Year 10 HPE Skeletal, Muscular and Joints Revision Flashcards

Support: The skeleton provides a structural framework for the body, supporting soft tissues and providing attachment points for the tendons of most skeletal muscles.
Protection: The skeleton protects vital internal organs from injury. For example, the cranium protects the brain, the vertebrae protect the spinal cord, and the rib cage protects the heart and lungs.
Movement: Most skeletal muscles attach to bones. When muscles contract, they pull on bones to produce movement. The bones act as levers, and the joints act as fulcrums.
Mineral Storage: Bone tissue stores several minerals, primarily calcium and phosphorus, which contribute to the strength of the bone. Bone can release these minerals into the bloodstream to maintain critical balances elsewhere in the body.
Blood Cell Production: Within certain bones, a connective tissue called red bone marrow produces red blood cells, white blood cells, and platelets through a process called hematopoiesis.

Ligaments: These are tough, fibrous bands of connective tissue that connect one bone to another bone. Their primary role is to provide joint stability and prevent excessive or unwanted movement that could result in injury.
Tendons: These are strong, inelastic cords of fibrous collagen tissue that attach a muscle to a bone. They transmit the force of muscle contraction to the bone to initiate movement.
Cartilage: This is a smooth, resilient, elastic tissue that covers the ends of bones at joints. It serves as a shock absorber and reduces friction between bones during movement, ensuring smooth joint operation.

The skeleton is divided into two main sections: the Axial Skeleton and the Appendicular Skeleton.
Axial Skeleton: This represents the central axis of the body and includes:
- Cranium (Skull)
- Mandible (Jawbone)
- Vertebral Column (Cervical, Thoracic, Lumbar, Sacrum, and Coccyx)
- Sternum (Breastbone)
- Rib Cage
Appendicular Skeleton: This includes the bones of the limbs and the girdles that attach them to the axial skeleton:
- Pectoral Girdle: Clavicle (Collarbone) and Scapula (Shoulder blade).
- Upper Limbs: Humerus (Upper arm), Radius (Lateral forearm), Ulna (Medial forearm), Carpals (Wrist), Metacarpals (Hand), and Phalanges (Fingers).
- Pelvic Girdle: Pelvis (Hip bones).
- Lower Limbs: Femur (Thigh bone), Patella (Kneecap), Tibia (Shin bone), Fibula (Lateral lower leg), Tarsals (Ankle), Metatarsals (Foot), and Phalanges (Toes).

There are six primary types of synovial joints, categorized by the type of movement they allow:

Ball and Socket Joint: Allows for the greatest range of motion, including movement in all axes and rotation (e.g., Shoulder and Hip).
Hinge Joint: Allows movement in only one plane, specifically flexion and extension (e.g., Elbow and Knee).
Pivot Joint: Allows for rotation around a single axis (e.g., the joint between the first and second cervical vertebrae, or the radioulnar joint at the elbow).
Saddle Joint: Both surfaces have concave and convex areas, shaped like a saddle. Allows for a variety of movements including flexion, extension, abduction, and adduction (e.g., the Carpometacarpal joint of the thumb).
Condyloid (Ellipsoid) Joint: An oval-shaped bone fits into a similar-shaped cavity of another bone. Allows for flexion, extension, abduction, and adduction, but not rotation (e.g., Wrist/Radiocarpal joint).
Gliding (Plane) Joint: Two flat or slightly curved bone surfaces slide over each other. Allows for limited movement (e.g., joints between the carpals in the wrist or tarsals in the ankle).

Skeletal Muscle: Attached to bones, these muscles are under voluntary control. They are striated in appearance and are responsible for all external body movements.
Smooth Muscle: Found in the walls of internal organs such as the stomach, intestines, and blood vessels. These are involuntary muscles (not under conscious control) and lack striations.
Cardiac Muscle: Found exclusively in the heart. Like skeletal muscle, it is striated, but like smooth muscle, it is involuntary. It is designed to pump blood throughout the body continuously.

Flexion: Decreasing the angle between two bones (e.g., bending the arm at the elbow).
Extension: Increasing the angle between two bones (e.g., straightening the arm at the elbow).
Abduction: Moving a body part away from the midline of the body.
Adduction: Moving a body part toward the midline of the body.
Dorsiflexion: Flexing the foot at the ankle so the toes move toward the shin.
Plantar Flexion: Pointing the toes downward, increasing the angle at the ankle.
Elevation: Moving a body part in an upward or superior direction (e.g., shrugging the shoulders).
Depression: Moving a body part in a downward or inferior direction (e.g., lowering the shoulders).

Body planes are imaginary geometric surfaces used to divide the body into sections:

Sagittal Plane: Divides the body vertically into left and right halves.
Frontal (Coronal) Plane: Divides the body vertically into front (Anterior) and back (Posterior) portions.
Transverse Plane: Divides the body horizontally into top (Superior) and bottom (Inferior) portions.

Agonist (Prime Mover): The muscle that is primarily responsible for producing a specific movement.
Antagonist: The muscle that relaxes and lengthens to allow the movement to occur; it opposes the agonist. If the agonist contracts, the antagonist must be relaxed to avoid resistance.
Reciprocal Inhibition: The process where the central nervous system sends a signal to the antagonist muscle to relax while the agonist is contracting.

There are three main types of muscle contractions:

Concentric Contraction (Isotonic): The muscle shortens while producing force (e.g., the upward phase of a bicep curl).
Eccentric Contraction (Isotonic): The muscle lengthens while producing force (e.g., the lowering phase of a bicep curl; providing resistance against gravity).
Isometric Contraction: The muscle produces force but does not change length, resulting in no joint movement (e.g., holding a plank position or pushing against a wall).

Type I (Slow Twitch): These fibers are red in color because they contain more blood vessels and mitochondria. They are very resistant to fatigue and are used for endurance activities (e.g., long-distance running).
Type IIa (Fast Oxidative Glycolytic): These are "intermediate" fibers that can use both aerobic and anaerobic metabolism. They provide more power than Type I but fatigue more quickly (e.g., mid-distance swimming).
Type IIb/x (Fast Glycolytic): These fibers are white and provide high-power, explosive force. They fatigue very quickly and are used for short-duration activities (e.g., sprinting or heavy weightlifting).