BIO 220 Exam 3 Review PDF

Chapter 8 Two ways joints can be classified: Structure and Function Structural: Based on the material binding the bones and whether a cavity is present. Fibrous joints: bones are joined by fibrous tissue; no joint cavity (ex. Skull sutures) Cartilaginous joints: bones are connected by cartilage;...

Chapter 8 Two ways joints can be classified: Structure and Function Structural: Based on the material binding the bones and whether a cavity is present. Fibrous joints: bones are joined by fibrous tissue; no joint cavity (ex. Skull sutures) Cartilaginous joints: bones are connected by cartilage; no joint cavity (ex. Vertebral disks) Synovial Joints: bones are separated by a fluid-filled joint cavity (ex. Knee joint) Bony Joints (Synostoses): When two bones fuse together, forming a single bony structure. (Example: Fusion of the two halves of the mandible.) Functional: based on range of motion: Synarthroses: immovable joints Example: Sutures of the skull. Ampiarthroses: slightly movable joints Example: Pubic symphysis (cartilaginous joint). Diarthroses: freely movable joints. Example: Shoulder (glenohumeral joint). Types of Synarthrosis Joints: Immovable joints. 1. Sutures: ○ Found between the bones of the skull. These are fibrous joints where the bones are held together tightly by a thin layer of fibrous tissue. ○ Example: Coronal suture between the frontal and parietal bones. 2. Gomphoses: ○ A peg-in-socket fibrous joint where a tooth is secured in its socket by periodontal ligaments. ○ Example: Tooth in the alveolar socket. 3. Synchondroses: ○ Cartilaginous joints where the bones are united by hyaline cartilage. ○ Example: The epiphyseal plate in long bones during childhood. A synostosis is a type of synarthrotic joint where the bones eventually fuse into a single bone, such as the fusion of the two halves of the mandible or the fusion of the epiphyseal plate as an adult. Types of Amphiarthrosis Joints: slightly movable joints. 1. Symphyses: ○ Cartilaginous joints where the bones are connected by fibrocartilage, allowing limited movement. ○ Example: Pubic symphysis. 2. Syndesmoses: ○ A fibrous joint where the bones are connected by a ligament or an interosseous membrane. ○ Example: Distal tibiofibular joint (between the tibia and fibula). Types of Synovial Joints: 1. Plane Joints (Gliding Joints): ○ Allow sliding or gliding movements. The flat or slightly curved articular surfaces allow the bones to slide past each other. ○ Example: Intercarpal joints in the wrist. 2. Hinge Joints: ○ Allow movement in one plane (like a hinge on a door), permitting flexion and extension. ○ Example: Elbow joint. 3. Pivot Joints: ○ Allow rotation around a single axis. ○ Example: Atlantoaxial joint (between the first and second cervical vertebrae). 4. Condyloid (Ellipsoidal) Joints: ○ Allow movement in two planes (flexion/extension, abduction/adduction), but no rotation. ○ Example: Wrist joint. 5. Saddle Joints: ○ Allow movement in two planes with more freedom of movement than a condyloid joint. One bone is shaped like a saddle and the other fits like a rider. ○ Example: Thumb (carpometacarpal joint). 6. Ball-and-Socket Joints: ○ Allow movement in all planes, including rotation. These are the most freely movable joints in the body. ○ Example: Shoulder joint and hip joint. Major Components of a Synovial Joint: Articular Cartilage: Hyaline cartilage that covers the surfaces of bones, reducing friction and absorbing shock. Joint Cavity: A space between the articulating bones filled with synovial fluid. Synovial Fluid: Lubricates the joint, reducing friction, nourishes cartilage, and acts as a shock absorber. Articular Capsule: A fibrous capsule surrounding the joint, containing two layers: the outer fibrous layer and the inner synovial membrane. Ligaments: Dense fibrous connective tissue that connects bones to other bones, providing stability and limiting movement. Accessory Structures for Synovial Joints: 1. Bursae: Fluid-filled sacs that reduce friction between bone and soft tissue. 2. Menisci: Cartilage pads that help absorb shock and stabilize the joint, especially in the knee. 3. Tendon Sheaths: Tubular structures that surround tendons to reduce friction during movement. Types of Movement: 1. Flexion: Decreasing the angle between two body parts. ○ Example: Bending the elbow. 2. Extension: Increasing the angle between two body parts. ○ Example: Straightening the elbow. 3. Abduction: Moving a limb or part of the body away from the midline. ○ Example: Raising the arm sideways. 