Forward from: Ethio Entrance exam🔐
📚 Components of the Musculoskeletal System
1. Bones:
⦁ Structure:
⦁ Bones are composed of a matrix of collagen fibers and inorganic mineral salts, primarily calcium phosphate, which provide strength and rigidity.
⦁ The interior of bones contains bone marrow, responsible for producing blood cells.
⦁ Types of Bones:
⦁ Long bones: Found in limbs (e.g., femur, humerus) and act as levers for movement.
⦁ Short bones: Found in the wrists and ankles; they provide stability and support (e.g., carpals, tarsals).
⦁ Flat bones: Protect organs and provide a surface for muscle attachment (e.g., skull, ribs).
⦁ Irregular bones: Have complex shapes; e.g., vertebrae and pelvic bones.
2. Muscles:
⦁ Types of Muscle:
⦁ Skeletal Muscle: Voluntary muscles that are attached to bones; responsible for movement and posture. They appear striated (striped) under a microscope.
⦁ Cardiac Muscle: Involuntary muscle found only in the heart; it's also striated and responsible for pumping blood.
⦁ Smooth Muscle: Involuntary muscle found in walls of hollow organs (e.g., intestines, blood vessels); it's non-striated and regulates various bodily functions.
⦁ Muscle Contraction: Muscles contract through the sliding filament theory, where actin and myosin filaments slide past each other to shorten the muscle.
3. Cartilage:
⦁ A flexible connective tissue that reduces friction in joints, provides support and cushioning, and allows for smooth movement.
⦁ Types of cartilage include:
⦁ Hyaline cartilage: Found at the ends of bones, in the ribs, and in the trachea.
⦁ Fibrocartilage: Provides tensile strength and can be found in intervertebral disks and the pubic symphysis.
⦁ Elastic cartilage: Provides flexibility and can be found in the ear and epiglottis.
4. Tendons and Ligaments:
⦁ Tendons: Dense connective tissues that connect muscles to bones; they transmit the force generated by muscles to produce movement at a joint.
⦁ Ligaments: Connective tissues that connect bones to other bones, providing joint stability and support.
📚 Functions of the Musculoskeletal System
1. Support and Structure:
⦁ Provides a framework for the body, supporting soft tissues and maintaining shape.
⦁ Enables upright posture due to its rigid structure, particularly in the spine and legs.
2. Movement:
⦁ Facilitates movement through the action of muscles on bones at the joints.
⦁ Muscles contract, pulling on tendons, which then move bones at joints.
3. Protection of Vital Organs:
⦁ Encloses and protects vital organs (e.g., the skull protects the brain, the rib cage protects the heart and lungs).
4. Production of Blood Cells:
⦁ Bone marrow within bones produces red blood cells, white blood cells, and platelets (hematopoiesis).
5. Storage of Minerals:
⦁ Bones act as a reservoir for minerals, notably calcium and phosphorus, which can be released into the bloodstream as needed.
6. Energy Storage:
⦁ Adipose tissue found within bones stores energy in the form of lipids.
📚 Joints and Movement
⦁ Types of Joints:
⦁ Synovial Joints: Freely movable joints (e.g., knees, elbows); characterized by a fluid-filled joint capsule. These joints allow for various types of movement—flexion, extension, rotation, gliding, etc.
⦁ Cartilaginous Joints: Limited movement (e.g., intervertebral discs); connected by cartilage.
⦁ Fibrous Joints: No movement or very limited (e.g., sutures of the skull); connected by dense connective tissue.
⦁ Types of Movements:
⦁ Flexion and Extension: Decrease or increase in the angle between
two body parts.
⦁ Abduction and Adduction: Movement away from or toward the midline of the body.
⦁ Rotation: Turning around an axis, such as the head turning side to side.
📚 Common Disorders of the Musculoskeletal System
1. Osteoporosis:
⦁ A condition characterized by reduced bone density and increased risk of fractures. It is often associated with aging, hormonal changes, and nutritional deficiencies.
