Untitled Document - Biology Past Paper PDF

# Jadon Regus ## Types of Joints | Synarthroses | Amphiarthroses | Diarthroses | |---|---|---| | Not Moving | Slightly movable | Movable | | Bones tightly together | Pubic bones meet the Pelvis | Elbow, knee, neck | | Skull has this | | | ### Structural Type | Fibrous | Cartilaginous | Synov...

# Jadon Regus ## Types of Joints | Synarthroses | Amphiarthroses | Diarthroses | |---|---|---| | Not Moving | Slightly movable | Movable | | Bones tightly together | Pubic bones meet the Pelvis | Elbow, knee, neck | | Skull has this | | | ### Structural Type | Fibrous | Cartilaginous | Synovial | |---|---|---| | Binds the body together | Rigid but slightly movable | Almost frictionless | | It's connected with collagen fibers of dense tissue | Act as shock absorbers | Found in about every joint | # Skeletal System ## Functions of the Skeletal System 1. **Support**: The skeletal system provides the framework for the body. 2. **Protection**: The skeletal system protects vital organs, such as the brain (skull) and heart (rib cage). 3. **Movement**: Skeletal muscles attach to bones via tendons and use bones as levers to produce movement. 4. **Storage**: Bones store minerals like calcium and phosphate, which can be released into the blood if needed. 5. **Blood cell formation (hematopoiesis)**: Red bone marrow produces blood cells. 6. **Hormone production** : Bones produce osteocalcin, which can regulate insulin secretion, glucose, and energy usage. ## Bone Structure ### Compact Bone - The basic structural unit is the **osteon**, a long cylinder acting as a tiny weight-bearing pillar in the bone made up of tubes called **lamellae**. - The **Haversian Canal** runs through the middle of each osteon and contains blood vessels for nourishment and nerve fibers for signaling. ### Spongy Bone - Spongy bone is less organized than compact bone. - There are no osteons present. - Contains **trabeculae**, tiny bone struts that help to resist stress and house bone marrow. ### Bone Markings - The external surface of a bone is rarely smooth and often has distinct markings. ## Bone Matrix ### Key cells involved in bone remodeling - **Osteoblasts** : Build and construct bones by calcifying bone as it forms. - **Osteoclasts**: Break down and reabsorb bone tissue. - **Osteocytes** : Maintain healthy bone structure. ### Bone remodeling - Bone remodeling is a lifelong process that involves breaking down old bone tissue and building new bone in response to stimuli like stress, strain, or lack thereof. ## Types of Bone Tissue 1. **Long Bones**: Longer than they are wide and have a long shaft with either end being wider. Found in the limbs. - Examples: Humorous, radius, ulna, femur, tibia, fibula, metacarpals, phalanges, metatarsals. 2. **Short Bones**: More cube-shaped, tend to be as wide as long. Provide support and stability with little movement. - Examples: Carpals (wrist), tarsals (ankles), sesamoid bones. 3. **Flat bones**: Thin, flat bones often curved. Have a large surface area attaching to muscles. - Examples: Sternum, scapula, ribs, most of the cranial bones in the skull. 4. **Irregular bones**: Have a highly specialized shape and structure. - Examples: Vertebrae, hip bones. ## Bone Repair ### Stages of bone repair 1. Immediately following the bone break, a **hematoma** (blood clot) forms. 2. A **fibrocartilaginous callus** forms that spans the break and connects the broken ends. 3. The **bone remodeling** step is when osteoblasts begin forming spongy bone and replacing the cartilaginous callus. 4. The **bone is remodeled** with the fibrocartilaginous callus replaced by compact bone. ## Types of Joints ### Functional Classification **Based on how much movement**: - **Synarthroses**: Non-moving joints. Example: The part of the skull that protects the brain, the cranium. - **Amphiarthroses**: Slightly-moving joints. Example: Where the pubic bones meat in the pelvis. - **Diarthroses**: Freely moving joints. Example: Knee and elbow joints, mainly in our limbs. ### Structural Classification **Based on what type of tissue makes up the joint**: - **Fibrous Joints**: Connect bones with the collagen fibers of dense connective tissue. Mostly immovable. Examples: Bones of the skull held together by sutures. - **Cartilaginous Joints**: Connect bones with cartilage. Can be rigid, but also slightly moveable. Examples: The sternum and the first rib are connected by synchondrous cartilage, the vertebrae by symphysis. - **Synovial Joints**: Connect bones by dense connective tissue and a fluid-filled joint cavity. Freely movable. These have six special features. #### Six Special Features of Synovial Joints: 1. **Articular Cartilage**: Covers the opposing bone surfaces. 2. **Joint (articular) cavity**: A space between the opposing bones that contains synovial fluid. 3. **Synovial Fluid**: Acts as a lubricant in the joint cavity. 4. **Joint (articular) Capsule**: A fibrous capsule that encloses the joint cavity. 5. **Ligaments**: Bandlike structures that reinforce the joint capsule. 6. **Sensory nerve fibers and blood vessels**: Present in the joint capsule and synovial membrane, allowing for sensation and nourishment. ## Configurations of Synovial Joints - **Gliding Joints**: Also known as plane joints. Allow gliding movements. - Examples: Intercarpal joints (wrist), intertarsal joints (ankle). - **Hinge Joints**: Allow angular movements like flexion and extension. - Examples: Elbow, interphalangeal (finger joints). - **Pivot Joints**: Allow rotation as well as twisting movements back and forth. - Examples: Where the humerus meets the radius and ulna at the elbow. - **Condylar Joints**: Like a pedestal with a joint on top. Allow movements like flexion/extension, abduction, & adduction. - Examples: Wrist joints. - **Saddle Joints**: Allow opposition movements as well as flexion/extension, abduction/adduction. - Examples: Thumb joints - **Ball and Socket Joints**: Allow rotational movements, abduction/adduction, flexion/extension. - Examples: Shoulder and hip joints. ## Other Types of Movement - **Circumduction**: Moving a limb in a circle. Example: Making circles with arms. - **Elevation and Depression**: Lifting (then lowering) a body part superiorly. Example: Shrugging shoulders, jaw dropping. - **Protraction and Retraction**: Sticking a body part out (then back). Example: Sticking jaw out, shrugging your shoulders back in. - **Dorsiflexion and Plantarflexion**: Lifting the foot up and down at the ankle. - **Inversion and Eversion**: Turning the foot towards the midline of the body (inversion) or away from the midline of the body (eversion). ## Muscle Contractions - Muscle contractions move bones. - Muscles always pull, never push. ### Types of Muscle Contractions - **Isotonic Contraction**: A change in the length of the muscle. - Example: Lifting a box or doing push-ups. - **Isometric Contraction**: No change in length of a muscle. - Example: Standing with good posture or doing a plank. ### Movement - **Origin**: The bone that does not move during a muscle contraction. - **Insertion**: The movable bone during a muscle contraction. - Example: In a bicep curl, the radius is the insertion point and pulls towards the scapula, which is the origin.