4. Adduction: Moving a limb or part of the body toward the midline. ○ Example: Lowering the arm back to the body. 5. Rotation: Turning a body part around its axis. ○ Example: Turning your head from side to side. Flexion/Extension: Example: Elbow joint. Abduction/Adduction: Example: Shoulder joint. Rotation: Example: Neck (atlantoaxial joint). Supination/Pronation: Example: Forearm. Elevation/Depression: Example: Shoulder (shrugging). Distinguishing Features of Joints: 1. TMJ (Temporomandibular Joint): ○ A hinge and gliding synovial joint between the temporal bone and mandible, allows jaw movement for chewing. 2. Intervertebral Joints: ○ Cartilaginous joints (symphyses) between vertebrae, providing flexibility and shock absorption via intervertebral discs. 3. Shoulder Joint (Glenohumeral Joint): ○ A ball-and-socket joint with a large range of motion but less stability, supported by rotator cuff muscles and ligaments. 4. Elbow Joint: ○ A hinge synovial joint, primarily allowing flexion and extension, stabilized by ligaments such as the ulnar collateral ligament. 5. Hip Joint (Coxal Joint): ○ A stable ball-and-socket joint, allowing movement in all planes and protected by a strong articular capsule and ligaments. 6. Knee Joint: ○ A hinge synovial joint with added complexity due to menisci and multiple ligaments (ACL, PCL, MCL, LCL) providing stability and limiting excessive motion. Chapter 9 Three Types of Muscle Tissue: 1. Skeletal Muscle: ○ Structure: Long, cylindrical fibers with multiple nuclei located at the periphery. ○ Control: Voluntary (controlled consciously). ○ Function: Primarily responsible for body movement, posture, and stability. ○ Example: Biceps brachii. 2. Cardiac Muscle: ○ Structure: Branching, striated fibers with a single central nucleus. Connected by intercalated discs. ○ Control: Involuntary (controlled by the autonomic nervous system). ○ Function: Pumps blood throughout the body via the heart. ○ Example: Heart muscles (myocardium). 3. Smooth Muscle: ○ Structure: Non-striated, spindle-shaped cells with a single central nucleus. ○ Control: Involuntary (controlled by the autonomic nervous system).  ○ Function: Moves substances through hollow organs like blood vessels, digestive tract, and respiratory passages. ○ Example: Walls of the stomach and intestines. b) Four Basic Muscle Properties: 1. Excitability (Responsiveness): ○ Muscle tissue can respond to electrical stimuli (nerve impulses) and chemical signals (e.g., hormones). 2. Contractility: ○ Muscle fibers can shorten and generate force, allowing movement. 3. Extensibility: ○ Muscle fibers can be stretched beyond their normal resting length without being damaged. 4. Elasticity: ○ After being stretched, muscle fibers can return to their original shape and length. Five Functions of Skeletal Muscle: 1. Movement: ○ Skeletal muscles generate force to move the body and its parts. 2. Posture Maintenance: ○ Skeletal muscles maintain body posture and stabilize joints. 3. Joint Stabilization: ○ Muscles help stabilize and support joints during movement. 4. Heat Production: ○ Muscle contraction generates heat, which is important for maintaining body temperature. 5. Protection: ○ Skeletal muscles act as a barrier to protect internal organs and structures. Gross Anatomy Components: Muscle Belly: The main body of the muscle, consisting of many muscle fibers bundled together. Tendons: Connect muscle to bone and transmit the force generated by muscle contraction. Fascia: Connective tissue surrounding muscles and groups of muscles (superficial and deep). Microscopic Anatomy Components: Muscle Fibers: The individual cells of skeletal muscle that contract. Myofibrils: Bundles of protein filaments that are responsible for muscle contraction. Sarcomeres: The basic contractile units of muscle, containing actin and myosin filaments. Mitochondria: Provide energy for muscle contractions through ATP production. Three Layers of Connective Tissue Found in Muscles 1. Endomysium: ○ A delicate connective tissue surrounding each individual muscle fiber (cell). ○ Function: Provides support and contains capillaries and nerve fibers that supply the muscle fiber. 2. Perimysium: ○ A thicker layer of connective tissue surrounding a group of muscle fibers (fascicles). ○ Function: Divides the muscle into fascicles and provides pathways for blood vessels and nerves. 3. Epimysium: ○ The outermost connective tissue layer that surrounds the entire muscle. ○ Function: Protects the muscle and helps transmit the force of contraction to tendons. Definition of Tendons and Aponeuroses Tendons: ○ Tendons are fibrous connective tissue that attaches muscle to bone. Tendons are made of dense collagen fibers and transmit the force generated by muscle contractions to the bones, causing movement at the joints. ○ Example: Achilles tendon (attaches the calf muscles to the heel bone). Aponeuroses: ○ Aponeuroses are broad, flat sheets of connective tissue that function similarly to tendons, but they cover a larger surface area and connect muscles to bones or to other muscles. ○ Example: The aponeurosis of the abdominal