Unit 4 Review Lesson 1: Muscle Tissue

Unit 4 Review: Lesson 1: Muscle Tissue ● List and discuss the general functions of skeletal muscle tissue. ○ Excitability: ability to receive and respond to a stimulus ○ Contractility: muscle can shorten when stimulated ○ Extensibility: ability to stretch ○ Elasticity: ability to recoil back to original shape ● Outline the structure and organizational level of skeletal muscle, from the whole muscle (organ), through muscle fiber (cell), myofibril (complex organelle), down to the myofilament (macromolecular structure). ○ 3 layers of connective tissue: ■ Epimysium: connected to the deep fascia ■ Perimysium: surrounds the muscle fascicles ■ Endomysium: within the fascicles, they surround the individual muscle cells (muscle fibers) ○ Muscle: made of bundles of fascicles ○ Fascicles: made of bundles of muscle fibers ○ Muscle fiber: contains bundles of myofibrils ○ Myofibrils: made of bundles of myofilaments ○ Myofilaments: made of thin (actin) and thick (myosin) filaments ● Describe the microscopic structure and functional roles of the myofibrils, sarcoplasmic reticulum, and T tubules of skeletal muscle cells. ○ Myofibrils: made of thin and thick myofilaments that slide along the length of the sarcomere during contraction ○ Sarcoplasmic reticulum: a tubular network around each myofibril that helps with storage and release of calcium ions ○ T-tubules: narrow passageways that are continuous with the sarcolemma and extend deep into the sarcoplasm, can propagate action potentials ● Describe the series of steps that occur in muscle contraction. ○ When an action potential reaches the triad, calcium is released from the terminal cisternae. Calcium then binds with troponin on the tropomyosin strand, and then the strand moves over and makes space for attachments of the globular heads of the thick filaments. Cross bridges form with the actin and myosin filaments with the globular heads by attachment of an ATP molecule to the head, then the head goes through a power stroke and ADP and phosphate is released. A new AYP molecule is then needed for the head to detach and start over. ● Describe the sliding filament theory of contraction. ○ Sliding filament theory: during skeletal muscle contraction, thin filaments slide toward the center of each sarcomere and shortens the muscle fibers ● List the events that occur during cross-bridge cycles and describe the role of ATP in muscle contraction. ○ Listed above ● What is a motor unit? and explain how motor units are used to control muscle contraction. ○ Motor unit: one motor neuron and all the muscle fibers it controls ○ Small motor units produce precise, delicate movements, large motor units produce large powerful movements ● Distinguish between isometric and isotonic contraction. ○ Isometric: same length, changing tension (like pushing on a wall) ○ Isotonic: different length, same tension (like lifting weights) ■ Concentric: muscle shortens, lifting weight up ■ Eccentric: muscle lengthens, lowering weight down ● Describe the anatomical and functional characteristics of cardiac and smooth muscle and compare these muscle types to skeletal muscle. ○ Cardiac muscle ■ Only in heart ■ Intercalculated discs, gap junctions, desmosomes ■ Functional syncytium ■ Pacemaker cells ■ Does not need neural stimulation ○ Smooth muscle ■ Involuntary control ■ Internal body systems ■ Nonstriated ■ No t-tubules Lesson 2: Muscular System o Axial Musculature ● Explain how muscles are described according to their location and cooperative function. ○ They are :) ● What is meant by synergistic and antagonistic muscle groups? ○ Agonist: prime muscle most responsible for movement ○ Antagonist: muscle that opposes the action of the agonist ○ Synergist: muscle helps agonist and provides “additional pull” ○ Fixator: muscle that provides stability by limiting movement ● Locate the major muscles of the axial skeleton and define the major actions of each muscle. ○ Dude that's a lot ● Use the name of muscle to help identify and remember its orientation, location, appearance and action. ○ Predict the actions of a muscle on the basis of its name, origin and insertion ■ Muscles of the head and neck: Facial muscles, Sternocleidomastoid muscle ■ Muscles of the spine ■ Oblique and rectus muscles ● Note: Oblique muscles can compress underlying structures or rotate the spinal column. Includes scalene, external intercostals/internal intercostals, external oblique/internal oblique, transversus abdominis muscles. Rectus muscles are for flexion of the spine. Include – diaphragm, rectus abdominis ■ Muscles of the pelvic floor ● List the names and functions of the muscles of respiration ○ Muscles of inspiration ■ Pectoralis minor - elevates ribs 3-5 ■ External intercostals - libs ribs superiorly ■ Diaphragm - moves ■ Sternocleidomastoid - elevates sternum ○ Muscles of expiration ■ Internal intercostals - move ■ Abdominal muscles - moves lower ribs inferiorly ● For each of the following muscles, learn the name, location and function/action: ○ Orbicularis oris: mouth, opens and closes for food entry ○ Orbicularis oculi: eye, opens and closes to see ○ Zygomaticus major: cheek muscle, for smiling ○ Masseter: cheek muscle, for chewing ○ Temporalis: synergistic muscle for jaw closure ○ Sternocleidomastoid: nodding your head ○ Rectus abdominis: helps with exhalation, movies the body between the ribcage and pelvis ○ External oblique: rotating and twisting the trunk of the body ○ Internal oblique: flex, laterally flex, and rotate the trunk ○ Transversus abdominis: helps hold in internal organs and compresses the abdomen ○ Diaphragm: breathing ○ External intercostals: muscles of quiet breathing ○ Internal intercostals: muscles of forced exhalation o Appendicular Musculature ● Identify the following major muscles of the appendicular skeleton (upper limb) ○ Pectoralis major (pecs), deltoid (shoulder), latissimus dorsi (middle back) ○ Biceps brachii and triceps brachii ○ Brachialis near the elbow ● Muscles of the pectoral girdle and upper limbs ○ Muscles that position the pectoral girdle ■ Posterior view – trapezius, rhomboideus, levator scapulae; Anterior view – pectoralis minor, pectoralis minor, serratus anterior ○ Muscles that move the arm ■ Pectoralis major, Deltoid, Biceps, Triceps ■ Latissimus dorsi ■ Supraspinatus, infraspinatus and subscapularis (SITS muscles) ○ Muscles that move the forearm ■ Anterior (flexors) in the forearm ● Brachioradialis, pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris, flexor digitorum (superficialis and profundus) ■ Posterior (extensors) in the forearm ● Extensor carpi radialis longus and brevis, extensor digitorum, extensor carpi ulnaris, supinator ● Identify the following major muscles of appendicular skeleton (lower limb) ○ Muscles of the thigh: ■ The gluteal group, lateral rotator group, adductor group, iliopsoas group. ○ Muscles that move the leg: ■ Flexors of the knee - Biceps femoris, semimembranosus, semitendinosus, sartorius, popliteus. ■ Extensors of the knee – Rectus femoris, vastus intermedius, vastus lateralis, vastus medialis ○ Muscles that move the foot: ■ Tibialis anterior, Tibialis posterior, gastrocnemius