Muscular System PPT PDF

WEEK 3 MUSCULAR SYSTEM Part 1 HAPP – Laboratory Instructor: Jerra May Mercado, MD  OUTLINE OF ACTIVITIES PRE-LAB DISCUSSION Topic – MUSCULAR SYSTEM Activity proper Dismissal OVERVIEW Organization of Skeletal Muscle: Whole Muscle  Muscle Fascicle  Muscle F...

WEEK 3 MUSCULAR SYSTEM Part 1 HAPP – Laboratory Instructor: Jerra May Mercado, MD  OUTLINE OF ACTIVITIES PRE-LAB DISCUSSION Topic – MUSCULAR SYSTEM Activity proper Dismissal OVERVIEW Organization of Skeletal Muscle: Whole Muscle  Muscle Fascicle  Muscle Fiber  Myofibrils  Myofilaments HISTOLOGY OF THE MUSCLES Muscle Actions  MUSCLE ACTIONS Flexion: action that bends a part of the body anteriorly, such as flexing the elbow. The exception is the knee. Flexion of the knee moves the lower leg posteriorly. Extension: action that bends a part of the body posteriorly, such as straightening the arm at the elbow. As with flexion, the exception is the knee. Extending the knee straightens the lower leg. 7  MUSCLE ACTIONS Abduction: movement of a part of the body away from the midline Adduction: movement of a part of the body toward the midline 8  MUSCLE ACTIONS Protraction: movement that brings part of the body forward Retraction: movement that brings part of the body backward 9  MUSCLE ACTIONS Lateral excursion: movement of the jaw laterally to either side Medial excursion: movement of the jaw back to the midline 10  MUSCLE ACTIONS Dorsiflexion: position of standing on the heels with the toes pointing up off the floor Plantar flexion: position of standing on tiptoes with the heels off the floor Inversion: position in which the soles of the feet are together, facing each other Eversion: position in which the soles of the feet point away from each other 11  MUSCLE ACTIONS Rotation: the act of spinning on an axis Circumduction: the act of making a circle with part of the body 12  MUSCLE ACTIONS Supination: rotation that turns the palms up Pronation: rotation that turns the palms down Access the text alternative for slide images. 13  MUSCLE ACTIONS Opposition: the act of bringing the thumb to the palm Reposition: the act of taking the thumb away from the palm Elevation: the act of closing the jaw or raising the shoulders Depression: the act of opening the jaw or lowering the shoulders 14 Muscle Nomenclature  MUSCLE NOMENCLATURE The names of the muscle are in Latin. Muscle names are commonly a combination of two or three words, although some are only one word. Example: Deltoid  because the muscle is shaped like delta Δ (Greek letter Delta) Some muscles are named according to their points of attachment (origin and insertion). Example: sternocleidomastoid muscle has attachments on the sternum, clavicle, and mastoid process  MUSCLE NOMENCLATURE Naming by SHAPE Naming by RELATIVE SIZE Deltoid shaped like delta Brevis Short Δ Longus Long Orbicularis Circular Magnus Large Platy Flattened; Maximus Largest Platelike Medius Moderately Quadratus Square sized Rhomboideus Diamond-shaped Minimus Small Trapezius Trapezoidal Naming by DIRECTION Triangularis TriangularOF FIBERS Oblique Diagonal to the body’s midline Rectus Parallel to the midline Sphincter Circling an opening Transversus At a right angle to the midline MUSCLE NOMENCLATURE Naming by ACTIONS produced Naming by REGION in which they Abductor Abducts a part are found Brachialis Arm Adductor Adducts a part Frontalis Frontal (Bone) Depressor Depresses a part Femoris Femur Extensor Extends a part Gluteus Posterior of Flexor Flexes a part hip/thigh Oculi Eye Levator Elevates a part Radialis Radius Rotator Rotates a part Ulnaris Ulna Muscles by Regions  MUSCLES BY REGIONS MUSCLES OF THE HEAD AND NECK MUSCLES OF THE THORAX AND ABDOMEN MUSCLES OF THE BACK AND BUTTOCKS MUSCLES OF THE ARM MUSCLES OF THE FOREARM MUSCLES OF THE THIGH MUSCLES OF THE LEG 20 Muscles (Anterior Muscles (Posterior View) View) 21 MUSCLES BY REGIONS Muscles of the Action Head and Neck Occipitalis Moves scalp Orbicularis oculi Closes eye Orbicularis oris Closes lip Buccinator Compresses cheek (ex. whistling) Zygomaticus Elevates angle of mouth, upper lip major Frontalis Elevates brows, wrinkles skin of forehead Temporalis Closes jaw Masseter Closes jaw Platysma Depresses mandible and angle of mouth Tenses skin of lower face and (c) Rebecca