muscles. Definitions and Labels for Key Muscle Terms a. Sarcolemma: The sarcolemma is the plasma membrane of a muscle fiber. It surrounds the muscle cell and helps propagate action potentials that trigger muscle contraction. b. Sarcoplasm: The sarcoplasm is the cytoplasm of a muscle cell. It contains the organelles and the myofibrils, and is rich in glycogen and myoglobin. c. Muscle Fiber/Muscle Cell: A muscle fiber (or muscle cell) is a long, cylindrical cell that makes up skeletal muscle. It is multinucleated and capable of contraction. d. Myofibril: A myofibril is a long, thread-like structure found inside the muscle fiber. Myofibrils are made up of repeating units called sarcomeres, and they are responsible for muscle contraction. e. Sarcomere: The sarcomere is the basic contractile unit of a muscle. It is the segment between two Z-discs (or Z-lines) and contains the actin and myosin filaments responsible for contraction. f. Sarcoplasmic Reticulum (SR): The sarcoplasmic reticulum is a specialized smooth endoplasmic reticulum in muscle fibers. It stores calcium ions (Ca²⁺), which are released during muscle contraction and taken back up during relaxation. g. Myofilament: Myofilaments are the thin and thick protein filaments that make up the myofibrils. There are two types: ○ Actin: Thin filaments that form part of the sarcomere and slide past myosin during contraction. ○ Myosin: Thick filaments with cross-bridges that pull on actin filaments to cause muscle contraction. i. Actin: -A thin filament that forms part of the sarcomere. Actin molecules link together to form a double helix structure and serve as the track for myosin to generate muscle contraction. ii. Myosin: -A thick filament with myosin heads that bind to actin filaments, forming cross-bridges to generate force during muscle contraction. Motor Unit: A motor unit is a single motor neuron and all the muscle fibers it innervates. Relationship to Muscle Tension: The more motor units recruited, the greater the muscle tension. When a motor neuron sends an impulse to its associated muscle fibers, those fibers contract. More motor units = more muscle fibers contracting = greater force produced. Motor Units and Precise vs. Less Precise Control: Precise Control: Small motor units (1 motor neuron innervates few muscle fibers) provide fine, controlled movements. These are found in muscles requiring precise movements, such as the eye muscles. Less Precise Control: Large motor units (1 motor neuron innervates many muscle fibers) generate more power but with less precision. These are found in muscles involved in large movements, such as the gluteal muscles. Recruitment: Recruitment refers to the process of activating more motor units to increase muscle force. It’s important because it allows for gradual increases in muscle tension based on the task. For smaller tasks, only a few motor units are recruited, while for larger, more forceful tasks, more motor units are recruited. After contraction, muscle relaxation occurs through the following mechanisms: 1. Cessation of Nerve Stimulation: ○ When the motor neuron stops sending action potentials, acetylcholine (ACh) release stops. This halts the depolarization of the muscle fiber and the contraction process. 2. Reuptake of Calcium Ions: ○ The sarcoplasmic reticulum actively pumps calcium ions (Ca²⁺) back into storage. Without calcium, troponin-tropomyosin complex blocks the  actin-binding sites, preventing further cross-bridge formation between actin and myosin. 3. Elastic Recoil: ○ Muscle fibers are elastic. Once the calcium is removed, and the cross-bridges are broken, the muscle fibers return to their resting length through the inherent elastic properties of the muscle tissue (such as tendons and connective tissues). Treppe (The “staircase effect”): A phenomenon where muscle tension increases progressively with each successive stimulus when a muscle is stimulated after it has fully relaxed. Each contraction is slightly stronger than the previous one, similar to the way stairs "step up" in height. Wave Summation: When a second stimulus is applied before the muscle has completely relaxed, the tension generated by the second contraction adds to the first, producing a stronger contraction. This results in increased muscle tension due to overlapping contractions. Incomplete Tetanus: A state where muscle fibers are stimulated rapidly but still have partial relaxation between stimuli. The muscle tension is sustained but does not reach its maximum. Complete Tetanus: When a muscle is stimulated at a high frequency and does not have time to relax between stimuli. This results in maximum sustained contraction, where the muscle reaches a state of continuous contraction and exhibits the greatest force. Muscles require ATP to contract, and they generate ATP through three main processes: 1. Direct Phosphorylation (Creatine Phosphate): ○ Creatine phosphate (CP) donates a phosphate group to ADP to regenerate ATP quickly. ○ Provides immediate but short-term energy during high-intensity activities (like sprinting or heavy lifting). 