many sarcomeres joined end to end. |
| A bundle of skeletal muscle fibers enclosed by a perimysium forms a(n)____ within a muscle | fascicle |
| Within myofibrils, the area between two successive Z lines is called a(n) ______. | sarcomere |
| A skeletal muscle fiber is ______. | a single muscle cell |
| What are myofibrils? | bundles of proteins in a muscle cell |
| Within myofibrils, thick filaments are composed of the protein_____,while thin filaments primarily contain_____ | myosin, actin |
| The ______are repeating units within muscle fibers that act as the functional units of muscle contraction | sarcomeres |
| In a skeletal muscle fiber, each myofibril is surrounded by a network of membranous channels that runs parallel to the myofibril and is called the_________ | sarcoplasmic reticulum |
| What is muscle fiber? | a muscle cell |
| What is the name of the process on a neuron that carries electrical impulses toward the cell to be stimulated? | axon |
| During excitation of a muscle fiber, which one of the following events comes immediately after the release of acetylcholine from the motor neuron? | acetylcholine diffuses across the synaptic cleft |
| In excitation-contraction coupling, the protein called______moves to expose binding sites on the actin filaments that can form cross-bridges. | tropomyosin |
| True or false: Myofilaments shorten during contraction. | F |
| In a muscle contraction, the force that shortens the sarcomeres comes from the myosin cross-bridges pulling on the_____ filaments | thin |
| Communication networks throughout the body are established by specialized cells that are known as nerve cells or______ | neuron |
| Which statements correctly describe changes in a skeletal muscle cell during muscle contraction? | Sarcomeres shorten during contraction.,Muscles shorten during contraction.,Myofilaments overlap during contraction. |
| What generates the force that shortens the sarcomeres to bring about muscle contraction? | myosin cross-bridges pulling on the actin filaments |
| What is the name of the process on a neuron that carries electrical impulses toward the cell to be stimulated? | axon |
| During muscle relaxation, calcium levels in the sarcoplasm fall because ______. | calcium is actively transported into the sarcoplasmic reticulum |
| During excitation-contraction coupling, calcium binds to ______. | troponin |
| During muscle contraction, the sarcomeres shorten because ______. | thick and thin filament slide past one another, increasing their overlap |
| 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 |
| During which phase are calcium ions actively transported into the sarcoplasmic reticulum? | relaxation |
| The process of glycolysis is ______. | anaerobic |
| The product of glycolysis, pyruvic acid, is converted to ______ when oxygen is not available. | lactic acid |
| Muscle fatigue is a condition described by ______ and is usually caused by prolonged use of a muscle. | the loss of a muscle's ability to contract |
| What is the role of creatine phosphate during skeletal muscle contraction? | It is used to quickly regenerate ATP from ADP. |
| Glycolysis is used to produce ATP for muscle contraction and is best described as ______. | anaerobic breakdown of glucose to produce ATP |
| Muscle contractions generate ______, which is important for the overall functioning of the body. | 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 calle | threshold stimulus |
| When a single muscle fiber contracts when stimulated by a single impulse, the contractile response is called a(n) | twitch |
| Why does summation result in an increased force of contraction? | Individual twitches combine due to the high frequency of stimulation. |
| True or false: Muscles generate heat when they contract. | T |
| A motor unit is comprised of a ______ and the ______ that it controls. | motor neuron; muscle fibers |
| Which type of motor unit is more easily stimulated and, thus, is recruited first? | small motor units (fewer muscle fibers) |
| What is the meaning of the term threshold stimulus? | The minimum strength of an electrical impulse that can stimulate contraction in an isolated muscle fiber. |
| A muscle response called a(n)______consists of a period of contraction during which the fiber pulls at its attachment, followed by a period of______ | twitch & relaxation |
| When a muscle fiber is stimulated at a high enough frequency that it doesn't have time to relax, the forces of the individual twitches combine. What is this process called? | summation |
| What is a motor unit composed of? | several muscle fibers, a single motor neuron |
