Kinetic Anatomy and Body Structures Flashcards

Kinetic Anatomy Overview

• Definition: Kinetic Anatomy is the study of movement.

• Overview of human body systems:

  • Endocrine System

  • Digestive System

  • Reproductive System

  • Urinary System

  • Respiratory System

  • Circulatory System

  • Autonomic Nervous System

• Core focus of study: Structures that support human movement.

Human Tissue Types

• Connective Tissue:

  • Bone

  • Cartilage

  • Soft tissue

  • Skin

  • Fascia

  • Tendons

  • Ligaments

• Muscle Tissue:

  • Skeletal muscle

  • Cardiac muscle

  • Smooth muscle

• Nerve Tissue:

  • Neurons

  • Spinal Cord

  • Spinal Nerves

  • Cranial Nerves

  • Neuroglia

• Epithelial Tissue:

  • Serves as protective barriers that line all organs and surfaces of the body.

  • Systems lined by epithelial tissue include:

  • Respiratory System

  • Gastrointestinal System

  • Urinary System

  • Reproductive System

Skeletal System and Bone Structure

• Total Bone Quantity: The human body contains 206 bones.

• Primary Functions of Bones:

  • Support

  • Protection

  • Movement

  • Mineral Storage

  • Formation of blood

• Wolff's Law:

  • Bone adapts to the stresses placed upon it.

  • The physical shape of bones demonstrates the pull of attached muscles and the direction of applied forces.

  • Examples demonstrating Wolff's Law include the Femur and Scapula.

Classifications of Bones

• Long Bones:

  • Anatomical features include Diaphysis, Epiphyses, Epiphyseal plate, Periosteum, and Articular cartilage.

  • Examples: Femur and Humerus.

• Short Bones:

  • Lack a Diaphysis.

  • Symmetrical in shape.

  • Examples: Bones in the wrist and ankle.

• Flat Bones:

  • Characterized by a flat shape.

  • Examples: Head, chest, and shoulder bones.

• Irregular Bones:

  • Bones that do not fit into long, short, or flat classifications.

  • Example: Vertebrae.

• Sesamoid Bones:

  • Sesame seed-shaped bones.

  • Found within tendons and muscles; free-floating.

  • Example: Patella.

Anatomical Landmarks of Bones

• Tuberosity: A large bump on a bone.

• Process: Any projection from a bone.

• Tubercle: A smaller bump on a bone.

• Spinous Process: A longer and thinner projection of bone.

• Condyles: Bony knobs located at the ends of long bones.

• Epicondyles: Smaller knobs located just above the condyles.

• Fossa: A smooth, hollow surface on a bone.

• Facet: A smaller, flatter smooth surface.

• Notch: An area of bone that appears to be cut out, allowing for the passage of other structures.

• Foramen: A hole in the bone.

Articular System and Joints

• Definition: A joint (or articulation) is a location where two or more bones join together.

• Arthrokinematics: Joint surface movement actions, which include:

  • Rolling

  • Spinning

  • Gliding

• Structural Stabilization: Joints are held together by fibrous connective tissue called ligaments (e.g., radial collateral ligament, annular ligament, oblique cord, interosseous membrane, posterior ligaments).

Major Joint Classifications

Diarthrodial Joints (Synovial Joints)

• Key Characteristics:

  • Contain a joint cavity, synovial fluid, and a joint capsule.

  • Feature an explicit space between articular surfaces.

  • Lined with a synovial membrane.

  • Synovial fluid provides essential nutrients to the joint structure.

  • Allow the largest amount of movement in the body.

• Functional Movement Classifications:

  • Gliding Joint

  • Uniaxial Joint

  • Biaxial Joint

  • Triaxial Joint

• Structural Subdivisions (6 Types):

  • Hinge Joint: Example includes the articulation between humerus and ulna.

  • Ball-and-Socket Joint: Example includes the head of the humerus articulating with the scapula.

  • Irregular Joint: Example includes carpal bones.

  • Condyloid Joint: Example includes metacarpal articulating with a phalanx.

  • Saddle Joint: Example includes carpal articulating with a metacarpal.

  • Pivot Joint: Example includes the articulation between radius and humerus.

Synarthrodial Joints

• Key Characteristics: Do not have a joint cavity.

• Structural Subdivisions (3 Types):

  • Suture Joint: Found in the skull.

  • Cartilaginous Joint: Joined by fibrocartilage (e.g., connection between tibia and fibula).

  • Ligamentous Joint: Connected via interosseous ligaments (e.g., interosseous membrane between tibia and fibula).

Muscular System

• General Muscle Numerical Data:

  • Approximately 680 muscles exist in the human body.

  • 240 muscles have separate individual names.

• Criteria Used for Naming Muscles:

  • Action: e.g., flexor, extensor.

  • Attachment to bones: e.g., sternocleidomastoid.

  • Direction of pull: e.g., oblique, rectus.

  • Location: e.g., tibialis, ulnar.

  • Size: e.g., maximus, minor.

  • Shape: e.g., teres, trapezius.

  • Structure: e.g., triceps, quadriceps.