Gray/McGraw Hill Education anterior neck Sternocleidomasto Rotates, flexes neck id 22 MUSCLES BY REGIONS Muscles of the Action Thorax and Abdomen Pectoralis major Adducts, flexes arm Pectoralis minor Depresses scapula Serratus anterior Protracts scapula External abdominal Compresses abdomen obliques Internal abdominal Compresses abdomen obliques Transverse abdominal Compresses abdomen Rectus abdominis Flexes waist (c) Christine Eckel/McGraw Hill Education 23 MUSCLES BY REGIONS Muscles of the Action Thorax and Abdomen Diaphragm Inhalation External intercostals Expands thorax Internal intercostals Compresses thorax 24 MUSCLES BY REGIONS Muscles of the Back and Action Buttocks Trapezius Extends head, neck; Elevates, depresses, or rotates scapula Latissimus dorsi Extends, adducts arm Erector spinae Straightens and rotates the back Gluteus maximus Extends thigh Gluteus medius Abducts thigh (b) Rebecca Gray/Don Kincaid/McGraw Hill Education 25 MUSCLES BY REGIONS Muscles of the Arm Action Deltoid Abducts arm Biceps brachii Flexes, supinates forearm Triceps brachii Extends forearm Brachialis Flexes forearm Brachioradialis Flexes forearm (b) Rebecca Gray/McGraw Hill Education 26 MUSCLES BY REGIONS Muscles of the Action Forearm Extensor carpi radialis Extends, abducts wrist Extensor carpi ulnaris Extends, abducts wrist Palmaris longus Flexes wrist Flexor carpi radialis Flexes, abducts wrist Flexor carpi ulnaris Flexes, abducts wrist Extensor digitorum Extends fingers Flexor digitorum Flexes fingers (b) Rebecca Gray/McGraw Hill Education (c) Christine Eckel/McGraw Hill 27 MUSCLES BY REGIONS Muscles of the Action Thigh (Anterior) Tensor Fascia Abducts thigh Latae Gracilis Adducts thigh Adductor longus Adducts thigh Pectineus Adducts and flexes hip Iliacus Flexes hip Iliopsoas Flexes hip Psoas major Flexes hip Sartorius Flexes hip, flexes knee Rectus femoris Flexes hip, extends knee Quadriceps femoris Vastus lateralis Extends knee Rectus femoris Vastus medialis Extends knee Vastus lateralis Vastus Extends knee Vastus medialis intermedius Vastus intermedius 28 MUSCLES BY REGIONS Muscles of the Thigh Action (Posterior) Biceps femoris Flexes knee, extends hip Semitendinosus Flexes knee Semimembranos Flexes knee us (b) Rebecca Gray/McGraw Hill 29 MUSCLES BY REGIONS Muscles of Action the Leg Gastrocnemius Plantar-flexes foot Soleus Plantar-flexes foot Peroneus/ Everts foot fibularis Tibialis anterior Dorsiflexes and inverts foot (b) Rebecca Gray/McGraw Hill 30 REFERENCES: CHAPTER 5 Roiger, D. Bullock, N. (2023). Anatomy, Physiology, & Disease: Foundations for the Health Professions. (3rd Edition). McGraw-Hill Education LAB EXERCISE 17, & 18 Patton, K. (2019). Anatomy & Physiology Laboratory Manual. (10th edition). Elsevier Inc.  WEEK 3 MUSCULAR SYSTEM Part 2 HAPP – Laboratory Instructor: Jerra May Mercado, MD Anatomy of a Skeletal Muscle ANATOMY OF A SKELETAL MUSCLE A muscle has a fibrous covering called the epimysium. A muscle is composed of a bundle of fascicles. Each fascicle is surrounded by perimysium. A fascicle is composed of muscle cells (muscle fibers) surrounded by endomysium. The connective tissues of the muscle come together at the end of the muscle cell, or fiber, to form a tendon. 3 Connective Tissues and Structural Components of a Thigh Muscle 4 ANATOMY OF A SKELETAL MUSCLE SKELETAL MUSCLE CELL Sarcolemma is the plasma membrane. The sarcoplasmic reticulum is the name given to the smooth endoplasmic reticulum in a muscle cell. Stores2calcium (Ca ) ions 5 ANATOMY OF A SKELETAL MUSCLE MYOFIBRIL A muscle cell is composed of myofibrils. Each myofibril is composed of thick and thin myofilaments arranged in sarcomeres. Thick and thin myofilaments are composed of protein molecules. 6 ANATOMY OF A SKELETAL MUSCLE MYOFIBRIL Each myofibril consists of repeating contractile units called sarcomeres. Sarcomere extends from Z line to Z line. Actin filaments are attached to Z lines and extend towards center of sarcomere but do not meet. Myosin filaments reside in the A band and do not contact the Z lines. 