| Which type of motor unit produces more force when recruited? | large motor unites (more 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. |
| During a(n______)muscle contraction, the muscle either lengthens or shortens, while the tension stays constant. | isotonic |
| Which of the following is a characteristic of slow-twitch (type I) fibers? | red in color |
| The cells of________ muscle are tapered, lack striations, and have a sarcoplasmic reticulum that is not very extensive. | smooth muscle |
| What is an isotonic contraction? | A muscle changes in length, but its tension stays constant. |
| Which type of muscle can change length without changing tautness? | smooth muscle |
| Which type of muscle have striated cells that form interconnected, branching, three-dimensional networks? | cardiac muscle |
| List the four components of a lever. | rigid bar or rod, pivot point, force, object to move |
| What type of muscle cells lack striations? | smooth muscle |
| True or false: Smooth muscle can maintain a forceful contraction longer than skeletal muscle. | T |
| Muscle tissue that has a well-developed sarcoplasmic reticulum, many mitochondria, and branching cells with one nucleus is classified as ______ muscle. | 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)______ | lever |
| Choose all characteristics of smooth muscle cells. | They are not striated, Their sarcoplasmic reticula are not well developed, They have a single nucleus. |
| The point of attachment for a muscle that remains relatively stationary is its | origin |
| Compared to skeletal muscle, smooth muscle is ______ to contract and ______ to relax. | slower, slower |
| Indicate three characteristics of cardiac muscle. | Each cardiac muscle cell has a single nucleus., Cardiac muscle cells have abundant mitochondria, Cardiac muscle cells have large transverse tubules. |
| When describing the roles of muscles in an action, what is the role of the agonist? | to cause an action |
| The end of a muscle that is fixed (relatively immovable) is called its ______. | origin |
| Consider the naming of the triceps brachii muscle. What does the name tell you about the muscle? | It provides information about the number of heads (origins). |
| A muscle that functions to cause action is referred to as the ______. | agonist |
| The muscles of mastication include the medial and lateral pterygoid,_____ & _______ | masseter & temporalis |
| Consider the naming of the temporalis muscle. What does the name tell you about the muscle? | It provides information about the locations of the origins and/or insertions for the muscle. |
| The trapezius, the rhomboid major and minor, and the levator scapulae are all muscles that move the_____ girdle | pectoral |
| The masseter, the temporalis, and the two pterygoid muscles are the four muscles responsible for ______. | mastication |
| A single muscle acts to extend the elbow joint. This muscle is located on the ______. | posterior surface of the humerus |
| Where are the extensors of the hand located? | posterior side of the forearm |
| What four pairs of muscles are considered muscles of mastication? | medial pterygoid, masseter, temporalis, lateral pterygoid |
| 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 |
| Muscles found on the ______ surface of the humerus cause flexion of the forearm at the elbow. | anterior |
| The ______ is part of the perineum and is located within the pubic arch. | urogenital diaphragm |
| Which of the following muscles is a flexor of the hand? | palmaris longus |
| Contraction of muscles of the ______ group of the thigh can result in extension, abduction, or rotation of the thigh. | posterior |
| Muscles that move the thigh are attached to the ______ girdle and the _______ | pelvic & femur |
| The gluteus maximus and piriformis are part of the ______ group of muscles that move the thigh. The pectineus and gracilis are part of the ______ group. | posterior; medial |
| Muscles with attachment points at the (1) pelvic girdle and (2) the femur will cause what type of movement? | movement of the thigh |
| Muscles of the ______ muscle group flex the knee and those of the ______ muscle group extend the knee. | hamstrings; quadriceps femoris |
| The knee is flexed by the action of the three muscles in the hamstring group, and the______ muscle | sartorius |
| To move the foot upwards towards the shin is known as_____ to turn the sole of the foot medially is known as ______ | dorsiflexion & inversion |
| True or false: Muscles tend to atrophy with age. | T |
Created by:
Thuythi15