  • Combination of criteria: e.g., flexor digitorum brevis.

• Three Major Types of Muscle:

  • Smooth Muscle: Found inside internal organs and blood vessels.

  • Cardiac Muscle: Unique strictly to the heart.

  • Skeletal Muscle: Causes physical movement of bones.

Skeletal Muscle Function and Characteristics

• Attachments:

  • Attached to bones via tendons.

  • Muscle Origin: Attached to the proximal bone of a joint.

  • Muscle Insertion: Attached to the distal bone of a joint.

• Four Primary Functions of Skeletal Muscle:

  • Movement

  • Protection

  • Joint support

  • Heat production

• Four Fundamental Muscle Characteristics:

  • Extensibility

  • Elasticity

  • Contractility

  • Excitability (Irritability)

• Types of Muscle Contraction (Activation):

  • Concentric

  • Eccentric

  • Isometric

• The SAID Principle:

  • Stands for Specific Adaptation to Imposed Demands.

  • Dictates that muscle can adaptively change in both size and strength.

Structural Organization and Microanatomy of Skeletal Muscle

• Anatomical Hierarchy:

  • Fascia surrounds the skeletal muscle.

  • Epimysium forms the outer sheath around muscle.

  • Perimysium surrounds muscle bundles (fascicles).

  • Endomysium surrounds individual muscle fibers.

  • Muscle Fiber Components: Sarcolemma (outer membrane), Sarcoplasm (fluid matrix), Nuclei, and Myofibrils.

  • Myofibrils contain Myofilaments: Thick (myosin) filaments and Thin (actin) filaments.

• Sarcomere Architecture:

  • Z-line: Boundaries defining individual functional sarcomere units.

  • H-zone: Central zone containing thick myosin filaments.

  • I-band: Light band containing thin actin filaments.

  • A-band: Dark band where thick myosin and thin actin filaments overlap.

  • Cross-bridge: Projections on thick myosin filaments that connect to thin actin filaments.

• Tendon Connection: Connects skeletal muscle to the periosteum of the bone.

Factors Influencing Strength of Muscle Fibers

• Cross-Sectional Area: All else equal, a larger cross-sectional area contains more muscle fibers, producing greater force.

• Length: Longer fibers generate force creating more motion because they shorten across a greater distance.

• Texture: Muscles containing less noncontractile tissue have more muscle fibers per given unit area and generate greater force.

• Specificity: The chemical structure of muscle (fluid viscosity, amount of sarcoplasm, number of amino acids) influences muscle actions.

• Tension: Muscle generates greater force when placed on stretch or under tension.

• Coordination: Poor coordination between muscles generates internal friction between muscle fibers, decreasing generated force.

Muscle Fiber Types

• Type 1 Fibers:

  • Slow Twitch Fibers.

  • Smaller in size.

  • Darker in color.

  • Slow to fatigue.

• Type 2 Fibers:

  • Fast Twitch Fibers.

  • Larger in size.

  • Lighter in color.

  • Fatigue faster.

Biomechanics of Levers

• Definition: Mechanical systems that enable human movement.

• Core Components:

  • Axis (Fulcrum)

  • Force Arm

  • Resistance Arm

  • Resistance

  • Force

• First-Class Lever:

  • The axis is located directly between the resistance and the force.

  • Structural layout: Resistance - Axis - Force.

  • Example: The head balancing on the first cervical vertebra.

• Second-Class Lever:

  • The resistance is located directly between the axis and the force.

  • Structural layout: Axis - Resistance - Force.

  • Example: Standing on tiptoes.

• Third-Class Lever:

  • The force is located directly between the resistance and the axis.

  • Structural layout: Axis - Force - Resistance.

  • Example: Flexing the elbow joint using the biceps brachii muscle.

Nervous System and Motor Units

• Primary Nervous System Divisions:

  • Autonomic Nervous System: Regulates glands and smooth muscle function.

  • Parasympathetic Division

  • Sympathetic Division

  • Central Nervous System: Consists of the Brain and Spinal Cord.

  • Peripheral Nervous System: Located as nerves exit the spine into the extremities (includes Spinal Nerves, Cranial Nerves, Neurons, and Neuroglia).

Motor Unit Physiology

• Definition: A motor nerve and all of the individual muscle fibers it supplies.

• Fiber Ratio Range: Varies from 10 to 2,000 muscle fibers supplied by a single motor nerve.

• Determinants of Muscle Contraction Gradation:

  1. The total number of motor units recruited.

  2. The frequency at which motor units are stimulated.

Circulatory System and Supporting Soft Tissues

• Blood Vessel Functions: Provide essential nutrients to tissues and clear metabolic waste.

• Vessels Types and Roles:

  • Arteries: Carry blood away from the heart to body tissues.

  • Capillaries: Deliver blood directly to individual cells.

  • Veins: Transport blood from capillaries back to the heart.

• Additional Soft Tissues:

  • Fascia: Fibrous connective tissue that covers, connects, or supports other body tissues.

  • Bursa: A fluid-filled sac that protects muscles, tendons, and ligaments as they cross over bony prominences.