2. Anaerobic Glycolysis: ○ The breakdown of glucose into lactic acid in the absence of oxygen. This produces 2 ATP per glucose molecule.  ○ This process occurs in the cytoplasm and provides energy for activities lasting up to around 2 minutes (e.g., 400-meter dash). 3. Aerobic Respiration: ○ The breakdown of glucose, fatty acids, or amino acids in the presence of oxygen in the mitochondria to produce ATP, carbon dioxide, and water. ○ Provides a sustained supply of ATP for longer, lower-intensity activities (e.g., marathon running). ○ Produces a large amount of ATP, up to 36-38 ATP per glucose molecule. EPOC (Excess Post-Exercise Oxygen Consumption): EPOC is the increased oxygen consumption that occurs after exercise to restore the body to its resting state. During EPOC, the body clears metabolic waste products, replenishes oxygen stores, and resynthesizes creatine phosphate. It helps in recovery and is responsible for the "afterburn" effect of exercise. Slow-Twitch Fibers (Type I): ○ Function: Specialized for endurance activities, these fibers contract slowly and fatigue slowly. ○ Characteristics: High in myoglobin (red), mitochondria, and capillaries for aerobic respiration. ○ Example: Muscles used for long-distance running. Fast-Twitch Fibers (Type II): ○ Function: Specialized for explosive, short-term activities like sprinting. ○ Characteristics: Low in myoglobin (white), fewer mitochondria, and generate more force but fatigue quickly. ○ Type IIa (Intermediate): Combine aerobic and anaerobic capabilities, providing both speed and endurance. Example: 800-meter race. ○ Type IIb (Fast Glycolytic): Rely heavily on anaerobic glycolysis, generate high power, but fatigue rapidly. Example: Weightlifting, sprinting. Red vs. White Muscles: ○ Red Muscles: High in Type I fibers, rich in myoglobin, mitochondria, and capillaries. These are used for endurance and long-term activities. ○ White Muscles: High in Type II fibers, with less myoglobin and fewer mitochondria, suited for rapid, powerful contractions. 11. Unique Features of Cardiac and Smooth Muscle Cardiac Muscle: Automaticity: Cardiac muscle cells can generate their own electrical impulses (action potentials), allowing the heart to contract without external stimuli. Striated like skeletal muscle, but fibers are branched and connected by intercalated discs, which help synchronize contractions. Involuntary control by the autonomic nervous system. Smooth Muscle: Plasticity: Smooth muscle can stretch and maintain tension over a wide range of lengths without losing its ability to contract. This allows smooth muscle to function in organs that expand and contract (e.g., bladder, digestive tract). Non-striated and involuntary. Found in the walls of hollow organs and blood vessels. Comparison of Muscle Types: Feature Skeletal Cardiac Muscle Smooth Muscle Muscle Striations Yes Yes No Control Voluntary Involuntary Involuntary Nuclei Multinucleated Uninucleated (central) Uninucleated (central) Contraction Fast Moderate Slow Speed Fatigue Moderate High High Resistance Special Features Tetanus Automaticity, Intercalated Plasticity, possible discs Stretchability Muscle Fiber Arrangements 1. Parallel Muscles: ○ Structure: Fibers run parallel to the long axis of the muscle. ○ Example: Sartorius (muscle of the thigh). ○ Function: Produces a great range of motion but moderate force. 2. Convergent Muscles: ○ Structure: Fibers converge at a single tendon. ○ Example: Pectoralis major (chest muscle). ○ Function: Allows for powerful contraction in many directions. 3. Pennate Muscles (Feather-like fibers): ○ Structure: Muscle fibers are arranged obliquely to a central tendon. ○ Examples: i. Unipennate: All fibers are on one side of the tendon (e.g., extensor digitorum longus). ii. Bipennate: Fibers are on both sides of the tendon (e.g., rectus femoris). iii. Multipennate: Multiple tendon branches (e.g., deltoid). 4. Circular Muscles: ○ Structure: Fibers arranged in concentric circles around an opening. ○ Example: Orbicularis oris (around the mouth). ○ Function: Controls openings and closes (e.g., blinking, sphincter muscles). 13. Origin and Insertion Origin: The fixed attachment point of a muscle, typically on a bone. Insertion: The movable attachment point of the muscle, Labeling Muscles and Their Origins, Insertions, and Actions This would depend on the specific figures provided in your review materials. For example: Biceps Brachii: ○ Origin: Scapula (coracoid process and supraglenoid tubercle). ○ Insertion: Radius (radial tuberosity). ○ Action: Flexes the elbow and supinates the forearm.