Lecture 2
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This document provides an overview of muscles and joints in the human body. It discusses the basic parts and types of muscles, including skeletal, cardiac and smooth muscles. It also describes the different components of muscles like origin, fleshy belly, and tendon. Additionally, it covers the classification and types of joints, including fibrous, cartilaginous and synovial joints. Specifically, it details the seven types of synovial joints like hinge, pivot, ball and socket joints. The document aims to introduce students to the key structures and functions of muscles and joints in the musculoskeletal system.
Lecture 2
- 1. Introduction to Medical Terminologies Lecture # 2 PREPARED BY MUHAMMAD SALMAN BUTT 1SAUDI ELECTRONIC UNIVERSITY
- 2. Lecture: 2 o Basic functions of Muscles oWhat are the different types of muscles. oWhat are the different parts of muscles. oWhat are the different components attached with muscles. oWhat are fascia and its types. oWhat are joints and its different types present in the human body oWhat are the structure of various types of joints presents in human body. 2SAUDI ELECTRONIC UNIVERSITY
- 3. Chapter 4: The Muscle 3SAUDI ELECTRONIC UNIVERSITY
- 4. Introduction to Muscles oThe scientific study of muscles is known as myology. oThe word muscle is derived from Latin word “Mus” meaning mouse. Most of muscles of humans resemble a mouse in their external appearance, the tail of the mouse representing the tendon of the muscle. oThe bones, muscles, and joints together form an integrated system called the musculoskeletal system. SAUDI ELECTRONIC UNIVERSITY 4
- 5. Parts of a skeletal muscles oOrigin: It is the proximal attachment, which usually remains fixed during contraction of the muscles. oFleshy Belly: A muscle may be completely or partly fleshy throughout its entire length. It consists of skeletal muscle cells. oTendon: It is the rounded fibrous end of a skeletal muscle. oAponeurosis: It is a fibrous and membranous part of a muscle by which it is attached to distant parts, e.g. Bicipital aponeurosis of biceps brachii muscle. oInsertion: It is the distal moveable end of a skeletal muscle which moves during contraction. SAUDI ELECTRONIC UNIVERSITY 5
- 6. Types of Muscular Tissues Depending upon the microscopic structure of muscle cells, the muscles are classified into three types 1- Striated or Skeletal muscles: Most skeletal muscle tissue is attached to bones and moves parts of the skeleton. It is striated; that is, striations, or alternating light and dark protein bands, are visible under a microscope. 2- Cardiac Muscles: Found only in the heart, forms the bulk of the heart wall. The heart pumps blood through blood vessels to all parts of the body. Like skeletal muscle tissue, cardiac muscle tissue is striated. However, unlike skeletal muscle tissue, it is involuntary. 3- Smooth Muscles: Smooth muscle tissue is located in the walls of hollow internal structures, such as blood vessels, airways, the stomach, and the intestines. It participates in internal processes such as digestion and the regulation of blood pressure. Smooth muscle is nonstriated (lacks striations) and involuntary (not under conscious control). SAUDI ELECTRONIC UNIVERSITY 6
- 7. SAUDI ELECTRONIC UNIVERSITY 7 Summary of the Principal Features of Muscular Tissue CHARACTERISTICS SKELETAL MUSCLE CARDIAC MUSCLE SMOOTH MUSCLE Cell Appearance and Features Long cylindrical fiber with many peripherally located nuclei; striated; unbranched Branched cylindrical fiber, usually with one centrally located nucleus intercalated discs join neighboring fibers; striated Fiber is thickest in the middle tapered at each end, has one centrally located nucleus; not striated Location Primarily attached to bones by tendons Heart Walls of hollow viscera, airways, blood vessels, iris and ciliary body of the eye, arrector pili of hair follicles Fiber Diameter Very large (10–100 m)* Large (10–20 m) Small (3–8 m) Fiber Length Very large (100 m–30 cm) Small (50–100 m) Intermediate (30–200 m) Speed of Contraction Fast Moderate Slow Nervous Control Voluntary Involuntary Involuntary
- 8. Group Action of Muscles The skeletal muscles are classified into following subgroups depending upon their simple role during movements at a joint. 1. Prime movers (Agonists): These are those muscles which are constantly active in the initiation and maintenance of a particular movement. E.g. Biceps is a prime mover of elbow joint during flexion. 2. Antagonists: These are those muscles which undergo relaxation when the prime mover start contracting; then they remain silent and finally again contract in order to restrict the range of mobility. E.g. Triceps brachii is an antagonist during flexion at the elbow. 3. Fixators: stabilizing the origin of the prime mover so that the prime mover can act more efficiently. 4. Synergists: Most movements also involve muscles called synergists which help the prime mover function more efficiently by reducing unnecessary movement. SAUDI ELECTRONIC UNIVERSITY 8