1. Bones:
⦁ Structure:
⦁ Bones are composed of a matrix of collagen fibers and inorganic mineral salts, primarily calcium phosphate, which provide strength and rigidity.
⦁ The interior of bones contains bone marrow, responsible for producing blood cells.
⦁ Types of Bones:
⦁ Long bones: Found in limbs (e.g., femur, humerus) and act as levers for movement.
⦁ Short bones: Found in the wrists and ankles; they provide stability and support (e.g., carpals, tarsals).
⦁ Flat bones: Protect organs and provide a surface for muscle attachment (e.g., skull, ribs).
⦁ Irregular bones: Have complex shapes; e.g., vertebrae and pelvic bones.
2. Muscles:
⦁ Types of Muscle:
⦁ Skeletal Muscle: Voluntary muscles that are attached to bones; responsible for movement and posture. They appear striated (striped) under a microscope.
⦁ Cardiac Muscle: Involuntary muscle found only in the heart; it's also striated and responsible for pumping blood.
⦁ Smooth Muscle: Involuntary muscle found in walls of hollow organs (e.g., intestines, blood vessels); it's non-striated and regulates various bodily functions.
⦁ Muscle Contraction: Muscles contract through the sliding filament theory, where actin and myosin filaments slide past each other to shorten the muscle.
3. Cartilage:
⦁ A flexible connective tissue that reduces friction in joints, provides support and cushioning, and allows for smooth movement.
⦁ Types of cartilage include:
⦁ Hyaline cartilage: Found at the ends of bones, in the ribs, and in the trachea.
⦁ Fibrocartilage: Provides tensile strength and can be found in intervertebral disks and the pubic symphysis.
⦁ Elastic cartilage: Provides flexibility and can be found in the ear and epiglottis.
4. Tendons and Ligaments:
⦁ Tendons: Dense connective tissues that connect muscles to bones; they transmit the force generated by muscles to produce movement at a joint.
⦁ Ligaments: Connective tissues that connect bones to other bones, providing joint stability and support.
📚 Functions of the Musculoskeletal System
1. Support and Structure:
⦁ Provides a framework for the body, supporting soft tissues and maintaining shape.
⦁ Enables upright posture due to its rigid structure, particularly in the spine and legs.
2. Movement:
⦁ Facilitates movement through the action of muscles on bones at the joints.
⦁ Muscles contract, pulling on tendons, which then move bones at joints.
3. Protection of Vital Organs:
⦁ Encloses and protects vital organs (e.g., the skull protects the brain, the rib cage protects the heart and lungs).
4. Production of Blood Cells:
⦁ Bone marrow within bones produces red blood cells, white blood cells, and platelets (hematopoiesis).
5. Storage of Minerals:
⦁ Bones act as a reservoir for minerals, notably calcium and phosphorus, which can be released into the bloodstream as needed.
6. Energy Storage:
⦁ Adipose tissue found within bones stores energy in the form of lipids.
📚 Joints and Movement
⦁ Types of Joints:
⦁ Synovial Joints: Freely movable joints (e.g., knees, elbows); characterized by a fluid-filled joint capsule. These joints allow for various types of movement—flexion, extension, rotation, gliding, etc.
⦁ Cartilaginous Joints: Limited movement (e.g., intervertebral discs); connected by cartilage.
⦁ Fibrous Joints: No movement or very limited (e.g., sutures of the skull); connected by dense connective tissue.
⦁ Types of Movements:
⦁ Flexion and Extension: Decrease or increase in the angle between
two body parts.
⦁ Abduction and Adduction: Movement away from or toward the midline of the body.
⦁ Rotation: Turning around an axis, such as the head turning side to side.
📚 Common Disorders of the Musculoskeletal System
1. Osteoporosis:
⦁ A condition characterized by reduced bone density and increased risk of fractures. It is often associated with aging, hormonal changes, and nutritional deficiencies.