7 ANATOMY OF A SKELETAL MUSCLE Skeletal Muscle Cells Striations A-band (dark), anisotropic H-band – middle of A-band Heller: ‘brighter’ M-line – bisects H-band Mittelscheibe: ‘middle’ I-band (light), isotropic Z-line (Z-disc) – bisects the I-band Zwischensheiben: ‘slide between’ ANATOMY OF A SKELETAL MUSCLE MYOFILAMENTS THICK MYOFILAMENT Myosin subunits look like a doubleheader golf club. THIN MYOFILAMENT Actin subunits make up a double chain of beads twisted together. Tropomyosin is a thread that holds the actin chained together. Troponin is a calcium regulatory molecule. 9 CARDIAC MUSCLES SMOOTH MUSCLES Physiology of the Muscular System PHYSIOLOGICAL CHARACTERISTICS OF MUSCLE TISSUE Excitability. A muscle cell can be stimulated by a nerve to contract. Conductivity. The stimulation from the nerve moves quickly along the length of the muscle cell. Contractility. A muscle cell can shorten with force. Muscles can only pull; they cannot push. Extensibility. A muscle cell can be stretched. If the biceps brachii contracts to flex the arm, the triceps brachii needs to stretch to accommodate the motion. Muscles are stretched by the contraction of other muscles. Elasticity. If a muscle cell is stretched, it will return to its original shape. 13  NEUROMUSCULAR JUNCTION Stimulation of a muscle cell by a nerve happens at a neuromuscular junction. Generically referred to as a synapse. An electrical stimulation along the nerve cell results in the release of acetylcholine. Acetylcholine fits into (b) Dr. Thomas Caceci receptors on the muscle cell to stimulate it to 14  NEUROMUSCULAR JUNCTION A minimal amount of stimulus called a threshold is needed for the muscle to respond. As long as the threshold is reached, the muscle cell will contract in an all-or-nothing manner. 15  MUSCLE CONTRACTION AT THE MOLECULAR LEVEL The sliding filament theory of muscle contraction involves thick myofilaments grabbing thin myofilaments and pulling them toward the center of the sarcomere. As all of the sarcomeres are shortened, so too is the muscle cell. Energy contained in A T P is needed for the contraction to happen and to actively transport calcium ions back to the sarcoplasmic reticulum so that the 16 COMPARISON OF MUSCLE TISSUES SKELETAL MUSCLE TISSUE CARDIAC MUSCLE TISSUE SMOOTH MUSCLE TISSUE Composed of long, striated Composed of branched, striated Smooth muscle tissue is cells with multiple nuclei cells with a single nucleus and composed of spindle-shaped pushed off to the side. junctions between cells called cells with a single nucleus. The cells are under voluntary intercalated disks. The cells are not under control, rely on aerobic or The cells are autorhythmic, rely voluntary control, rely on anaerobic respiration for on aerobic respiration for energy aerobic respiration for energy energy production, and are production, and are located in production, and are located associated with bones, skin, the heart. in the walls of blood vessels and body openings. and hollow organs. 17 Part 2 Online Activity  Activity 5: Labster Investigate the function of muscle tissues Your first task is to learn about the different types of muscle tissues found in the human body. Interact with the anatomical 3D holograms to explore the distribution and main functions of skeletal, smooth, and cardiac muscle tissues. Using the control panel to navigate the different models, you will have to collect information about the tissues to solve different scenarios related to the muscular system. Take a look inside the muscle cells Continue your investigation by examining the muscle tissues at the cellular level to see how the individual muscle cells of each muscle tissue compare and contrast from one another. Pick up the cellular 3D models and examine the nuclei, myofibrils, mitochondria and more to understand how the intracellular components enable each muscle cell to perform the functions characteristic for that muscle tissue. Observe how a muscle cell contracts Follow the pathway that allows a nerve signal initiated in the brain to induce an actual muscle contraction in a skeletal muscle. Dive into the molecular level and see how the myofibrils are arranged in repeating units of sarcomeres. Compare a 3D model of a sarcomere to its electron micrograph and observe the changes that take place during contraction and relaxation. Finally, immerse yourself in the process of the sliding filament theory by interacting with the contractile proteins of a sarcomere. Activity 4: Complete Anatomy