- 9. Functions of Muscle 1. They take part in locomotion (movement) . 2. They maintain the posture and stability. 3. They conserve the internal heat of the body. 4. Sorrow and grief is expressed by contraction of muscle of face. 5. Storing and moving substances with the body e.g. Temporary storage of the food in the stomach or urine in the urinary bladder. Sphincters: Storage is accomplished by sustained contractions of ring like bands of smooth muscle called sphincter. SAUDI ELECTRONIC UNIVERSITY 9
- 10. Chapter 05 Structures related to the muscles A- Fascia: These are fibro-areolar membranous sheets of variable thickness and strength found in all regions of the body investing the softer and more delicate structures. Types of fascia: 1- Superficial fascia 2- Deep Fascia 1- Superficial Fascia: It is a membranous sheet consisting of fibro-areolar tissue the meshes of which are filled with fatty or adipose tissue. 2- Deep Fascia: It is a dense elastic membrane forming covering for the muscles and in some cases affording for them blind surfaces for attachments. It is devoid of fat cells and is usually tough and inelastic. B- Synovial Bursae: These are sac like structures lined by synovial membrane and contain synovial fluid. They develop at those places where friction is liable to occur during sliding of tendon. SAUDI ELECTRONIC UNIVERSITY 10
- 11. Characteristics Used to Name Skeletal Muscles NAME MEANING EXAMPLE Direction: Orientation of muscle fibers relative to the body’s midline Rectus Parallel to midline Rectus abdominis Transverse Perpendicular to midline Transverse abdominis Oblique Diagonal to midline External oblique Size: Relative size of the muscle Maximus Largest Gluteus maximus Minimus Smallest Gluteus minimus Longus Longest Adductor longus Latissimus Widest Latissimus dorsi Longissimus Longest Longissimus muscles Magnus Large Adductor magnus Major Larger Pectoralis major Minor Smaller Pectoralis minor Vastus Great Vastus lateralis SAUDI ELECTRONIC UNIVERSITY 11
- 12. SAUDI ELECTRONIC UNIVERSITY 12 NAME MEANING EXAMPLE Action: Principal action of the muscle Flexor Decreases joint angle Flexor carpi radialis Extensor Increases joint angle Extensor carpi ulnaris Abductor Moves bone away from midline Abductor pollicis longus Adductor Moves bone closer to midline Adductor longus Levator Produces superior movement Levator scapulae Depressor Produces inferior movement Depressor labii inferioris Supinator Turns palm anteriorly Supinator Pronator Turns palm posteriorly Pronator teres Sphincter Decreases size of opening External anal sphincter Tensor Makes a body part rigid Tensor fasciae latae Number of Origins: Number of tendons of origin Biceps Two origins Biceps brachii Triceps Three origins Triceps brachii Quadriceps Four origins Quadriceps femoris
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- 14. Lecture Link SAUDI ELECTRONIC UNIVERSITY 14 Important link Hear the illustration http://edugen.wileyplus.com/edugen/lti/main.uni
- 15. Chapter 06: The joints Joints: A joint (also called an articulation) is a point of contact between bones, between cartilage and bones, or between teeth and bones. When we say one bone articulates with another bone, we mean that the two bones form a joint. Arthrology: is the scientific study of joints Kinesiology: The study of motion of the human body is called kinesiology SAUDI ELECTRONIC UNIVERSITY 15 Knee Joint
- 16. Classification of Joints The structural classification of joints is based on two criteria: i. The presence or absence of a space between the articulating bones, called a synovial cavity. ii. The type of connective tissue that holds the bones together. Structurally, joints are classified as one of the following types: 1. Fibrous Joint: There is no synovial cavity and the bones are held together by dense irregular connective tissue that is rich in collagen fibers. 2. Cartilaginous joints: There is no synovial cavity and the bones are held together by cartilage. 3. Synovial joints: The bones forming the joint have a synovial cavity and are united by the dense irregular connective tissue of an articular capsule, and often by accessory ligaments. SAUDI ELECTRONIC UNIVERSITY 16
- 17. Functional Classification of Joints The functional classification of joints relates to the degree of movement they permit. Functionally, joints are classified as one of the following types: 1. Synarthrosis: An immovable joint. The plural is synarthroses. 2. Amphiarthrosis: A slightly movable joint. The plural is amphiarthroses. 3. Diarthrosis: A freely movable joint. The plural is diarthroses. All diarthroses are synovial joints. They have a variety of shapes and permit several different types of movements. SAUDI ELECTRONIC UNIVERSITY 17
- 18. Types of Fibrous Joints Fibrous joints permit little or no movement. The three types of fibrous joints are (1) sutures, (2) syndesmoses, and (3) interosseous membranes. 1- Suture: is a fibrous joint composed of a thin layer of dense irregular connective tissue. Sutures unite the bones of the skull. An example is the coronal suture between the frontal and parietal bones. 2- Syndesmosis: is a fibrous joint in which there is a greater distance between the articulating surfaces and more dense irregular connective tissue than in a suture. The dense irregular connective tissue is typically arranged as a bundle (ligament) and the joint permits limited movement. One example of a syndesmosis is the distal tibiofibular joint, where the anterior tibiofibular ligament connects the tibia and fibula. 3- Interosseous membranes: a substantial sheet of dense irregular connective tissue that binds neighboring long bones and permits slight movement (amphiarthrosis). There are two principal interosseous membrane joints in the human body. One occurs between the radius and ulna in the forearm and the other occurs between the tibia and fibula in the leg SAUDI ELECTRONIC UNIVERSITY 18
- 19. Types of Cartilaginous Joints Like a fibrous joint, a cartilaginous joint allows little or no movement. There are two types of cartilaginous joints; 1- Synchondrosis is a cartilaginous joint in which the connecting material is hyaline cartilage. An example of a synchondrosis is the epiphyseal (growth) plate that connects the epiphysis and diaphysis of an elongating bone. 2- Symphysis: is a cartilaginous joint in which the ends of the articulating bones are covered with hyaline cartilage, but the bones are connected by a broad, flat disc of fibrocartilage. The pubic symphysis between the anterior surfaces of the hip bones is one example of a symphysis. SAUDI ELECTRONIC UNIVERSITY 19
- 20. Characteristics of Synovial Joints Synovial joints have certain characteristics that distinguish them from other joints. The unique characteristic of a synovial joint is the presence of a space called a synovial ( joint) cavity between the articulating bones. Synovial joints have the following characteristics; 1. The bony articular surface are covered by articular cartilage and not attached to each other. 2. The bony articular surfaces are connected with each other by tubular fibrous capsule (Articular capsule). 3. The fibrous capsule is lined by mesothelial membrane called synovial membrane. This membrane does not cover the articular cartilage covering the articular bony ends. 4. Between the articular bones a specific joint cavity is present which is lined by synovial membrane. The joint cavity is filled with fluid secreted by synovial membrane. 5. The joint capsule in strengthened by the presence of accessory ligament. 6. The joint cavity may be divided partially or completely by an articular disc composed of white fibro cartilage. SAUDI ELECTRONIC UNIVERSITY 20
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- 22. Types of synovial joint According to the structural classification the synovial joint can be divided into 7 varieties 1. Plane joints: These are formed by the opposition of fairly flat articular surfaces e.g. Intermetatarsal joint 2. Hinge Joints: They roughly resemble the hinge of a door where the articulating surface are so molded that they restrict the to and fro movement to one plane. The sides of the joint are typically provided with strong collateral ligaments, e.g. Elbow joint, Interphalangeal joints. 3. Pivot Joint: These are uni axial joints. They are composed of pivot surrounded by an osteoligamentous ring. Movement is restricted to a rotation around a longitudinal axis passing through the centre of the pivot. E.g. Atlanto Axial Joint. 4. Condylar or condyloid Joints: Here two condyles are received into two concave cavities. It allows principal movement occurring in one plane. E.g. Knee joint. SAUDI ELECTRONIC UNIVERSITY 22
- 23. SAUDI ELECTRONIC UNIVERSITY 23 5. Ellipsoid Joint: These are biaxial joints formed by reception of an oval convex surface into an elliptical concavity. E.g. Radiocarpal joint. 6. Saddle Joint: These are biaxial joint which are formed by reception of cancavo convex opposing surfaces. E.g. Ankle joint. 7. Ball and socket joint: They are poly axial joint and are formed by reception of globular head into a cup like concavity or socket. E.g. Shoulder and Hip Joint.
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